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Pesticides are accumulated in organisms with a high fat content. The conclusion was reached by the researchers of Far Eastern Federal University (FEFU), who have been studying seabirds and mammals of the Sea of Okhotsk and Bering Sea for several years. The series of studies is supported by the Russian Science Foundation.

The group of authors has presented the results of the study of organochlorine pesticides (OCPs) in organisms of seabirds and mammals of the Northwest Pacific Ocean in a scientific paper published in the authoritative journal Marine Pollution Bulletin. These synthetic substances are widely used in the chemical industry and agriculture, they are highly toxic, slowly disintegrate, and accumulate in adipose tissue and organs of living organisms. Many of these substances, for example, DDT (Dichlorodiphenyltrichloroethane) and its derivatives, are included in the so-called Dirty Dozen banned by the Stockholm Convention as persistent organic pollutants (POPs).

The FEFU researchers came to the following conclusion: the higher the living entity is in the food chain, the more toxins accumulate in its body. The paper also notes that species that live long, accumulate more pesticides. For example, the organisms of small fish contain little pesticide residue. However, the concentration of OCPs is high in seabirds, mammals and predators that feed on this fish.

The samples of organisms of gray whales, Pacific walruses and sea birds (fulmars, crested auklets, least auklets, Pacific gulls, and gray petrels) were studied. The researcher point to the overall high level of OCPs in the organs of seabirds and animals, specifying that such level is higher in mammals, since there is more fat in their body.

Interestingly, the OCPs are contained less in the mammalian bodies of the Bering Sea than in the organs of similar animals from other regions of the Pacific Ocean. At the same time, the level of pesticide contamination of the Bering and Okhotsk Seas is close to other subarctic regions of the World Ocean. The researchers call global atmospheric processes as the source of the spread of pesticides, since OCPs have been found in organisms even of those mammals that live in areas free from sources of release of substances.

“Organochlorine pesticides are a serious threat to people. And this situation only worsens over the years. For example, due to China and India the concentration of OCPs is constantly growing in the Pacific Ocean. The USA also produces pesticides as products for sale,” comments Kirill Golokhvast, Dr.Sc. (Biology), FEFU Vice President for Research.

The level of OCP accumulation in marine organisms is an important indicator of the ecological state of the planet. This parameter is taken into account when monitoring environmental conditions both locally and globally. By studying the accumulation of OCPs in organisms of marine inhabitants with a long life cycle, researchers can determine the overall level of pollution of the oceans. At the same time, the study of fish helps to control the local environmental situation.

The research was conducted by Vasiliy Tsygankov, Head of the Environmental Biotechnology Lab, Assistant Professor, FEFU School of Biomedicine; Olga Lukyanova, Lead Researcher, Pacific Fisheries Research Center, Professor, FEFU School of Natural Sciences; and Margarita Boyarova, Assistant Professor, FEFU School of Biomedicine.