Chlordane transport

Chlordane degrades in air by both photolysis and oxidation, trans- Chlordane photochemically degrades more readily than the cis isomer. This is indicated from the fact that the trans/cis ratio of chlordane transported long distances to the Norwegian Arctic changes from around 1 in the winter to 0.5 in the summer (Oehme 1991). Many papers have been published that detail the photoproducts of chlordane (principally cis- chlordane) and mechanisms of photoproduct formation (Feroz et al. 1981 Ivie et al. 1972 Onuska and Comba 1975 Parlar and Korte 1973, 1977, 1979,... 

Chlordanes and their metabolites are ubiquitous in the environment at low concentrations, but at a high occurrence in samples analyzed. Atmospheric transport is considered to be the major route of global dissemination. Some chlordane isomers persist in soils for 3 to 15 years, although there seems to be little accumulation of chlordanes by crop plants grown in these soils. Lengthy persistence of various chlordane isomers, especially m-chlordane and trans-nonachlor, has been reported in certain organisms, but this has varied greatly between species and tissues. 

Atmospheric transport may be the main source of chlordane in Finland — a country that prohibits chlordane use — because chlordanes are distributed evenly in the Finnish environment (Pyysalo et al. 1983). No chlordane compounds were detected in rainbow trout (Oncorhynchus... 

Past chlordane use, coupled with atmospheric transport as the major route of dissemination, produced global contamination of fish and wildlife resources and human populations. The chemical and its metabolites were frequently detected in all species examined, but usually at low concentrations. Residues in fish muscle sometimes exceeded the U.S. Food and Drug Administration action level of 0.3 mg/kg fresh weight recommended for human health protection. In general, chlordane in animals is highest near areas where the chemical has been applied to control termites concentrations are highest in fat and liver, especially in predatory species. 

Cyclodiene pesticides, of which endrin and its oxidized analogs are representative, can also be estimated by receptor-assay technique. Cyclodiene pesticides exert their mode of action by altering central nervous system membrane ion transport. In work reported by Saleh et al. (1993), a labeled amino acid, GABA, that binds to the chloride channel receptor is displaced by endrin (and other similar molecules), and thus serves as an assay for these pesticides. The GABA receptor was shown to be a potentially useful biomarker for organochlorine pesticides such as lindane, toxaphene, endrin, chlordane, and others. The assay involves small quantities of blood (0.1 mL), and requires only that the plasma be separated from the... 

Historically, less attention has been paid to atmospheric deposition to connecting channels and tributary rivers of the Great Lakes, mainly because of the smaller surface areas presented by rivers for direct atmospheric deposition, compared with deposition and transport to rivers from their watersheds. The atmospheric deposition of chlordanes and HCHs to the St. Lawrence River ranged from < 1 kg/yr for a-chlordane to 5 kg/yr for a- and y-HCHs these loadings represented < 1 to 14% of the atmospheric deposition to the watershed [58]. 

While studying the global fate and transport of POPs, Iwata et al. (1993) measured POPs in the atmosphere over the South China Sea and the East Sea and detected HCH, chlordane, DDTs, and PCBs. The concentrations of EDDTs in the East and South China Sea were 2.9 43 and 7.8-140pgm-3, higher than the concentrations measured in the Bering Strait, North Atlantic, and the East Indian Ocean, while close to those measured in the Mediterranean Sea, Red Sea, and Mexico Bay andlower than those measured in the Strait of Malacca and Bengal Bay (Iwata et al., 1993). 

The potential for OC pesticide enantiomers to be used for air-surface source apportionment was first suggested by Finizio, Bidleman, and Szeto [167], who found an air concentration gradient with the same enantiomer composition (EFs of 0.54 to 0.57 for a-HCH and 0.59 for heptachlor epoxide) up to 1.4 m above British Columbia agricultural soils with the same EFs (Figure 4.16). The subsequent measurements of nonracemic a- HCH, c/i-chlordane, and trara-chlordane in these soils [146] indicated that local and regional air burdens of these pesticides were influenced more by agricultural emissions than by trans-Pacific transport from China and India where these compounds are still... 

Chlordane compounds were detected in the blubbers of Weddel seals caught near to the Syowa Station (75). Sampling, dissection and pretreatment were all conducted so as to prevent any possible contamination from chlorinated hydrocarbons, e.g., by washing the electric devices, knives, polyethylene bags and other materials with high purity acetone. Quantification was performed by GC-MS and values of 12-62 ng g were ascertained. Airborne transport can probably account for the presence of these substances in Antarctica. 

Chlordane may be transported long distances in the atmosphere. The United States appears to be the main source of chlordane in the air over the North Atlantic (Bidelman et al. 1987). 

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