Methodology for In-situ Analysis of Soils, 
Contaminated with Cutting Fluids 

 
 
 

 
 
 

Thesis for the completion of Masters of Science 
In Applied Environment Measurement Techniques 

 
 
 

Muhammad Babar 
 
 
 

Water Environment Transport 
CHALMERS UNIVERSITY OF TECHNOLOGY 

Göteborg, Sweden 
 

April 2002 



 
 
 
 

Methodology for In-situ Analysis of Soils, 
Contaminated with Cutting Fluids 

 
 
 
 
 
 
 
 
 

Muhammad Babar 
April 2002 

 
 
Supervisors  
 
Henrik Kloo    Ann-Margret Strömvall 
      Sebastien Rauch 
Environment and Chemistry  Water Environment Transport 
Volvo Technical Development AB  Chalmers University of Technology 
 

 1



Abstract 
 
The clean up of soils contaminated with cutting fluids is associated with several 
challenges, especially of analytical methodologies and data interpretation. Treatment 
technology and site remediation progress will lean heavily on analytical techniques 
that are accurate, reproducible and of real time value. Most of the existing analytical 
techniques for petroleum hydrocarbons especially cutting fluids are different for 
different group of hydrocarbons, moreover they are expensive and time consuming. 
This study focuses on the development of methodology for the in-situ analysis of 
cutting fluids. The project was initiated and financed by Volvo Technical 
Development AB, Sweden which has shown their interest in the determination of 
cutting fluids in contaminated soils. Analytical techniques adopted for the project 
were; (1) photoionization detector, a screening technique for a wide range of volatile 
hydrocarbons; (2) Immunoassay, an efficient method to detect aromatic hydrocarbons; 
and (3) PetroFlag, a system for analysis of a wide range of all hydrocarbons especially 
heavy oils. The results of only one method could be used to decide the concentration 
levels of petroleum hydrocarbons, however combination of more than one technique 
for example PID and PetroFlag give a good idea of the concentration levels for a wide 
range of hydrocarbons. All of these analytical approaches are reliable, economical, 
and give real time values of the concentration levels in the field. 
A part of the study was to investigate the mobility of soluble cutting fluids in 
saturated as well as in unsaturated soils. Cutting fluids containing a base of mineral 
oil and 30% - 85% water with some polar organic compounds were found to be highly 
mobile in the saturated soils. The high mobility of cutting fluids is attributed to the 
water-soluble constituents present in the cutting fluids. In the vadose zone oil can 
move as dissolved phase, non – aqueous phase liquid (NAPL), and gaseous phase. 
The NAPL stays in the unsaturated zone while the dissolved phase may move to the 
saturated zone with the rainfall and groundwater fluctuations. A higher flow rate may 
allow greater momentum to be transferred from the leaching water to the oil in the 
pore fluid, thereby providing more kinetic energy to reduce the interfacial between oil 
and water and hence poses a threat to the surrounding environment in the form of 
surface and groundwater contamination. 
The environmental soil investigations were also performed at an old industrial site in 
Sweden to illustrate field analytical approaches for the characterization of complex 
petroleum hydrocarbon contaminants. Comparison of the field results and Swedish 
guideline values show higher concentration levels of aliphatic hydrocarbons at two 
locations of the site. 
 
 

 2



Table of Contents 
  
Abstract ............................................................................2 

Table of Contents.............................................................3 

List of figures...................................................................6 

List of tables.....................................................................7 

List of tables.....................................................................7 

Introduction......................................................................8 

Introduction......................................................................8 

Background Information..................................................9 
1.Cutting fluids ..................................................................................................9 

1.1 Main types of cutting fluids.....................................................................9 
1.2 Common additives used in cutting fluids...........................................10 
1.4 Cutting fluid used in the project ...........................................................11 

2. Soil vadose zone.........................................................................................12 
2.1 Sources of soil pollution......................................................................13 

2.1.1 Underground storage tanks ................................................................14 
2.1.2 Landfills ..................................................................................................14 
2.1.3 Surface water and sediments .............................................................15 
2.1.4 Agricultural waste ................................................................................15 
2.1.5 Land application and mining .............................................................15 
2.1.6 Radioactive contamination.................................................................16 
2.1.7 Accidental spills....................................................................................16 

3. Transport of organic contaminants in the soil ............................17 
3.1 Physiochemical processes controlling the Transport 
Pathways.............................................................................................................18 

3.1.1 Advection................................................................................................19 
3.1.2 Diffusion and dispersion.....................................................................19 
3.1.3 Sorption...................................................................................................20 
3.1.4 Biotransformation and biodegradation............................................21 
3.1.5 Volatilization .........................................................................................22 
3.1.6 Gas-phase transport..............................................................................22 

3.2 Factors influencing the distribution of organic 
contaminants in soil ......................................................................................22 

Permeability coefficient.................................................................................23 
Diffusive properties of soil ...........................................................................23 
Water solubility ...............................................................................................23 
Density and viscosity .....................................................................................23 

 3



Vapour pressure and density of vapour phase .........................................23 
3.2.6 Grain size effect ....................................................................................23 

4.Field analytical techniques..........................................25 
4.1 Field analysis versus analytical laboratory..............................25 
4.2 Photo ionization detector (PID)......................................................26 

4.2.1 Principle and method summary.........................................................26 
4.2.2 PID instrument limitations .................................................................27 

4.3 Immunochemical techniques.............................................................28 
4.3.1 Method selection consideration ........................................................28 
4.3.2 Interferences...........................................................................................29 
4.3.3 Advantages and limitations................................................................29 

4.4 PetroFLAG™ System ...........................................................................29 
4.4.1 Interferences...........................................................................................32 

Materials and methods ...................................................33 
1 Soil sampling ................................................................................................33 
2 Soil sampling at the old industrial site ............................................33 
3 Experimental.................................................................................................34 
4 Cylinder- unsaturated ..............................................................................34 
5 Soil column experiment ...........................................................................34 
6 Analysis procedure for the soil samples .........................................35 

6.1 Particle size analysis................................................................................35 
6.2 Soil moisture content...............................................................................36 
6.3 Determination of mass loss of ignition...............................................36 
6.4 Soil pH ........................................................................................................36 

7 Procedures for the screening and analysis of organic 
contaminants in the soil ..............................................................................36 

7.1 Screening procedure with PID..............................................................36 
7.2 Analysis procedure with Immunoassay..............................................37 
7.3 Analysis procedure with PetroFlag system .......................................38 

Results and Discussion ..................................................40 
1 Selected parameters of soils..................................................................40 
2 Response of photoionization detector (PID) for the soil 
samples ................................................................................................................41 

2.1 Cylinder – unsaturated ............................................................................41 
2.2 PID results of soil-column leaching experiment ..............................42 
2.3 PID Results of field measurements at the old industrial site ........43 

3 Results of PetroFlag System .................................................................45 
3.1 Unsaturated-cylinder ...............................................................................45 
3.2 Soil column experiment..........................................................................46 

 4



3.3 Measurements of TPH with PetroFlag system at an old industrial 
site .......................................................................................................................48 

4 Results of Immunoassay analysis .......................................................50 
4.1 Unsaturated-cylinder ...............................................................................50 
4.2 Immunoassay results of soil column experiment .............................51 
4.3 Immunoassay results of field measurements.....................................51 

5 Comparison of the results with the results of GC/MS..............52 
6 Comparison of field results with Swedish guideline values..53 

Conclusions....................................................................56 

Future Recommendations ..............................................58 

Acknowledgements........................................................59 

References......................................................................60 
 

 5



List of figures 
 

Figure 1 Schematic diagram of vertical profile of soil vadose zone............................12 

Figure 2 Contamination of soil as well as groundwater by different sources..............14 

Figure 3 Transport of soluble oils into the subsurface illustrating the distribution of 

the NAPL, the dense vapors, and the dissolved chemical plume ........................17 

Figure 5 Movement of contaminant showing movement under diffusion and 

dispersion mechanism..........................................................................................19 

Figure 6 Schematic of soil grain Sorption. ..................................................................20 

Figure 7 Evaporation of Iran and Arabia crude oils. ...................................................24 

Figure 8 Relative intensity data for common analytes.................................................30 

Figure 9 Locations of sampling sites in the Mölndal area. ..........................................33 

Figure 10 Sketch of sampling locations at an old industrial site in Sweden................34 

Figure 11 Schematic diagram of dilution process for TPH kit. ...................................38 

Figure 12 Textural class of the soil..............................................................................40 

Figure 13 PID response for the soil samples of cylinder-unsaturated .........................42 

Figure 14 Evaluation of samples with PID at different depths in the soil column. .....43 

Figure 15 PID response in the field after 4 hours in Rilsan bags. ...............................44 

Figure 16 PID response for the field samples after 48 hours.......................................45 

Figure 17 Results of the soil analysis with petroFlag ..................................................46 

Figure 18. Results of the soil analysis of column experiment with petroFlag.............47 

Figure 19 Hypothetical presentation of soil-oil-mixture. ............................................48 

Figure 20 Corrected results of the soil analysis of field measurement with petroFlag49 

Figure 21 Corrected results of the soil analysis of field measurement with petroFlag49 

Figure 22 Results of the soil samples analyzed with GC/MS......................................53 

Figure 23 Comparison of the measured results with Swedish guideline values for the 

field samples 0-5 cm depth. .................................................................................54 

Figure 24 Comparison of the measured results with Swedish guideline values for the 

field samples 5-15 cm depth. ...............................................................................55 

 6



List of tables 
 

Table 1 Compounds present in the cutting fluid..........................................................11 

Table 2 Octane-water coefficient (Kow). ......................................................................21 

Table 3 Volatile hydrocarbons detectable with Photovac............................................27 

Table 4 PetroFLAG™ system method detection limits and response factors for 

petroleum products...............................................................................................31 

Table 5 Specifications of PID used in the project........................................................37 

Table 7 Selected properties of soil samples.................................................................41 

Table 8 PID Values of volatile contents at different depths ........................................42 

Table 9 PID Results of Column Experiment. ..............................................................43 

Table 10 Field measurement of PID After 4 hours in Rilsan Bags .............................44 

Table 11 Field measurement photoionization detector after two days in Rilsan bags.45 

Table 12 Concentration of TPH calculated with PetroFlag system.............................46 

Table 13 Concentration of TPH calculated for column experiment ............................47 

Table 14 Concentration of TPH calculated for field measurements............................49 

Table 15 Concentration of TPH calculated for Field measurements...........................50 

