The article describes visually detectable anomalies in the structure of the crucian carpet, which make it possible to consider them as a reliable tool for operative ecological monitoring of aquatic ecosystems under the conditions of the anthropic press. The results of the conducted studies were tested in the course of the research "The Post-Mercury Control of Mercury Pollution in the Territory of the Former PO" Khimprom", and also appear to be important in assessing the environmental risk from groundwater pollution and adjacent water bodies in the northern industrial zone of Pavlodar.

The object of the study was water and bottom sediments of the lake Balkyldak of Pavlodar region, contaminated by mercury wastes.The purpose of the work is the creation of innovative cost-effective technologies for deep cleaning of aqueous media from mercury to the level of 1-10 parts per trillion, which will be tested for the cleaning of the lake Bylkyldak facilities in Pavlodar region.

On the territory of the Northern industrial zone of Pavlodar in the area of the industrial wastewater reservoir «Bylkyldak» in some areas of the earth there is soil contamination with mercury, exceeding the MPC for mercury (2.1 mg/kg) by 500 times. The total mass of mercury dispersed in the surface layer of soils is 2.8 tons. The mass of contaminated soil is approximately 208,000 tons. Pollution of the territory is historical. The purpose of the article is to determine the efficiency of chemical binding (immobilization) of mercury in the soil with the Japanese drug Denite® in real field conditions of the territory of mercury contamination in the Northern industrial zone of Pavlodar using an experimental study; to determine the stability of insoluble mercury compounds formed by the preparation at extreme winter and summer temperatures and seasonal fluctuations in open ground. Soil samples were taken for the study at 11 points in the centers of mercury pollution. Laboratory studies were carried out in an accredited analytical laboratory of the Testing Center of JSC Caustic. Soil samples were treated with Denite®, the preparations obtained were stabilized, and water extracts were prepared. The content of mercury in soils, extracts from them, and plants was determined by the atomic absorption method on a RA-915+ spectrometer equipped with RP-91 and RP-91S attachments. As a result of research, the effectiveness of Denite® in the chemical binding of mercury in the soil has been proven and its optimal dosages have been determined. As a result of the positive tests of the technology of chemical immobilization of mercury, the prospect of a practical solution to the issue of demercurization of mercury-contaminated soil on the territory of the Northern industrial zone appeared.