Determination of the heavy metals and arsenic in fish and water of Lake Balkhash, Kazakhstan: Proceedings of 9th Environmental Scientists Meeting, 9-11 March 2020, Waco, Texas, USA

The lake Balkhash is a large, endorheic lake in the south-west of Kazakhstan divided into two basins, slightly differed in salinity. The purpose of this work was to assess pollution of lake Balkhash by heavy metals in the area close to the
town Balkhash and located nearby metallurgic plant. Some heavy metals and arsenic became a matter of concern because of their toxicity and ability to accumulate in the aquatic food chain. Water samples were collected in
polyethylene bottles, acidified to pH 2, and stored at 4°C. The tissues from four species of fish (Cyprinus carpio, Sander lucioperca, Ritilus caspicus, Abramis brama) were separated, frozen, digested in Multiwave Digestion System
(Anton Paar, Multiwave Digestion System PRO), and analyzed by Inductively Coupled Plasma-Mass Spectrometry (iCAP-RQ, Thermo Scientific). The concentrations of Cu, Cr, Mn, Zn, Pb, Cd, Ni, and As were determined in water and muscles, gills and liver of fish by ICP-MS. The ion composition analysis of water samples was performed by Ion Chromatography (Dionex ICS 6000, Thermo Scientific, USA). Arsenic was detected the maximum permissible concentrations (according to the European Directives values) in water, but not in fish tissues. Furthermore, we calculated bioaccumulation factors (BAF) that correlated the metal concentrations in water and biota. The mean log BAFs of each heavy metal in our study followed the order: for muscles Zn> Fe> Mn> Cu> Pb> Ni> As, for gills Zn> Fe>Mn> Cu> Pb> As> Cd, for liver Cu> Zn> Fe> Mn> Pb> Ni. Higher concentrations of lead have accumulated in the gills of A.brama (5-6 times higher than maximum permissible concentration - MPC) and R.Caspicus (3.5 times higher than MPC) and in the liver of C.Carpio (3 times higher than MPC). Significant amounts of cadmium have accumulated in the liver of all tested fish species (concentrations from 3 to 80 times higher than MPC). Zinc has accumulated in the gills and liver of the all fish species in concentrations from 25 to 36 and from 35 to 70 MPC, respectively. Accumulation of copper was found in the liver of all fish species (2 to 20 times of MPC). In general, this study revealed
the increased concentrations of Cd, Zn, Cu, and Pb in the liver and lead and zinc in gills but not in the muscles of tested fish.