Table 16 Immunoassay results of unsaturated-cylinder experiment............................51 

Table 17 Immunoassay results of soil column leaching experiment ...........................51 

Table 18 Immunoassay results of field measurements ................................................52 

Table 19 Results of the samples with the techniques used in the project. ...................53 

Table 20Swedish guideline values for levels in polluted soils ....................................54 

Table 21 Comparison of the measured results with Swedish guideline values for the 

field samples 0-5 cm depth. .................................................................................54 

Table 22 Comparison of the measured results with Swedish guideline values for the 

field samples 5-15 cm depth. ...............................................................................55 

 7



Introduction 
 
Recent discovery of contaminated land in many industrialized countries has resulted 
in major environmental concern with substantial social and financial implications. 
The uncontrolled disposal of complex hydrocarbons to the soil phase of the 
environment has resulted in the accumulation of oil constituents beyond the 
assimilative capacity of receiving soils (Hrudey et al, 1993). Contaminated soil has 
been actualized by new legislations and incidents at some sites as well as in 
connection to purchase of new production units. It is important to know the impact of 
human activities on surface and groundwater. The evaluation of potential risks to 
human health and environment that result from these releases, and the allocation of 
resources for the site remediation decision, relies increasingly on the results of 
assessment and characterization of the sites. These figures are valuable if there will be 
leaching of oil to soil. It is also important to develop functional methods of sampling 
and analysis ready to use when necessary. 
Soil contaminated with petroleum hydrocarbon products as cutting fluids, poses a 
significant challenge for characterization and remediation programs that require rapid, 
accurate and comprehensive data in the field or laboratory. Oil based cutting fluids 
contain complex matrix of polar and non-polar petroleum hydrocarbons with a diverse 
range of physiochemical and toxicological properties. Organic contaminants in soil 
vary greatly in both space and time, and this variation depends on a host of factors 
specific to those particular sites of interest, including the nature of the soil, the 
behavior of the pollutants, its transport mechanism and the climates (Monge A., 
1998). A proper knowledge of the various mechanisms of interaction between PHCs 
and soil surface is important in assessing the level of concentration and predicting 
their movement. Ongoing studies of organic compounds contaminated sites have 
highlighted that different types of organic compounds require different strategies for 
measuring and assessment in field and at chemical laboratories. Most of the existing 
analytical techniques, available give good results for the non-polar constituents of the 
cutting fluids, but analysis of the water soluble polar compounds is still a challenge 
for the environmental assessment of cutting fluids, especially in the field. Existing 
analytical techniques necessary for detailed account of contaminant’s mass balance 
calculation are expensive and time consuming (Pollard et al., 1994). However 
calculations of mass balance of specific compounds of organic contaminants present 
in the soil media is beyond the scope of this project. 
Cutting fluids require disposal once their efficiency is lost due to contamination and 
degradation, and waste management and disposal are major problems concerning 
environmental liability. The primary concern for this study is the significant negative 
effects in soils associated with use and waste disposal of cutting fluids. Back in the 
1960s, people did not realize how dangerous spent cutting fluids could be, and 
therefore any treatment before disposal was not performed. In the present days, fluid 
disposal costs frequently exceed the cost of buying new fluids, when dilution factors 
are taking into account. In addition, water-soluble organic materials that do not 
respond well to either chemical or mechanical recycling techniques are often 
components of chemical and semi-chemical fluids. These materials ultimately can be 
a threat to the surrounding environment in the shape of soil and groundwater 
contamination (web ref. 1). 
 

 8



This study is performed in partial fulfillment of the requirements of international 
masters program “Applied Environmental Measurement Techniques”. The project has 
been initiated and financed by the department of Environment and Chemistry at 
Volvo Technical development AB, the study is focuses on the evaluation of 
economical analytical methodologies; for the in-situ determination of petroleum 
hydrocarbons products, especially cutting fluids. These field analytical methods 
should allow a rapid assessment of soils and can be used to direct further sampling 
and analysis to save time and resources. As a part of the study, an environmental soil 
investigation has been performed at an old industrial site located in Sweden.  
The objectives of the project are to: 
 
1. Introduce of a test and monitoring program for the field analysis, including 
screening techniques, as well as analytical methods that are accurate, reproducible and 
of real time value for cutting fluids. 
2. To understand the movement of cutting fluid in soil media under saturated as well 
as unsaturated conditions. 
3. Analysis of organic contaminants in soils at an old industrial area in Sweden, to 
illustrate field analytical approaches for the characterization of complex contaminants 
as cutting fluids. 

Background Information 

1.Cutting fluids 
Cutting fluids are product of petroleum hydrocarbons, and play a significant role in 
machining operations and impact shop productivity, tool life and quality of work. 
They are widely utilized to optimize the process of machining operations such as 
turning, drilling, tapping, spot facing, fly cutting, seat forming, engraving, broaching, 
boring, grinding, milling and many other type operations. Cutting fluids are very 
efficient for rust retardancy; also they reduce friction at the tool chip interface for 
minimizing the heat (web ref. 1). The primary function of cutting fluid is temperature 
control through cooling and lubrication A cutting fluid's effectiveness depends on 
factors such as the method used to apply the cutting fluid, temperatures encountered, 
cutting speed, and type of machining process. The role of a cutting fluid as a coolant 
or lubricant is very sensitive to the cutting speed. For example, in high-speed cutting 
operations such as turning and milling where the tool-work interface is small, the 
cooling characteristic of a coolant is extremely important. Conversely, in low-speed 
cutting operations such as broaching, threading, and tapping, lubricity is more 
important since it tends to reduce the formation of a built-up edge (BUE) and 
improves surface finish (web ref. 2). 

1.1 Main types of cutting fluids 
The main types of cutting fluids fall into two categories based on their oil content  

1. Oil-based fluids - including straight oils and soluble oils  
2. Chemical fluids - including synthetics and semi synthetics 

Straight oils are non-emulsifiable and are used in machining operations in an 
undiluted form. They are composed of a base mineral or petroleum oil and often 
contains polar lubricants such as fats, vegetable oils and esters as well as extreme 

 9



pressure additives such as chlorine, sulphur and phosphorus. Straight oils provide the 
best lubrication and the poorest cooling characteristics among cutting fluids. 

Soluble oils (also called mixture fluid) are composed of a base of petroleum or 
mineral oil combined with emulsifiers and blending agents. The concentration of 
listed components in their water mixture is usually between 30-85%. Usually the 
soaps, wetting agents, and couplers are used as emulsifiers, and their basic role is to 
reduce the surface tension. They provide good lubrication and heat transfer 
performance. They are widely used in industry and are the least expensive among all 
cutting fluids. 

Synthetic fluids contain no petroleum or mineral oil base and are instead formulated 
from alkaline inorganic and organic compounds along with additives for corrosion 
inhibition. They are generally used in a diluted form (usual concentration = 3 to 10%). 
Synthetic fluids often provide the best cooling performance among all cutting fluids. 

Semisynthetics fluids (also called semi chemical) contain a lower amount of refined 
base oil (5-30%) in the concentrate. They are additionally mixed with emulsifiers, as 
well as 30-50% of water. Since they include both constituents of synthetic and soluble 
oils, characteristics properties common to both synthetics and water-soluble oils are 
presented. 

1.2 Common additives used in cutting fluids 

Fatty oil. (Metal wetting agent) This additive adds lubricity and makes oil “wetter” 
thereby lubricating and cooling the metal better than oil without this additive. This 
allows better, cleaner cuts and promotes longer tool life.  

Sulfur. This additive performs an anti-wear function in cutting oils by forming a 
chemical bond between the cutting tool and work piece, thereby keeping the tool from 
coming in direct contact with the metal being cut.  There are two types of sulfur 
additives, active and inactive. The inactive compound is used for cutting mild (low-
carbon) steels and will not stain these softer materials.  The active sulfur forms a 
stronger bond than the inactive but will stain soft metals. So, oil containing active 
sulfur is recommended for cutting and broaching the harder varieties of steel only.   
The object of this chemical bond is to promote longer tool life and to keep the tool 
from welding itself to the work piece under the severe temperatures created in many 
metal cutting operations 

Synthetic metal wetting agent. This additive performs the same function as the fatty 
oil wetting agent; however, it has two distinct advantages. It will not turn rancid with 
age and it leaves the metal coated with a rust and corrosion inhibitor 

Chlorine. This additive works in the same fashion as the sulfur additive and tends to 
complement the sulfur by strengthening the chemical bond (film) around the tool 
Chlorine tends to be liberated to the atmosphere at elevated temperature; therefore 
chlorine additives are not particularly useful for extremely high temperature 
applications (web ref. 3). 
 
 

 10



1.4 Cutting fluid used in the project 
The cutting fluid used in this project to spike the soil for the laboratory experiments is 
a product of Castrol, and the sample was provided by Volvo technology AB. The fluid 
is soluble in nature and used as emulsion with 30 – 85 % water content. It contains 
petroleum based mineral oil as a major constituent and some other more polar and 
water soluble hydrocarbons as shown in the Table 1.  

Table 1 Compounds present in the cutting fluid  

 
Chemical Name Formula % 

Mineral oil NIL (definition) 30 

Poly(oxy-1,2-
ethanediyl), -(9Z)-9-
octadecenyl-
hydroxy-, phosphate 
 

P
O

OHHO

OH
 

n
(CH2)8 (CH2)7 MeCH CHOCH2CH2HO

 

1-5 

N,N'-
methylenebismorph
oline 
 

CH 2

N

N

O

O

 

1-5 

Ethanol, 2,2',2''-
nitrilotris 

N CH2CH2

CH2
CH2CH2

CH2
OHHO

OH

 

1-5 

2-Aminoethanol CH2 CH2H2N OH
 

1-5 

Poly(oxy-1,2-
ethanediyl), -(9Z)-9-
octadecenyl-
hydroxy 
 

n
(CH2)8 (CH2)7 MeCH CHOCH2CH2HO

1-5 

Ethane-1,2-diol 
 CH 2 CH 2HO OH

 

1-5 

 
Mineral oil is a complex petroleum product; it has no specific formula and the precise 
definition according to the European community legislation is “a complex 
combination of hydrocarbons obtained by treating a petroleum fraction with hydrogen 
in the presence of a catalyst.  It consists of hydrocarbons having carbon numbers 
predominantly in the range of C20 through C50 and produces a finished oil of at least 

 11



100 SUS at 100oF (19cSt at 40oC). It contains relatively few normal paraffins. 
(TSCA) 
 

2. Soil vadose zone 
The geological profile of soil extending from ground surface to the upper surface of 
the principal water-bearing formation is called the vadose zone. The term “vadose 
zone” is preferable to the often-used term “unsaturated zone”, because saturated 
regions are frequently present in some vadose zones. The term “zone of aeration” is 
also often used synonymously (holden P., et al, 2001). Generally the soil profile in the 
vadose zone is divided into horizons A, B, and C. these major horizons are further 
subdivided into sub horizons. A horizon starts from the surface, it contains large 
amount of humus material with vegetation roots and the color of this horizon is 
relatively darker than the horizons below. Thickness of A horizon varies form few cm 
to 1, 5 m. Below the A-horizon the relatively un weathered light color soil with platy 
or columnar structure is designated as B-horizon. It is rich in calcium and iron, 
secretion from upper layer. Thickness of B-horizon range from few cm to several 
meters. After B-horizon unconsolidated material of parent rock is present with least 
effects of weathering, called as C-horizon.  
 

