Chapter 1 - An Introduction to Modelling of Pollutants in the Environment

Abstract

This chapter discusses where a pollutant, such as fertilizer or herbicide, once introduced into the environment would end up. When any chemical is released into the air or water or sprayed on the ground, it ultimately appears in all parts of the environment, such as the upper and lower atmosphere; lakes, oceans, and soil; and all animal and vegetable matter. To predict the concentrations of a chemical species in various regions of a given environment, it is necessary to know the size of each region. These regions or compartments include the atmosphere (air), water (rivers and lakes), soil, river and lake sediments, fish (aquatic biota), and plant material (terrestrial biota). The chapter describes a flow model that takes into account both the flow of a chemical into and out of the environmental region and the degradation and formation of the chemical within the region. The model assumes that there is phase equilibrium among the environmental regions and that it is based on the mass balance. Experimental analysis of chemicals in animals has shown that in some cases, the concentration of chemicals increases as the position of the animal in the food chain increases. This process is known as biomagnification and appears to be a function of the magnitude of the octanol–water partition coefficient (KOW) of the chemical species involved.