Bibliography Background About KRIS

Pesticides and Potential Endocrine Disruption in Atlantic Salmon

The excerpts below are from Dill, R., C. Fay, M. Gallagher, D. Kircheis, S. Mierzykowski, M. Whiting, and T. Haines. 2002, Water quality issues as potential limiting factors affecting juvenile Atlantic salmon life stages in Maine rivers. Report to Maine Atlantic Salmon Technical Advisory Committee by the Ad Hoc Committee on Water Quality. Atlantic Salmon Commission. Bangor, ME. 28 pp. [162kb]. See references in Dill et al. (2002) for citations.

A large number of very different chemicals have been demonstrated to have endocrine disrupting activity, including herbicides (2,4-D, atrazine), fungicides (benomyl, zineb), insecticides (DDT, methoxychlor, synthetic pyrethoids), industrial chemicals (dioxin, PCB, nonylphenols, phthalates), and trace metals (cadmium, lead, mercury). Endocrine disruptors are believed to affect smoltification in Atlantic salmon by disrupting hormone systems that facilitate the physiological processes necessary for seawater adaptation (Fairchild et al. 1999).

Fairchild et al. (1999) documented a decline in returning adult Atlantic salmon in areas where a pesticide was applied for suppression of spruce budworm populations during the time of smolt outmigration. The particular pesticide used was not an endocrine disrupting compound, but the formulation included a known endocrine disruptor (4-nonylphenol) as an emulsifying agent. Exposure to 4-nonylphenol induced vitellogenin (an egg yolk protein) in Atlantic salmon smolts in the same manner as did exposure to 17 β-estradiol (Sherry et al. 2001). Moore and Lower (2001) showed that exposure to atrazine, a triazine herbicide, and pentabromodiphenyl ether, a brominated fire retardant, reduced gill Na/K-ATPase activity and caused osmoregulatory disruption in Atlantic salmon smolts, as well as elevated cortisol levels, reduced survival in sea water, and reduced migratory activity. These are the same effects reported by Magee et al. (2001) for Narraguagus River smolts.

A variety of endocrine disrupting chemicals have been detected in Maine Atlantic salmon rivers. Dioxin, PCBs, and DDT are found in most larger rivers. PCBs have been found in fish and sediments from the Dennys River, downstream from the Eastern Surplus Superfund Site (Mierzykowski and Carr 1998). PCBs and DDT have been found in fish from the Pleasant River (Maine Department of Environmental Protection 1999). Hexazinone, a triazine herbicide structurally similar to atrazine, is commonly found in the Pleasant and Narraguagus rivers (Beland et al. 1995; Chizmas 1999; Chizmas 2000) as a result of application to low bush blueberry lands. Other pesticides detected in Washington County rivers in recent years include terbacil (Chizmas 2000), phosmet (Chizmas 2001), triforine (Beland et al. 1995), azinphos-methyl (Magee 2001), and benlate (Magee 2001). In the 1970s, DDT and it’s metabolites, and dieldrin were also found in the Narraguagus River (Magee 2001).