THE INFLUENCE OF BITUMINIZATION IN KARST CONDITIONS ON THE NATURAL-TECHNOGENIC TRANSFORMATION OF A SMALL RIVER BASED ON GEOCHEMICAL DATA AND BIOTESTING

Abstract

A set of studies consisting of laboratory experiments and field surveys based on geochemical methods
and biotesting allows us to formulate and solve problems related to identifying the consequences of bituminization, natural-technogenic transformation of a small river in karst conditions. A small river acts as a receiver of natural-technogenic
hydrocarbon flow in the karst region. The chemical composition of the river waters is typical for the conditions of oilfield
technogenesis: samples are enriched with chlorides and hydrocarbons. The article presents original materials from experiments on bituminization modeling and field observations on the effect of hydrocarbon doses and concentrations on the
optical density of Chlorella. The study provides information on the content of chemical elements in bottom sediments
and the results of their biotesting. The experiments established a positive reaction of Chlorella to an increase in oil doses.
The quality of bottom sediments in the territory of an oil field is directly or indirectly related to bituminization, which
changes the ecosystem. The aquatic environment and bottom sediments of the Odinovskaya River sources are enriched
with oil organic matter and have a positive effect on the vital activity of Chlorella. The lowest optical density of Chlorella
is observed in the middle reaches of the small river. The study determined the geochemical series of elements as well as
features of their accumulation and migration under technogenic conditions. Arsenic, cobalt, and titanium accumulate in
the bottom sediments, while zinc and manganese migrate. The concentrations of arsenic and lead exceed sanitary standards. Experiments and field sampling for testing with the use of Chlorella showed that technogenic hydrocarbon flows
enhance the heterotrophy of the small river source’s ecosystem. An increase in the density of Chlorella in samples during
testing can be diagnosed as technogenic organic pollution. Under natural-technogenic conditions, Chlorella also reacts to
an increase in hydrocarbon content, as in the experiment. It is possible and advisable to diagnose bituminization by the
increased optical density of Chlorella.