Toxaphene in the United States: 2. Emissions and residues

Emission factors of toxaphene for spraying and tilling events are distributed for the United States on a 1°×1° latitude and longitude grid system. By using the gridded usage and emission factors, inventories of gridded toxaphene emissions and residues in agricultural soil in the United States with 1/6°×1/4° latitude and longitude resolution have been created. Total toxaphene emissions were around 190 kt between 1947 and 1999. At the beginning of 2000, almost 20 years after banning the use of toxaphene, there were still around 29 kt of toxaphene left in the agricultural soil, of which 360 t will emit to the air in 2000. The calculated toxaphene emissions and residues are in general consistent with published monitoring data. The trends of toxaphene emissions due to current use and residues in agricultural soil in the United States match both the historical atmospheric input function for toxaphene extending over the past 40 years derived from the composition of toxaphene in peat core from eastern Minnesota to Nova Scotia, and the trends of air concentration of toxaphene in the Arctic. This indicates that toxaphene residues in the United States agricultural soil could be a major source of toxaphene in the Canadian Arctic and the Great Lakes region.