Man-Made Chemicals Found in Drinking Water at Low Levels

Jan. 1, 2009
Low levels of certain man-made chemicals remain in public water supplies after being treated in selected community water facilities, according to a recent study by the U.S. Geological Survey.

By Patrick Crow, Washington Correspondent

Low levels of certain man-made chemicals remain in public water supplies after being treated in selected community water facilities, according to a recent study by the U.S. Geological Survey. Water from nine selected rivers, used as a source for public water systems, was analyzed in the study.

“Most of the man-made chemicals assessed in the USGS study are unregulated in drinking water and not required to be monitored or removed,” said Tom Jacobus, General Manager of the Washington Aqueduct. “These findings are not surprising and they will be important in helping regulators and assisting water utility managers arrive at decisions about future water treatment processes.”

Scientists tested water samples for about 260 commonly used chemicals, including pesticides, solvents, gasoline hydrocarbons, personal care and household-use products, disinfection by-products, and manufacturing additives. This study did not look at pharmaceuticals or hormones.

Low levels of about 130 of the man-made chemicals were detected in streams and rivers before treatment at the public water facilities. Nearly two-thirds of those chemicals were also detected after treatment.

Most of the chemicals found were at levels equivalent to one thimble of water in an Olympic-sized pool.

“Low level detection does not necessarily indicate a concern to human health, but rather indicates what types of chemicals we can expect to find in different areas of the country,” said USGS lead scientist, Gregory Delzer. “Recent scientific advances have given USGS scientists the analytical tools to detect a variety of contaminants in the environment at low concentrations; often 100 to 1,000 times lower than drinking-water standards and other human-health benchmarks.”

Testing sites include the White River in Indiana; Elm Fork Trinity River in Texas; Potomac River in Maryland; Neuse River in North Carolina; Chattahoochee River in Georgia; Running Gutter Brook in Massachusetts; Clackamas River in Oregon; Truckee River in Nevada; and Cache La Poudre in Colorado. The populations in communities served by these water treatment plants vary from 3,000 to over a million.

This study is among the first by the USGS to report on a wide range of chemicals found before and after treatment. The full source-water quality assessment and listing of chemicals are available online at

Chemicals included in this study serve as indicators of the possible presence of a larger number of commonly used chemicals in rivers, streams, and drinking water. The most commonly detected chemicals in the source water were herbicides, disinfection by-products, and fragrances. Many of these chemicals are among those often found in ambient waters of 186 rivers and streams sampled by USGS since the early 1990s, and are highly correlated with the presence of upstream wastewater sources or upstream agricultural and urban land use. About 120 chemicals were not detected at all.

Measured concentrations of chemicals detected in both source and treated water were generally less than 0.1 part per billion. Although potential human-health effects and risk were not assessed in this study, adverse effects to human health are expected to be negligible based on comparisons of measured concentrations and available human-health benchmarks.

Association Challenges Chemical Security Report

AWWA has warned against a one-size-fits-all approach to chemical security at water utilities.

It was responding to a Center for American Progress report that urged Congress to establish a chemical security program requiring chemical facilities - including water utilities – to assess and use “feasible alternatives that reduce the potential harm of a terrorist attack.”

The report said 15 water utilities could remove danger to 17 million people by converting from chlorine gas (and sometimes sulfur dioxide gas) to alternatives that include liquid bleach or ultraviolet light.

AWWA said chemicals used in drinking water treatment must be transported, stored, and handled with great care and vigilance. It said post-9/11, water security remains a top priority in the design, management and operation of water facilities.

“Water providers use disinfectants to inactivate harmful microorganisms during the treatment process and to prevent contamination while the finished water is in the distribution system. While no single disinfectant is right for all systems, some form of chlorine is necessary and required by state and federal regulations for all drinking water systems using surface water, and based on new federal regulations, for some systems using groundwater,” AWWA said.

“Decisions about which disinfectant to use must ultimately be made locally. Those decisions must take into account several factors, including source water quality, water treatment goals, regulatory requirements and storage capacity. Cost must also be examined, but it is just one of many considerations when determining the best way to assure safe water.”

AWWA said it would issue a document early next year to help water systems evaluate disinfection methods from security, water quality, safety, and other perspectives.

Bottled Water Testing

The Environmental Working Group (EWG) has warned the Food and Drug Administration that its Sept. 17 proposal to require more testing of bottled water for coliform bacteria “is not sufficient to guarantee bottled water quality.”

EWG said the new rules would leave the public in the dark, because unlike tap water, for which all test results are made public, manufacturers don’t disclose bottled water test results.

In October, an EWG study said 10 popular bottled water brands contained 38 chemical pollutants, and bacteria in four cases, some with contaminant levels no better than tap water.

EWG’s Dr. Olga Naidenko said, “For all the hoopla and high prices, bottled water should meet a far higher standard of purity than tap water. Bottled water can easily be filtered to meet the EPA’s health goals, but the industry and FDA have taken the low road, opting for the maximum allowable amount of contamination in their products.”

The environmental group said the FDA proposal contains a major loophole: bottlers would not be obligated to make public their test results, as EPA requires of municipal water treatment systems.

“Considering that bottled water is hundreds or even thousands of times more expensive than municipal water, consumers deserve much greater health protection from toxic contaminants in bottled water,” Naidenko said.

Meanwhile, Joe Doss, president of the International Bottled Water Association, told his members that they are under “unwarranted attacks by environmental activists.”

He said, “It is clear that a war is being waged against our products and the future of the bottled water industry is at stake.”

Doss said that the industry uses less than 0.02% of the total groundwater withdrawn in the U.S. each year. He said there is a consensus that IBWA should establish a goal for increasing bottled water plastic container recycling rates and a plan is being developed.

In other Washington news:

– EPA and 14 national water groups have reached an agreement that will help improve management of wastewater septic systems serving 25 million homes. The groups will exchange information and provide technical assistance to their members, states and local municipalities.

– EPA has outlined a plan to set pollution caps for the Chesapeake Bay. The Total Maximum Daily Load standard will be completed in December 2010 and will identify pollutant caps by major river basin in the 64,000-square-mile watershed.

– EPA is seeking comments on proposed guidelines to control the discharge of pollutants from construction sites. The proposal would require all construction sites to implement erosion and sediment control best management practices to reduce pollutants in stormwater discharges.

– EPA has given Union Sanitary District in Union City, Calif., an award for its achievements in wastewater treatment and pollution prevention. The district provides wastewater collection, treatment and disposal services for the cities of Fremont, Newark, and Union City, and has 50 significant industrial users.

– EPA is applying more stringent controls on stormwater pollution in the Charles River watershed in Massachusetts. It said stormwater containing high levels of phosphorus has caused algae blooms – including toxic cyanobacteria – in recent years.

– The Interior Department’s Bureau of Reclamation has set criteria for its new Rural Water Supply Program, which will help fund water-supply projects in western states. It is accepting public comment on the interim final rule. WW

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