『Abstract
　Since the early 1980s, investigations by health departments of eight countries in southern New Jersey, by the NJ Department of Environmental Protection (NJDEP), and subsequently by the US Geological Survey (USGS), have shown that Hg concentrations in water tapped by about 600 domestic wells exceed the maximum contaminant kevel (MCL) of 2μg/L. The wells are finished in the areally extensive unconfined Kirkwood-Cohansey aquifer system of New Jersey's Coastal Plain; background concentrations of Hg in water from this system are ＜0.01μg/L. Evidence of contributions from point sources of Hg, such as landfills or commercial and industrial hazardous-waste sites, is lacking. During 1996-2003, the USGS collected water samples from 203 domestic, irrigation, observation, and production wells using ultraclean techniques; septage, leach-field effluent, soils, and aquifer sediments also were sampled. elevated concentrations of NH4, B, Cl, NO3, and Na and presence of surfactants in domestic-well water indicate that septic-system effluent can affect water quality in unsewered residential areas, but neither septage nor effluent appears to be a major Hg source. Detections of hydrogen sulfide in ground water at a residential area indicate localized reducing conditions; undetectable SO4 concentrations in water from other residential areas indicate that reducing conditions, which could be conducive to Hg methylation, may be common locally. Volatile organic compounds (VOCs), nostly chlorinated solvents, also are found in ground water at the affected areas, but statistically significant associations between presence of Hg and VOCs were absent for most areas evaluated. Hg concentrations are lower in some filtered water samples than in paired unfiltered samples, likely indicating that some Hg is associated with particles or colloids. The source of colloids may be soils, which, when undisturbed, contain higher concentrations of Hg than do dosturbed soils and aquifer sediments. Soil disturbance during residential development and inputs from septic systems are hypothesized to mobilize Hg from soils to ground water.

Keyword: mercury (Hg); ground water; septic Systems; Sulfate (SO4); colloids; methylmercury; volatile Organic compounds (VOCs)』

1. Introduction
2. Study area
3. Methods
　3.1. Site selection and well installation
　3.2. Sample collection
　3.3. Sample analysis
　3.4. Data compilation and statistical analysis
4. Results
　4.1. Hg in soils
　4.2. Hg in aquifer materials
　4.3. Hg and other constituents in septic-system effluent
　4.4. Hg in ground water
　　4.4.1. Variations in Hg concentrations
　　4.4.2. Relation of Hg and other constituent concentrations to land use
　　4.4.3. Relation of Hg to anthropogenic organic constituents
　　4.4.4. Hg concentrations in unfiltered and filtered samples
5. Discussion
　5.1. Relation of colloids to Hg concentration
　5.2. Potential for mobilization of Hg from soils and sediments
　5.3. Effects of septic-system effluent on ground-water chemistry
　5.4. Spatial distribution of Hg-contaminated ground water
6. Conclusions
Acknowledgement
References

• Andren,A.W. and Nriagu,J.O.(1979): The global cycle of mercury. In: Nriagu,J.(Ed.), The biogeochemistry of mercury in the environment. Amsterdam, The Netherlands, Elsevier/North Holland Biomedical Press, 1-21.
• Barber,L. and Steele,K.F.(1980): Mercury content of waters in the midcontinent region. Arkansas Academy of science Proceedimg, 34, 19-21.
• Fischer,P. and Gustin,M.S.(2002): Influence of natural sources on mercury in water sediment and aquatic biota in seven tributary streams of the East Fork of the Upper Carson River, California. Water, Air, Soil Pollution, 133, 283-295.
• Krabbenhoft,D.P. and Babiarz,C.L.(1992): The role of ground water transport in aquatic mercury cycling. Water Research, 28, 3119-3128.
• Macfarlane,P.A., Whittemore,D.O., Townsend,M.a., Butler,J.J.,Jr., Doveton,J.H., Hamilton,V.J., Coleman,J., Chu,T.M. and WadamA.(1990): The Dakota Aquifer program: Annual report, FY90, Kansas Geological Survey Open-File Report 91-1.
  The Dakota Aquifer Program--Annual Report, FY91　　http://www.kgs.ku.edu/Dakota/vol3/fy91/index.htm
  　Kansas Geological Surveyの『Dakota Aquifer Program』の『Annual Reports』の中のページ。
• Reimann,C., Siewers,U., Skarphagen,H. and Banks,D.(1999): Influence of filtration on concentrations of 62 elements analyzed on crystalline bedrock groundwater samples by ICP-MS. Science of the Total Environment, 234, 155-173.
• Rytuba,J.J.(2000): Mercury mine drainage and processes that control its environmental impact. Science of the Total Environment, 260, 57-71.
• Sidle,W.C.(1993): Naturally occurring mercury in a pristine environment? Environmental Geology, 21, 42-50.
• Somasundaram,M.V., Ravindran,G. and Tellam,J.H.(1993): Ground-water pollution of the Madras urban aquifer, India. Ground Water, 31, 4-11.
• Srinkanth,R., Rao,A.M.M., Khanum,A. and Reddy,S.R.P.(1993): Mercury contamination of groundwater around H
• USEPA (1997): Mercury study - Report to Congress. v. 1, SPA-452/R-97-003.
  Mercury Study Report to Congress　　http://www.epa.gov/mercury/report.htm
  　EPAの『Mercury』の中のページ。
• USEPA (2001): Water quality criterion for the protection of human health: Methylmercury. EPA-823-R-01-001.
  Fish tissue criterion for methylmercury to protect human health document　　http://www.epa.gov/waterscience/criteria/methylmercury/document.html
  　EPAの『Water』の『Water Science』の『Water Quality Criteria』の『Human Health』の『Methylmercury』の中のページ。
• USEPA (2001): National primary drinking water standards. EPA 816-F-01-007.
  National primary drinking water standards　　http://www.rurdev.usda.gov/wi/programs/rhs/library/EPA-Water-Quality-Standards.pdf
  　USDA Rural Developmentの中のページ。
• Wiklander,L.(1969): The content of mercury in Swedish ground and river water. Geoderma, 3, 75-79.