Responses to reduced industrial metal emissions An ecotoxicological study on Pied Flycatcher (Ficedula hypoleuca, Aves)

Abstract: Metals have been used by humans for thousands of years, and this has resulted in increased concentrations in the biosphere. The environment around point-sources, such as mines and smelters, are of particular concern, as metals may accumulate to high concentrations, and potentially reach levels toxic to the local flora and fauna. This thesis focuses on the effects on pied flycatcher populations of two such point-sources, a lead mine and enrichment plant, and a sulfide ore smelter. Mining activities at the lead mine ceased in 2001 and pied flycatcher populations were assessed before and after the closure. At the sulfide ore smelter, pied flycatchers were studied during the 1980s. Since then, the metal emissions to air from the smelter (e.g. arsenic, cadmium, copper, mercury, lead and zinc) have been greatly reduced (by 93 – 99%).Pied flycatchers from these two contaminated environments differed in their responses to reduced atmospheric deposition. At the mine site, nestling responses reflected the reduced atmospheric deposition and less lead accumulated in their tissues. However, lead levels were still high enough to cause negative effects on blood status (?-aminolevulinic acid dehydratase [ALAD], hemoglobin [Hb], hematocrit [ht], and mean cell hemoglobin concentration) and reproduction (reduced clutch size, increased mortality and reduced breeding success), as was observed when the mine was in operation. Along the pollution gradient away from the smelter, nestling concentrations reflected the metal load in the soil pool, accumulating over time, rather than the atmospheric deposition. This resulted in only a minor response to decreased metal deposition (slightly reduced liver lead concentrations at 3.5 – 90 km from the smelter). This suggests that in environments with highly polluted soils, decreased inputs of atmospheric metal deposition have only minor impacts, and recovery from contamination should not be expected within decades.The high metal concentrations in the vicinity of the smelter contributed to poorer blood status (ALAD, Hb and ht), induced oxidative damage and defenses, and decreased reproduction (increased mortality and reduced breeding success). There were only minor improvements in blood and reproductive variables at 3.5 km from the smelter.