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.