 
Figure 1 Schematic diagram of vertical profile of soil vadose zone (Pollard et al 1994) 

 
The vadose zone is subdivided into three regions designated as: the soil zone, the 
intermediate vadose zone, and the capillary fringe. The surface soil zone is generally 
recognized as that region that manifests the effects of weathering of native geological 
material. The movement of water and chemical flow in the soil zone occurs mainly as 
unsaturated flow caused by in-filtration, percolation, redistribution, and evaporation. 
Water in the intermediate vadose zone may exist primarily in the unsaturated state, 
and in regions receiving little inflow from above, flow velocities may be negligible. 

 12



Perched groundwater, however, may develop in the interracial deposits of regions 
containing varying textures. Such perching layers may be hydraulically connected to 
small stream channels so that, respectively, temporary or permanent perched water 
tables may develop. Alternatively, saturated conditions may develop as a result of 
deep percolation of water from the soil zone during prolonged surface application. 
The base of the vadose zone, the capillary fringe, merges with underlying saturated 
deposits of the principal water-bearing formation. This zone is characterized by the 
nature of geological materials and by the presence of water under conditions of 
saturation or near saturation. (Bendient. 1994) 
The capillary rise varies inversely with the pore size of the soil and directly with the 
surface tension. In general, the thickness of the capillary fringe is greater in fine 
materials than in coarse deposits.  
Vadose zone plays an important role in the fate and movement of the organic 
contaminants. Most of the physiochemical processes like; adsorption, absorption, 
advection, dispersion and diffusion take place in the vadose zone. Nature of the 
gravity drainage of both water and non aqueous phase liquids in the saturated and 
unsaturated condition is different. As water and oil are immiscible, the movement of 
oil from pore spaces is difficult if they are already filled with water. However the 
fluctuations of groundwater and different pore sizes have significant affects on this 
movement. A prolonged draughty period can result in dropping water table while a 
rainy season can result in the increase of water table. Similarly drainage of the 
contaminant from the large pore size is easier than the smaller sizes pores. The 
sources and transport mechanism of organic contaminants is discussed in further 
sections. 
 

2.1 Sources of soil pollution 
The term soil contamination can have different connotations because anthropogenic 
sources of contaminants have affected virtually every natural ecosystem in the world; 
a commonly held view is that contamination occurs when the soil composition 
deviates from the non-contaminated composition (Monge A. 1998). 
The pollution problem started in the industrial sector in 1800s in Germany. In the 
1900s the variety of chemicals wastes increased drastically from the production of 
steel and iron, lead batteries, petroleum refining and automobile industries. The World 
War II era unshared in massive production of wartime products that required use of 
organic compounds for example polychlorinated solvents, polymers, plastic, paints 
and wood preservatives without having knowledge of their environmental 
consequences that resulted in severe accidents later. 
Now–a-days, large quantities of organic compounds are being manufactured by 
industry, government agencies, agriculture and municipalities. These organic 
compounds have created a great potential for soil as well as groundwater 
contamination. The organic compounds released in the soil can be divided into 
categories: fuels and derivates (BTEX), PAHs, alcohols and ketones; halogenated 
aliphatics(trichloroethylene), halogenated aromatics and polychlorinated biphenyls 
(Bedient B. et al, 1999). 
United States EPA has reported more than 30 potential sources of organic 
contaminants in the soil. Major sources of pollution spilled during the last decades, 
can be categorized into the following groups. 
 
Underground storage tanks 

 13



 

 
Figure 2 Contamination of soil as well as groundwater by different sources 

 
Atmospheric deposition  
Surface water and sediments 
Landfill nearby 
Agricultural waste 
Radioactive contamination 
Land application and mining 
Industrial wastes and Spills 

 

2.1.1 Underground storage tanks 
 
Nearly one out of every four underground storage tanks in the United States may now 
be leaching, according to U.S Environmental Protection Agency (Planas, 1996). 
These tanks are used by small and large industries, agriculture, governmental agencies 
and private homes for storage of products. In general fuels, oils, hazaradous chemicals 
and solvent and chemical waste products are stored in below ground tanks. 
Underground tanks can leach due to internal or external corrosion of the metal. Leach 
can occur through holes in the tank or associated piping and valves. The steel tanks 
are being replaced by fiberglass tanks but faulty piping and subsequent leach still 
occur. The leaching chemicals contaminate the soil and in case of porous media the 
plum reach the water table. 
 

2.1.2 Landfills 
 
Modern landfills are built with elaborate leach prevention system, but most, 
particularly the older ones are simply large hole in the ground filled with waste and 
covered with dirt. They were designed to reduce the air pollution and unsightly trash 
that accompanied open dumping and burning, landfills became the disposal method 
for every conceivable type of waste. However, many may poorly designed and are 
leaching liquids or leachates, which have contaminated surrounding, soil and shallow 

 14



ground water. Modern landfills have a leachate collection system to control the 
migration of contaminants so they can be collected and transported off-site to a 
treatment plant. A landfill must have a properly designed and constructed liner to 
minimize migration of the pollutants. 

 

2.1.3 Surface water and sediments 

 
Surface impounds are often called pits, ponds, or lagoons. Ranging in size from a few 
square feet to several thousand acres, surface impounds serve as disposal or 
temporary storage sites for hazardous or non hazardous wastes. They are designed to 
accept purely liquid waste, or mixed solid and liquid that separate in the 
impoundment. These surface impoundments are commonly used by municipal 
wastewater and sewage treatment operations. Water from surface impoundments may 
be discharged to streams and lakes. Many surface impoundments are found to leach 
and create large contaminated zones in the subsurface. Most industrial sites where 
contamination occurred have one or more impoundments located on the site. 
 

2.1.4 Agricultural waste 
 
During the last decades pesticides were identified as a source of pollution in the soil 
and groundwater but now it is a major source in several countries. Pesticides have 
been widely used for many purposes for example weed control, insecticides, 
fungicides, and defoliants.  United States EPA has identified 50,000 different 
pesticides products composed of 600 active ingredients. They are used in agricultural 
fields, golf courses, lawns and gardens, roadsides, parks, home foundations and in 
wood products. Fertilizers from agriculture can also provide a major source of 
elevated nutrient level in the subsurface. Nitrogen, Potassium and Phosphorous are 
three basic fertilizers, Nitrogen is the most mobile in the soil and leach to the ground 
water but the phosphorous is not very mobile. 
The production of millions of tons of manure by agricultural sources contaminates, 
soil and underlying aquifers with Nitrogen, bacteria, viruses, hormones and salts. The 
most obvious threat stems from animal feedlots, where dense livestock populations 
are confined to small areas. Agricultural sources of contamination to the soil have 
been generally ignored under hazardous waste legislation, but as urban sprawl 
continues to expand into former agricultural areas, especially in developing countries, 
the pesticides and nitrates may become important in the future. (Bedient B. et al, 
1999). 
 

2.1.5 Land application and mining 
 
The land application involve spreading waste sludge and wastewater generated by 
public treatment works, industrial operations such as papers, pulps and textile mills, 
tanneries and canneries, livestock farms, and oil and gas exploration and extraction 
operations. Wastewater is applied primarily by a spray irrigation system, while sludge 

 15



from wastewater plant is generally applied to the soil as a fertilizer. Oily wastes from 
refining operations have been land formed in soil to broken down microbes. If 
properly designed land application recycle nutrients and waters to the soil and aquifer. 
 

2.1.6 Radioactive contamination 
 
Since the World War II the massive production of radioactive isotopes and nuclear 
warhead has been accompanied by increasing concern about environmental and health 
affects (Bedient B. et al, 1999). The legacy of Cold War has been a nuclear weapons 
complex that spreads form one coast to the other, and include some of the most 
contaminates sites of the world.   
Radionuclides are unstable isotopes of elements, including fission and products of 
heavy nuclei such as Uranium and Plutonium and naturally occurring isotopes such as 
C-14. Large quantities of radioactive wastes have been produced by the nuclear 
weapons industry in the U.S and other countries actively involved in this field. The 
potential sources occur in Uranium mining and milling, fuel fabrication, power plant 
operation, fuel reprocessing and waste disposal. The health hazards associated with 
radioactive leaks from the soil are well known but the risks are difficult to asses at 
low levels of exposure.  
 

2.1.7 Accidental spills 
 
Accidental spills are not very common source of soil contamination but whenever it 
happens it causes a high concentration of pollutants in the soil. The spills are more 
often for organic copmounds during the processing and transportation. The spillage 
moves under the transport mechanism or suffer other transformations and can travel in 
the unsaturated zone and under the water table as well, and create the risk of the 
health of humans, animals, or plants; damage to buildings or structures on the soil; 
contamination of ground waters, or surface waters in contact with the contaminated 
soil (web ref. 4). 

 16



 

  
Figure 3 Transport of soluble oils into the subsurface illustrating the distribution of the NAPL, 

the dense vapors, and the dissolved chemical plume (Pollard 1994). 

