A new study, which looks at rivers and streams in 30 U.S. states, shows American waterways contain low concentrations of everyday household chemicals that are rinsed or flushed down the drain every day. The compounds include human and veterinary drugs, natural and synthetic hormones, detergents, insecticides, fire retardants and substances found in plastics.
The study, which measured these pollutants in the United States for the first time, was published by the U.S. Geological Survey, a government science agency.
Herb Buxton directs the USGS office responsible for the report. "Many of these compounds are used in our households or even consumed by us," he says. "They make it through our water treatment facilities, which are not designed to remove these compounds particularly at trace levels that we find, and then wind up in the discharges that go directly to our streams."
The chemicals, known as personal care pollutants, are routinely discharged in human and livestock waste and from chemical plant refuse. "Of the 95 compounds we studied, 33 are known or suspected to be hormonally active. That means that they may in some way interfere with the endocrine system of animals or humans," he says. "More than 45 of the compounds are pharmaceutically active and so are designed in some way to effect the operation of our bodies. Also, it is important to understand the mixture of compounds that are in the environment, and to understand that there are mechanisms for many of the compounds that we use every day to enter our environment and our waters through our waste stream."
Researchers took samples downstream from major urban, agricultural and industrial areas looking where they suspected they would find the pollutants.
Buxton: "We found one or more of the compounds in 80 percent of the streams we sampled. We did find 82 of the 95 compounds. The concentrations we found were generally very low, about a part per billion. A part per billion is a very small trace amount. But at the same time one part per billion is a level at which some health standards already exist for water. And, for some of these compounds, the hormonally active compounds, it is important to study them at concentrations even lower than one part per billion."
Skirble: "So, where do we go from here? Should we be concerned?"
Buxton: "I don't think that there is cause for alarm with this data. As a matter of fact, this is an important indication that we aggressively measure compounds that may be entering our environment.
What threat do these chemicals pose on human health and the environment? And, what is the cumulative effect of these pollutants? Herb Buxton says the USGS study, which is the first to explore such questions in the United States, is only a first step. He says the findings point to the need for more research in the future to answer those questions.