Mammals chlordane

A number of other chemicals suspected of having endocrine disrupting potential also occur at high levels in the tissues of marine mammals. For example, tribiityltin compounds are present in the tissues of the Steller sea lion (Eumetopias juhatus) from Hokaido, Japan, and in stranded bottlenose dolphins (Tursiops truncatus) found along the US Atlantic and Gulf coasts.Additional chemicals detected include PAHs, toxaphene and chlordane. ... 

Chlordane is readily absorbed by warm-blooded animals through skin, diet, and inhalation. It is quickly distributed in the body and tends to concentrate in liver and fat (WHO 1984). Up to 75% of a single oral dose of chlordane administered to rats and mice was absorbed in the gut, and up to 76% of an aerosol dose was absorbed in the respiratory tract (Nomeir and Hajjar 1987). Rabbits absorbed 33% in the gut following oral administration (USEPA 1988). Chlordane residues in mammals were usually not measurable 4 to 8 weeks after cessation of exposure (Ingle 1965). Chlordane persistence in human serum and whole body was estimated at 88 days and 21 days, respectively this compares to a Tb 1/2 of about 23 days in rats fed chlordane for 56 days (USEPA 1980). 

Metabolism of chlordanes and nonachlors to oxychlordane is orders of magnitude greater in fisheating and carnivorous birds than in marine mammals (Kawano et al. 1988). The reasons for this are unclear and merit further research. 

Concern for the continued widespread use of chlordane centers on its ability to cause liver cancer in domestic mice. Other adverse effects in mammals, such as elevated tissue residues and growth inhibition, were frequently associated with diets containing between 0.76 and 5.0 mg chlordane/kg feed. Metabolism of technical chlordane by mammals results primarily in oxychlordane, a metabolite that is about 20 times more toxic than the parent compound and the most persistent metabolite stored in adipose tissues. Chlordane interactions with other agricultural chemicals produced significant biological effects in warm-blooded organisms, indicating a need for additional research on this subject. 

Acute oral LD50 values for technical chlordane and sensitive mammals usually ranged between 25 and 50 mg/kg BW (Table 13.5). Chlordane-related compounds (i.e., d.v-chlordanc, trans-cblo-rdane, heptachlor, heptachlor epoxide) stimulate superoxide (()2 generation in guinea pig leukocytes,... 

Negative results for mutagenicity of d.v-chlordanc and tran.v-chlordanc were reported in various strains of bacteria and in hepatocyte cultures of small mammals. But technical chlordane proved mutagenic to selected strains of Salmonella typhimurium and induced gene conversions in certain strains of the yeast, Saccharomyces cervisiae (IARC 1979 USEPA 1980, 1988 WHO 1984). 

Table 13.5 (continued) Chlordane Effects on Selected Mammals... 

Chlordane is readily absorbed by warm-blooded animals via skin, diet, and inhalation, and distributed throughout the body. In general, residues of chlordane and its metabolites are not measurable in tissues 4 to 8 weeks after exposure, although metabolism rates varied significantly between species. Food chain biomagnification is usually low, except in some marine mammals. In most mammals, the metabolite oxychlordane has proven much more toxic and persistent than the parent chemical. 

Many species of aquatic organisms are adversely affected at concentrations in water between 0.2 and 3.0 pg/L technical chlordane. Sensitive bird species had reduced survival on diets containing 1.5 mg chlordane per kilogram ration, or after a single oral dose as low as 14.1 mg chlordane per kilogram body weight. Chlordane has produced liver cancer in laboratory strains of domestic mice, but carcinogenicity has not been established in other mammals. 

Chlordane criteria for protection of marine life (0.004 pg/L, 24-h mean not to exceed 0.09 pg/L) appear satisfactory. Proposed criteria for freshwater life protection (0.0043 pg/L, 24-h mean not to exceed 2.4 pg/L), however, overlap the range of 0.2 to 3.0 pg/L shown to adversely affect certain fish and aquatic invertebrates, suggesting that some downward modification in the maximum permissible level is needed. Chlordane criteria for protection of birds and mammals are inadequate because the database is incomplete. Until these data become available, a reasonable substitute is the criteria proposed for human health protection — namely, daily intake not to exceed 0.001 mg chlordane per kilogram body weight, and diet not to exceed 0.3 mg chlordane per kilogram fresh weight. 

Kannan, K., J. Falandysz, N. Yamashita, S. Tanabe, and R. Tatasukawa. 1992. Temporal trends of organochlorine concentrations in cod-liver oil from the southern Baltic proper, 1971-1989. Mar. Pollut. Bull. 24 358-363. Kawano, M., T. Inoue, T. Wada, H. Hidaka, and R. Tatasukawa. 1988. Bioconcentration and residue patterns of chlordane compounds in marine animals invertebrates, fish, mammals, and seabirds. Environ. Sci. Technol. 22 792-797. 

Figure 6. Simplified scheme of metabolic pathways of cis-chlordane in fish (Route A), desaturation and epoxidation and (Route B), hydroxylations. Both routes are operative in cichlids (as in mammals). Goldfish and bluegills seem to...

Environmental. The high lipophilicity of the cydodienes and the prolonged persistence of dieldrin and heptachlor epoxide (soil half-lives 2—10 yr) have resulted in severe environmental contamination. These compounds are bioaccumulated from water to fish up to 100,000- to 300,000-fold and are ubiquitous in human fat and milk. Oxychlordane [26880-48-8], mirex, and chlordecone are also bioaccumulative. The cydodienes are extremely toxic to fish with LC5Qs (ppm) to trout and bluegill of endrin, 0.001-0.002 endosulfan, 0.001-0.003 diddrin, 0.003-0.015 aldrin, 0.006-0.01 heptachlor, 0.03-0.026 and chlordane, 0.022—0.095. The LD5Qs to pheasant and mallard are aldrin 16.8 and 520, dieldrin 79 and 381, and endrin 1.6 and 5.6 mg/kg. As indicated by their rat oral LD - s, they are also extremdy toxic to small mammals in fact, endrin has been used as a rodenticide (see Pesticides). Compounds, eg, aldrin and heptachlor, which have unsubstituted double bonds, readily add oxygen to form epoxides in plant and animal tissues and are preferentially concentrated and stored in animal fats. Aldrin epoxide (dieldrin) and heptachlor epoxide are more stable (half-lives on alfalfa of seven to eight days) than aldrin and heptachlor (half-lives on alfalfa of less than one day). 

The government has been measuring PCB, HCB, DDT, chlordane, heptachlor epoxide and dieldrin since 1998 to identify their effects on wildlife as part of the Environmental Survey on Endocrine Disruptors. The specimens taken include land animals such as raccoons, bears, monkeys and frog, and marine mammals such as seals and whales, in addition to domestic birds and birds of prey. A relatively high concentration of POPs was seen in birds of prey and Phalacrocorax carbo. Eggs of mountain hawk eagles were also found to have a higher concentration of PCB, DDT, heptachlor epoxide, chlordane and dieldrin than other wildlife specimens... 

Chlordane was introduced as an insecticide in 1945 and was the first cyclodiene insecticide that was used in agriculture (Eisler, 1990). It was the second most important organochlorine pesticide after toxaphene from 1976 to 1977 (Stansley Roscoe, 1999). It has been used on agricultural crops and extensively in the control of termites (Smith, 1991). Chlordane and heptachlor can be metabolized into two persistent (oxygenated) epoxides—oxychlordane and heptachlor epoxide—in mammals (Nomeir Hajjar, 1987) such that the two compounds are always measured together with chlordane and heptachlor. 

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