Toxic substances can be found in all seafood from all parts of the world, but not as much as before

Scientists from the Institute of Oceanography. Scripps (San Diego, CA) released the results of an analysis of hundreds of scientific papers studying marine fauna from 1969 to 2012. The bad news: there are no populations of marine animals left in the ocean that are not contaminated with the so-called persistent organic pollutants. The good news is that pollution levels have been gradually declining over the past 30 years.

Persistent organic pollutants are the common name for the most dangerous organic compounds. The concept appeared in the Stockholm Convention on Persistent Organic Pollutants, formulated and open for signature on May 23, 2001 at the Conference of Plenipotentiaries in Stockholm. These are mainly insecticides and pesticides - for example, the infamous DDT.

The governments of many countries, having received information about the harm caused by certain substances used by humans in agricultural activities, have signed a convention banning or severely restricting their use. In the initial list there were 12 types of substances, and at the fourth congress in 2009 they added 9 more. Unfortunately, for some of them there are still no less harmful analogues, so they have to be used, albeit with certain limitations.

As a result of natural processes, pollutants enter rivers and then oceans, where they accumulate in the organisms of marine inhabitants. Analysis of studies shows that in the populations of the fauna of the oceans you can find all toxic substances - from DDT and mercury, to modern cooling agents and flame retardants. And this is true for all animal species and all populations.

True, the degree of pollution can vary greatly, depending on the region of research - sometimes a thousand times. Moreover, starting from the 1980s, every 10 years, the concentration of toxic substances drops by 15-30%.

“That means eating fish fillets, you absorb about half the amount of persistent organic pollutants that your parents got when they were your age,” explains Lindsay Bonito, a researcher and one of the authors of the work. “At the same time, there is still a chance to get the same contaminated fillet that your parents could get.”

Researchers found that the average levels of toxic substances in seafood meet US environmental standards, and some substances, such as DDT, are much lower than the maximum allowed. It can be concluded that the Stockholm Convention has borne fruit. At the same time, scientists warn that one should not stop there, since in general, the levels of pollution of the marine fauna remain still quite high.