Heavy Metal Contamination in an Industrially Affected River Catchment Basin: Assessment, Effects, and Mitigation.

The concentrations of some heavy metals (Fe, Zn, Mn, Cu, Mo, Pb, Cd) were measured in river waters, macrozoobenthos, and fish (Kura scrapers) from one of the most developed mining areas in Armenia, the Debed River catchment basin. In order to assess heavy metal contamination and its hydro-ecological and health effects, the macrozoobenthos quantitative and qualitative parameters, geo-accumulation index, and hazard index were determined. Microalgal extraction experiments were conducted to assess the microalgal remediation efficiency for heavy metal removal from mining wastewaters. The results showed that the rivers in many sites were polluted with different heavy metals induced by mining activities, which adversely affected macrozoobenthos growth and caused human health risks in the case of waters used for drinking purposes. However, the river fish, particularly Kura scrapers, were determined to be safe for consumption by the local people, as per the conditions of the evaluated fish ingestion rate. The results have shown that microalgal remediation, particularly with Desmodesmus abundans M3456, can be used for the efficient removal ~(62-100%) of certain emerging contaminants (Mn, Pb, Cu, Zn, Cd) from mining wastewater discharged in the Debed catchment basin.

An integrative evaluation of suitability of a river for natural reproduction of trout of Lake Sevan (Armenia).

Endemic fish species of Armenian ichthyofauna-Sevan trout (Salmo ischchan Kessler, 1877)-is registered in the Red Book of Animals of the Republic of Armenia as "Critically Endangered" (corresponds to IUCN category: CR A2cd). Its natural reproduction hardly occurs as a result of numerous problems related to the use and management of water and bio-resources in the Lake Sevan drainage basin. Masrik River is formerly known as a spawning river for two ecological races of the Sevan trout, but there is no up-to-date and in-depth studies of its potential to support natural reproduction. Thus, a set of spawning criteria was arranged as matrix and state of Masrik River as spawning area for the Sevan trout was assessed. The results showed that the potential of different parts of Masrik River to support natural reproduction of Sevan trout varied from quite appropriate to inappropriate. The main limiting factors revealed were water temperature, velocity and substrate conditions.