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.

Aliphatic hydrocarbons in fin spines of adult sturgeon (Acipenser stellatus) and their relationship with potentially toxic elements in the northern and southern regions of the Caspian Sea

“…Ni/V ratios have been used to classify those in crude oils (Barwise 1990 ). In the Caspian Sea, V can be trapped in the oil production process, while fuel is burned, although generally its concentration in the water is insignificant and it does not affect its quality (Tasmagambetova et al 2019 ). Concentrations of Ni found in sturgeons generally agree with the values reported previously in different tissues of other species (0.1–8.00 mg/kg) in the Caspian Sea (Sheikhzadeh and Hamidian 2021 ).…”

A review of science–policy interface for water governance in the Caspian Sea

“…The destruction of the Caspian Sea ecosystem can be shaped as soon as possible, but it is unlikely to recover, and restoring it certainly will be very timely if it is not impossible in some areas (Barannik et al, 2004;Leroy et al, 2020;Modabberi et al, 2020;Ragimova et al, 2020;Koriche et al, 2022;Lahijani et al, 2023). There will be no alternative in some cases, including the extinction and destruction of rare species (for example, the genetic reserves of sturgeons of the Caspian Sea) (Tasmagambetova et al, 2019;Verbitsky et al, 2019). Governmental measures alone cannot ensure sustainable conservation and exploitation of the Caspian Sea.…”

“…Governmental measures alone cannot ensure sustainable conservation and exploitation of the Caspian Sea Lack of a comprehensive approach and coherent activities, as well as a lack of utilization of national and regional power Severity of pollution and destruction in the Caspian region is so great that it is not possible to rely on the agreed legal regime on the Caspian Sea Negotiations and diplomatic agreements as well as overcoming the existing political bottlenecks, are processes that require time to resolve while protection of the Caspian Sea and the rights of the interested parties are not subject to the agreement of the legal regime (Bayramov, 2020;Pietkiewicz, 2021). Caspian ecosystems and the lives of their organisms do not depend on political borders and diplomatic agreements, and their right to life cannot be subject to the agreement of the coastal states (Tasmagambetova et al, 2019). Therefore, coastal governments and leaders of these countries should feel responsible for recognizing the right of the present generation and future generations to protect and exploit the Caspian Sea on their shoulders and realize their responsibility.…”

“…The Caspian Sea is also home to the sea's only marine mammal, the unique Caspian seal (Sanaee et al, 2020). However, many Caspian species are now endangered due to climate change, pollution, habitat destruction, and overexploitation (Tasmagambetova et al, 2019;Verbitsky et al, 2019). It has a negative impact on human well-being, the social and economic sectors, and the provision of environmental services.…”

First confirmed records of white-coat pups of the Endangered Caspian seal Pusa caspica on the coast of Iran

“…The decline in population size is thought to be because of increasing negative anthropogenic impacts including climate change, fisheries bycatch, anthropogenic disturbance, pollution and loss of habitat. Many of these threats are considered to be related to increased exploration and exploitation by the oil and gas industry (Härkönen et al, 2008; Dmitrieva et al, 2013; Volodina et al, 2018; Tasmagambetova et al, 2019). There was a documented minimum bycatch of 1,215 seals in the 2008–2009 fishing season, 93% of which occurred in illegal sturgeon fisheries (Dmitrieva et al, 2013).…”