Assessment of the Current State of the Caspian Sea and the Caspian Seal Habitat Analysis

Abstract

This article is devoted to the determination of heavy metals and harmful organic compounds in sea water – the habitat of the Caspian seal. The group of the most common heavy metals, according to many authors, includes manganese, nickel, zinc, iron, cadmium, lead, copper and their salts, characterized by long-term preservation and accumulation in water, sediments and hydrobionts. The studies were conducted from February 7–12, 2017 on the route from the Kalamkas (Kazakhstan) field through the islands of Kulaly to the village of Bautino. Water samples were taken 10‒20 cm below the sea ice and surface level, each sample was taken in 2 replicates: one for the Kazakhstan laboratory in Almaty and one for the French independent laboratory. Water samples were analyzed for the content of 13 heavy metals such as – Co, Cu, Ti, Bi, Ag, V, Al, Be, Sb, Sn, Fe, Cr, Mo. It was established that in all water samples the content of vanadium exceeds the maximum permissible concentration (MPC) level by 1.5–7.4 times, beryllium ‒ 140–445 times, antimony 13.2–17.2 times. The maximum concentrations of the V and Be contents were found in water samples taken at sampling points No. 1 and 2, and Sb ‒ at points No. 1.6, 7.8. Cobalt, copper, iron and chromium were not detected in the samples presented. The content of other metals (Ti, Bi, Ag, Al, Sn, Mo) was significantly below the permissible levels or below the detection limits of the method. All samples of sea water are contaminated by several organic chemical pollutants, to various degrees and from different origins. Data on the accumulation of petroleum hydrocarbons and heavy metals in the habitat of Caspian seals characterize the toxicological situation in the study region.

Keywords

• Caspian sea
• water sample
• heavy metals
• organic pollutants
• chemical analysis