 

3. Transport of organic contaminants in the soil  
 
Soil and other solids are complex materials that may support a range of transport 
mechanism for the organic compounds present in cutting fluids. A proper knowledge 
of various mechanisms of interaction between oil, water and soil surface is important 
in predicting the transport mechanism and long-term behavior of cutting fluid in the 
soil. An individual soil grain is an extraordinarily heterogeneous mixture of minerals 
and natural organic matter (Bendient et al 1999). The mineral surfaces are dominated 
by polar or ionic functional groups capable of interacting with polar or ionic 
contaminants. The natural organic matter is generally hydrophobic material that tends 
to exclude water and other highly polar molecules. This fraction of soil occurs 
typically where non-polar/hydrophobic molecules associate. 
The transport of emulsified cutting fluids (mixture of mineral oil and water with 
blending agents) in the vadose zone can be a product of the gravity, hydraulic gradient 
of ground water, and capillarity. The capillary transport is due to the suction of the 
porous media, the oil is moving under the tension force active above the capillary 
zone (Fitter, 1993). Under the capillary forces, within the pore fluid of soil, oil can 
exist in three separate phases: dissolved, liquids (non-aqueous phase liquids “NAPL”) 
or gaseous. The capillary forces are important in fine soils with low water content. 
However, a high amount of water in the soil can be a barrier for the insoluble 
products. As the aromatic and aliphatic compounds have lower density than the water, 
they will be above the water film as NAPL without any significant penetration into 
the saturated zone. The hydrocarbons spills can move horizontally due to capillary 
forces and hydraulic gradient. Figure 3 gives a demonstration of the movement of oil 
in the vadose zone.  

 
 

 17



Non-aqueous phase liquids (NAPLs) are defined as separate phase product that are 
either lighter than water (LNAPL) such as normal gasoline that can float on the water 
surface or denser than water (DNAPL) such as chlorinated solvents. Some of them are 
volatile and of environmental concern. They frequently enter groundwater systems 
after they have been spilled on the surface and pass through the unsaturated zone.  
These contaminants flow through the unsaturated zone, a portion of the liquid remains 
behind in fingers at residual saturation, in pools of material on small heterogeneities, 
or above the capillary fringe (Palmer et el, 1989). 
Since the mineral oil consists of large molecules with long chain lengths, it is 
expected that the primary mode of interaction in mixture of soil and water through 
vadose zone, will be via Ven der Waal’s attraction forces. As the number of contact 
points between the oil and soil particle surface increase, in addition to the Ven der 
Waal’s interactions, significant binding interactions of alkyl groups (oil) with surface 
oxygen or hydroxyls (soil or water) and exchangeable cations will also occur.  A 
schematic picture of the interactive mechanisms involved is shown in the fig 4. 
 

 

Figure 4 A schematic diagram of the 
interactive mechanisms involve in oil-soil-
water mixture VW is Ven der Waal’s 
attraction, WHB is weak hydrogen bonding, 
WB is water bonding, and CB is cation 
bridging (Source Young R., et al, 1994)

 
 

3.1 Physiochemical processes controlling the Transport 
Pathways 
 
The hydrocarbons that remain in the unsaturated zone are an important source of 
contamination because they are dissolved by the passing recharge water, and by the 
passing ground water as the water table rises. Such sources of contamination can last 
for many years and contaminate large volumes of groundwater. On the other hand the 
water soluble component of the contaminant are washed out readily and reach the 
groundwater if the strata is permeable enough. This phenomenon is called advection. 
However, in addition to this pathway, contaminants can also be transported through 
diffusion and dispersion, adsorption, biodegrading, chemical reaction and 
volatilization. These transport pathways may spread the contaminants over much 
broader areas. To get the idea of the transport of dissolved contaminants and the 
design of optimal remediation schemes, require knowledge of the physiochemical 
processes that control transport pathways.  
Some major physiochemical processes are given below: 
 

 18



3.1.1 Advection 
Advection represents the movement of a contaminant with the flowing ground water 
according to the seepage velocity in the pore space. It is defined as  

dl
dh

n
kvx −=   [3-1] 

It is important to realize that the seepage velocity is equal to the average linear 
velocity of the contaminant in the porous media, and is the correct velocity for use in 
governing solute transport scenario. The average linear velocity vx is equal to the 
Darcy’s velocity divided by effective porosity, n, associated with the pore spaces 
through which water can actually flow. This velocity is less than the microscopic 
velocities of water molecules moving through individual flow paths. So the one-
dimensional mass flux due to advection is equal to the product of flow and 
concentration of solute in the soil media (Bendient. et al, 1999). 
 

3.1.2 Diffusion and dispersion  
Diffusion is a micro-scale process, which cause spreading due to concentration 
gradient. Diffusive transport can occur in the absence of velocity, and is important 
where the relatively impermeable soil is present on the surface for example clay or 
silty clay. Mass transport in the soil due to diffusion in 1-D can be described by Fick’s 
first law of diffusion. 

x
CDf dx ∂
∂

=    [3-2] 

where fx is mass flux (M/L2/T) 
Dd is diffusion coefficient (L2/T) 
dC/dx is concentration gradient (M/L3/L) 

 
Figure 5 Movement of contaminant showing movement under diffusion and dispersion 

mechanism. (pollard et al, 1994) 

 
Dispersion is caused by the heterogenities in the medium that create variation in flow 
velocities and flow paths. This variation can occur due to friction with in single pore 
channel, due to velocity difference from one channel to another, (figure 5) or due to 
variable path lengths. Mass transport due to dispersion can also occur normal to the 

 19



flow. This transverse dispersion is caused by driving flow path in the porous media 
that cause mass to spread literally from the main direction of flow. 

3.1.3 Sorption 
The association of dissolved or gaseous contaminant with a solid material is called 
sorption. In the vadose zone the solid of interest are soil particles and typically the 
contaminants are in the dissolved phase. The term sorption encompasses two more 
specific processes referred to as adsorption and absorption. Adsorption is the 
association of contaminant with the surface of solid particle.  

 
Figure 6 Schematic of soil grain Sorption (Bendient. et al, 1999). 

 
Absorption is the association of contaminant with in the solid particle. Incase case of 
hydrocarbons; it is often difficult to distinguish between adsorption and absorption, 
since both may occur simultaneously. At least three different situations can be 
speculated that can co-exist in soil-oil-water mixture: 1) Oil may adsorb onto the 
surface of the soil constituents, 2) oil may form bond which link (aggregate) some of 
the soil particles and cause retention of oil in the soil and, 3) oil may exist separately 
in the soil pore space. When hydrocarbons are spilled on the soil, nonpolar or 
hydrophobic contaminants interact primarily with hydrophobic constituents of the soil 
media, while ionic or polar material interact with charged mineral surfaces. In either 
case, the extent to which sorption may occur is influenced by the chemical properties 
of both sorbent and the sorbate (Figure 6) 
Adsorption is described by the adsorption coefficient Kd. The ability of a compound 
to be absorbed by the soil is characterized by the adsorption coefficient. There are 
empirical results indicating that soils with higher content in organic matter than 1% 
adsorb some more amount of any contaminant agent. The Kd value can be obtained by 
knowing the amount of organic matter present in the soil (Koc) (Canter, 1996) 

Koc=(Kd/foc)    [3-3] 
Kd is the adsorption coefficient and foc is the organic matter present calculated by the 
octane-water coefficient (Kow). Kow represents the distribution of of a chemical 
between octanol and water in contact with each other at equilibrium conditions: 

Kow = Concentration in octanol/ concentration in aqeous phase. 
Kow has been measured in the laboratory for many chemicals and is readily available 
parameter. Measured values of Kow for organic chemicals have been found as low as 

 20



10-3 and as high as 107 (Bendient. et al, 1999). Kow values of some hydrocarbons of 
concern are given in the Table 2. 
 
The Koc values can be calculated in different ways:  
There exists several empirical correlation between Koc and Octane-water 
coefficient(Kow). For instance  
 

10 polyaromatic hydrocarbons Log Koc=Log Kow-0.21 [3-4] 
 

Miscellaneous Organic  Koc= 0.63 Kow  [3-5] 
 
 

Table 2 Octane-water coefficient (Kow) (Canter, 1996). 

 
Compound Log Kow (mean) Log Kow (std) 

Alkanes and alkenes 
Methane 
Ethane 
Propane 
Pentane 

Aromatics 
Benzene 

Naphthalene 
 

 
1,09 
1,81 
1,13 
3,39 
 

2,01 
3,32 

 

 
No data 
No data 
No data 

 
 

0,45 
0,35 

 
 
Taken into consideration the contaminants solubility in water according to the 
following relation: 

Log Koc= 0.44-LogS   [3-6] 
S is the contaminant’s solubility in water. 
The partition coefficient (Kd) can be defined by following equation. 

[ ]
[ ]aqueous

solid

A
Akd =   [3-7] 

A is the concentration of contaminant in either phase 
There are also other chemical mechanisms responsible of the adsorption process, such 
as Van der Waal’s interactions, hydrophobic binds, hydrogen bond, charge 
transference or ionic exchange. 
 

3.1.4 Biotransformation and biodegradation  
It is a complete conversion of a contaminant to mineralized end product (i.e., CO2, 
H2O and salts) through metabolism by living organism. In soil the organism that carry 
this process are bacteria indigenous to the system. In some cases, metabolic activity 
change the chemical form of the contaminant but does not result in the mineralization. 
The metabolism of soil and groundwater contaminants is an extremely important end 
process since it has the potential to impact the fate of all organic contaminants, and is 
a process that has the potential to yield nonhazardous products. It is a complicated 
process due to the diversity of bacteria that may be involved, and range of metabolic 
processes that can be expressed. Studies have shown total petroleum hydrocarbons 

 21



(TPH) in different oily soils showed that 90% of the alkanes and monocyclic saturates 
and 50-70% of aromatic compounds (<C44) were degraded (Mohamed, et al, 1992) 
 

3.1.5 Volatilization  
Near a spill of organic contaminant especially hydrocarbons, a four-phase system 
exists. The phases include (1) the aquifer matrix, (2) the residual soil water, (3) the 
NAPL, and (4) the air-filled pore space (Figure 4-3). A volatile NAPL partitions from 
the NAPL phase into the gas phase where it then can be transported to other portions 
of the unsaturated zone. The vapor pressure of a particular contaminant, Pk, in the gas 
phase can be calculated from Raoult’s Law:   

Pk= XkPo
K   [3-8] 

Where xk is the mole fraction of component k in the NAPL and P0
k is the vapor 

pressure above the pure component. For example, if the NAPL is gasoline, the partial 
pressure on benzene, one of the many components of gasoline, is the mole fraction of 
benzene in the gasoline times the ideal vapor pressure above pure benzene. The 
concentration of the gas in the soil atmosphere can be calculated from the ideal gas 
law: 

(n/V)k=Pk/(RT)  [3-9 ] 
Where n is the number of mole of component k, V is the volume of gas, T is the 
kelvin temperature, and R is the gas constant.  

