Abstract

Methylmercury (MeHg) transfer from water into the base of the food web (bioconcentration) and subsequent biomagnification in the aquatic food web leads to most of the MeHg in fish. But how important is bioconcentration compared to biomagnification in predicting MeHg in fish? To answer this question we reviewed articles in which MeHg concentrations in water, plankton (seston and/or zooplankton), as well as fish (planktivorous and small omnivorous fish) were reported. This yielded 32 journal articles with data from 59 aquatic ecosystems at 22 sites around the world. Although there are many case studies of particular aquatic habitats and specific geographic areas that have examined MeHg bioconcentration and biomagnification, we performed a meta-analysis of such studies. Aqueous MeHg was not a significant predictor of MeHg in fish, but MeHg in seston i.e., the base of the aquatic food web, predicted 63% of the variability in fish MeHg. The MeHg bioconcentration factors (i.e., transfer of MeHg from water to seston; BCFw-s) varied from 3 to 7 orders of magnitude across sites and correlated significantly with MeHg in fish. The MeHg biomagnification factors from zooplankton to fish varied much less (logBMF(z-f), 0.75 +/- 0.31), and did not significantly correlate with fish MeHg, suggesting that zooplanktivory is not as important as bioconcentration in the biomagnification of fish MeHg across the range of ecosystems represented in our meta-analysis. Partial least square (PLS) and linear regression analyses identified several environmental factors associated with increased BCF, including low dissolved organic carbon, low pH, and oligotrophy. Our study reveals the widespread importance of MeHg bioconcentration into the base of the aquatic food web for MeHg at higher trophic levels in aquatic food webs, as well as the major influences on the variability in this bioconcentration. (C) 2018 The Authors. Published by Elsevier B.V.

Keywords

Hg; MeHg; Meta-analysis; Seston; Fish; Bioconcentration factors; Biomagnification factors

Published in

Science of the Total Environment
2019, Volume: 646, pages: 357-367
Publisher: ELSEVIER SCIENCE BV

SLU Authors

• Wu, Pianpian

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Åkerblom, Staffan

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Sonesten, Lars

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Bishop, Kevin

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Conserve and sustainably use the oceans, seas and marine resources for sustainable development
Ensure healthy lives and promote well-being for all at all ages


UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1016/j.scitotenv.2018.07.328

Permanent link to this page (URI)

https://res.slu.se/id/publ/96734