Can I Eat What I Catch?
What You Need to Know About Houston’s Fish Consumption Advisory
The Houston/Galveston area has been blessed with water resources and nothing beats a day out on Galveston Bay or the rivers that feed the bay, but it is important to remember that many of those waterways are under fish consumption advisories. For more than 30 years, the Texas Department of State Health Services (DSHS) has been reminding people that it has a seafood consumption advisory in place that recommends avoiding the consumption of all seafood caught in the Houston Ship Channel, the San Jacinto River (below the Lake Houston Dam), and all connected waterways north of the State Highway 146 bridge.
Unsafe levels of toxic contaminants including PCBs and dioxins have been found in the tissue of both fish and shellfish in this area. As a result, DSHS recommends that children and women of childbearing age do not consume any seafood from these areas. Adult men and women beyond childbearing age may be able to consume a maximum of one meal (8 oz) per month of catfish, spotted seatrout, or blue crab without experiencing negative impacts.
The map below illustrates the precise areas to which the seafood consumption advisory applies:
Iterations of this advisory have been in place since 1990 when DSHS first began testing local fish for toxic contaminants. As previously mentioned, the contaminants in our local seafood that are of most concern are PCBs and dioxins. Both of these toxic chemical compounds are carcinogenic to humans. In addition to causing cancer, exposure to these chemicals can result in reproductive and developmental problems, damage to the immune system, and hormone changes that can cause a variety of health symptoms.
Over 90% of human exposure to dioxins and PCBs comes from consuming contaminated food. However, when present in fish or shellfish tissue, these chemicals often do not cause any type of odor, discoloration, or other signs of decay. It’s very possible to catch a fish that appears completely healthy, but high levels of harmful chemicals may still be present in its tissue.
What’s more, consuming seafood contaminated with PCBs or dioxins is not likely to cause any immediate health concerns. You will not experience a stomach ache, headache, or any type of acute response. It is possible to experience skin lesions as a short-term response to dioxin exposure, but it is not likely that a single meal of seafood would contain enough dioxin to cause such a response. The danger of consuming these highly toxic chemicals lies in their long-term effects. Consumption of contaminated seafood will lead to a buildup of toxins in the body, leaving you at a high risk for cancer, reproductive issues, developmental issues, and a weakened immune system. Due to their smaller body masses and rapidly developing organ systems, children and breastfeeding infants are considered the population group most vulnerable to dioxin and PCB health effects.
Given that the Houston Ship Channel and Upper Galveston Bay have been under this advisory for over 30 years, local residents often express concern over where the contamination comes from and what’s being done to address it. PCBs and dioxins are typically released into the environment as a byproduct of industrial processes including smelting, chlorine bleaching of paper pulp, and the manufacturing of some herbicides and pesticides. The San Jacinto River Waste Pits are considered the largest source PCBs and dioxins being released into the San Jacinto River and connected waterways.
The Waste Pits are two sets of impoundments located in the San Jacinto River near the I-10 bridge. They were built in the mid-1960s for disposing of paper mill waste that was contaminated with dioxins and other harmful chemicals. The pits were left unmanaged for decades, resulting in the release of dioxins and PCBs into the river and surrounding environment. THEA has been advocating for several years for the Environmental Protection Agency (EPA) to oversee a complete removal of the toxic material from these pits, and back in 2017, the EPA signed the Record of Decision stating that a complete removal was required to adequately protect the environment and local public health. Currently, the Northern Pit is in the remedial design process, meaning plans are being created for the safe removal of the toxic waste from this site. The Southern Pit is in the remedial action phase, meaning construction to remove the waste is underway. Once this major source of PCB and dioxin contamination is removed from the river, it is possible that contamination in our local seafood will return to levels safe for consumption within 15 years.
Dioxins and PCBs are bioaccumulative compounds, meaning they build up within the food chain. When they are leaked into the local environment, they contaminate plants and algae. Small fish consume these plants in large quantities, meaning they consume all of the dioxins and PCBs being held in the plants. Larger fish then consume the smaller fish, meaning they consume all of the dioxin that was in all of the plants that all of the smaller fish ate. This pattern continues up the food chain until it reaches humans. The relatively large, long-lived fish that we consume have eaten so many smaller fish by the time they reach us that they are contaminated with exponential levels of dioxin and PCB compared to what might be found in a single environmental sample of algae or soil. That’s why consuming contaminated seafood is so dangerous and will remain under advisory until the source of contamination is removed and the aquatic life has had sufficient time to cycle the toxins out of its ecosystem.
If, however, you find yourself in a situation in which you must consume seafood from the areas under advisory, there are certain steps you can take to make doing so slightly safer. When preparing a possibly contaminated fish, we recommend removing the skin, dark (reddish-color) muscle tissue, and fatty portions (i.e. belly fat, side fat, and fat along the top of the back) before cooking. DSHS recommends baking or broiling skinned, trimmed fish on a rack or grill to allow fat to drip away from the filet. This is because PCBs and dioxins tend to accumulate in the fatty tissue. If fish are fried, the frying oil should not be reused because any toxins that drain out of the fish in the cooking process will remain present in the oil. These cooking methods can reduce exposure to many of the most common organic contaminants in fish.
Although there is no legal ban on fishing in our local waterways, heeding the consumption advisory as much as possible and taking care to reduce exposure pathways if and when you do consume local fish can go a long way in protecting your family from the harmful effects of toxins polluting our environment.
To stay up to date with progress being made to remove the toxic waste pits from the river, you can sign up for our email list here.
(sources: https://cdn.who.int/media/docs/default-source/food-safety/dioxins.pdf?sfvrsn=4bcd5f4d_1
https://www.who.int/news-room/fact-sheets/detail/dioxins-and-their-effects-on-human-health