A seasonal study of arsenic in groundwater, Snohomish County, Washington, USA
A series of arsenic poisonings near Granite Falls in Snohomish County, Washington, were identified during 1985–87. An initial investigation revealed the source of arsenic exposure to be high levels of arsenic in well water. A large number of wells in eastern Snohomish County were tested, residents were interviewed and sources of contamination, both natural and man-made, were investigated. More than 70 private drinking-water wells were found to contain elevated levels of arsenic . One well contained 33 mg As L−1. The finding of elevated arsenic levels in a previously approved drinking-water well for a restaurant, plus suggestions of symptoms consistent with arsenic poisoning among people with wells with no detectable arsenic, raised concern over possible temporal variation in arsenic levels. To evaluate this temporal variation, a 12-month study of arsenic in groundwater was conducted in selected wells near Granite Falls. The 12-month study of 26 wells, conducted between February 1988 and January 1989, found arsenic levels for individual wells to vary from one to 19 fold over time. Because of this variability, four out of the eight wells with arsenic levels close to the Maximum Contamination Level (MCL) of 0.050 mg As L−1 would have been considered safe on the basis of a single sample, but would have exceeded the MCL at another time of the year.
In areas with a high occurrence of arsenic contaminated drinking water, approval of well water prior to the sale of a house or issuance of a building permit which is based on a single arsenic test may result in later findings of unacceptable drinking water. When the arsenic is near the MCL, it may be prudent to follow well-water arsenic concentrations over time to assure that the arsenic level remains within acceptable bounds. If lower arsenic standards are adopted for drinking water, the issue of temporal variation around the standard will become a matter of more widespread concern.
KeywordsArsenic Drinking Water Arsenic Concentration Arsenic Exposure Arsenic Level
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- Armstrong, C.W., Stroube, R.B., Rubio, T., Siudyla, E.A. and Miller, G.B. 1984. Outbreak of fatal arsenic poisoning caused by contaminated drinking water. Arch. Environ. Health, 39, 276–279.Google Scholar
- Cebrian, M.E., Albores, A., Aguilar, M. and Blakely, E. 1983. Chronic arsenic poisoning in the north of Mexico. Human Toxicol., 2, 121–131.Google Scholar
- Feinglass, E.J. 1973. Arsenic intoxication from well water in the United States. New England J. Med., 288, 828–830.Google Scholar
- Ficklin, W.H., Frank, D.G., Briggs, P.K. and Tucker, R.E. 1989. Analytical results for water, soil, and rocks collected near Granite Falls, Washington, as part of an arsenic in groundwater study. US Geological Survey Open-File Report, pp.89–148.Google Scholar
- Geyer, L. 1977. Ueber die chronischen Hautveranderungen beim Arsenicismus und Betrachtungen. Arch. Derm. Syph., 43, 221.Google Scholar
- Harrington, J.M., Middaugh, J.P., Morse, D.L. and Housworth, A. 1978. A survey of populations exposed to high concentrations of arsenic in well water in Fairbanks, Alaska. Amer. J. Epidemiol., 108, 377–385.Google Scholar
- Heyman, A., Pfeiffer, J.B., Willett, R.W. and Taylor, H.M. 1956. Peripheral neuropathy caused by arsenical intoxication. New England J. Med., 254, 401.Google Scholar
- Huntting, M.T. 1956. Inventory of Washington minerals. Part II: metallic minerals. Washington State Division of Mines and Geology Bulletin No.37.Google Scholar
- Nadakavukaren, J.J., Ingermann, R.L., Jeddeloh, G. and Falkowski, S.J. 1984. Seasonal variation of arsenic concentration in well water in Lane County, Oregon. Bull. Environ. Contam. Toxicol., 33, 264–269.Google Scholar
- Reynolds, E.S. 1901. An account of the epidemic outbreak of arsenical poisoning occurring in beer drinkers in the North of England. Lancet, 1, 166.Google Scholar
- Roth, F. 1957. The sequelae of chronic arsenic poisoning in Moselle vintners. Ger. Med. Mont., 2, 172.Google Scholar
- Yamashita, N., Boi, M. and Nishio, M. 1972. Recent observations of Kyoto children poisoned by arsenic tainted Morinaga Dry Milk. Japan J. Hygiene, 27, 364.Google Scholar