Chlordane birds

In birds, chlordane is only moderately to slightly toxic. The LD50 in bobwhite quail is 83 mg kg The... 

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. 

Although technical chlordane is a mixture of compounds, two metabolites — heptachlor epoxide and oxychlordane — can kill birds when administered through the diet (Blus et al. 1983). These two metabolites originate from biological and physical breakdown of chlordanes in the environment, or from metabolism after ingestion. Heptachlor can result from breakdown of cis- and trans-chlordane, eventually oxidizing to heptachlor epoxide oxychlordane can result from the breakdown of heptachlor, m-chlordane, tra .s-chlordane, or fram-nonachlor (Blus et al. 1983). Heptachlor epoxide has been identified in soil, crops, and aquatic biota, but its presence is usually associated with the use of heptachlor, not technical chlordane — which also contains some heptachlor (NRCC 1975). Various components in technical chlordane may inhibit the formation of heptachlor epoxide or accelerate the decomposition of the epoxide, but the actual mechanisms are unclear (NRCC 1975). 

Chlordane-induced mortality of the long-billed curlew (Numenius americanus) has been documented at least four times since 1978, despite restriction of technical chlordane use since 1980 to subterranean applications for termite control (Blus et al. 1985). Death of these curlews was probably due to over-winter accumulations of oxychlordane of 1.5 to 5.0 mg/kg brain FW and of heptachlor epoxide at 3.4 to 8.3 mg/kg — joint lethal ranges for oxychlordane and heptachlor epoxide in experimental birds — compared to 6 mg/kg brain for oxychlordane alone and 9 mg/kg for heptachlor epoxide alone (Blus et al. 1985). Additional research is needed on toxic interactions of chlordane components with each other and with other chemicals in the same environment. 

Reproductive impairment was reported in several species of waterfowl from a marsh treated with 1.12 kg technical chlordane/ha (Table 13.4). Studies by Lundholm (1988) with two species of ducks (Anas spp.) and the domestic chicken (Gallus sp.) demonstrated that various organochlorine compounds, including chlordane, interfered (in a dose-dependent manner) with reproduction by reducing the binding of progesterone to its cytoplasmic receptor in the shell gland mucosa of birds, especially ducks. 

The lethal effect of technical chlordane in birds is attributed primarily to chlordane metabolites, especially oxychlordane and, to a lesser extent, heptachlor epoxide (Shekel et al. 1983). Oxychlor-dane was the most persistent chlordane component in avian brain tissues. The half-time persistence of oxychlordane in brain was 63 days, and 95% loss was estimated in 280 days. The Tb 1/2 for heptachlor epoxide was 29 days, and for /ran.v-nonachlor it was 19 days (Shekel et al. 1979). Oxychlordane residues in brain tissue approaching 5 mg/kg FW were considered within the lethal hazard zone to birds (Shekel et al. 1979). 

Chlordane interachons with other agricultural chemicals are significant and merit additional research. In one study, male Japanese quail (Coturnix japonica) pretreated for 8 weeks with 10 mg chlordane/kg diet had increased resistance to parathion, but not to paraoxon, as judged by cholinesterase activity (Ludke 1977). In another study, northern bobwhites (Colinus virginianus) treated with 10 mg chlordane/kg diet for 10 weeks, followed by endrin stress, had greater accumulations of chlordane in the brain than did birds treated only with chlordane (Ludke 1976). 

Table 13.4 (continued) Chlordane Effects on Selected Birds... 

BIRDS, 4 species, from marsh treated with 1.12 kg chlordane/ha... 

BIRDS, 4 species, fed diets containing 71% c/ s-chlordane and 23% trans-chlordane at 50-500 mg/kg diet... 

BIRDS, 3 species, fed diets containing 150 mg technical chlordane/kg CALIFORNIA QUAIL, Callipepla californica... 

Mortality reached 50% on day 40 maximum residues in brains of birds dying during exposure (or sacrificed), in mg/kg FW, were 6.5 (9.0) for c/s-chlordane, 4.5 (9.0) for trans-nonachlor, 3.2 (9.0) for trans-chlordane, and 1.0 (2.0) for c/ s-nonachlor (Dr. O.H. Pattee, Patuxent Wildlife Research Center, personal communication)... 

Measurement of effects of depleted soil fertility from chlordane-induced earthworm suppression on migratory birds and other wildlife (NRCC 1975 WHO 1984)... 

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. 

Blus, L.J., O.H. Pattee, C.J. Henny, and R.M. Prouty. 1983. First records of chlordane-related mortality in wild birds. Jour. Wildl. Manage. 47 196-198. 

Ludke, J.L. 1977. DDE increases the toxicity of parathion to coturnix quail. Pest. Biochem. Physiol. 7 28-33. Lundholm, C.E. 1988. The effects of DDE, PCB and chlordane on the binding of progesterone to its cytoplasmic receptor in the eggshell gland mucosa of birds and the endometrium of mammalian uterus. Comp. Biochem. Physiol. 89C 361-368. 

Stickel, L.F., W.H. Stickel, R.D. McArthur, and D.L. Hughes. 1979. Chlordane in birds a study of lethal residues and loss rates. Pages 387-396 in W.B. Deichmann (ed.). Toxicology and Occupational Medicine. Elsevier/North Holland, New York. 

Very little published information is available about the interaction of endrin with other chemicals. The toxicity of endrin may be influenced by interactions with other chemicals and physical agents. Quails treated with endrin and chlordane had significantly lower endrin residues in brain tissue (p<0.025) than birds treated with endrin alone (Ludke 1976). The authors attributed this difference to the presence and accumulative toxic action of one or more of the chlordane components in the nervous system. Dietary endrin pretreatment potentiated CC14 hepatotoxicity, producing slight elevation of the serum enzymes... 

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