3.1.6 Gas-phase transport 
The movement of the contaminants in the gas phase of the unsaturated zone can be 
described by performing a mass balance on a volume of aquifer: 

RXN
t
C

x
Cv

x
CD ±=−

δ
δ

δ
δ

δ
δ

2

2

 [3-10] 

Where v is the groundwater velocity (L/T), D is the dispersion coefficient (L2/T), C is 
the concentration of the dissolved constituent (M/L3), t is time, and RXN represents a 
general chemical reaction term or the retardation factor which depend on the bulk 
mass density, porosity and partition coefficient (Kd). The first term in equation 3-9 
describes the net advective flux of the contaminant in and out of a volume of the 
aquifer; the second term describes the net dispersive flux of the contaminant. The first 
term on the right-hand side of the equation describes the change in concentration of 
the contaminant in the water contained within the volume of aquifer, the second term 
on the right-hand side represents the amount of contaminant that may be added or lost 
to the groundwater by chemical or biological reaction. If there is no reaction term, 
then the equation describes the transport of a conservative, nonreacting tracer such as 
chloride or bromide (Palmer et al,1989). 
 

3.2 Factors influencing the distribution of organic 
contaminants in soil 
The contaminant distribution is a function of hydrogeological properties of soil as 
well as the initial concentration of the contaminant, contaminant phase, and volatility 
of the compound. These parameters are described as permeability coefficient, 
Diffusive properties of soil and adsorption by the soil. 
 

 22



Permeability coefficient  
It is related to how easy a liquid can propagate through the soil, it depends on the 
shape and size of the pores and adsorptive properties of soil grains. Low permeability 
soils are clays and silt having saturated hydraulic conductivity below 10-5cm/s 
 

Diffusive properties of soil  
It relates to the movement of a solute in water from higher concentration to low 
concentration (Fitter1993). Where the soil is highly permeable the diffusion is 
negligible but dominates in the soil having low permeability like clay and silt etc. 

Water solubility  
The amount of the contaminants dissolved and transported by the water is indicated 
by the water solubility. The higher solubility of the contaminant the higher 
concentration of this product in the aqueous phase, and the component with lowest 
density will be adsorbed to the soil grains. 

Density and viscosity 
This property influences the mobility and location of the final non-aqueous phase. If 
non-aqueous phase is lighter than the water, the contaminant will situate over the 
water table. On the other hand, if it is heavier than the water. this pollutant will 
penetrate through the soil towards the impermeable layer. The detection and soil 
remediation depend on the location of the contaminant in reference to the water table 
(Callabo de Roa 1996) 

Vapour pressure and density of vapour phase  
Vapour pressure is defined as the pressure exerted by the vapour phase of a pure 
compound. Vapour pressure gives the relative volatility of the compound. The density 
of the vapour pressure indicates whether a gas will rise or sink in the atmosphere. It is 
related to equilibrium vapour pressure, the molecular weight of the gas, and the 
temperature (Fitter, 1993). 
 

3.2.6 Grain size effect 
The size of soil particles is very important in the spatial distribution of the 
contaminants. The relationship between horizontal and vertical propagation velocity 
and internal spatial extension along those two directions depends on the soil 
permeability, which is a function of soil’s texture, water content and chemical 
composition of a blend present in the soil. For instance a low velocity blend 
penetrates into the sand more quickly and spread area is smaller (Pons et al., 1992). 
If 1 m3kerosene is poured over 10 m2 of coarse sand, the final penetration depth will 
be of 20 m. If the same spill is discharge over the fine or medium sand the depth will 
be 6.7 m. If the medium is clay it will penetrate to only depth of 2.5 m. The time 
propagation is the same for the three examples (Pons et al., 1992; Monge.,  1998).  
 
 

 23



 
Figure 7 Evaporation of Iran and Arabia crude oils (Monge. 1998). 

 
The grain size is important in the case of evaporation calculation of the volatile 
content spilled on the soil. For example, spilled occurred over a fine sand will 
evaporate more than medium or coarse sand. Since the permeability of coarse sand is 
high, the large amount of hydrocarbons will percolate downward. 
A study of evaporation rates of crude oils in different soil performed by Bergueiro et 
al., 1988, shows the results presented in the Figure 7. The wind speed of 5,8 m/s at 
150C was set for experimental condition. The evaporation was measured after 100 
minutes and 150 hours on heavy crude oils (Monge., 1998).  

 24



4.Field analytical techniques  
 

In evaluating the effects and to be able to take decision about remedial action for 
organic contaminants especially petroleum hydrocarbons, selection of the appropriate 
analytical method is essential. The study of soils contaminated with organic 
contaminants is associated with several challenges, especially of analytical 
methodologies and data interpretation. Organic contaminants, especially petroleum 
product comprise a vast continuum of hydrocarbons from short chain aliphatic and 
simple aromatic hydrocarbons in gasoline to kerosene, diesel and heavy oils to 
lubricant oils or vaseline, each gradation with increasing carbon chains and 
complexity. Properties of these hydrocarbons vary and composition of the 
hydrocarbons Is of environmental concern. Treatment technology and site remediation 
progress will lean heavily on analytical techniques, that are accurate reproducible and, 
of real time value. There are several methods currently available for the analysis of 
organic contaminants. These field analytical techniques contain screening as well as 
in-situ analytical methods. Screening methods provide an indication of the presence or 
absence of a particular chemical or chemical class of concern, or provide an indication 
of whether the chemical or chemical class of concern is above or below a 
predetermined threshold. Screening methods provide relative concentrations for 
chemical classes, but rarely provide chemical specific information (EPA/625/R-
93/003b, May 1993). Field analytical methods include all chemical analysis methods 
capable of providing chemical-specific quantitative data in the field or in non-
laboratory setting. Field analytical and screening techniques can be classified as: 
Portable: Require no external power source, are compact and are rugged enough to 
be carried by hand in the field. 
Fieldable: Require limited external power, are compact and are rugged enough to be 
transported in small van or pick-up. 
Mobile: Are small enough to carry in a mobile laboratory, which is feasible for most 
analytical instruments although power consideration can be a limitation. 
However standards by which the sensivity, precision, and accuracy of field screening 
techniques are measured are those obtained in fixed-base laboratories. 
Field measurement devices may be categorized as quantitative, semi quantitative, and 
qualitative. A quantitative measurement device measures hydrocarbon 
concentrations ranging from its reporting limit through its linear range. The 
measurement result is reported as a single, numerical value that has an established 
precision and accuracy. A semi quantitative measurement device measures TPH 
concentrations above its reporting limit. The measurement result may be reported as a 
concentration range with lower and upper limits. A qualitative measurement device 
indicates the presence or absence of PHCs above or below a specified value (for 
example, the reporting limit or an action level). 
 

4.1 Field analysis versus analytical laboratory 
Key advantages of field analytical techniques include: 
1. Results can be obtained within hours compared to the normally 20 to 40 days 
required for laboratories, which allows for more rapid definition of the scope of 
contamination and allows the optimal selection of permanent monitoring locations. 

 25



2. Lower cost per sample (commonly one-tenth of lab. Cost) allows for more detail 
characterization of contaminant distribution and reduces the overall cost.  
3. The techniques are best suited for preliminary site characterization, emergency 
remedial actions and monitoring of remediation activities. 
 
Some general disadvantages of field analytical techniques includes: 
1. Application of analytical QA/QC procedures is more difficult in the field. 
2. Generally less sophisticated instrumentation and have generally higher detection 
limits and lower precision and accuracy compared to the laboratories analysis. 
3. The data may be more liable to challenge by litigation. 
 
The following sections address various methods for analyzing the soil samples in the 
field, employed for the project. 
 

4.2 Photo ionization detector (PID)  
 
PID is a portable nonspecific, vapor/gas detector employing the principle of photo 
ionization to detect a variety of chemical compounds, both organic and inorganic. The 
PID is a useful general survey instrument at hazardous waste sites. A PID is capable 
of detecting and measuring real-time concentrations of many organic and inorganic 
vapors. A PID is similar to a flame ionization detector in application; however, the 
PID has somewhat broader capabilities in that it can detect certain inorganic vapors 
and also can be used in combination with gas chromatography for detecting specific 
compounds. 
Conversely, the PID is unable to respond to certain low molecular weight 
hydrocarbons, such as methane and ethane that are readily detected by FID 
instruments. 
 

4.2.1 Principle and method summary 
 
The PID employs the principle of photo ionization. The analyzer responds to most 
vapors that have an ionization potential less than or equal to that supplied by the 
ionization source, which is an ultraviolet (UV) lamp. Photo ionization occurs when an 
atom or molecule absorbs a photon of sufficient energy to release an electron and 
form a positive ion. This will occur when the ionization potential of the molecule in 
electron volts (eV) is less than the energy of the photon. The sensor is housed in a 
probe and consists of a sealed ultraviolet light source that emits photons with an 
energy level high enough to ionize many trace organics, but not enough to ionize the 
major components of air (e.g., nitrogen, oxygen, carbondioxide). The ionization 
chamber exposed to the light source contains a pair of electrodes, one a bias electrode, 
and the second the collector electrode. When a positive potential is applied to the bias 
electrode, an electro-magnetic field is created in the chamber. Ions formed by the 
adsorption of photons are driven to the collector electrode. The current produced is 
then measured and the corresponding concentration displayed on a meter, directly, in 
units above background. Several probes are available for the PID, each having a 
different eV lamp and a different ionization potential. The selection of the appropriate 
probe is essential in obtaining useful field results. Though it can be calibrated to a 

 26



particular compound, the instrument cannot distinguish between detectable 
compounds in a mixture of gases and, therefore, indicates an integrated response to 
the mixture (web ref. 5) 
Three probes, each containing a different UV light source, are available for use with 
the photovac. Energies are 9.5, 10.2, and 11.7 eV. All three detect many aromatic and 
large molecular hydrocarbons. The 10.2 eV and 11.7 eV probes, in addition, detect 
some smaller organic molecules and volatile halogenated hydrocarbons. The 10.2 eV 
probe is the most useful for environmental response work, as it is more durable than 
the 11.7 eV probe and detects more compounds than the 9.5 eV probe. Gases with 
ionization potentials near to or less than that of the lamp will be ionized. These gases 
will thus 
be detected and measured by the analyzer. Gases with ionization potentials higher 
than that of the lamp will not be detected. Ionization potentials for various atoms, 
molecules, and compounds that could not be present in the cutting fluids are given in 
Table 3. 

