Modelling Behaviour of Pollutants in Soil for Risk Assessment Purposes

Abstract

Once a chemical has been released on soil surface (due to accidental leakage or agricultural exposure) it may be subjected to a great number of processes, most of them resulting in the spreading of the pollutant in the environment and in different kinds of human exposure. Human health may be affected by soil pollution via inhalation or ingestion of contaminated dust transported in air, via consumption of water coming from sources sited within contaminated areas, as well as via consumption of vegetables grown on contaminated soils. These ways of exposure, together with the transport processes leading to them, are shown in Figure 7.1. As it can be deduced from this figure, the evaluation of risk for humans requires the quantitative evaluation of the rate at which each process will occur. For instance, the evaluation of dietary exposure requires estimation of leaching and plant uptake rates, estimation of the contamination of the food chain and drinking water, as well as the evaluation of the rate of consumption of contaminated food and water. Thus, the evaluation of the overall risk deriving from soil pollution is a very difficult task to deal with, and screening of the process most likely to occur in different situations is necessary. In fact, a pollutant may be subject to very different processes in the same soil under different meteorological conditions.