environmental health

by Peter Philbrook, chemist, EPA Region 1 Laboratory and Todd Borci, environmental scientist, EPA Region 1 Office of Environmental Stewardship

What Clean Water Act problem were you facing in EPA Region 1?

The bacterial impairment of surface water which exceeds minimum water quality criteria. The criteria are based on the use of two bacterial indicators of fecal contamination, E. coli and enterococci. Exceedances trigger investigations into the source, and, if found to be of human origin, preventative measures that remediate the problem area( s) are required. Human sources are targeted because they represent a higherrisk health threat and typically the solution can be engineered. One of the major sources of contamination is aging urban sewage infrastructure that discharges to storm drains and nearby surface waters. Identifying, locating and removing sources of human sewage that impair waterways is critically important to EPA’ s mission to ensure compliance with the Clean Water Act.

High bacteria concentrations were found in this urban waterway. Additional chemical testing revealed high levels of surfactants / ammonia / chloride and pharmaceuticals, which indicated the presence of human sewage and initiated further investigation for remediation purposes. Photo by Todd Borci

These two protocols, combined with microbial testing, give investigators more definitive information to use when making decisions on impacted waterways.

What new laboratory and field methods did you develop to find a viable solution?

In 2009, our field investigators and chemists worked together to focus on determining whether bacteria found in surface waters originated from human sanitary sewage. This effort resulted in two new chemical procedures by the EPA Region 1 Laboratory that are used to definitively track sources of human waste in surface water. The first is a practical, low-cost suite of chemical screening kits for surfactants, ammonia and chloride that identify problem spots while in the field. Surfactants represent the presence of soaps / detergents, ammonia is found at high concentrations in untreated human sewage and chloride indicates the source is a chlorinated water system. The second is a laboratory procedure that forensically identifies and quantifies human pharmaceutical compounds using high-performance liquid chromatography with tandem mass spectrometry( HPLC / MS / MS). We look for caffeine, acetaminophen, cotinine, atenolol, metoprolol, 1,7-dimethylxanthine and carbamazepine. These two protocols, combined with microbial testing, gives investigators more definitive information to use when making decisions on impacted waterways. It also allows Region 1 to delineate problem drainage areas faster and with greater accuracy, and has given investigators convincing source tracking evidence when pursuing enforcement actions.

How is this positively impacting the region?

As we near our eighth year using this protocol, we have made significant strides in getting sewage out of stormwater throughout New England. For instance, the direct use of this protocol in Boston Harbor has eliminated over 68 million gallons of raw sewage annually which would have otherwise entered the harbor and associated watersheds.

Given this and other experiences, how would you recommend that public health / environmental laboratories face this or other source tracking problems?

The HPLC / MS / MS method we developed incorporates multiple automated sample prep steps which streamlines the process, reduces time and minimizes solvent usage. This, along with an abbreviated target compound list, also significantly reduces analysis cost. Implementation of this method may take approximately 30 days and only several commercial laboratories currently offer this analysis in the US. If more laboratories offered the test, costs would be driven down and municipalities would be more likely to use this to detect sewer leaks.

What are your future source tracking plans?

The field work and investigative / detective piece of source tracking is by far the most important aspect of this project. As we better learn the method advantages and limits, we are able to tackle more complex projects, such as areas with frequent beach closures and other chronic bacterial impairments. We continually strive to train and inform our partners on how to implement this tool and are also constantly looking into new technologies to help us accomplish our mission.

The beach stormwater outfall above discharges into a saltwater marsh. High bacteria concentrations were found here, but chemical indicators showed no evidence of sewage contamination

For more information on these source tracking techniques and methods, please contact Peter Philbrook at Philbrook. Peter @ epa. gov.