 
Table 3 Volatile hydrocarbons detectable with Photovac 

Compound Ionization Potential (ev) 
Benzene 9,53 

Cyclohexane 10,50 
Cyclopentane 10,52 

Dicyclopentadiene 9,82 
Dimethylaniline 8,24 

n-Heptane 10,07 
Methylcuclohexane 11,25 

Naphthalene 8,10 
n-Nonane n.p. 
n-Octane 9,19 
Toluene 8,82 
o-Xylene 8,56 
m-Xylene 8,56 
p-Xylene 8,45 

 
The ionization potential of the major 5 components of air, oxygen, nitrogen, and 
carbon dioxide, range from about 12.0 eV to about 15.6 eV and are not ionized by any 
of the three lamps.  
While the primary use of the PID is to get quantitative results, it can also be used to 
detect certain contaminants, or at least to narrow the range of possibilities. Noting 
instrument response to a contaminant source with different probes can eliminate some 
contaminants from consideration instance, a compound's ionization potential may be 
such that the 9.5 eV probe produces no response, but the 10.2 eV and 11.7 eV probes 
do elicit a response (web ref. 6). 

 

4.2.2 PID instrument limitations 
 
1. The PID is a nonspecific total vapor detector. It cannot be used to identify unknown 

 27



substances; it can only roughly quantify them. 
2. The PID must be calibrated to a specific compound. 
3. The PID does not respond to certain low molecular weight hydrocarbons, such as 
methane and ethane. In addition, the PID does not detect a compound if the probe has 
a lower energy than the compound's ionization potential. 
4. Certain toxic gases and vapors, such as carbon tetrachloride and hydrogen cyanide, 
have high ionization potentials and cannot be detected with a PID. 
5. They measures concentration from about 1-2000ppm, although the response is not 
linear over this entire range. For example, if calibrated to benzene the response is 
linear from about 0-600 units above the background. This means the PID reads a true 
concentration of benzene only between 0 and 600. Greater concentrations are detected 
at a lower level then the true value. 
6. This instrument dos not give response if it is exposed to precipitation.  
7. This instrument cannot be used for headspace analysis where liquids can 
inadvertently be drawn into the probe (web ref.5) 
8. The response of PID varies greatly with the nature of the volatile organic 
compound. While the PID response to halogenated volatiles and aromatics may be 
fairly similar between similar compounds, the PID response to alkanes may be lower 
by an order of magnitude or more. As a result, knowledge of the site-specific 
contaminants of concern will be essential to successful application of this procedure 
(web ref. 6). 

4.3 Immunochemical techniques 
 
Immunoassay is an analytical technique useful for the separation, detection and 
quantitation as both organic and inorganic analytes in diverse environmental and 
waste matrices. Immunoassay methods are used to produce two types of quantitative 
results: 1) range-finding or screening results indicative of compliance with an action 
level, and 2) assay values (www.epa.gov test method 4000).  These techniques are in 
the framework of wet analytical chemistry and may be called as enzyme 
immunoassay (EIA), enzyme linked immunosorbent assay (ELISA), 
radioimmunoassay (RIA) or flouroimmunossay. Out of these techniques EIA is used 
to analyze benzene, toluene, xylene (BTX), PCB, PCP, cocaine, heroin, and 
pesticides. 
 

4.3.1 Method selection consideration 
 
Immunoassay test products use an antibody molecule to detect and quantitate 
substance in a test sample. These testing products combine the specific binding 
characteristics of an antibody molecule with a detection chemistry that produces a 
detectable response used for interpretation. In general antibody molecules specific for 
the method’s intended target are provided at a predefined concentration (web ref. 7). 
Immunoassay testing products have a quantitative basis, and produce a signal that is 
dependent on the concentration of the analyte present in the sample. For 
environmental immunoassay methods, the signal produced is exponentially related to 
the concentration of the compounds present. 
EIA methods use enzymes to develop chromogenic response and are termed as 
enzyme immunoassays. This technique involves the use of antibodies reagents that 

 28

http://www.epa.gov/


react with the analyte of interest to produce reaction that can be analyzed 
calorimetrically and are a recent development for the trace organic analysis. EIA is 
the best-suited techniques for the primary screening where only a few contaminants 
are of interest. EIA kits are very simple rapid and inexpensive. It has potential for 
specific field tests for a large number of toxic organics with very low detection limits 
up to ppb. Assays that generate a chromogenic response are analyzed photometrically, 
and use the principle of Beer’s Law (Absorbance= Extinction Coefficient* 
Concentration* path Length) to determine the concentration of analyte in the sample. 
 

4.3.2 Interferences 
Non-target analytes may bind with the antibody present, producing a false-positive 
result. These non-target analytes may be similar to the target analytes, or may be 
chemically dissimilar to co-contaminants. 
Some test products have designated temperature ranges for operation. When these 
products are used, all tests must be performed with in specific operating temperature 
limits, or else false negative/positive results may exceed performance claims. 
 

4.3.3 Advantages and limitations 
 
The two key features of the immunoassay technology are the rapid turn-around time 
for results and the portability and ease of use of the kits. These rapid analytical 
solutions can lead to substantial savings in time and expenses when applied to 
environmental projects. The kits are prepared to be used by nonchemists with minimal 
training. These capabilities have enabled environmental professionals to shorten the 
time frame in which site assessment and remediation projects are completed, saving 
up to 50% of the project costs and reduce the owner liability. 
The immunoassay technology is generally specific in its detection capabilities, 
thereby prohibiting detection of broad groups of compounds (i.e., the immunoassay 
detects PCBs but not all chlorinated compounds). However, the antibody might 
recognize a compound chemically very similar to the target compound, causing false 
positive results. The analysis can also be affected by specific matrix conditions. For 
example, analyte recovery for analytes such as PCBs and PAHs can be affected by 
excessive soil moisture. Also, percent levels of oil can result in false positive results. 
Immunoassay technology is not applicable for all classes of small, environmentally 
significant molecules (e.g., long chain aliphatic hydrocarbon compounds and most 
metals). Temperature extremes can affect test results; the operational temperature 
ranges are typically between 40o and 100oF. Immunoassay kits have a limted shelf life 
(between 1 month to 1 year) dependent upon the vendor development and enzyme 
congugate stability (web ref. 7) 
 

4.4 PetroFLAG™ System 
 
The PetroFLAG™ System is a field measurement device capable of providing 
quantitative TPH measurement results. Measurements made using the PetroFLAG 
Systems are based on emulsion turbidimetry. Turbidimetry may be described as 
measurement of the attenuation, or loss in intensity, of a light beam as the beam  

 29



  
Figure 8 Relative intensity data for common analytes (Dexil corporation, 1999). 

 
passes through a solution with particles large enough to scatter the light. Emulsion 
turbidimetry involves measurement of the light scattered by an emulsion (in an 
emulsion, one liquid is stably dispersed in a second, immiscible liquid). The 
relationship between the amount of light scattered (turbidity) and the concentration of 
the emulsion may be expressed as shown in Equation 5-1. 

T = kbc [5-1] 
Where 
T = Turbidity 
k = Proportionality constant 
b = Light path length (centimeter) 
c = Concentration of emulsion (milligram per 
liter [mg/L]) 
 
Unlike other field screening this techniques does not target specific compounds such 
as BTEX or PNAs that may be a part of hydrocarbon mixture. Because of its broad 
linear response, PetroFLAG kit can be used on a wide range of hydrocarbons analytes 
including fuels, lubricants, hydraulic fluids and greases. This makes PetroFlag kit 
useful as fast, low cost general screening tool for the hydrocarbons, as well as for the 
quantitative determination of hydrocarbons determination in the soil samples, while 
provide the user with real time data for onsite decision making. PetroFlag system is 
most sensitive to heavier hydrocarbon such as mineral oils and greases and less 
sensitive to the lighter more volatile hydrocarbon fuels. The PetroFlag responses to 
some typical hydrocarbon contaminants are plotted in Figure 8. 
The PetroFLAG system extracts PHCs in soil using a proprietary organic solvent 
mixture composed of alcohols, primarily methanol. The device also uses a proprietary 
developer solution that is polar in nature and acts as the emulsifying agent. The 
developer solution also contains water and surfactants that stabilize the emulsion. The 
PetroFLAG system can be used to measure the petroleum products listed in Table 4 
the device does not distinguish between aromatic and aliphatic hydrocarbons and it 
responds to compounds in the C8 until C36 carbon range. Method detection limits 
(MDL) for the device are also listed in Table 4 and range from 10 mg/kg for hydraulic 
fluid to 1,000 mg/kg for weathered gasoline. In addition, Table 4 lists the device’s 

 30



response factors, which are based on mineral oil. The response factors range from 2 
for weathered gasoline to 10 for transformer oil, indicating that the instrument is more 
sensitive to transformer oil than weathered gasoline. If no information is available 
regarding the type of contamination in a sample, use of an average response factor of 
5 is recommended (web ref. 8). 
 

Table 4 PetroFLAG™ system method detection limits and response factors for petroleum 
products (web ref. 8, and 9). 

 
 
The Petro-FLAG test is easily performed at the contaminated sites where a variety of 
sampling strategies are to be used. The test is useful at sites requiring lateral and 
vertical definition of soil contamination plume throughout the vadose zone, including 
the sites that are being drilled and sampled or excavated and sampled prior to the 
collection of expensive laboratory confirmation samples. 
The Petro-FLAG test is well suited for use at large sites where a grid-sampling plan is 
strategy of choice. It will help to economically locate and define the extent of the soil 
contamination, locate and define hotspot. This could help to save unnecessary drilling 
and sampling costs and equipment relocation costs caused by waiting for laboratory 
analytical data, and allow more area to be tested thus reducing the possibility of future 
liability caused by failing to identify contaminated areas (T.B Lynn et al, 1994).  
 
 

 31



4.4.1 Interferences 
This method is considered a screening technique because of broad spectrum of 
hydrocarbons it detects. It cannot distinguish between co-extracted naturally occurring 
hydrocarbons and petroleum hydrocarbons. The PetroFlag has also  been shown to be 
susceptible to interference from vegetable oils. It is anticipated that co-extracted 
naturally occurring oils from vegetative material would be one of the most probable 
positive interferants found in the field. Therefore in situations where the soil contain a 
high organic content is suspected, the background level outside the spill site should be 
determined (T.Lynn et al, 1994). 

