An assessment of the potential hazards of environmental selenium for Canadian water birds

Abstract

Elevated dietary intake of selenium (Se) causes dramatic teratogenic and other reproductive effects in water birds at dietary levels only a few times greater than those that are generally regarded as nutritionally essential. Possible risks to the health of Canadian water birds and other wildlife from Se may be posed by seleniferous habitats in western Canadian provinces, and over-wintering by migratory water birds in some National Wildlife Refuges in the western U.S.A. where Se-related deaths and embryonic deformities in birds have occurred. These Refuges have in common an arid climate, closed drainage basins, seleniferous Cretaceous geology, and they receive irrigation drainage water from nearby agricultural areas. Similar conditions occur in SW Saskatchewan and SE Alberta, and these areas overlap parts of the critical water bird habitat of the region. Selenium concentrations in wetland ponds, agricultural tile drainage water and bird tissues in the western provinces are, with a few exceptions, generally lower than threshold concentrations for reproductive toxicity. However, some surface waters and aquifers contain dissolved Se concentrations that exceed guidelines for the protection of aquatic life, irrigation uses, and human and livestock drinking water. Use of this aquifer water for irrigation or replacement of freshwater flows into wetlands would greatly increase the risk of Se bioaccumulation to hazardous levels in water bird food chains.Key words: selenium, toxicity, birds, wildlife, Canada.

Trace element accumulation in relation to trophic niches of shorebirds using intertidal mudflats

“…Presumably, birds are protected against Hg toxicity but this result raises concern about the surplus of Se and its possible toxicity. Hepatic Se concentrations exceeding 10 µg g -1 dw were associated with lower reproductive success in breeding female mallards (Heinz et al, 1987;Outridge et al, 1999;Stanley et al, 1996). It is remarkable that this element was highly accumulated in female dunlins and redshanks compared to males, as previously observed in American avocets Recurvirostra americana from the San Francisco Bay (Ackerman and Eagles-Smith, 2009).…”

“…This study demonstrated that shorebirds using the same habitats in the Pertuis Charentais were characterized by differential trace element bioaccumulation. Concentrations of As and Se tend to be elevated in red knots and dunlins and possibly could trigger adverse effects in these species (Heinz et al, 1987;Kunito et al, 2008;Outridge et al, 1999;Stanley et al, 1996). Redshanks displayed however higher Cd concentrations in internal tissues.…”

Insight on trace element detoxification in the Black-tailed Godwit (Limosa limosa) through genetic, enzymatic and metallothionein analyses

“…Se has the property to react with thiols which generate reactive oxygen species (Spallholz and Hoffman, 2002). Based on a review of the literature, Outridge et al (1999) suggested that hepatic Se concentrations > 10 µg g -1 dw are associated with reduced adult weight gain, lower reproductive success in breeding female and increased teratogenesis in their offspring. Moreover, Se concentrations exceeded 33 µg g -1 dw could be considered harmful to the health of birds (Heinz, 1996).…”

Decline in Performance of Biochemical Reactors for Sulphate Removal from Mine-Influenced Water is Accompanied by Changes in Organic Matter Characteristics and Microbial Population Composition

“…Mine-influenced water (MIW) contains constituents, such as selenium and sulphate, at levels that are potentially toxic to aquatic life [1][2][3] and needs to be treated before discharging to the receiving environment. One cost-effective method for remediating MIW is to use sub-surface flow constructed wetlands, commonly called biochemical reactors (BCRs), that contain waste organic material such as wood-chips, straw, hay, leaf compost, pulp mill biosolids, etc.…”