A study was released in April comparing the amount of contaminants in 20 national park waters. Pesticides and higher levels of mercury were among the findings.
The National Park Service led the study published in the Journal of the American Water Resources Association. It found “historic-use” contaminants in waters at three Alaska parks. Ecologist for the National Park Service Air and Resource Division Colleen Flanagan Pritz is the lead author on the study. She says when the very high contaminant numbers came back she wanted to know how that was effecting the fish in those waters.
“As part of that effort, the biologists went out to the park on our behalf and collected fish and then we worked with a containments laboratory at OSU to have the fish analyzed for contaminants. Specifically for semi-volatile organic compounds which include pesticides and other legacy compounds and PCBs, we also looked at PAHs and the results indicated quiet similarly to that initial study that indeed there are contaminants in fish and many of these other locations.”
Pritz says some of the fish had levels of containments far higher than what is safe for human and wild life. She says the thresholds of levels the study used to judge what would cause a problem for human consumption came from the Environmental Protection Agency.
If a fish is bigger, Pritz says, it’s more likely to be filled with contaminants.
“One of the prevailing thoughts is the fish that were caught in Alaska were very big, which means it’s usually links to size and age. We can presume then that the fish were very old. And in that light if they are old fish they have had more time to accumulate contaminants. Some of these lake trout are 40 years old plus.”
She says the fish on the top of the food chain are also more likely to have higher levels of chemical contaminants because of the smaller fish they eat that may contain trace amounts.
Alaska’s State Veterinarian Robert Gerlach says the issue has many sources but the largest is manmade.
“Well there are a number of concerns and a number of issues associated with the contaminant issue. One of them is overall, Alaska is pretty isolated, and we don’t have a lot of industry that’s impacting our fisheries resources so a majority of the contamination comes from long range transport.”
Gerlach says although it’s important to worry about the health hazards to humans, one can’t forget the real victims of high contamination levels-- the fish.
“They’re another stress on the fish’s environment and the fish. Take for example a person going on their normal everyday activities and then they go on a trip, they spend all night on the plane and they get into another environment and they can be exposed to different disease agents and because of the stress from being up all night, or because of not having sleep, you become more susceptible to those things and can get sick with them. The contaminants act as another stress on the fish’s environment that can go ahead and imbalance that. It can make them more susceptible to problems or the chemicals themselves can sometimes cause problems for the fish.”
Pritz says she’s not sure why the contaminant levels in Alaska is high. However, she says that’s something that scientists will look into.