DOI: 10.5285/9371ce24-7a5a-4964-93bf-884b42fd5fc3
title: Flame retardants in the livers of the Eurasian otter collected from Scotland between 2013 and 2015 (PBMS)

description: Data comprise concentrations of polybrominated diphenyl ethers (PBDEs) determined using Gas Chromatograph - Mass Spectrometry (GC-MS) in the liver tissue of a small sample of Eurasian otters (Lutra lutra) that died in Scotland between 2013 and 2015. The otters analysed included adult and sub-adult males and females although there were insufficient sample numbers to test for differences among demographic groups.

Otter liver tissue collected during post mortem by Cardiff University Otter Project (from otters found deceased) was analysed for the Predatory Bird Monitoring Scheme by the CEH Lancaster Analytical Chemistry Facility.

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology's National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife.
description: Otters found dead were examined by Cardiff University Otter Project to determine sex and age. Age-class (adult, sub-adult or juvenile) was estimated from a combination of morphometric data and indicators of reproductive activity. Nutritional and reproductive status, lesions, growths and concretions were noted. 
Tissue samples, including the liver, were taken as part of the post-mortem examination. Between 2013 and 2015, livers were collected from 16 otters found dead in Scotland for analysis of PBDE, tri-BDE through nona-BDEs, residues.

Age was estimated using weight and signs of sexual maturity. Females weighing less than 2.1 kg and males weighing less than 3 kg were recorded as juvenile. Females above this weight but with no sign of reproductive activity (nipples not showing, immature uterus) and males with a baculum less than 60 mm in length were recorded as sub-adult. Females above this weight and with signs of having reproduced at least once and males above this weight and with a baculum length greater than or equal to 60 mm were recorded as adult.

Liver samples were analysed at the centralized analytical laboratories at the Centre for Ecology & Hydrology, Lancaster. Concentrations of 32 BDEs (6 tri-BDEs, 6 tetra-BDEs, 6 penta-BDEs, 4 hexa-BDEs, 2 hepta-BDEs, 5 octa-BDEs and 3 nona-BDEs) were quantified.

A sub- sample of each liver (~1 g) was thawed, weighed accurately, ground with sand and dried with anhydrous sodium sulphate. Each sample was spiked with labeled recovery standards (13C PBDEs and 13C BFRs) and Soxhlet extracted in DCM for 16 h. A small portion of the extract was evaporated to zero volume and the lipid content was determined gravimetrically. The remaining extract was cleaned using automated size exclusion chromatography followed by deactivated alumina column. 

All BDEs were analysed by GCMS. Each extract was spiked with labelled internal standards and 100μl of sample was injected into a GC-MS with programmable temperature vaporization (PTV) inlet. The PTV injector was kept at 55°C for 0.45 min, and heated to 325°C at a rate of 700°C min-1 and kept at 325°C for 5 min. Then the temperature was reduced to 315°C min-1 at a rate of 10°C min-1. The GC-MS had a 25 m HT8 column (0.22 mm internal diameter and 0.25μm film thickness, SGE Milton Keynes, UK) and the carrier gas was helium (2.0 ml min-1). The temperature programme was: isothermal at 80°C for 2.4 min, 25°C min-1 to 200°C, 5°C min-1 to 315°C and was held at 315°C for 9.8 min.

Residues were quantified as recovery corrected concentrations using an internal standard correction method and calibration curves based on PBDE standards (Greyhound Ltd, Birkenhead, UK and LGC Ltd, Teddington, UK).. Average recoveries for 13C-PBDE recovery standards for BDE 28, BDE 47, BDE 126, BDE 153 and BDE 197 ranged between 94% and 98%.

Liver concentrations of flame retardants are reported as ng/g wet weight (wet wt). When all summed PBDE concentrations were calculated, individual congener concentrations below the limit of detection (non-detected) were assigned a zero value.