Persistent pollutants exceed toxic thresholds in a freshwater top predator decades after legislative control

Kean, E.F.; Shore, R.F.; Scholey, G.; Strachan, R.; Chadwick, E.A.. 2021 Persistent pollutants exceed toxic thresholds in a freshwater top predator decades after legislative control. Environmental Pollution, 272, 116415. 11, pp.

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Declining emissions of persistent organic pollutants (POPs), subject to international control under the Stockholm convention, are not consistently reflected in biotic samples. To assess spatial and temporal variation in organochlorine pesticides and PCBs in UK freshwaters, we analysed tissues of a sentinel predator, the Eurasian otter, Lutra lutra between 1992 and 2009. Past declines in otter populations have been linked to POPs and it is unclear whether otter recovery is hampered in any areas by their persistence. PCBs, DDT (and derivatives), dieldrin and HCB were detected in over 80% of 755 otter livers sampled. Concentrations of ∑PCB, ∑DDT and dieldrin in otter livers declined across the UK, but there was no significant time trend for ∑PCB-TEQ (WHO toxic equivalency, Van den Berg et al., 2006) or HCB. In general, higher concentrations were found in the midlands and eastern regions, and lowest concentrations in western regions. Concentrations of PCBs and HCB in otters increased near the coast, potentially reflecting higher pollutant levels in estuarine systems. Decades after legislative controls, concentrations of these legacy pollutants still pose a risk to otters and other freshwater predators, with spatially widespread exceedance of thresholds above which reproduction or survival has been reduced in related species.

Item Type: Publication - Article
Digital Object Identifier (DOI):
UKCEH and CEH Sections/Science Areas: Pollution (Science Area 2017-)
ISSN: 0269-7491
Additional Keywords: persistent organic pollutants, PCBs, freshwater ecosystem, contaminant, otter
NORA Subject Terms: Ecology and Environment
Date made live: 12 Jan 2021 11:50 +0 (UTC)

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