[Rare-earth metals as a factor in mutagenicity].

Both the regions of the Orenburg Region area and individual examined streams and reservoirs were shown to be characterized by a varying load index for rare earth elements. The total level of rare earth elements was directly correlated with different types of mutations.

[Mercury in the streams and reservoirs in the territory of the Orenburg Region].

The State Education Institution of Higher professional education "The Orenburg State Medical Academy of Federal Agency in Public Health and Social Development". The state of some freshwater streams and reservoirs in the Orenburg Region was estimated from the level of mercury in the water extract of their bed silt. The concentration of this pollutant is shown to exceed the set standards.

[Monitoring of the levels of metals in the bottom sediments of rivers in the central area of the Orenburg Region].

Among the pollutants of the biosphere, heavy metals present the greatest hazard since they show a high stability and toxicity and are able to migrate in the water ecosystems and to accumulate in the bottom sediments and hydrocoles, by impairing the stability of hydrobiocenoses. Chemical monitoring of the level of bottom sediments of rivers was made in the Central district of the Orenburg Region. Samples were taken at 11 stations of the Central district of the region and 5 stations in a district of Orenburg.