Author(s): Akerblom S, Bignert A, Meili M, Sonesten L, Sundbom M
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Abstract The variability of mercury (Hg) levels in Swedish freshwater fish during almost 50 years was assessed based on a compilation of 44 927 observations from 2881 waters. To obtain comparable values, individual Hg concentrations of fish from any species and of any size were normalized to correspond to a standard 1-kg pike [median: 0.69 mg kg⁻¹ wet weight (ww), mean ± SD: 0.84 ± 0.67 mg kg⁻¹ ww]. The EU Environmental Quality Standard of 0.02 mg kg⁻¹ was exceeded in all waters, while the guideline set by FAO/WHO for Hg levels in fish used for human consumption (0.5-1.0 mg kg⁻¹) was exceeded in 52.5 \% of Swedish waters after 2000. Different trend analysis approaches indicated an overall long-term decline of at least 20 \% during 1965-2012 but trends did not follow any consistent regional pattern. During the latest decade (2003-2012), however, a spatial gradient has emerged with decreasing trends predominating in southwestern Sweden.
This article was published in Ambio
and referenced in Journal of Aquaculture Research & Development