- Utah monitors fish safety by testing for PCBs, mercury, lead and PFAS arsenic.
- Channel catfish remain under advisory due to elevated PCB levels from sediment.
- Officials recommend limiting catfish consumption and using preparation methods to reduce exposure.
SALT LAKE CITY — The toxic chemical that made Utah Lake carp unsafe to eat for years still exists in the lake today, even though that type of fish is no longer under a consumption advisory.
State scientists continue monitoring fish for polychlorinated biphenyls, better known as PCBs, along with contaminants such as mercury, lead, PFAS and arsenic to determine whether eating certain species poses a health risk.
Channel catfish remain under a consumption advisory because of elevated PCB levels. Carp and catfish are bottom feeders, which absorb the chemicals from the sediment.
"We have those fish meal consumption limits to protect your health," said Dr. Alejandra Maldonado, a state toxicologist.
PCBs are manmade industrial chemicals that were widely used in electrical equipment and other products before being banned in the United States in 1979. Officials believe PCBs found in Utah Lake likely originated from improper disposal at the former Geneva Steel plant.
Even decades after the ban, the chemicals persist in the environment.
"PCBs is what we call a legacy contaminant," Maldonado said. "It doesn't degrade in the environment very easily."
The Utah Division of Wildlife Resources, Division of Water Quality and state health experts work together to monitor contaminants in fish across the state.
The process begins with wildlife officials collecting fish samples from lakes and reservoirs.
Those samples are then analyzed by the Division of Water Quality before being sent to specialized laboratories capable of detecting contaminants at extremely low levels.
"The Division of Wildlife Resources will collect the fish, send them to the Division of Water Quality, where we'll analyze the fish and do a lot of the technical extraction and analysis," said Ben Ridgway, with the Utah Division of Water Quality.
The Division of Water Quality then sends the fish to a national laboratory. Some of the testing requires sophisticated equipment and techniques.
"These labs use really expensive machinery that literally involve acids and lasers to get really high-precision measurements," Ridgway said. "After they separate out the compounds from the fish tissue that they report back to us, and they have all sorts of quality assurance measurements to make sure that the data are right and representative of the sample there, and the Division of Water Quality will kind of follow through and make sure those quality assurance steps were followed."
Once contaminant levels are identified, scientists use risk assessments and mathematical models to determine whether public health advisories are necessary.
Those advisories vary depending on age and other risk factors.
Maldonado said recommendations are developed for several groups, including adults beyond childbearing age, women who may become pregnant, children ages 6 to 16, and the most vulnerable populations: pregnant women and children younger than 6.
While officials do not expect PCBs to disappear completely, they say contamination levels are gradually declining.
"The reality may be that we may never have PCBs be entirely gone," Maldonado said. "We may still see very low levels. I think the concern for us is, do those levels present a risk to public health?"
For now, health officials are not telling people to avoid eating catfish altogether. Instead, they recommend limiting consumption and preparing the fish in ways that reduce exposure.
Maldonado advises anglers to eat only the fillet and discard the organs, head and tail. Broiling or grilling fish can also help reduce some contaminants concentrated in fat.
Ridgway said PCB levels have been trending downward across the country, including in Utah, giving scientists hope that fish advisories may eventually be lifted.
"I'm pretty optimistic that if we keep doing these management practices, at some point in the future, it's hard to put an exact date on it, we'll see at least the removal of the fish advisory," he said.
Officials acknowledge fish testing does not occur as frequently as they would prefer because of the cost involved. They say additional funding could allow for more frequent sampling and provide anglers with more current information about the fish they catch and eat.
"We're trying, in lieu of the EPA kind of budget cuts, to find routine state monitoring to get that to be year to year," he said.
