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In the frame of the current Project the estimation on contents of nutrients, petroleum hydrocarbons, phenols and heavy metals in water and bottom sediments in the basins of rivers Terek, Sulak and Samur over the last years was carried out. Research was conducted within a framework of the State Monitoring Programme on Roshydromet in the central and lower parts of the Terek delta. The data of Roshydromet standard investigations was used to assess the concentration of pollutants, namely petroleum hydrocarbons, heavy metals, phenols, detergents, nutrients (nitrites, nitrates, ammonium and total nitrogen) and silicates, and also expenditure of river water during the estimation of their flows at hydrological Karagalinsky hydro system and
Alikazgan stations in the Terek delta. The Roshydromet data cover the period 2002-2005.

Toxicity tests are commonly used as a tool to determine the standards of water quality for chemicals and to discover appropriate organisms as bioindicators in toxicological studies, and also could be used as an essential tool for evaluation of the pollutant effects in aquatic ecosystems. The aim of the present study was to evaluate the sensitivity of two Caspian fish species, Caspian trout as an endangered species and Caspian Kutum using the static acute toxicity in response to nonylphenol, which is widely discharged into the Caspian Sea environment.

In addition, Caspian trout was approximately 6 times more sensitive than Caspian Kutum. Nonylphenol was reflected to be "highly toxic" to Caspian trout and "moderately toxic" to Caspian Kutum. The results could be considered in preparing plans for conservation and restocking management of Caspian Kutum and the endangered Caspian trout.