 32



Materials and methods  

1 Soil sampling 
 
The soil samples were collected from two different places in the Mölndal area. For the 
first site sampling was done near the Sisjön centrum using PVC sampling tube of one 
meter in length and 8 cm in diameter. The soil was moved from the sampling tube 
into an airtight glass jars according to the depth profile recovered from the tube. The 
second sample was taken as a composite sample separately for horizon A and B from 
the working site of NCC near the Mölndal station. This sample was collected in 
diffusion less plastic bags and was transferred into glass jars after arrival to the 
laboratory. 
These sampling sites were selected on the basis of the soil textural class (sandy Loam) 
shown by the soil map of Mölndal area (SGU Ser Ae nr 96, 6B Kungsbacka NV). The 
same texture class is present in the soil of the case study area. The two sampling 
locations are marked with a star in figure 9. 
 

 
Figure 9 Locations of sampling sites in the Mölndal area (web ref. 8). 

2 Soil sampling at the old industrial site 
During the environmental soil investigations of the old industrial area in Sweden, 
samples were collected from the five locations. Out of these five locations four 
locations were within the project area of investigation as shown in the Figure 10. 
Location five was outside that area; the sample was taken to compare the background 
values of the parameters to be investigated in the study. Almost whole project area is 
covered with asphalt pavement. Sampling location 1, 3, and 4 are on the right bank of 
the watercourse. Location 2 is at the small grassland made between the asphalt 
pavements.  

 33



 
 

Figure 10 Sketch of sampling locations at an old industrial site in Sweden. 

 

3 Experimental 
 
Two experiments were designed for the laboratory. The object of these soil 
experiments was to check the validity of the analytical techniques used for soil 
samples contaminated with cutting fluids, and to get an idea of the transport 
mechanism of the polar as well as non-polar compounds present in the cutting fluids 
in two different scenarios. In the first experiment, the soil was kept unsaturated to 
stimulate controlled conditions, but in the column-leaching test saturated conditions 
were proposed to simulate more realistic environmental conditions. A description of 
these two experiments is given below. 
 

4 Cylinder- unsaturated 
 
The object of the experiment was to verify the validity of the analytical techniques 
used for organic contaminants in the soil samples and to get an idea of the transport of 
cutting fluid in unsaturated soil media. For this first experiment a glass cylinder of 10 
cm in diameter and 50 cm in length was used. 2 kg of soil was spiked with 16 ml of a 
12% solution of cutting fluid to get a total concentration of approximate 1000ppm. 
The soil was kept in the glass cylinder for 8 weeks at room temperature. The total 
length of the soil column in the cylinder was 35 cm. The cylinder was covered with 
aluminum foil to reduce the process of photodegradation. After 8 weeks samples were 
collected at different depths by pressing a tube of smaller diameter than the glass 
cylinder, into the soil.  

5 Soil column experiment 
 
Evaluation of the potential leaching of organics compounds to soil can be performed 
by several approaches. For this EPA standard method 1311 give the guideline for 
toxicity characteristic leaching procedures (TCLP). This method is designed to 

 34



determine the mobility of both organic and inorganic analytes present in liquid, solid, 
and multiphasic wastes under anaerobic conditions (web ref. 11). As the nature of the 
soil being discussed in this project is different, as we are dealing with upper horizons 
(A and B) of soil profile. Both of these horizons contain oxygen and thus can not 
follow TCLP for this type of experiment. The column-leaching test was designed to 
simulate more realistic environmental conditions. The object of leaching experiment 
of soil column was to get an idea of the transport mechanism of the polar as well as 
non-polar compounds present in the cutting fluids. 
The testing apparatus consists of a glass leaching columns. The Column was 0.75 m 
tall and 8 cm in diameter. The column contained soil (passing #4 sieve) with a known 
concentration of cutting fluid, 1000 ppm. The soil was kept in the glass column, and 
the profile of the column contained 50 cm of soil divided into two horizons (A&B), 
with a thin filter of medium sand at the top and bottom of the soil column. The filter 
was applied for the uniform distribution of fluid in the soil. A leachate collection port 
was fixed at the bottom of the column to collect the dripping of fluid from the column 
outlet. 
5.22 ml of the cutting fluid with 1500 ml of distilled water was added on the soil at 
the inlet of the column to get the total concentration of approximate 1000 ppm. The 
calculations of this added amount were done by the following formulas 

mcf = ms.cw/ccf   [ 5-1] 
Where: 
mcf is mass needed of the cutting fluid 
cw is the wanted concentration i.e 1000mg/kg=1000ppm=0,001%. 
ms is the mass of soil= 5,362 kg=5362 g. 
The mass of the cutting fluid calculated from the equation 5-1is used in the formula  

vcf  = mcf/δcf   [5-2] 
Where: 
vcf is the volume of the cutting fluid in ml. 
mcf is the mass calculated from equation 5-1 
δcf is the density of the cutting fluid= 1,027g/l. 
After addition of the cutting fluid, the column was left for 42 days 42 days to get an 
idea of the movement of the chemicals with time at several depths. Unfortunately the 
dripping collected in the sample port at the column outlet was not larg enough in 
volume to make any analysis using immunoassays and PetroFlag kits. The analyses 
were performed only for soil samples collected from the column. 
 

6 Analysis procedure for the soil samples 
 
For the soil samples collected from the Mölndal area as well as from the area of the 
case study, the following parameters were tested: 

 

6.1 Particle size analysis 
Particle size analysis was conducted using the method described in the ASTM method 
D, 1140-54, method for particle size analysis of soils. The sieving was carried out 
using an electric sieving machine, having stainless steel sieves with mesh width sizes 
4,760 mm, 2,0 mm, 1 mm, 0,05 mm, 0,025 mm, 0,0125 mm, and a residue of grains 

 35



<0.125 mm. The sieving results are reported as the mass percent of soil within the 
respective fractions (Borg G., 1985). 

6.2 Soil moisture content  
The moisture content of the soil samples was performed according to the ASTM test 
method D2216, method-determining moisture content for soils. Approximately 50 g 
of soil was taken and weighed in ceramic crucible. The soil was heated in oven at 105 
Co for 8 to 12 hours until constant weight. The soil was weighed again and mass loss 
in gram percent w/w was calculated (Borg G., 1985). 

6.3 Determination of mass loss of ignition 
Approximately 50 g of dried soil sample was taken in a ceramic crucible and was 
weighed carefully. It was heated in an electric furnace at 500 Co for 6 hours. The 
sample was cooled in desiccators and weighed. The mass loss in gram and percent 
was calculated (Borg G., 1985). 

6.4 Soil pH 
The pH of soil samples was analyzed using distilled water. For pH measurement 20 g 
of dry soil (< 2mm) was transferred in 200 ml plastic container. About 70 ml of 
distilled water was added in the container and the lid was screwed. The containers 
were places on a shaking table and shaked well for one hour. After one hour the 
containers were removed from the shaking table and left for few hours to settle sand 
grains. The pH was calculated putting directly the electrode of pH meter in to the 
container (McLean, E.O. 1987). 
‘ 

7 Procedures for the screening and analysis of organic 
contaminants in the soil 
The analysis procedures for the screening of organic contaminants in the soil samples 
were performed using photo ionization detector and wet chemistry analytical 
techniques, Immusoassay and PetroFlag system. A description of these analytical 
techniques is given below. 
 

7.1 Screening procedure with PID 
 
The screening of soil samples was performed with the Photovac 2020 PID. The 
specification of the instrument used are given in the Table 5. 
For the screening of soil samples in the field the EPA standard method 3815 
“Screening of solid samples for volatile organics” was followed with some 
modification. Method 3815 suggests the use of glass vials with about 5 g of sample 
but the quantity of the sample can be changed depending on the field conditions. In 
the environmental soil investigations, soil is normally put into diffusion tight plastic 
bags (Rilsan-bag). About 100-200 g of soil was taken and left with air in the bag 
(about the same volume in all bags), the bags were folded and swirrelled and tighten 
with plastic tape to control the emission of VOC. The Rilsan bag is almost completely 
diffusion tight for the volatiles. Readings were taken after 2-3 hours and after 24 

 36



hours. It should be interesting to find out correlations between time elapsed and 
diffusion through these bags. 

Table 5 Specifications of PID used in the project (web ref. 12). 

Model Photovac 2020 
Detector Instant on photo ionization detector with 

standard 10.6eV UV lamp 
Operating Temperature Range 0°C to 40°C ( 32°F to 105°F ) 

Operating Humidity Range 0 to 100% relative humidity (non-
condensing) 

Operating Concentration Range 0.5 ppm to 2000 ppm isobutylene 
equivalent 

Response Time Less than 3 seconds, to 90% 
 

Accuracy ± 10 % or ± 2 ppm, whichever is greater 
 

7.2 Analysis procedure with Immunoassay 
 
The analysis of soil samples to find the total petroleum hydrocarbon concentration 
(TPH) was performed using EPA standard method 4030 “Soil screening for petroleum 
hydrocarbons by Immunoassay”. 
The analyses were performed using Ensystm Petro Soil test kit, 7042301, produced by 
SDI (Strategic Diagnostic Inc) USA (web ref 13). The EnSys Petro Test System 
includes antibody-coated test tubes containing monoclonal antibodies, which are 
produced using m-xylene as the antigen. The enzyme conjugate used to produce color 
is composed of m-xylene as the target compound and horseradish peroxidase as the 
enzyme. The washing step is made with a dilute detergent solution. Color 
development is achieved using hydrogen peroxide as the substrate and 
tetramethylbenzidine (TMB) as the chromogen. The stop solution added to terminate 
color development is 0.5 percent sulfuric acid. A differential spectrophotometer that 
emits light in the visible range of the electromagnetic spectrum at 450-nm wavelength 
is used to measure the absorbance of the sample extract and of a reference standard 
containing 3 mg/L m-xylene during color measurement. The concentration of PHCs in 
the sample extract is then determined by comparing the absorbance readings 
associated with the sample extract and the reference standard. 
 The analysis consists of two parts; extraction of the analyte and assay procedure. 
 
7.2.1 Sample extraction 
All analysis of soil samples begins with an extraction step, where the contaminants 
are extracted by a solvent. The extraction of soil sample with the immunoassay 
method was done with the methanol. 20 g of the soil sample were collected in 
extraction container (plastic), and 20 ml of 100% methanol was added. The container 
was shaked well for one minute and then left for 3-4 minutes until a liquid solvent 
layer was observed. The upper layer containing the contaminant was separated using a 
bulb pipette. This extract was filtered by special filter supplied with the extraction kit. 
 

