Watershed influences on mercury in tributaries to Lake Ontario

Denkenberger, Joseph S.; Fakhraei, Habibollah; Branfireun, Brian A.; Montesdeoca, M.; Driscoll, Charles T.

doi:10.1007/s10646-019-02157-4

Cited by 10 publications

(4 citation statements)

References 69 publications

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“…The THg concentration of unfiltered water in Lake Taihu was 12.3–42.1 ng L –1 (Table S1), and the DTHg (<0.45 μm) concentration was 10.5–30.4 ng L –1 (Table S1). In general, the aqueous Hg concentrations in Lake Taihu were significantly higher than those reported in European and Northern American lakes, such as in the Venice Lagoon (5.0–20.1 ng L –1 of DTHg, Italy), Ontario Lake (0.5–1.5 ng L –1 of DTHg, USA), or in the Great Salt Lake (0.7–3.9 ng L –1 of DTHg, USA). The spatial distributions of THg (Figure S3) and DTHg (Figure f) concentrations in water were in accord with the distribution of THg in sediments of Lake Taihu reported previously, both showing the highest Hg concentrations in the northern region, owing to the anthropogenic inputs from the adjacent highly industrialized large cities (Wuxi and Changzhou).…”

Section: Resultsmentioning

confidence: 54%

Algal Density Controls the Spatial Variations in Hg Bioconcentration and Bioaccumulation at the Base of the Pelagic Food Web of Lake Taihu, China

Wang

Kainz

et al. 2022

Environ. Sci. Technol.

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Algal density can significantly impact mercury (Hg) bioaccumulation and biomagnification in aquatic food webs, but the underlying mechanisms remain controversial especially in subtropical and tropical regions. We conducted a comprehensive field study on Hg bioconcentration in phytoplankton and bioaccumulation in size-fractionated zooplankton across 17 sampling sites in Lake Taihu, a large shallow lake in eastern China with large spatial differences in algal density. The higher algal density in the northern sites is highly associated with the lower THg bioconcentration factor (BCF) in phytoplankton and lower THg bioaccumulation factor (BAF) in zooplankton. The low Hg BCFs or BAFs at productive sites could not be explained by algal bloom dilution but attributed to the low Hg bioavailability, which is highly associated with the elevated pH levels at productive sites. The smaller body size of the dominant zooplankton species at higher algal density sites also contributed to their lower Hg bioaccumulation. Importantly, we provide evidence that high algal density is associated with a low proportion of methylmercury (MeHg) in total Hg (% MeHg) in phytoplankton, which is further transferred to zooplankton. Such a low THg BCF or BAF and low % MeHg in plankton at high algal density sites hamper the entry of Hg into the pelagic food webs, which are important but yet underestimated driving forces for the low Hg contents in pelagic fish that are commonly observed in anthropogenic-impacted eutrophic lakes in subtropical regions.

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Section: Resultsmentioning

confidence: 54%

Algal Density Controls the Spatial Variations in Hg Bioconcentration and Bioaccumulation at the Base of the Pelagic Food Web of Lake Taihu, China

Wang

Kainz

et al. 2022

Environ. Sci. Technol.

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“…Agriculture in the watershed increases nutrient and organic matter inputs 63 as well as dissolved organic carbon and total suspended solids. 64 As Hg binds tightly to particulate or dissolved organic matter (DOM), agricultural activities can increase Hg loading to streams. 33,65 Previous work suggests that within the Finger Lakes region, DOC varies little across individual streams 46 and that stream DOC does not predict stream fish Hg or macroinvertebrate MeHg concentrations.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Within our study region, Razavi et al found percent agriculture was among the top predictors explaining Hg concentrations in Blacknose dace ( Rhinichthys atratulus ) but not MeHg concentrations in stream insects. Agriculture in the watershed increases nutrient and organic matter inputs as well as dissolved organic carbon and total suspended solids . As Hg binds tightly to particulate or dissolved organic matter (DOM), agricultural activities can increase Hg loading to streams. , Previous work suggests that within the Finger Lakes region, DOC varies little across individual streams and that stream DOC does not predict stream fish Hg or macroinvertebrate MeHg concentrations .…”

Section: Resultsmentioning

confidence: 99%

Emergent Freshwater Insects Serve as Subsidies of Methylmercury and Beneficial Fatty Acids for Riparian Predators Across an Agricultural Gradient

Twining

Razavi

Brenna

et al. 2021

Environ. Sci. Technol.

