Bioassay as a method of integral assessment for remediation of oil-contaminated ecosystems

The development of new technologies and improvement of existing ones for the restoration of oil-contaminated lands, the neutralization and disposal of oil drilling waste are important measures to solve environmental problems. Bioassay is successfully used to determine the danger of pollution of environmental objects by oil and oil industry wastes. With the help of biotests, it is possible to assess the state of contaminated objects, which is not always possible to do by chemicalanalytical methods, considering the complex chemical composition of petroleum hydrocarbons. An analytical review confirms the need to develop a biotesting system to assess the state of ecosystem components in the event of oil pollution and to determine the effectiveness of measures to restore them. Taking into account the nature of the pollution, presented in the article by a number of provisions on the chemical characteristics of petroleum hydrocarbons and the duration of the recovery processes, bioassay should be carried out at each stage of the reclamation process, in dynamics. Determination of the degree of neutralization of contaminated objects consists in a step-by-step transfer of the hazard level from a higher class to a lower one. Bioassay, in this case, remains a mandatory method for determining the total toxicity. In the course of sample preparation for biotesting, it is advisable to consider the possibility of increasing the bioavailability of hydrocarbon components. A prerequisite for the use of biotesting is the use of eluate and contact approaches. The main methods that can be included in the abbreviated scheme for determining the efficiency of remediation of oil-contaminated objects can be considered the method of biotesting using hydrobionts in the eluate (water extract) and phytotesting performed using the contact and eluate approaches. The battery of biological tests included in the extended scheme should be developed taking into account the specific case, taking into account the specifics of the ecosystem components, soil and climatic conditions, the methods of reclamation used, etc. The strategy for the development of biotesting is closely related to the solution of issues on the assessment of the real danger of oil pollution and the neutralization of oil drilling waste, which are among the priority ones.