 37

http://www.photovac.com/


7.2.2 Assay procedure 
The samples obtained from the filtered extract were diluted using 140 µl and 540 µl 
of methanol. First dilution ampoule is to test the sample for 10 ppm and second 
dilution ampoule is the test the sample for 100 ppm. There was no intermediate 
dilution ampoule.60 µl of sample was applied in the first dilution ampoule (140 µl) 
and then same volume from first to second ampoule (540 µl). From each ampoule 60 
µl mixture of sample and dilution methanol was transferred to the corresponding 
conjugate tubes, which contain 1.25 ml of buffer solution. The schematic diagram of 
dilution process is shown in Figure 11.  
 
 

140µl 

Figure 11 Schematic diagram of dilut

 
After the dilution process, the antibody-coated tu
tubes and shaked 2/3 times. The conjugate tub
tubes were kept for ten minutes for the incubatio
the samples in the antibody tubes were vigorous
and tubes were washed with the wash solution. A
A” was applied in the tube followed by start so
2.5 minutes of the reaction 200 µl stop solution c
to stop the reaction. The color of the tubes were
differential photometer. The color produced
concentration.  

7.3 Analysis procedure with PetroFl

 
The PetroFLAG™ test kit, is a quantitative
Corporation (Dexsil®). It is based on emulsion 
using the PetroFLAG™ test kit involves the foll
filtration and emulsion development, and (3) turb
the TPH concentration. 
 

 

540µl
 
ion process for TPH kit. 

bes were fit firmly on the conjugate 
es were thrown away and antibody 
n. After the completion of incubation 
ly shaken out to the waste containers 
fter washing the 200 µl of “substrate 
lution labeled as “substrate B. After 
ontaining sulphuric acid was applied 
 interpreted visually as well as with 

 is inversely proportional to the 

ag system 

 device manufactured by Dexsil® 
turbidimetry. Measuring TPH in soil 
owing three steps: (1) extraction, (2) 
idity measurement and calculation of 

38



7.3.1 Extraction 
 
Extraction of 5-10 samples consists of following procedure: 
10 grams (± 0.1 gram) of the each soil sample was weighed, and placed in a 
polypropylene tube. To extend the quantification range for the samples containing 
very high concentration of PHCs 1g sample were analyzed. One breaktop vial of 
extraction solvent was poured into the tube, and the tube was caped. The timer was set 
to 5 minutes, and the tube was shaked for 15 seconds or until the sample is fully wet. 
Shaking was continued for the tube intermittently for a minimum of 4 minutes, and 
then let to stand for 1 minute.  

 
7.3.2 Filtration and emulsion development 
 
The solvent extraction from the polypropylene tube containing the soil and extraction 
solvent was poured into the syringe barrel. Care was taken to stop soil to enter the 
syringe, as too much soil might plug the filter. First a few drops of the extract from 
the filter were discard into a waste container, and then the extract was filtered into the 
vial containing developer solution. The extract was added into the vial one drop at a 
time until the meniscus just enters the vial neck. The vial was shaked for 10 seconds. 
Then the timer was set to 10 minutes, and the vial let to stand. During the 10-minute 
period, an emulsion associated with the hydrocarbons in the extract is developed.  
 
7.3.3 Turbidity measurement and calculation of TPH concentration 
 
After the 10-minute development period, the vial was placed in the turbidimeter, 
which was calibrated using a blank and a single calibration standard. The samples 
were analysed with the response factor of 10 (for mineral oil) and 5 (for diesel fuel). 
When the vial is placed in the turbidimeter, the TPH reading of the sample extract is 
displayed on the turbidimeter as mg/kg (ppm) TPH in soil on a wet weight basis. In 
certain circumstances, the water content of the soil and analyte carbon number range 
may require a correction factor to account for soil-water content (web ref. 8). To 
correct the TPH concentration in mg/kg, on a wet weight basis for solvent dilution 
associated with the moisture content of a given soil sample, the following formula is 
used  

“mg/kg TPH after correcting for solvent dilution = mg/kg TPH before correcting 
for solvent dilution x (100 + percent moisture)/100.” 

 

 39



Results and Discussion 
 
The experimental program consisted of two parts. The first part involved 
determination of properties of the soil samples, cylinder-unsaturated soil experiment 
and soil column leaching experiment. In the second part, environmental soil 
investigations at an old industrial site in Sweden were analyzed using the same 
analytical approaches that were used in the laboratory experiments. Brief description 
of the results of all experiment is given in following section. 
 

1 Selected parameters of soils 
 
Particle size analysis was performed to calculate hydrogeological properties of the 
soils being used in the project. Textural class of the soil is shown in figure 12. The 
values of hydraulic conductivity (K), and bulk density were calculated using a grain 
size distribution curve shown in Table 6. 
 

  

Table 6 Hydrogeological properties of the soil 
samples: 

Sand % 74,5 
Clay % 25 
Silt % 0,5 
Texture Sandy Clay Loam 
Bulk density 1,44g/cm3 
Hydraulic 
conductivity (K) 

0,37 cm/hr 

 

Figure 12 Textural class of the soil. 

 
Particle size plays an important role in the mobility and fate of organic contaminants 
in soil. Colloidal particles exhibit the largest sorption capacity, with a diameter of 10-6 
to 10-3 mm. High clay content results in the lower permeability of the soil, it allows 
the fluid to stay more in the vadose zone. This will cause complex bonding 
mechanism in the soil-oil-water mixture. The sorption capacity decreases with 
increasing size, and particles larger than 2 mm in diameter especially do not affect the 
soil sorption capacity  (J. Tölgyessy, 1993). 
One of the first operational parameters that were investigated in the laboratory 
experiments was the moisture content of the soil samples. Moisture content plays an 
important role in the efficiency and must be considered in the measurement of oil 
contents of soils. Water may cause oil-in-water emulsion that makes the extraction 
difficult, which ultimately makes the extraction efficiency low (O’Shay et al; 1994). 
The moisture content of the soil samples are given in Table 7. For all the samples 

 40



containing high moisture content (> 30%w/w for immunoassay and >15%w/w for 
PetroFlag), appropriate correction was applied for different analytical methods. 
The results of pH and loss of ignition are also given in Table 7. There is no significant 
influence of pH of soil on the detection efficiency of the analytical approaches 
applied.  However pH less than 4 affects the bonding mechanism of the hydrocarbons 
with the soil particles. With decreasing pH the adsorption process is increased and 
bioactivity is decreased. All the samples had pH in the range of 6-7. 
 

Table 7 Selected properties of soil samples. 

Sample No. Moisture content 
(w/w%) 

pH∗ Mass Loss of 
ignition (%) 

Lab. Ex1 8% 5,9 9% 
Field Samples    

1 10 6,67 1,17 
2 10,2 6,90 5,34 
3 26 6,44 7,56 
4 29,4 6,56 7,36 
5 20,8 6,50 10,35 
6 24,4 6,54 11,21 
7 6,8 6,93 1,71 
8 6,2 7,05 1,49 
9 13,8 6,76 3,9 

 
Mass loss of ignition was calculated to get an estimation of the organic contents 
present in the soil samples. The presence of calcium carbonate in the soil may 
somewhat affect the result due to slight decomposition of carbonate, thereby giving a 
larger mass loss than caused solely by the incineration of the organic remains. 
Furthermore, with a high content of clay minerals in the soil, there may also be a 
slight decrease in mass due to loss of chemically bound water in the clay minerals, but 
with negligible significance (Swedish EPA report 4639). 

2 Response of photoionization detector (PID) for the soil 
samples 
Photoionization detector is basically used for the air monitoring operations, as it gives 
the real time values. Use of this analytical method for screening of soils is a new 
approach. The preliminary objective of this screening is to check the volatile content 
of the soil samples. The results of PID for the laboratory experiments as well as of 
environmental soil investigations of old industrial site are given below. 
 

2.1 Cylinder – unsaturated 
 
The results of the experiment are given in Figure 13 and Table 8. The values were 
measured with both glass jar (250ml) and Rilsan bags. The concentration of the 
volatiles is higher for the sample No. 2, 3, 4 and 5 for depth ranging from 10 cm to 25 
cm. The spiked value for the 12% solution in this experiment was 1000 ppm. The 
cutting fluid was added on the surface of the soil column in the glass cylinder. In the 
upper layer low result show the evaporation of the volatile content with time but its  

 41



Cylinder-unsaturated  PID Results 

0
50

100
150
200
250
300
350
400

0-5cm 5-10cm 10-15cm 15-20cm 20-25cm 25-35cm

Depth

C
on

ce
nt

ra
tio

n 
(p

pm
)

PID Response with riisan
bags
PID Response Glass Jar

 
Figure 13 PID response for the soil samples of cylinder-unsaturated 

Table 8 PID Values of volatile contents at different depths 

Sample 
No Depth BkGd 

Sample 
(glass jar)

Sample 
(Rils.Bags) 

1 0-5cm 5.5 15 37,2 
2 5-10cm 4.5 347 146 
3 10-15cm 0.1 286 102 
4 15-20cm 0.0 101 141 
5 20-25cm 0.0 79 107 
6 25-35cm 0.0 19,3 49,8 

 
presence at lower depth shows movement of the cutting fluid in unsaturated soils. The 
movement of hydrocarbons in this case can be partially related to the sorption 
(adsorption and absorption) of organic contaminants with soil particles. However in 
the unsaturated soil at room temperature the volatilization rate is very high as 
compared to the saturated conditions that result in lower volatile content values by 
PID. 
The relative higher values for the samples with glass jars are due to the small air 
volume in it. The PID suction capacity is about 300 ml/min, it consumes all the air 
readily, and as a result a sharp response curve is seen and then suddenly nothing. On 
the other hand Rilsan bags have a larger volume of air, but the response curve is not 
as sharp as with the glass jar. The results with rilsan bags are more reliable because of 
their larger volume, as the instrument has more time to reach the average of values it 
has calculated in a specific span of time.  
 

2.2 PID results of soil-column leaching experiment  
 
The results of soil column leaching experiment are shown in the Figure 14. The soil 
used for this project contains about 65 ppm of background value. Background value is 
obtained by the analysis of blank sample from the same sampling site. All the samples 
show relatively higher values of volatile content. For the samples 2, 4 and 5 the PID 
response is almost equal to the spiked value. Which shows the high mobility of 
cutting fluids in the saturated media. Moreover higher response of photoionization 
dete