Inorganic elements in the livers of Eurasian otters, Lutra lutra, from England and Wales in 2009 - a Predatory Bird Monitoring Scheme (PBMS) report

Abstract

This is the second report on the findings of a collaborative study between the Predatory Bird Monitoring Scheme (PBMS) and the Cardiff University Otter Project (CUOP). The study analysed the concentrations of 15 metals and semi-metals in the livers of 50 Eurasian otters (Lutra lutra) that had been found dead between 2007 and 2009 and collected by the CUOP. This report specifically presents data for otters found dead in 2009. The aim of this work was to determine the current concentrations of inorganic elements accumulated by otters and whether exposure to heavy metals (lead, mercury, cadmium) in particular is likely to be associated with adverse effects. The otters that were analysed were from England and Wales and included adult and sub-adult males and females. Liver tissue was analysed using Inductively Coupled Plasma mass spectrometry (ICP-MS) techniques. The concentrations of inorganic elements measured in the present study were within the range previously reported for Eurasian otters in Britain and elsewhere in Europe. Concentrations varied with age and/or sex for some elements. For the heavy metals mercury and cadmium, liver concentrations generally increased with age. Five elements, aluminium, antimony, arsenic, chromium, and strontium, varied significantly in concentrations between years. It is unclear whether the inter-year variations in these elements represent significant inter-year changes in exposure and/or accumulation or may simply reflect local-scale variation in the provenance of otters and their associated exposure. The liver concentrations of the heavy metals mercury and cadmium in all the otters analysed were below those associated with toxic effects in mammals