Organochlorine pesticides in ambient air in Durban, South Africa.

Despite the existence of numerous sources and continuing use, information regarding emissions and airborne concentrations of organochlorine pesticides in Africa is extremely limited. This paper presents results of a monitoring program conducted in Durban, South Africa that was designed to characterize levels, trends and possible sources of pesticides in both industrial and residential areas. Three monitoring sites were established, two in an industrialized area in the southern part of the city, and the third in a northern residential area. Particulate and vapor samples were sampled over the 2004-5 period and analyzed by GC/MS to estimate long-term levels of a wide range of pesticides. Based on a year of sampling, the sites had comparable levels of many pesticides with exceptions of alpha-chlordane and lindane. Levels of p,p'-DDT (42+/-27 pg m(-3)) and its derivatives were relatively high and showed an unusual mixture with high levels of p,p'-DDD (12+/-11 pg m(-3)). Other pesticides detected and quantified included aldrin, chlordanes, hexachlorobenzene and dieldrin. Potential source areas, identified using concentration patterns, local and regional gradients, compositional information and trajectory analyses, suggest that chlordane and lindane arise from both local sources as well as regional/global sources; DDT from regional sources elsewhere in South Africa, Africa and India; and most of the other long-lived pesticides detected, including gamma-nonachlor, hexachlorobenzene and toxaphene, from global sources. This monitoring results, which represent the most detailed study to date of pesticides in air in Africa, serve several purposes, including documenting the presence and use of long-banned pesticides like aldrin, aiding the understanding of the fate of persistent compounds, identifying pollutants that may contribute to health problems, and informing decision-making aimed at reducing exposures and risks.

Comparisons of PBDE composition and concentration in fish collected from the Detroit River, MI and Des Plaines River, IL.

Polybrominated diphenyl ethers (PBDEs) were identified in fish collected from the Detroit River, MI and Des Plaines Rivers, IL. In the Detroit River fish, carp and large mouth bass, the congener patterns were dominated by the 2,2',4,4'-tetrabromo (BDE-47) congener, however, in Des Plaines River carp the dominant isomers were the heptabromo congeners BDE-181 and BDE-183 and lesser amounts of another heptabromo congener, BDE-190, and two hexabromo congeners, BDE-154 and BDE-153. Three possible sources exist for these less-commonly identified PBDE congeners: (a) waste discharge from manufacturing or discarded products near the river, (b) public owned treatment work (POTW) effluents which constitute more than 75% of the flow in the Des Plaines River, (c) or formation of these congeners by debromination of in-place deposits of decabromodiphenyl ether. Average concentration totals (sum of concentrations for seven of the dominant PBDE congeners) were similar on a wet weight bases for the carp (5.39 ng/g wet weight) and large mouth bass (5.25 ng/g) in the Detroit River samples; however, the bass were significantly higher, p = 0.01, when compared on a lipid basis (bass--163 ng/g vs. carp--40.5 ng/g lipid weight). Some of the PBDE congeners were positively correlated with increasing lipid levels in both fish species. Average total PBDE concentrations in the carp from the Des Plaines River (12.48 ng/g wet weight) were significantly higher, p = 0.01, than in carp from the Detroit River. The residues were isolated using standard organochlorine methods for fish and analyzed using gas chromatography/mass spectrometry-negative chemical ionization methods.

Trends of chlorinated organic contaminants in great lakes trout and walleye from 1970 to 1998.

Levels of chlorinated organic contaminants in predator fish have been monitored annually in each of the Great Lakes since the 1970s. This article updates earlier reports with data from 1991 to 1998 for lake trout (Salvelinus namaycush) and (Lake Erie only) walleye (Sander vitreus) to provide a record that now extends nearly 30 years. Whole fish were analyzed for a number of industrial contaminants and pesticides, including polychlorinated biphenyls (PCBs), dichloro-diphenyl-trichloroethane (DDT), dieldrin, toxaphene, and mirex, and contaminant trends were quantified using multicompartment models. As in the past, fish from Lakes Michigan, Ontario, and Huron have the highest levels of PCBs, DDT, and dieldrin; Superior has the highest levels of toxaphene; and Ontario has the highest levels of mirex. In the period after curtailment of chemical use, concentrations rapidly decreased, represented by relatively short half-lives from approximately 1 to 9 years. Although trends depend on both the contaminant and the lake, in many cases the rate of decline has been decreasing, and concentrations are gradually approaching an irreducible concentration. For dioxin-like PCBs, levels have not been decreasing during the most recent 5-year period (1994 to 1998). In some cases, the year-to-year variation in contaminant levels is large, mainly because of food-web dynamics. Although this variation sometimes obscures long-term trends, the general pattern of a rapid decrease followed by slowing or leveling-off of the downward trend seems consistent across the Great Lakes, and future improvements of the magnitude seen in the 1970s and early 1980s likely will take much longer.