Separation of polychlorobiphenyls from chlorinated pesticides in sediment and oyster samples for analysis by gas chromatography.

Polychlorobiphenyls (PCBs) have been separated from DDT and its analogs and from the other common chlorinated pesticides by adsorption chromatography on columns of alumina and charcoal. Elution from alumina columns with increasing fractional amounts of hexane first isolates dieldrin and heptachlor epoxide from a mixture of chlorinated pesticides and PCBs. The remaining fraction, when added to a charcoal column, can be separated into two fractions, one containing the chlorinated pesticides, the other containing the PCBs, by eluting with acetone-diethyl ether (25:75) and benzene, respectively. The PCBs and the pesticides are then determined by gas chromatography on the separate column eluates without cross interference. The method is applicable to sample extracts prepared for gas chromatography. Recoveries of the PCBs (Aroclors) and the chlorinated pesticides are good and the method is applicable to sediment and marine biota samples.

Mirex residues in wildlife and soils, Hawaiian pineapple-growing areas--1972-74.

A monitoring program was conducted in the pineapple-growing areas of Hawaii from 1972 to 1974 to survey mirex residues in sediments, soils, and aquatic and terrestrial wildlife. Residues in pineapple field soils ranged from 3 to 18 ppb 9 months after mirex had been applied. No residues were found in the sediments. Only 8 fish of 110 aquatic animals sampled contained mirex; these levels were low and ranged from 3 to 7 ppb. Mirex residues in birds ranged from undetectable to 10 ppm; residues in rodents were quite variable, but in terms of the geometric mean, the amounts in the Polynesian rat decreased with time from 1,270 to 56 ppb. Similarly, values for the roof rat ranged from 666 to 17 ppb. The geometric mean for residues in mongooses decreased from 2,200 ppb immediately after application to 238 ppb 39 weeks later. Aerial application of mirex to the pineapple fields did not contaminate the marine environment of Hawaii and no evidence of mirex residue buildup in the aquatic food chain was apparent. Mirex accumulation in terrestrial biota was temporary; there was no definitive indication of permanent accumulation in the wildlife of the areas studied.