Eggshell thinning

Although eggshell thinning attributable to DDE exposure has occurred in birds in the UK, the lethal and siiblethal effects of the cyclodiene pesticides aldrin, dieldrin and heptachlor are also believed to have contributed to the population effects, particularly in the case of the sparrowhawk and peregrine falcon. Following the withdrawal of DDT and the cyclodienes from use in the UK, Europe and North America, bird of prey populations that were severely affected have shown partial or complete recovery. ... 

From an ecotoxicological point of view, it has often been suspected that sublethal effects, such as those described here, can be more important than lethal ones. Both p,p -DDT and p,p -DDD are persistent neurotoxins, and may very well have caused behavioral effects in the field. This issue was not resolved when DDT was widely used, and remains a matter for speculation. More is known, however, about eggshell thinning caused by p,p -DDE and its effects upon reproduction, which will be discussed in Section 5.2.5.I. 

The two examples just given are of localized effects associated with the acute toxicity of DDT and DDD to organisms in higher trophic levels. A more wide-ranging toxic effect associated with population decline was eggshell thinning caused by the relatively high levels of p,p -DDE in some predatory birds (see Table 5.7). 

Population Declines Associated with Eggshell Thinning Caused by p,p -DDE... 

Thus, as with studies on the double-crested cormorant in the Great Lakes (see Chapter 16 in Walker et al. 2006), there is evidence of a continuing (although reduced) effect of p,p -DDE on reproductive success even after environmental levels had fallen and eggshell thinning was much less. This raises the possibility that p,p -DDE may have had toxic effects other than eggshell thinning on these species (Nisbet 1989). There is the further complication that other OCs such as PCBs, dieldrin, and hep-tachlor epoxide were present in the same samples and may have had toxic effects. 

Elliott, J.E., Norstrom, R.J., and Keith, J.A. (1988). Organochlorines and eggshell thinning in Northern gannets Sula bassanus) from Keith, Eastern Canada. Environmental Pollution 52, 81-102. 

Hohn, L., Blomqvist, A., and Brandt, I. et al. (2006). Embryonic exposure to o,/ -DDT causes eggshell thinning and altered shell gland carbonic anhydrase expression in the domestic hen. Environmental Toxicology and Chemistry 25, 2787-2793. 

Lundholm, E. (1997). DDE induced eggshell thinning in birds effects of p,p -iyDE on the calcium and prostaglandin metabolism of the eggshell gland. Comparative Biochemistry and Physiology 118C, 113-128. 

Peakall, D.B., Lincer, J.L., and Risebrough, R.W. et al. (1973). DDE-induced eggshell thinning structural and physiological effects in three species. Comparative and General Pharmacology 4, 305-313. 

Fox GA, Yonge KS, Sealy SG. 1980. Breeding performance, pollutant burden, and eggshell thinning in Common Loons Gavia immer nesting on a boreal forest lake. Omis Scand 11 243-248. 

Elliott, J.E., R.J. Norstrom, and J.A. Keith. 1988. Organochlorines and eggshell thinning in northern gannets (Sula bassanus) from eastern Canada, 1968-1984. Environ. Pollut. 52 81-102. 

Grubb, T.G., S.N. Wiemeyer, and L.F. Kiff. 1990. Eggshell thinning and contaminant levels in bald eagle eggs from Arizona, 1977 to 1985. Southwestern Natural. 35 298-301. 

Eggshell thinning and deformities in certain species of fisheating birds... 

Newton, I., and Bogan, J. Organochlorine residues, eggshell thinning and hatching success in British sparrow-hawks. Nature 249, 582-583 (1974). 

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