Pb, Cd, As, and Se concentrations in livers of dead wild birds from the Ebro Delta, Spain

Abstract

Wild bird populations are susceptible to the environmental presence of toxic elements and substances, especially those that are non-degradable and tend to concentrate through the food chain. Monitoring of such substances in selected bird species could be useful to evaluate the health condition of the species involved and to assess contamination in the ecosystem. One of the most important wild bird sanctuaries of Europe, the Ebro Delta, is situated in NE Spain. The Ebro Delta is an alluvial plain of about 32,000 ha. Because of its special hydrological conditions and geographical situation, the Ebro Delta supports an important and diverse bird population, estimated at 180,000 in the winter period, constituting 311 different species. Most of the Ebro Delta's surface is dedicated to agriculture, principally rice, also serving as an excellent wild bird habitat. Accordingly, agricultural pesticides could be a major problem for wildlife. But in the last few decades the Ebro River and the Tarragona coast have also undergone considerable industrial development. The area is now facing environmental threats by industrial activities, and the ecosystem is becoming contaminated with heavy metals, petroleum hydrocarbons and PCBS. Heavy metal concentrations in marine organisms have been reported, but metal and metalloid concentrations inmore » birds have not been available. This study monitors lead (Pb), cadmium (Cd), arsenic (As) and selenium (Se) concentrations in bird livers from diverse trophic levels in the Ebro Delta. Pb, Cd and As are well recognized as toxic elements, while Se, although causing well known deleterious effects for humans and domestic animals, has only recently been recognized as toxic for aquatic birds. The determination of contaminant loads in several avian species would be useful to control and prevent, when possible, pathological conditions derived from toxic levels of these contaminants for wild bird populations living in the Ebro Delta. 10 refs., 2 tabs.« less