Over the Limit?
New, unpublished data showing spiking levels of a toxic pollutant in Galveston Bay speckled trout has prompted state health officials to consider warning fishermen that consuming large quantities of the highly popular game fish could damage their health.
Speckled trout collected at sites around Upper Galveston Bay last year contained elevated concentrations of PCBs, a widely used industrial compound that was banned decades ago based on links to brain damage, reproductive defects and other health problems.
Some environmental health experts found the new levels of PCBs alarming. "This poses a health risk to people, and therefore something must be done," says David Carpenter. He is a toxicology professor with the State University of New York at Albany who has studied PCBs extensively. "I think my recommendation would be to consider the upper levels found in the fish and issue an advisory."
Such an advisory, if issued in line with the trout's migratory patterns, would be the first widespread health warning the state has ever posted for a major game fish in Galveston Bay. It could potentially hobble the local sport-fishing industry.
"I think [the effects] would be pretty profound," says Ted Venker, a spokesperson for the Coastal Conservation Association, which represents many local fishermen. "It's one of the bay's big three fish: flounder, redfish and speckled trout. That would create a big stir."
An official with the Texas Department of Health, the agency responsible for issuing advisories, declined to say whether the state is leaning toward posting such a warning. "I'm not saying for sure that we are going to establish one for spotted sea trout," says Kirk Wiles, director of the department's Seafood Safety Program. "I'm saying that's the one [contaminant] that shows the most concern at this point."
Part of the concern stems from the rapid increase of the contaminant in the trout. In other parts of the United States, levels of PCBs in fish have been on the decline for years. Yet average concentrations in Galveston Bay trout are more than eight times higher than those detected in a small sample of the fish in 1999, the last time such a study was conducted.
The presence of PCBs in other marine organisms went mostly unchanged.
Some authorities say the sheer speed of the spike should warrant more drastic action. Rick Schiao, environmental projects manager for Scenic Hudson, a group that studies toxic substances in New York State's PCB-laced Hudson River, says the state should prohibit trout fishing in the bay until the cause of the contamination can be identified.
"It would be wise to take a precautionary approach," he says. "Temporarily ban consumption of the speckled trout, find the source of the PCBs and remediate it."
In fact, the state has banned fishing from other areas contaminated with PCBs based on much lower pollution levels. In 2003, a fishing ban was maintained at Mountain Creek Lake southwest of Dallas after PCBs were detected at .120 parts per million. The average levels detected in Galveston Bay speckled trout were four times that concentration.
Seafood safety director Wiles says the fishing ban at those PCB concentrations could have reflected interactions between PCBs with other contaminants in the lake, which magnified the health threats. He notes that the trout data should be considered preliminary and says officials are studying similar chemical interactions in Galveston Bay to see if stricter protections are warranted.
Even so, other scientists have criticized the agency for not acting on the findings sooner. The last fish samples were collected in April, and the season for speckled trout fishing is year-round. "If this information is out there, it needs to get out," says Pat Murray, director of the Texas chapter of the Coastal Conservation Association. "The public sure needs to know if it's a real threat."
PCBs -- polychlorinated biphenyls -- were used between the 1930s and the 1970s in the production of sealing and caulking compounds, paint additives, coolants and lubricants. Most varieties of the substances were banned in the United States in 1977. Since then, a mounting body of science has documented their dangers. PCBs are similar to dioxin, a variety of chemical that was used this summer to poison Ukrainian president Viktor Yushchenko. In lower doses over long periods, PCBs are considered by the Environmental Protection Agency to be probable carcinogens.
The U.S. Food and Drug Administration prohibits the sale of fish with levels of PCBs higher than two parts per million, or about half the level detected in the most contaminated Galveston Bay trout. But that standard is meant to apply to commercial fisheries. States have been known to issue much more stringent advisories for fish caught by sport anglers, who often eat higher quantities of fish caught from the same contaminated location.
In fact, PCBs pose more serious threats, in some ways, than other common pollutants found in fish. The most widespread fish consumption advisory along the Texas coast applies to mercury contamination in king mackerel. For the most part, mercury is typically flushed from the human body in the span of a few years. A dose of PCBs will persist for decades. PCBs also tend to accumulate in fatty tissues, which means mothers can pass high levels of the pollutant to their children through breast milk.
"If a ten-year-old girl eats contaminated fish, when she's 20 and gets pregnant she's still going to have half of those PCBs in her body," toxicology professor Carpenter says, "and [she'll] pass them on to her child, with the resulting loss in IQ and disruption of reproductive functions and that sort of thing."
Despite the obvious health threats, Carpenter has limited faith in the ability of state regulators to act on the findings. "When it comes down to real-world government action," he says, "states often are reluctant to set really stringent standards for fear that it will decrease the recreational income from selling fishing licenses. So I think one's got to view some of the state actions with a certain amount of skepticism."
The difficulty of establishing an effective advisory is also compounded by the speckled trout's behavior. The trout data was collected in the Upper Galveston Bay, but the fish migrate frequently to different regions of the bay system. That means an effective advisory may need to cover a large portion of the bay area.
At a glance, the data would seem to back up this conclusion. The highest level of PCBs in a speckled trout was detected in a fish caught off Shoreacres, near the Houston Yacht Club just south of La Porte. That's one of the most distant locations in the study area from the Houston Ship Channel, where most PCB contamination is known to be concentrated.
High levels of PCBs have been detected for several years at the confluence of the Houston Ship Channel and the San Jacinto River, and in the channel's turning basin. In 2001, the state issued a fish consumption advisory for all species in these areas.
Even so, Wiles frowns on the idea of extending a fish consumption advisory further into the bay. "I would not personally recommend that we extend beyond where we have data that we can prove," he says. "But, again, I don't know what will ultimately come from the risk assessment or the department's actions."
Wiles also doesn't know what might be causing the spike in PCBs in the fish.
One potential source of new PCB contamination is dredging. The pollutants can persist for years beneath mud sediments. Parts of the lower and upper bay were dredged in 2000 and 2001, possibly releasing PCBs in the sediments into the environment.
Scientists say the data should spur the state to aggressively seek the source of the pollution. "It suggests the contamination is recent and perhaps ongoing," Carpenter says. So "that should be a very major danger signal."
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