La Crosse, Wisconsin 54602. Abstract. Profiles of total mercury (Hg) concentra- tions in sediments were examined in 11 lakes in north-central Wisconsin having ...
Arch. Environ. Contain. Toxicol. 18, 175-181 (1989)
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Recent Increases in Atmospheric Deposition of Mercury to North-Central Wisconsin Lakes Inferred From Sediment Analyses Ronald G. Rada*, James G. Wiener**, Michael R. Winfrey*, and David E. Powel]* *River Studies Center, Department of Biology and Microbiology, University of Wisconsin-La Crosse, La Crosse, Wisconsin 54601, **U.S. Fish and Wildlife Service, National Fisheries Contaminant Research Center, Fietd Research Station, La Crosse, Wisconsin 54602
Abstract. Profiles of total mercury (Hg) concentrations in sediments were examined in 11 lakes in north-central Wisconsin having a broad range of pH (5.1 to 7.8) and alkalinity ( - 1 2 to 769 txeq/L). The sediments, which were hydrous and flocculent, were collected at or near the area of maximum depth in each lake with a diver-operated sampler that permitted in situ sectioning of a 1-m core. Mercury concentrations were greatest in the top 15 cm of the cores and were much lower in the deeper strata. The Hg content in the most enriched stratum of individual cores ranged from 0.09 to 0.24 ~g/g dry weight, whereas concentrations in deep, precolonial strata ranged from 0.04 to 0.07 l~g/g. Sediment enrichment factors varied from 0.8 to 2.8 and were not correlated with lake pH. The increase in the Hg content of recent sediments was attributed to increased atmospheric deposition of the metal. Eight of the 11 systems studied were low-alkalinity lakes that presumably received most (i>90%) of their hydrologic input from precipitation falling directly onto the lake surface. Thus, the sedimentary Hg in these lakes seems more likely linked to direct atmospheric deposition onto the lake surfaces than to influxes from the watershed. The data imply that a potentially significant fraction of the high Hg burdens measured in game fish in certain lakes in north-central Wisconsin originated from atmospheric sources.
High concentrations of mercury (Hg) have been found in piscivorous fishes from rural, low-alkalinity lakes in north-central Wisconsin (Wiener
1983). The observation of Hg concentrations exceeding 0.5 and t .0 Ixg/gfresh (wet) weight in edible muscle of fish has prompted health advisories by the State of Wisconsin recommending that human consumption of certain sport fishes from several waters be limited or avoided (WDNR and WDH 1987). In north-central Wisconsin, Hg levels are typically greatest in fish from lakes with pH 90%) of their hydrologic inflow as precipitation falling directly onto the lake surface (Eilers et al. 1983; Cook et al. 1987). Hydrologic infows to these low-alkalinity lakes from their terrestrial catchments (ground-water inflow and overland flow) are small. Given their hydrologic characteristics, it seems probable that Hg inputs to low-alkalinity lakes in the study area are largely atmospheric. Johnson (1987) and Evans (1986) similarly concluded that atmospheric deposition was an important influx of Hg into Ontario lakes. Mercury is released into the atmosphere by many processes, both natural and anthropogenic (Lindq-
vist and Rodhe 1985; Lindberg 1987; Pacyna 1987). Most (>80%) of the Hg in the atmosphere is the elemental form, Hg ~ which has a long atmospheric residence time (about 0.5-2 yr; Lindqvist and Rodhe 1985; Slemr et al. 1985)--a situation conducive to long-range transport (Lindberg 1987). Precipitation scavenging of Hg ~ is considered the major process for Hg removal from the atmosphere (Lindberg 1987); the Hg ~ is oxidized to water-soluble ionic forms that can enter aquatic systems in wet deposition (Lindqvist and Rodhe 1985; Brosset 1987). From our findings, it is hypothesized that a potentially significant fraction of the Hg burdens in fish in north-central Wisconsin lakes is atmospheric in origin. Acknowledgments. This study was funded by the Wisconsin Department of Natural Resources; the University of Wisconsin-La Crosse Foundation, Inc. funded grants for student help. K. E. Webster provided numerous documents and existing data for the study lakes. The following persons participated with the collection and analysis of samples or with preparation of the manuscript: J. Barker, W. Cope, R. Davis, G. Howe, T. Mitchell, J. Rogala, K. Rusch, M. Schmidt, M. Steingraeber, P. Thorson, and K. Van Vreede. The manuscript was reviewed by C. J. Watras, W. G. Brumbaugh, T. A. Haines, and C. G. Ingersoll.
