Arsenic and heavy metals in the bottom sediments of the Balaklava Bay (Black Sea)

Abstract

We present the results of investigation of the contents of metals (As, Cr, Co, Cu, Ni, Pb, Zn, V, Sr, Mn, Ti, and Fe) in the bottom sediments of the Balaklava Bay (Black Sea) carried out in July 2005. It is shown that the pollution of the bottom sediments with metals has a polyelemental character. We establish the specific features of changes in the contents of the analyzed elements and localize the sources of their appearance in the ecosystem. On the basis of the results of evaluation of the intensity of technogenic action upon the marine medium, we determine a group of toxic elements (As, Cr, Cu, Pb, and Zn) accumulated in the bottom sediments of the bay in amounts significantly exceeding the background values typical of sediments of the Black Sea shelf. The comparative analysis of the degrees of pollution of the bay and some other coastal water areas with metals is performed.The accumulation of toxic metals in bottom sediments is realized as a result of the gravitational sedimentation of suspended substances, sorption processes on the water-sediment interface, and biogenic sedimentation. Thus, bottom sediments reflect, in a certain sense, the processes running in the water column. The bottom sediments also serve as the habitat of benthic organisms, the state of development of which characterizes the aquatic ecosystem.By analyzing the contents of metals in the bottom sediments of various parts of the water area, one can estimate the level of pollution, determine the regions with different levels of anthropogenic loading, and establish the characteristic features of toxic metals depending on the natural geochemical processes and anthropogenic influence.Among the semiclosed water areas of the Sevastopol region, the Balaklava Bay occupies a special place due to its geographic location, morphometry, landscape and geochemical characteristics, and the character of nature management. The bay is located in the south part of the Crimean Peninsula between Cape Fiolent and Cape Aiya. This is a narrow (up to 240 m) estuary-type basin oriented in the meridional direction with high steep indented coasts 1.4 km in length and 4-34 m in depth. The area of the water surface is equal to 236,000 m 2 , the volume of water masses accumulated in the bay is 2,840,000 m 3 . Its mean depth is equal to 12.5 m. According to the bottom morphometry and configuration of the coasts, the water area of the bay can be split into the shallow-water part at the head of the bay, the central part, the south deep-water expansion, and the elbowed narrowness connecting the last two parts [1,2]. The head of the bay is supplied by the seasonal water flow of the Balaklavka River. In the dry season of the year, its discharge is equal to 196.9 ⋅ 10 3 m 3 /yr (according to the data obtained by Terekhin in 1991; cited according to [3]).

Elemental accumulation in the black sea brown algae cystoseira studied by neutron activation analysis

“…High concentration of elements in Cystoseira spp. from Balaklavskaya Bay and Karantinnaya Bay appears to be due to the high level of integrated pollution of their aquatorium which is worsened due to the poor water exchange of these bays with the open sea [18]. Minimal concentrations of trace elements in the "stems" of Cystoseira spp.…”

Organic Matter and Grain-Size Distribution of the Modern Bottom Sediments in the Balaklava Bay (the Black Sea)

“…As already noted, the Balaklava Bay was subjected to a prolonged anthropogenic load [7,11]. Sources of bottom sediment industrial pollution were the wastewaters from "Metalist" shipyard discharged into the upper part of the bay without treatment, as well as pollution resulting from the dock repair of ships.…”

“…The data on physical-chemical indicators of bottom sediments, the composition and quantitative characteristics of macrozoobenthos were obtained, as well as water area ecological status was assessed. The studies performed by Marine Hydrophysical Institute (MHI) in 2005 provided the assessment bottom sediments contamination with metals and consideration of accumulation and distribution of organic carbon (C org) features in the surface layer (0-5 cm) [11]. In 2006, a comprehensive study of the Black Sea coastal water sediments was carried out with the participation of IMBR, including the OM of Balaklava Bay [12].…”

New genera and species of monothalamous Foraminifera from Balaclava and Kazach’ya Bays (Crimean Peninsula, Black Sea)

“…Current pollution sources include sewage, domestic waste and waste material (mud) associated with ore extraction and storm-related surges of mud-laden river water. About 4.4 × 10 6 m 3 of crude waste water are discharged into Balaclava Bay every year (Ovsyaniy et al 2009). During the period when it was used as a naval base, the Bay lost much of its importance as an area for fish farming and recreation.…”