That morning cup of coffee, the medicines we take, household cleaners, pesticides and a host of chemicals…What do they have in common?  Besides being useful and sometimes lifesaving, particularly that cup of coffee on Monday morning, they all eventually end up in the environment. 

As everyday as these products are, we really know little about them as environmental contaminants. And the lack of data is feeding the concern for what scientists call “emerging contaminants.” We do not know the prevalence of these compounds in drinking-water supplies and the potential for effects on the environment or human health.

The problem in getting information on emerging contaminants is twofold: a compound dissolved in water and occurring at a very low concentration. The concentration is so low in a typical stream that conventional chemical testing would not detect the presence of a contaminant targeted for identification.

USGS scientist David Alvarez developed and patented the Polar Organic Chemical Integrated Sampler, one of the newest tools to increase the knowledge and understanding of emerging contaminants. POCIS is a portable device so sensitive that if you breathe on it, it can detect the coffee you had for breakfast. POCIS is becoming an important tool in learning more about water quality.

Forgoing their morning coffee and bug spray last spring, USGS scientists, led by John Tertuliani, set the POCIS devices at 18 sites on Tinkers Creek, the largest tributary to the Cuyahoga River, which is the second largest tributary to Lake Erie in Ohio.

Tinkers Creek was chosen as a study site after biological surveys by the Ohio Environmental Protection Agency indicated that the numbers of fish in the population did not match the available habitat. When fish are not abundant enough to use the habitat available, it is normally a sign of harmful chemical compounds in the water. But chemical surveys done in conjunction with the biological surveys did not identify the usual chemical suspects. The Ohio Environmental Protection Agency then asked Tertuliani for help investigating whether emerging contaminants were having an effect on the fish population.

The POCIS device is designed to mimic the exposure to chemicals that aquatic organisms, such as fish, would experience while living in the stream. It can accumulate trace to ultra-trace concentrations of chemicals over a long-term exposure, which is proving to be a more effective approach for these kinds of studies than traditional monitoring methods such as grab sampling. By sampling over an extended period, chemicals in the water are eventually captured in the POCIS device. The membranes in the device are able to accumulate the emerging contaminants in concentrations high enough to be identified.

Primary research such as this can pose many challenges, both in the field and in the laboratory. The Tinkers Creek study is the first of its kind in Ohio and the largest study undertaken with POCIS technology. Deploying a curious-looking device in popular areas such as parks and other sections of streams with public access can result in equipment being disturbed or vandalized and loss of important data. During this study, the POCIS devices were deployed for 28 days. Numerous storms made constant inspections necessary.  Each device had to be checked and moved back to the main channel area if needed. A POCIS device must remain underwater at all times during deployment; it will otherwise sample the air as readily as the water and comprise the data.

Final results on the Tinkers Creek study are still pending, but should prove worth the challenges faced by the USGS Ohio Water Science Center and its cooperators. POCIS technology, though in its infancy, may prove a pivotal point in the future of water quality research.