The paper presents a scientific approach to developing and evaluating the efficiency of composite sorbents for remediation of oil‑contaminated soils along the Arctic coastlines. The authors use a chitin‑chitosan complex derived from crab processing waste as the sorption base. Activated sludge – a by-product of wastewater treatment facilities in the Murmansk Region – serves as a source of oil‑oxidizing microorganisms adapted to northern conditions. The study reports results of initial material characterization, including comparative spectral analysis of the chitin‑chitosan complex, analytical control of heavy metal content in the activated sludge, and its microbiological assessment. The composite sorbent formulation is developed via mathematical modelling using orthogonal central composite design. The va-riable factors are the component contents in the sorbent; the response function is the residual petroleum content in soil after remediation. Researchers run the experiments at 10±2 °C, matching the average daily temperature along the Kola Peninsula coastlines during summer. The resulting mathematical models describe how sorbent efficiency, assessed by residual petroleum content in soil, depends on component ratios; these models guide the selection of the optimal formulation. 3D models of oil pollution degradation are built to visualize and compare the performance of sorbents with different formulations. The correctness of the optimal sorbent formulation, selected based on the mathematical models, is additionally verified through phytotoxicity test. The paper also demonstrates the high remediation efficiency of the developed sorbent for oil‑contaminated soils compared to the commercial analogue. The study finds that the residual petroleum content stays 2-4 times lower with the composite sorbent throughout the entire research period. Based on the research conducted, the authors propose engineering principles for producing the composite sorbent from organic wastes and for its application in effective treatment of oil-contaminated coastlines under Arctic conditions.

The development and operation of new oil fields on the Arctic shelf increases the risks of oil spills, which require the use of oil spill response tools and materials that are efficient in harsh climatic conditions. The question of actual efficiency of sorbents for reducing the level of oil pollution in the conditions of the Arctic and subarctic waters is relevant. The work is aimed at a comparative study of the efficiency of sorbents of mineral and organic origin used by coastal enterprises in the Kola Bay as well as a sorbent based on chitin in model systems simulating real conditions in sea waters. The characteristics of sorption agents were determined applying ASTM F716-18 procedure. Sorption capacity was evaluated in respect of ARCO grade oil, diesel fuel and marine oil. The efficiency of sorbents was estimated in model systems “sea water – oil” at water temperature corresponding to the average annual surface temperature in the Barents Sea. Actual data on sorption capacity of commercial sorbents “Lessorb”, “Novosorb”, a sorbent based on vermiculite and chitin sorbent in relation to potential pollutants of waters were obtained. The dynamics of sea water saturation with oil products at –0.5 (±1) and 10 (±1) °С was determined. It is shown that at higher temperature the concentration of oil products in sea water column (in the presence of an oil film on the surface) is on average four times higher than at low temperature. Kinetic dependences were obtained that describe the content of oil products in water column and near-surface layer of sea water in the presence of the studied sorbents at 5 (±1) °C, corresponding to the average annual temperature in the Kola Bay of the Barents Sea. A method is proposed for evaluating the efficiency of sorbents from the values of regression coefficients characterizing the dependence of oil products content in sea water on the character of sorbent and duration of its action.