Ecological risk assessment for a contaminated sites with p,p'-DDT and its metabolites

Dichlorodiphenyltrichloroethane (DDT) is a persistent pollutant that can still be observed in significant amounts in the lands where it was applied in the past and in agricultural products grown on these soils, even though its use as a pesticide is prohibited. This thesis is an ecological risk assessment study aiming to predict the ecological risks that may be caused by agricultural soils contaminated with DDT and its metabolites (DDX). The study was carried out by focusing on agricultural land soils in Sakarya province, where a significant amount of agricultural production activities are still carried out. The pollutant concentrations in the aforementioned soils evaluated in the study are the results of DDX analyzes of 53 soil samples (94 – 2,608 ng DDX/gr dry soil) obtained after a vegetable production carried out in 2 different ways as in-situ and ex-situ. Using these analysis results, firstly, 14 different mammals (short-tailed shrew, meadow vole, white-footed mouse, eastern cottontail, red fox, white-tailed deer, Canadian lynx, masked shrew, snowshoe hare, woodland caribou, black- tailed prairie dog, white-tailed prairie dog, opossum, and raccoon) and 10 different bird species (American robin, American woodcock, wild turkey, red-tailed hawk, short-eared owl, spruce grouse, Canadian goose, stilt sandpiper, sandpiper and semipalmated sandpiper), DDX uptakes that could occur as a result of oral exposure to the soil in question were calculated.These calculated probable soil ingestions were adapted to scenarios organized with a stochastic approach based on a Monte Carlo simulation configured specifically for this study. On the other hand, the findings point to a significant risk of reproductive toxicity for both birds and mammals. As a consequence of these simulations, risk assesments of probable acute toxicity and reproductive toxicity were calculated. It should be necessarily taken into account that, different ways of exposure to polluted soils other than eating and consumption of agricultural products grown in the relevant regions were not taken into account in the calculations made in the study. Based on these findings, it is recommended that risk assessment studies and legal restrictions applied only in terms of human health should be taken into account for other living species too and the researches should be expanded.