Abstract  BIOSIS COPYRIGHT: BIOL ABS. The objective of this research was to identify chemical, physical, bacteriological, and viral contaminants, and their sources, which present the greatest health threat in public ground water supplies in the USA; and to classify (prioritize) such contaminants and relative to their health concerns. The developed contaminant prioritization methodology was based on frequency of occurrence and adverse health effects. Adverse health effects were based on carcinogenic potency, toxicity, hazardous chemical priorities and drinking water standards. Application of the methodology for wellhead protection areas, (WHPAs) revealed that approximately 200 different contaminants have been detected in the nation's public ground water supplies. The seven chemical constituents with the highest priority were arsenic, chromium, cadmium, carbon tetrachloride, chloroform, 1, 1-dichloroethylene, and ethylene dibromide. Other contaminants of concern were trichloroethylene, nitrates, barium, 1,1,

Abstract  High concentrations of tetrachloroethylene were discovered in groundwater samples taken from the Honkala aquifer in the municipality of Sakyla in southwestern Finland. The contamination was traced to a dry-cleaning laundry located close to a tributary esker which is connected to the Sakylanharju esker in the northeastern part of the area. The Weichselian and Holocene sediments of the area include till, sand and gravel and also glacial and postglacial clay deposits. The groundwater flows west towards Pyhajarvi (a lake in the municipality of Sakyla). A study was launched to test the applicability of numerical groundwater models in developing an overview of groundwater flow and contaminant transport in the area and prediction of the timing of natural attenuation. Modelling was conducted with the MODFLOW, MODFLOWP and MT3D codes, the resulting simulations indicating a natural attenuation time of more than 30 years would be required for the aquifer. Active aquifer restoration would require pumping and treatment of the polluted groundwater.

Abstract  Pentachlorophenol, 2,3,4,6-tetrachlorophenol, 4-nonylphenol, 4-nonyl-phenolmonoethoxyl ate, 4-nonylphenoldiethoxylate, tetrachloroethylene and 1,4-dichlorobenzene were quantitatively determined in surface waters of the Glatt Valley, Switzerland. Monthly samples were collected during one year from four locations along the Glatt River, from two small creeks and from the effluents of two municipal wastewater treatment plants. The longitudinal concentration and load profiles found in the Glatt River indicated that all of these micropollutants are mainly introduced into the river via treated wastewater effluents. The highly chlorinated phenols remain unchanged in the river, while the other pollutants are affected by various physico-chemical and biological processes. Depth profiles of tetrachloroethylene in the Greifensee, the lake which feeds the Glatt, showed that this compound was eliminated from the epilimnion by transfer to the atmosphere and by discharge into the Glatt River.

Abstract  Letter from Dow Chemical Co submitting several studies with trichloroethylene and other chemicals in humans with attachments (sanitized)