https://hal.archives-ouvertes.fr/hal-02107191/document

How closely do mercury trends in fish and other aquatic wildlife track those in the atmosphere? - Implications for evaluating the effectiveness of the Minamata Convention

Polyhalogenated carbazoles (PHCZs) were recently discovered in Great Lakes sediment and other aquatic systems. However, knowledge about their bioaccumulation and potential risks to fish and wildlife remains very limited. The present study investigated PHCZs in Great Lakes lake trout ( Salvelinus namaycush) and walleye ( Sander vitreus; Lake Erie only) composites collected between 2004 and 2016. Median concentrations of ∑PHCZs by lake ranged from 54.7 to 154 ng/g lipid weight or lw (6.8-28.0 ng/g wet weight). Dominant congeners included 3,6-dichlorocarbazole, 1,3,6-tribromocarbazole, and 1,3,6,8-tetrachlorocarbazole. The highest ∑PHCZs concentrations were found in Lakes Michigan and Ontario fish, followed by Lake Huron, whereas Lakes Erie and Superior fish contained the lowest concentrations. Congener profiles of PHCZs also exhibited spatial variations. After age normalization to minimize fish age influence on bioaccumulation rates, fish ∑PHCZs' concentrations declined significantly over time in all lakes except Lake Erie, with slopes ranging from -10.24% to -3.85% per year. The median toxic equivalent (TEQ) of PHCZs due to their dioxin-like activity was determined to range from 8.7 to 25.7 pg/g lw in Great Lakes fish. This study provides the first insight into the bioaccumulation and spatiotemporal trends of PHCZs in Great Lakes and suggests the need for further research on this group of chemicals.

Bioaccumulation and Spatiotemporal Trends of Polyhalogenated Carbazoles in Great Lakes Fish from 2004 to 2016

AMERICAN METEOROlOGICAl SOCIETy | July 2013| 997 PB AFFILIATIONS: Donat, alexanDer, anD Yang—Climate Change Research Centre, and ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, Australia; Durre anD Vose—NOAA’s National Climatic Data Center, Asheville, North Carolina; Caesar—Met Office Hadley Centre, Exeter, United Kingdom CORRESPONDING AUTHOR: Markus Donat, Climate Change Research Centre, University of New South Wales, Sydney, Australia E-mail: m.donat@unsw.edu.au

GHCNDEX: Global Land-based Datasets for Monitoring Climatic Extremes

The U.S. Environmental Protection Agency’s Great Lakes Fish Monitoring and Surveillance Program (GLFMSP) has traced the fate and transport of anthropogenic chemicals in the Great Lakes region for decades. Isolating and identifying halogenated species in fish is a major challenge due to the complexity of the biological matrix. A nontargeted screening methodology was developed and applied to lake trout using a 2-dimensional gas chromatograph coupled to a high resolution time-of-flight mass spectrometer (GC×GC-HR-ToF MS). Halogenated chemicals were identified using a combination of authentic standards and library spectral matching, with molecular formula estimations provided by exact mass spectral interpretation. In addition to the halogenated chemicals currently being targeted by the GLFMSP, more than 60 nontargeted halogenated species were identified. Most appear to be metabolites or breakdown products of larger halogenated organics. The most abundant compound class was halomethoxyphenols accounting for mo...

Comprehensive Analysis of the Great Lakes Top Predator Fish for Novel Halogenated Organic Contaminants by GC×GC-HR-ToF Mass Spectrometry

Identifying the sources of methylmercury (MeHg) and tracing the transformations of mercury (Hg) in the aquatic food web are important components of effective strategies for managing current and legacy Hg sources. In our previous work, we measured stable isotopes of Hg (δ202Hg, Δ199Hg, and Δ200Hg) in the Laurentian Great Lakes and estimated source contributions of Hg to bottom sediment. Here, we identify isotopically distinct Hg signatures for Great Lakes trout (Salvelinus namaycush) and walleye (Sander vitreus), driven by both food-web and water-quality characteristics. Fish contain high values for odd-isotope mass independent fractionation (MIF) with averages ranging from 2.50 (western Lake Erie) to 6.18‰ (Lake Superior) in Δ199Hg. The large range in odd-MIF reflects variability in the depth of the euphotic zone, where Hg is most likely incorporated into the food web. Even-isotope MIF (Δ200Hg), a potential tracer for Hg from precipitation, appears both disconnected from lake sedimentary sources and compa...

Factors Affecting Mercury Stable Isotopic Distribution in Piscivorous Fish of the Laurentian Great Lakes

Mercury (Hg) concentration trends in top predator fish (lake trout and walleye) of the Great Lakes (GL) from 2004 to 2015 were determined by Kendall–Theil robust regression with a cluster-based age normalization method to control for the effect of changes in lake trophic status When data from the GLs (except Lake Erie) are combined, a significant decreasing trend in the lake trout Hg concentrations was found between 2004 and 2015 with an annual decrease of 41% per year, consistent with the decline in regional atmospheric Hg emissions and water Hg concentrations However, a breakpoint was detected with a significant decreasing slope (−81% per year) before the breakpoint (2010), and no trend after the breakpoint When the lakes are examined individually, Lakes Superior and Huron, which are dominated by atmospheric Hg inputs and are more likely than the lower lakes to respond to declining emissions from areas surrounding the GL, have significant decreasing trends with rates between 52 and 78% per year f

Mercury Temporal Trends in Top Predator Fish of the Laurentian Great Lakes from 2004 to 2015: Are Concentrations Still Decreasing?

Polychlorinated biphenyls and organochlorine pesticides concentration patterns and trends in top predator fish of Laurentian Great Lakes from 1999 to 2014.

Bernard A. Crimmins

Papers

Mercury Temporal Trends in Top Predator Fish of the Laurentian Great Lakes from 2004 to 2015: Are Concentrations Still Decreasing?

Polychlorinated biphenyls and organochlorine pesticides concentration patterns and trends in top predator fish of Laurentian Great Lakes from 1999 to 2014.