Organochlorine contaminants in the muscle, liver and brain of seabirds (Larus) from the coastal area of the Southern Baltic

The presence of persistent organic pollutants in the environment manifests itself most strongly in the marine trophic chain, where the highest link is comprised of seabirds. At the same time, seabirds are excellent indicators of contamination in their habitat. The present study concentrates on toxic substances: polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDFs) and chlorinated organic pesticides (OCPs) accumulated in the livers, pectoral muscles and brains of dead gulls collected along the Polish coast of the Baltic Sea in the years 2010–12. The highest toxic equivalence was determined in the livers of Larus argentatus (TEQ(birds TEF)−28.3pgg−1 ww) and Larus marinus (TEQ(birds TEF)−29.9pgg−1 ww.). However, the toxic equivalence of muscles was lower and amounted to 3.9pgg−1 ww. and 7.8pgg−1 ww. respectively for the two species. The lowest toxic equivalence was found in the brains of birds, where only one, the most toxic, 2,3,7,8 TCDD congener was found (TEQ(birds TEF) 0.87pgg−1 ww). The highest concentration of chloroorganic pesticides was determined in the brains of the birds (total OCP 167.8pgg−1 ww.), lower concentrations were found in the livers (total OCP 92.1pgg−1 ww.) and muscles (total OCP 43.1pgg−1 ww.). With regard to pesticides, the highest proportion in the total OCP content was constituted by DDT and its isomers (liver 81%, muscles 77% and brain 55%). High concentrations of the studied pollutants in the livers of gulls found dead on the coast of the Southern Baltic could have been effected by levels of contamination in the birds’ last meals, which resulted in a seven-fold increase of the liver’s toxic equivalence and a two-fold increase in OCP concentration in relation to muscles. •PCDDFs concentration in liver of gulls from Polish coast was higher than in muscle.•In the brains of gulls, only one, the most toxic, 2,3,7,8-TCDD congener was found.•The organ distribution of most OCPs in gulls was as follows: brain>liver>muscles.