Human health risk assessment for intake of root vegetables grown in DDT-contaminated soils
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Infrastructure and environmental engineering (MPIEE), MSc
Publicerad
2024
Författare
Galindo Fernández, Ginés Inocencio
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This thesis has evaluated the SEPA model that determines the acceptable concentration of
DDT in the soil, Cig, for private individuals to grow vegetables in the DDT-contaminated soil.
DDT was considered in this thesis because it was used extensively in plant nurseries in Sweden
in the decades of the 60s and early 70s, and since then, some of this terrain has been sold to
individuals and converted to family homes with gardens where it is possible to grow
vegetables for self-consumption. To evaluate the model, a sensitivity analysis was performed
to find the most sensitive parameters of the model, a systematic literature review following
the PRISMA statement was completed to find bibliographic sources with data on the sensitive
parameters. Using this data, statistical distributions were calculated using @RISK to replace
the point values used for the sensitive parameters in the SEPA model, and with them a
probabilistic distribution for Cig was obtained. To evaluate how human behaviour and
characteristics affect the exposure risk, different exposure scenarios were developed based on
different behaviours. The probabilistic model was compared to an experimental study
measuring the uptake of DDT in potatoes. Furthermore, the uptake of DDT in potatoes was
compared with the uptake of DDT in radishes presents in another experimental study.
This thesis found that the SEPA model calculates a higher exposure risk (lower Cig value) than
the probabilistic model the default scenario. The scenario analysis logically confirms that the
higher the intake of plants the higher the risk; the SEPA model is a good predictor for the
uptake of DDT in potatoes. However, the DDT uptake in radishes is higher than its uptake in
potatoes, so the risk of consuming radishes grown in the DDT-contaminated soil likely will be
higher than for consuming potatoes grown in the same soil. There is a lack of experimental
values for the sensitive parameters available in the searched literature databases. The
correction factor between root lipids and octanol, broot, which is the most sensitive parameter
of the uptake model had no information available in the literature and should be studied
experimentally at more depth.