Model ecosystem studies of the environmental fate of six organochlorine pesticides.

Despite more than 20 years of intensive use there are major uncertainties about the environmental distribution and degradative fate of the various organochlorine pesticides in food web organisms. The problem is both controversial and momentous, as 88,641,000 pounds of cyclodienes and toxaphene and 59,316,000 pounds of DDT were produced in the United States in 1970 (1). The laboratory model ecosystem devised in this laboratory (2) has been used to estimate the comparative environmental properties of DDT, methoxychlor, and other DDT analogs (3-5). These investigations have demonstrated environmental degradative pathways and have provided quantitative data on ecological magnification and biodegradability index (6). This paper presents data on six additional organochlorine pesticides which should be of value in judging their overall effects on environmental quality. Furthermore, the data provide a realistic background of the environmental toxicology of standard substances against which screening data for new candidate pesticides can be weighed.