Health Risk Assessment of Pesticides in Drinking Water in South Africa - A case study on Piketberg and Withoogte drinking water treatment plants along Berg River applying QCRA
Typ
Examensarbete för masterexamen
Program
Infrastructure and environmental engineering (MPIEE), MSc
Publicerad
2022
Författare
Pettersson, Malin
Engman, Mia
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Pesticides are applied to a broad extent within the South African agricultural sector.
The sector lack clear regulations regarding the amount applied or which pesticides
are legally permitted to use. Exposure to pesticides has been recognized as one of the
main chemical threats to human health globally. Watercourses are often surrounded
by agricultural land and the spread of pesticides from these lands poses a risk to the
aquatic environment. Berg River is a watercourse located in an agricultural area
in the Western Cape, South Africa. The river is used as raw water source for the
two drinking water treatment plants, DWTPs, Piketberg and Withoogte. Hence,
pesticides may pose a risk to the quality of the drinking water. Consequently, this
thesis aims to investigate if long-term exposure to pesticides in drinking water poses
a human health risk.
A quantitative chemical risk assessment, QCRA, was conducted to evaluate the
health risk. The pesticides atrazine, imidacloprid and simazine were analysed for
different population groups; infants, children and adults, and three different scenarios
in the DWTPs. These scenarios included normal operation, lack of treatment
and normal operation with the addition of a granular activated carbon filter, GACfilter.
Field studies were conducted at both DWTPs where raw water and drinking
water samples were collected. The remaining input for the QCRA-model was compiled
through a literature study. A sensitivity analysis was performed to evaluate
which input affected the result the most.
There were detectable levels of all studied pesticides in the raw water and the drinking
water. However, the study concluded that there is no human health risk for
long-term consumption of drinking water from Piketberg DWTP and Withoogte
DWTP for any of the scenarios. Infants that are formula-fed was the population
group that was prone to the highest health risk when exposed to simazine. Adding
a GAC-filter resulted in lower concentrations of pesticides in drinking water.
Beskrivning
Ämne/nyckelord
QCRA , Pesticides , Atrazine , Imidacloprid , Simazine , Berg River , Piketberg , Withoogte , South Africa , Sensitivity analysis , Health risks , Water treatment