References APHA (American Public Health Association) (1985) Standard Methods for the Examination of Water and Wastewater. 16th Edition, New York, 1268 pp
Atmospheric Deposition of Mercury Brosset C (1987) The behavior of mercury in the physical environment. Water Air Soil Pollut 34:145-166 Burley M (1964) Climate of Wisconsin. In: The Wisconsin bluebook. pp 143-148 Charles MJ, Hites RA (1987) Sediments as archives of environmental pollution trends. In: Hites RA, Eisenreich SJ (eds) Sources and fates of aquatic pollutants. Am Chem Soc, Washington, DC, p 365 Cook RB, Kelley CA, Kingston JC, Kreis RG, Jr. (1987) Chemical limnology of soft water lakes in the Upper Midwest. Biogeochemistry 4:97-117 Eilers JM, Brakke DF, Landers DH (1988) Chemical and physical characteristics of lakes in the Upper Midwest, United States. Environ Sci Technol 22:164-172 Eilers JM, Glass GE, Webster KE, Rogalla JA (1983) Hydrologic control of lake susceptibility to acidification. Can J Fish Aquat Sci 40:1896-1904 Environment Canada (1979) Analytical Methods Manual. Inland Waters Directorate, Water Quality Branch, Ottawa, Ontario Evans RD (1986) Sources of mercury contamination in the sediments of small headwater lakes in south-central Ontario, Canada. Arch Environ Contam Toxicol 15:505-512 Evans RD, Dillon PJ (1982) Historical changes in anthropogenic lead fallout on southern Ontario, Canada. Hydrobiologia 91:131-137 Hakanson L, Nilsson A, Andersson T (1988) Mercury in fish in Swedish lakes. Environ Pollut 49:145-162 Hole FD (1976) Soils of Wisconsin. University of Wisconsin Press, Madison, WI Johnson MG (1987) Trace element loadings to sediments of fourteen Ontario lakes and correlations with concentrations in fish. Can J Fish Aquat Sci 44:3-13 Johnson MG, Culp LR, George SE (1986) Temporal and spatial trends in metal loadings to sediments of the Turkey Lakes, Ontario. Can J Fish Aquat Sci 43:754-762 Lindberg SE (1987) Emission and deposition of atmospheric mercury vapor. In: Hutchinson TC, Meema KM (eds) Lead, mercury, cadmium, and arsenic in the environment. John Wiley and Sons, New York, pp 89-106 Lindqvist O, Rodhe H (1985) Atmospheric mercury--a review. Tellus 37B: 136-159 Linthurst RA, Landers DH, Eilers JM, Brakke DF, Overton WS, Meier ER Crowe RE (1986) Characteristics of lakes in the eastern United States. Volume I. Population descriptions and physico-chemical relationships. EPA-600/4-86007a, US Environmental Protection Agency, Washington, DC Meger SA (1986) Polluted precipitation and the geochronology of mercury deposition in lake sediment of northern Minnesota. Water Air Soil Pollut 30:411-419 Norton SA (1985) The sedimentary record of atmospheric pollution in Jerseyfield Lake, Adirondack Mountains, New York. In: Adams DD, Page WP (eds) Acid deposition: environ-
181 mental, economic, and policy issues. Plenum Press~ New York, pp 95-107 Oakes EL, Cotter RD (1975) Water resources of Wisconsin: Upper Wisconsin River basin. US Geol Survey Hydrol Invest Atlas HA-536. Reston, VA, 3 sheets Pacyna JM (1987) Atmospheric emissions of arsenic, cadmium, lead and mercury from high temperature processes in power generation and industry. In: Hutchinson TC, Meema KM (eds) Lead, mercury, cadmium and arsenic in the environment. John Wiley and Sons, New York, pp 89-106 Powell DE, Rada RG (1987) Effects of pH on the release of aluminum, cadmium, and lead from littoral and profundal sediments of Lakes Clara and McGrath, northern Wisconsin. In: Lindberg SE, Hutchinson TC (eds) Heavy metals in the environment. CEP Consultants Ltd, Edinburgh, United Kingdom, pp 178-180 Rada RG, Findley JE, Wiener JG (1986) Environmental fate of mercury discharged into the Upper Wisconsin River. Water Air Soil Pollut 29:57-76 Rada RG, Winfrey MR, Wiener JG, Powell DE (1987) A comparison of mercury distribution in sediment cores and mercury volatilization from surface waters of selected northern Wisconsin lakes. Final Report to the Wisconsin Department of Natural Resources, Madison, WI Schnoor JL, Nikolaidis NP, Glass GE (1986) Lake resources at risk to acidic deposition in the Upper Midwest. J Water Pollut Control Fed 58:139-148 Slavin S, Barnett WB, Kahn HL (1972) Determination of atomic absorption detection limits by direct measurement. Atomic Absorption Newsletter 11:37-41 Slemr F, Schuster G, Seller W (1985) Distribution, speciation, and budget of atmospheric mercury. J Atmos Chem 3:407434 Talbot RW (1981) Atmospheric fluxes and geochemistries of stable Pb, zl~ and 21~ in Crystal Lake, Wisconsin. PhD dissertation, University of Wisconsin, Madison, WI USEPA (United States Environmental Protection Agency) (1983) Methods for chemical analysis of water and wastes. EPA 600/4-79-020 (revised 3-83), Washington, DC Wiener JG (1983) Comparative analyses of fish populations in naturally acidic and circumneutral lakes in northern Wisconsin. FWS/OBS-80/40.16, US Fish and Wildlife Service, Eastern Energy and Land Use Team - (1987) Metal contamination of fish in low-pH lakes and potential implications for piscivorous wildlife. Trans N Am Wildl Nat Resour Conf 52:645-657 WDNR and WDH (Wisconsin Department of Natural Resources and Wisconsin Division of Health) (1987) Health advisory for people who eat sport fish from Wisconsin waters. Madison, WI, 7 pp
Manuscript received June 2, 1988.