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Aquatic-to-terrestrial subsidies have the potential to provide riparian consumers with benefits in terms of physiologically important organic compounds like omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs). However, they also have a "dark side" in the form of exposure to toxicants such as mercury. Human land use intensity may also determine whether subsidies provide benefits or come at a cost for riparian predators. We sampled insects as well as Eastern Phoebe (Sayornis phoebe) chicks in 2015−2016 within the southern Finger Lakes region to understand how food quality, in terms of n-3 LCPUFAs and methylmercury (MeHg), of emergent freshwater insects compared with that of terrestrial insects and how land use affected the quality of prey, predator diet composition, and MeHg exposure. Across the landscape, freshwater insects had a significantly higher percentage of the n-3 LCPUFA eicosapentaenoic acid (EPA) compared to terrestrial insects and contained significantly more MeHg than terrestrial insects did. In spite of differences in MeHg concentrations between aquatic and terrestrial insects, chick MeHg concentrations were not related to diet composition. Instead, chick MeHg concentrations increased with several metrics of human land use intensity, including percent agriculture. Our findings suggest that freshwater subsidies provide predators with both risks and benefits, but that predator MeHg exposure can vary with human land use intensity.

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“…As a result, Hg deposited to the region accumulates in soils, and some of this legacy Hg is gradually leached to surface waters. Mercury recently deposited to the landscape tends to be more bioavailable than Hg long buried in soils and sediments (Hintelmann et al 2002); although, Hg in soils can be mobilized by disturbances, such as storm runoff events, fires, and logging (Willacker et al 2019;Denkenberger et al 2020).…”

Section: Mercury Concentrations In Waters Of New York Statementioning

confidence: 99%

A synthesis of patterns of environmental mercury inputs, exposure and effects in New York State

et al. 2020

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Mercury (Hg) pollution is an environmental problem that adversely affects human and ecosystem health at local, regional, and global scales—including within New York State. More than two-thirds of the Hg currently released to the environment originates, either directly or indirectly, from human activities. Since the early 1800s, global atmospheric Hg concentrations have increased by three- to eight-fold over natural levels. In the U.S., atmospheric emissions and point-source releases to waterways increased following industrialization into the mid-1980s. Since then, water discharges have largely been curtailed. As a result, Hg emissions, atmospheric concentrations, and deposition over the past few decades have declined across the eastern U.S. Despite these decreases, Hg pollution persists. To inform policy efforts and to advance public understanding, the New York State Energy Research and Development Authority (NYSERDA) sponsored a scientific synthesis of information on Hg in New York State. This effort includes 23 papers focused on Hg in atmospheric deposition, water, fish, and wildlife published in Ecotoxicology. New York State experiences Hg contamination largely due to atmospheric deposition. Some landscapes are inherently sensitive to Hg inputs driven by the transport of inorganic Hg to zones of methylation, the conversion of inorganic Hg to methylmercury, and the bioaccumulation and biomagnification along food webs. Mercury concentrations exceed human and ecological risk thresholds in many areas of New York State, particularly the Adirondacks, Catskills, and parts of Long Island. Mercury concentrations in some biota have declined in the Eastern Great Lakes Lowlands and the Northeastern Highlands over the last four decades, concurrent with decreases in water releases and air emissions from regional and U.S. sources. However, widespread changes have not occurred in other ecoregions of New York State. While the timing and magnitude of the response of Hg levels in biota varies, policies expected to further diminish Hg emissions should continue to decrease Hg concentrations in food webs, yielding benefits to the fish, wildlife, and people of New York State. Anticipated improvements in the Hg status of aquatic ecosystems are likely to be greatest for inland surface waters and should be roughly proportional to declines in atmospheric Hg deposition. Efforts that advance recovery from Hg pollution in recent years have yielded significant progress, but Hg remains a pollutant of concern. Indeed, due to this extensive compilation of Hg observations in biota, it appears that the extent and intensity of the contamination on the New York landscape and waterscape is greater than previously recognized. Understanding the extent of Hg contamination and recovery following decreases in atmospheric Hg deposition will require further study, underscoring the need to continue existing monitoring efforts.

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Watershed influences on mercury in tributaries to Lake Ontario

Cited by 10 publications

References 69 publications

Algal Density Controls the Spatial Variations in Hg Bioconcentration and Bioaccumulation at the Base of the Pelagic Food Web of Lake Taihu, China

Algal Density Controls the Spatial Variations in Hg Bioconcentration and Bioaccumulation at the Base of the Pelagic Food Web of Lake Taihu, China

Emergent Freshwater Insects Serve as Subsidies of Methylmercury and Beneficial Fatty Acids for Riparian Predators Across an Agricultural Gradient

A synthesis of patterns of environmental mercury inputs, exposure and effects in New York State

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