While we’re all aware we need to limit the amount of large fish we eat due to the risk of contamination from mercury, this is not the only chemical we need to think about when we’re putting perch on the table.
A new global analysis of seafood from around the world found that fish from all the world’s oceans are contaminated with industrial and agricultural pollutants, which are collectively known as persistent organic pollutants (POPs). These pollutants included ‘legacy’ chemicals, such as DDT and mercury, as well as newer industrial chemicals, such as flame retardants and coolants.
“Based on the best data collected from across the globe, we can say that POPs can be anywhere and in any species of marine fish,” said biologist Stuart Sandin from Scripps Institution of Oceanography at UC San Diego.
It’s not all bad news, however, by comparing studies from 1969 to 2012, the researchers observed that concentrations of these chemicals have been consistently dropping over the three decades, implying that the global community has responded well to global calls-to-action to limit the release of potentially harmful chemicals into the environment, the Stockholm Convention for example.
The concentrations of POPs found in fish meat were variable by as much as 1000-fold, but overall the observation is that concentrations have decreased 15-30 percent per decade.
“This means that the typical fish that you consume today can have approximately 50 percent of the concentration of most POPs when compared to the same fish eaten by your parents at your age,” said the lead author of the study.
The researchers found that the average levels of contaminants were at or below the standards set by the US Environmental Protection Agency (EPA). Mercury and PCBs (polychlorinated biphenyl) concentrations were at the EPA threshold for occasional human consumption, while concentrations of DDT were consistently much lower than the established threshold.
The authors caution that although pollutant concentrations in marine fish are steadily declining, they still remain quite high, and that understanding the cumulative effects of numerous exposures to pollutants in seafood is necessary to determine the specific risk to consumers.