Efficiency of conventional drinking-water-treatment processes in removal of pharmaceuticals and other organic compounds

Water samples collected from 1992 through 2001 from 186 streams and rivers and from 5,047 wells in 51 of the nation's major river basins and aquifer systems were summarized to provide the most comprehensive national-scale analysis of pesticide occurrence to date. At least one pesticide was detected in water from all streams studied, and at least one pesticide was detected more than 90 percent of the time in water from streams draining agricultural, urban, or mixed land uses. Pesticides were less common in groundwater than in streams, but were detected in more than 50 percent of the sampled shallow wells beneath agricultural and urban areas. About one-third of the deeper wells sampled, which tap major aquifers used for water supply, contained one or more pesticides or pesticide degradates.

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Pesticides in the Nation's Streams and Ground Water, 1992-2001

Four chlorinated solvents-methylene chloride, perchloroethene (PCE), 1,1,1-trichloroethane, and trichloroethene (TCE)-were analyzed in samples of groundwater taken throughout the conterminous United States by the U.S. Geological Survey. The samples were collected between 1985 and 2002 from more than 5,000 wells. Of 55 volatile organic compounds (VOCs) analyzed in groundwater samples, solvents were among the most frequently detected. Mixtures of solvents in groundwater were common and may be the result of common usage of solvents or degradation of one solvent to another. Relative to other VOCs with Maximum Contaminant Levels (MCLs), PCE and TCE ranked high in terms of the frequencies of concentrations greater than or near MCLs. The probability of occurrence of solvents in groundwater was associated with dissolved oxygen content of groundwater, sources such as urban land use and population density, and hydraulic properties of the aquifer. The results reinforce the importance of understanding the redox conditions of aquifers and the hydraulic properties of the saturated and vadose zones in determining the intrinsic susceptibility of groundwater to contamination by solvents. The results also reinforce the importance of controlling sources of solvents to groundwater.

Chlorinated solvents in groundwater of the United States.

https://ca.water.usgs.gov/pubs/frambelitz2011pharms.pdf

Occurrence and concentrations of pharmaceutical compounds in groundwater used for public drinking-water supply in California.

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1372&context=usgsstaffpub

Comparison of a novel passive sampler to standard water-column sampling for organic contaminants associated with wastewater effluents entering a New Jersey stream

/pdf/new-reporting-procedures-based-on-long-term-method-detection-2fapdoibgj.pdf

New reporting procedures based on long-term method detection levels and some considerations for interpretations of water-quality data provided by the U.S. Geological Survey National Water Quality Laboratory

A method for the determination of 30 individual organochlorine pesticides, total toxaphene, and total poly chlorinated biphenyls (PCBs) in aquatic bottom sediment is described and laboratory performance data are provided. The method was developed in support of the U.S. Geological Survey's National Water-Quality Assessment program and is based on conventional Soxhlet extraction using dichloromethane. Two aliquots of the sample extract are quantitatively injected onto a styrene-divinylbenzene gel permeation column and eluted with dichloromethane. This gel permeation chromatography step removes inorganic sulfur and large naturally occurring molecules from the sediment extract. The first aliquot is analyzed for semivolatile organic compounds by gas chromatography with mass spectrometric detection. The second aliquot is further split into two fractions by combined alumina/silica adsorption chromatography prior to determination of the organochlorine pesticides and PCBs by dual capillary-column gas chromatography with electron-capture detection (GC/ECD). This report completely describes and is limited to the determination of the organochlorine pesticides and PCBs by GC/ECD. Current (February 1995) data-reporting limits have been set at 1 to 5 micrograms per kilogram for 30 chlorinated pesticides, 50 micrograms per kilogram for total PCBs, and 200 micrograms per kilogram for toxaphene.

/pdf/methods-of-analysis-by-the-u-s-geological-survey-national-2uayq0yrkg.pdf

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of organochlorine pesticides and polychlorinated biphenyls in bottom sediment by dual capillary-column gas chromatography with electron-capture detection

Brooke F. Connor

Papers

New reporting procedures based on long-term method detection levels and some considerations for interpretations of water-quality data provided by the U.S. Geological Survey National Water Quality Laboratory

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of organochlorine pesticides and polychlorinated biphenyls in bottom sediment by dual capillary-column gas chromatography with electron-capture detection