Long range transport of toxaphene insecticide in the atmosphere of the western North Atlantic

Abstract

OVER the past ten years toxaphene has been used in the USA in larger quantities than any other insecticide, with an estimated consumption of 58 million pounds per year (ref. 1). In spite of this widespread use, the composition of toxaphene remains largely undetermined, and recent work indicates that the technical product contains nearly 200 polychlorinated camphenes². Because of the difficulties in analysing such a complex mixture, little is known about the dissipation of toxaphene in the environment. Residues in soils may persist for years, with volatilisation suggested as a major loss mechanism³. Toxaphene has been identified, however, in US air samples in only three locations⁴, all in southern agricultural areas, at levels of 16–2,520 ng m⁻³. The ability of high molecular weight chlorinated hydrocarbons to be transported long distances through the atmosphere has been well established within the past decade. Polychlorinated biphenyls (PCBs)^5,6, and the chlorinated pesticides DDT^6–9, dieldrin^7,9, and chlordane⁶ have been identified in the air over the western North Atlantic. We now report that toxaphene is also carried through the atmosphere at least 1,200km out to sea.