Main criteria for assessing the content of heavy metals in bottom sediments of water bodies

The main criteria for assessing the content of heavy metals in sediments of water bodies. At present, the methodology for rationing pollutants in bottom sediments of surface watercourses is clearly not sufficiently developed. There are various and significantly different approaches to the assessment of soil contamination with heavy metals. The maximum permissible concentration (MAC), which is the main criterion for assessing the levels of pollution, is not perfect and needs to be significantly adjusted. A number of methodological assessments of contamination of bottom sediments with heavy metals with comparative characteristics are considered, of which a method for estimating the anthropogenic load on a reservoir according to its geo-classes has been proposed as one of the best. The gross content of heavy metals in bottom sediments of water bodies does not give a sufficient idea of the possibility of secondary pollution of water masses and, as a result, subsequent toxic effects. A much more important indicator is their content and distribution by forms of existence in the solid phase and pore solution of bottom sediments. As a consequence, this article develops a topic for estimating possible secondary pollution of water bodies by determining the content and distribution of TM by forms of existence in the solid phase and pore sediment solution.