Monitoring and Evaluating Trends in Methylmercury Accumulation in Aquatic Biota

Wiener, James G.; Bodaly, R. A.; Brown, Steven D.; Lucotte, Marc; Newman, Michael; Porcella, Donald B.; Reash, Robin J.; Swain, Edward B.

doi:10.1201/9780849388897.ch4

Cited by 50 publications

(59 citation statements)

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“…A fraction of inorganic Hg undergoes microbial conversion to methylmercury (MeHg), a potent toxin to both humans and wildlife (Wiener et al 2003(Wiener et al , 2006aMergler et al 2007). MeHg enters aquatic food webs at their base through uptake and sequestration by phytoplankton and benthic algae, and bioaccumulates and biomagnifies in food webs (Wiener et al 2003).…”

Section: Introductionmentioning

confidence: 99%

“…System-level factors include differences in the loadings of inorganic Hg to ecosystems (Hammerschmidt and Fitzgerald 2006b;Harris et al 2007), and different environmental conditions within ecosystems that influence methylation and MeHg bioavailability (e.g., pH, redox conditions, organic carbon levels and activity of methylating bacteria; Benoit et al 2003;Wiener et al 2006b). Organism-level factors include prey MeHg concentration (Hall et al 1997) and trophic position (TP), which have great influence on MeHg levels in biota due to biomagnification (Wiener et al 2003). Although fish of the same species might be expected to feed at approximately the same TP, the TP of individuals can vary due to omnivory (Kidd et al 1995) and ontogenetic dietary shifts (Eagles-Smith et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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Speciation leads to divergent methylmercury accumulation in sympatric whitefish

et al. 2012

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Central European lake whitefish (Coregonus spp.) colonized Swiss lakes following the last glacial retreat and have undergone rapid speciation and adaptive radiation. Up to six species have been shown to coexist in some lakes, and individual species occupy specific ecological niches and have distinct feeding and reproductive ecologies. We studied methylmercury (MeHg) accumulation in sympatric whitefish species from seven Swiss lakes to determine if ecological divergence has led to different rates of MeHg bioaccumulation. In four of seven lakes, sympatric species had distinctly different MeHg levels, which varied by up to a factor of two between species. Generally, species with greater MeHg levels were smaller in body size and planktivorous, and species with lower MeHg were larger and benthivorous. While modest disparities in trophic position between species might be expected a priori to explain the divergence in MeHg, d 15 N of bulk tissue did not correlate with fish MeHg in five of seven lakes. Results of a nested ANCOVA analysis across all lakes indicated that only two factors (species, lake) explained substantial portions of the variance, with species accounting for more variance (52 %) than inter-lake differences (32 %). We suggest that differences in MeHg accumulation were likely caused by diverging metabolic traits between species, such as differences in energy partitioning between anabolism and catabolism, potentially interacting with species-specific prey resource utilization. These results indicate substantial variability in MeHg accumulation between closely related fish species, illustrating that ecological speciation in fish can lead to divergent MeHg accumulation patterns.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Speciation leads to divergent methylmercury accumulation in sympatric whitefish

et al. 2012

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“…Hg concentrations in biota were evaluated relative to integrated streambed sediment MeHg production potential (42), atmospheric depositional Hg loading (15,43) (not shown), and wetland abundance as a percent of the watershed area in the stream basin (16). Mercury in biota was not significantly correlated to either in-stream MeHg production potential or depositional loading (τ < 0.5, p > 0.1); however, Hg concentrations in invertebrates, forage fish, and predators were significantly and positively correlated to percent wetland ( Figure 3).…”

Section: Ss (Mg Lmentioning

confidence: 99%

Mercury Cycling in Stream Ecosystems. 3. Trophic Dynamics and Methylmercury Bioaccumulation

Chasar

Scudder

Stewart

et al. 2009

Environ. Sci. Technol.

