Modeling global emissions and residues of pesticides
A major portion of persistent organic pollutants (POPs) is organochlorine pesticides (OCPs), in which carbon and chlorine are combined. During the last decade, a number of researches have been devoted to create emission inventories of OCPs at regional and global scales. The studies on residue inventories of OCPs, however, are sparse. In the absence of complete data and information on worldwide inventories of pesticides emissions and residues, a Simplified Gridded Pesticide Emission and Residue Model (SGPERM) has been developed to estimate the emissions and residues, and build pesticide emission and residue inventories. The SGPERM is an integration of a mathematical module, a relational database system, and a geographic information system. In this paper, a complete description of the model is given. A brief review of the models application in developing emission inventories for -HCH is introduced. The model is used to create global gridded residue inventories of -HCH on cropland with a 1° latitude by 1° longitude resolution for 1980, 1990, and 2000, the first such residue inventories for any pesticide. The total global residues of -HCH on cropland were 198 kt in 1980, 35 kt in 1990, and 1.2 kt in 2000, and the emissions from these residues were 11.8 kt in 1980, 2.3 kt in 1990, and 0.15 kt in 2000. Historical trends of -HCH concentration in agricultural soil are also estimated at some locations in China and Japan, and match the monitoring data quite well.