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For the last five years, GERG researchers Jose Sericano, Stephen Sweet and Terry Wade have been working under a contract with the Texas Department of State Health Services (DSHS) to provide analytical testing for environmental contaminants in fish tissue samples from Texas lakes, rivers, bays and estuaries.

An advisory means that eating more fish than recommended from a particular water body may pose a human health risk

GERG staff has ground up thousands of frozen fish filets - carp, flathead, bass, etc. - to conduct more than 5,000 analytical tests on the tissue samples. Once the analytical results are reported, the remaining samples are stored in freezers at GERG 's facility on Graham Road. The Seafood and Aquatic Life Group (SALG ) at DSHS is charged with determining whether chemical contaminants in fish and shellfish living in public water bodies in Texas pose a health risk to people who consume them. Since 2004, GERG 's environmental Sciences Group has been doing all of the fish tissue testing for SALG . Based on this testing, SALG decides whether to issue or rescind health advisories and possession bans. According to GERG Environmental Sciences Deputy Director Terry Wade, this contract was awarded to GERG based on its experience working with other national and international environmental monitoring programs and its reputation for producing valid analytical data.

“When we take custody of fish filets shipped to us in coolers or brought in from the field by SALG staff, we have to track each sample throughout the analytical process. We log in the samples, note the types of contaminants each is to be tested for, and then store them in our freezers until we complete the testing,” said Wade.

The tissue samples are tested for a variety of common contaminants including mercury, trace elements, pesticides such as DDT, polychlorinated biphenyls (PCB), volatile and semivolatile organic compounds, and dioxins and furans. These analyses require the use of sophisticated and expensive instrumentation. Concentrations of contaminants are measured at very low concentrations, as parts per billion to parts per trillion. “DSHS determines which tests they want done on each sample based on historical data they have on areas of concern for a particular water body,” Wade added. “Many times we’re testing samples to see if things have gotten better so that DSHS can remove a fish advisory. They compare our results to their historical data and EPA criteria and make decisions regarding whether or not it is safe to consume fish from that water body.”

"We want to continue this relationship because it is a way for GERG to use its analytical expertise to benefit the residents of Texas ... "

Since GERG has been doing this work for DSHS , new advisories have been issued for several water bodies in Texas. As of last January, there were 27 public water bodies with advisories in effect and five with possession bans. An advisory means that eating more fish than recommended from a particular water body may pose a human health
risk, but harvesting fish from that water body is not illegal. A possession ban means that it is illegal to even take fish from a water body where tissue testing indicates the likelihood of a serious or imminent threat to public health from consumption of those fish.

Based on the success of the work GERG has completed thus far for DSHS , the group has proposed to begin additional analytical work this fall. “We want to continue this relationship because it is a way for GERG to use its analytical expertise to benefit the residents of Texas,” Wade said.

For additional information on fisheries advisories, visit the Seafood and Aquatic Life Group website.

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