212

226

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Trophic dynamics (community composition and feeding relationships) have been identified as important drivers of methylmercury (MeHg) bioaccumulation in lakes, reservoirs, and marine ecosystems. The relative importance of trophic dynamics and geochemical controls on MeHg bioaccumulation in streams, however, remains poorly characterized. MeHg bioaccumulation was evaluated in eight stream ecosystems across the United States (Oregon, Wisconsin, and Florida) spanning large ranges in climate, landscape characteristics, atmospheric Hg deposition, and stream chemistry. Across all geographic regions and all streams, concentrations of total Hg (THg) in top predator fish and forage fish, and MeHg in invertebrates, were strongly positively correlated to concentrations of filtered THg (FTHg), filtered MeHg (FMeHg), and dissolved organic carbon (DOC); to DOC complexity (as measured by specific ultraviolet absorbance); and to percent wetland in the stream basins. Correlations were strongest for nonurban streams. Although regressions of log[Hg] versus δ 15 N indicate that Hg in biota increased significantly with increasing trophic position within seven of eight individual streams, Hg concentrations in top predator fish (including cutthroat, rainbow, and brown trout; green sunfish; and largemouth bass) were not strongly influenced by differences in relative trophic position. Slopes of log[Hg] versus δ 15 N, an indicator of the efficiency of trophic enrichment, ranged from 0.14 to 0.27 for all streams. These data suggest that, across the large ranges in FTHg (0.14-14.2 ng L ) found in this study, Hg contamination in top predator fish in streams likely is dominated by the amount of MeHg available for uptake at the base of the food web rather than by differences in the trophic position of top predator fish.

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“…Hg typically accumulates in fish as their age and size increases due to relative exposure times and food web position (Downs et al 1998;Chen and Folt 2005). Variability in fish Hg concentrations can be reduced by controlling for fish species and fish age or length (Wiener et al 2007 Substantial additional data may exist in state, federal, and other databases; however, additional efforts to compile data were beyond the scope of this paper.…”

Section: Introductionmentioning

confidence: 99%

“…Industrial and municipal point-sources of mercury to rivers and lakes were very important historically, but have been greatly reduced since the implementation of stricter regulatory controls in the 1970s (Balogh et al 1999;Krabbenhoft et al 2005). Widespread Hg contamination of fish in remote areas with low rates of Hg deposition suggests Hg loading in an ecosystem alone does not define Hg concentration in fish (Krabbenhoft et al 2005;Wiener et al 2007). Transport of atmospheric Hg to aquatic ecosystems and Hg cycling within aquatic systems are complex and not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Mercury trends in fish from rivers and lakes in the United States, 1969–2005

Chalmers

Argue

Brigham

et al. 2010

Environ Monit Assess

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A national dataset on concentrations of mercury in fish, compiled mainly from state and federal monitoring programs, was used to evaluate trends in mercury (Hg) in fish from US rivers and lakes. Trends were analyzed on data aggregated by site and by state, using samples of the same fish species and tissue type, and using fish (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) were compared to wet Hg deposition data from the Mercury Deposition Network (MDN) over the same period. Downward trends in Hg concentrations in fish from data collected during 1969-1987 exceeded upward trends by a ratio of 6 to 1. Declining Hg accumulation rates in sediment and peat cores reported by many studies during the 1970s and 1980s correspond with the period when the most downward trends in fish Hg concentrations occurred. Downward Hg trends in both sediment cores and fish were also consistent with the implementation of stricter regulatory controls of direct releases of Hg to the atmosphere and surface waters during the same period. The southeastern USA had more upward Hg trends in fish than other regions for both site and state aggregated data. Upward Hg trends in fish from the southeastern USA were associated with increases in wet deposition in the region and may be attributed to a greater influence of global atmospheric Hg emissions in the southeastern USA. No significant trends were found in 62% of the fish species from six states from 1996 to 2005. A lack of Hg trends in fish in the more recent data was consistent with the lack of trends in wet Hg deposition at MDN 176 Environ Monit Assess (2011) 175:175-191 sites and with relatively constant global emissions during the same time period. Although few significant trends were observed in the more recent Hg concentrations in fish, it is anticipated that Hg concentrations in fish will respond to changes in atmospheric Hg deposition, however, the magnitude and timing of the response is uncertain.

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Monitoring and Evaluating Trends in Methylmercury Accumulation in Aquatic Biota

Cited by 50 publications

References 0 publications

Speciation leads to divergent methylmercury accumulation in sympatric whitefish

Speciation leads to divergent methylmercury accumulation in sympatric whitefish

Mercury Cycling in Stream Ecosystems. 3. Trophic Dynamics and Methylmercury Bioaccumulation

Mercury trends in fish from rivers and lakes in the United States, 1969–2005

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