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Currently, the pollution of the Caspian Sea by the oil industry is one of the highest problems in this area. Critically endangered species inhabit this sea, such as sturgeons, whose ecological value is incalculable. Thus, we aimed to evaluate the level of contamination of aliphatic hydrocarbons of petroleum and its relation with several toxic elements directly on sturgeons spines. A total of 40 adult starry sturgeons (Acipenser stellatus) were obtained within a repopulation programme in the northern and southern coastal waters of the Caspian Sea. The marginal pectoral fin was extracted from each fish to determine aliphatic hydrocarbons, arsenic, cadmium, mercury, nickel, lead, and vanadium. Subsequently, the sturgeons were released. Clearly, the presence of hydrocarbons was evidenced in all the sampled areas finding higher concentrations in the northern areas (N1 = 1.35 ± 0.4; N2 = 1.65 ± 0.46; N3 = 1.27 ± 0.40; S1 = 0.61 ± 0.22; S2 = 0.85 ± 0.43 mg/kg). Furthermore, to a greater or lesser extent, some toxic elements, mainly Hg and As, have been linked to aliphatic hydrocarbons. [ABSTRACT FROM AUTHOR]

Rare earth elements are essential for modern life, although they are also classified as emerging pollutants. Currently, fish studies on these elements are very limited in general, but, with regard to the Caspian Sea, there is no reference to them at all. For this reason, our objective was to determine the concentrations of these elements in the golden grey mullet (Chelon auratus) and to contrast its bioaccumulation patterns with those of arsenic, cadmium, mercury and lead. For that purpose, 20 fish were caught in the southern part of the Caspian Sea. Heavy rare earth element concentrations were higher than light ones and the terbium levels were very high, probably due to anthropogenic contamination. The intestine tissue gave the highest concentrations, which could be indicative of a very low gastrointestinal absorption. For both rare earth and trace elements, muscle was the tissue that accumulated the least, despite which, cadmium and lead levels in muscle were of concern. [ABSTRACT FROM AUTHOR]

Heavy metals are one of the most serious pollutants in aquatic ecosystems, and their accumulation in fish products causes harmful effects on human health. In this context, we set out to determine the concentrations of heavy metals in the muscle of two fish species of commercial interest, Chelon auratus and Chelon saliens on the south coast of the Caspian Sea. We aimed to assess the degree of environment contamination in this area and to estimate the potential risk to human health derived from the consumption of fish. The mean concentrations of the different metals analysed were very varied in both species. In fact, some concentrations exceeded the permissible limits for the protection of human health for Cd and Pb, and some values of As were above those referenced by other authors in same species in the Caspian Sea. None of the estimated daily intake values exceeded the tolerable intake based on the consumption under consideration. Nonetheless, the accumulative hazard values evidenced a potential risk to human health, Pb and Hg being those giving a higher target hazard quotient. The cancer risk from exposure to As from fish consumption in children was above the "acceptable" risk to life. Thus, in view of the accumulative nature of heavy metals, a moderate and non-abusive fish consumption in this area, particularly in children, would be recommendable. [ABSTRACT FROM AUTHOR]