Provenance & quality
Carcasses from 278 Eurasian otters (Lutra lutra), sent in to Cardiff University Otter Project (www.cardiff.ac.uk/otter-project) between 2006 and 2017, were subjected to a detailed post-mortem examination. This examination included the documentation of phenotypic characteristics (e.g. sex, length, weight, age class) and the collection of liver tissue samples. Liver tissue samples were acid digested after which toxic metals/semi-metals were quantified using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) at the Centre for Ecology & Hydrology in Lancaster.
For each otter carcass, location (National Grid Reference) and date of collection was recorded. Otter locations were used as the centre of 20-km-diameter circles that were assumed to be the otter’s habitat range. For each 20-km-diameter circle, data describing spatial variation in habitat biogeochemistry and habitat contamination sources was collated from a range of sources.
Geological and anthropogenic variables were summarised either as mean values (soil elements, soil pH, sediment elements, stream pH, rainfall, silver nanoparticle concentrations in surface water, human population density) or sum values (number of consented discharges to controlled waters, annual mass inputs of metals to controlled waters).