Contamination Characteristics And Risk Assessment Of Polycyclic Aromatic Hydrocarbons In Soils And Pine Needles In The Oil Industrial Park In Karamay

PAHs are representative pollutants of persistent organic pollutants that are widely present in various environmental media and are products of fossil resources and biomass fuel processes.PAHs have attracted widespread attention because of their tri-causal effects and their ability to enrich in different environmental media,ultimately endangering the environment and human health.However,most domestic and foreign researchers have focused on urban and rural areas,and less on oil industrial parks based on oil fields.In order to fill the research gap in this area,and to respond positively to the national "14th Five-Year Plan" for ecological environmental protection and environmental health plan for VOC emission reduction,and for the transformation of petrochemical industry to "clean production".In this study,soil and pine needle samples were collected from the petroleum industrial park in Karamay in four seasons.Using pine needles as passive samplers,we investigated the distribution of PAHs in soil and air,the differences in composition,the main sources and health risk assessment in each of the four seasons.(1)The distribution of PAHs in pine needles in the Karamay Petroleum Industrial Park showed a seasonal trend of winter(74.92 ng/g)> summer(55.81 ng/g)> autumn(52.17 ng/g)> spring(44.71 ng/g).Σ18PAHs concentrations ranged from 322.26 to 7297.27 ng/g,with the highest concentrations of naphthalene,followed by phenanthrene and fluoranthene.The concentration of PAHs on the surface of pine needles ranged from 322.26 to 7297 ng/g,with the highest concentration of naphthalene and the second highest concentration of fluoranthene.The PAHs adsorbed on the surface of pine needles are mostly low-ring PAHs,whose sources are mostly fossil fuels and biomass combustion in industrial parks and during the heating period.(2)The distribution of PAHs in soils in the Karamay Petroleum Industrial Park showed a seasonal trend of autumn(13.02 ng/g)> spring(7.71 ng/g)> winter(6.15 ng/g)> summer(3.51 ng/g),with little variation in concentration between seasons.Σ18PAHs concentrations ranged from 22.62 ～ 485.94 ng/g.The content of PAHs in the soil is dominated by the middle ring,and the source contribution is mainly the combustion of petrochemical resources and traffic emissions.(3)The content of PAHs in soils and pine needles in the Karamay Petroleum Industrial Park is greater than that of the Dushanzi Ethylene Petrochemical Plant,both in terms of the average content over the four seasons and the range of concentrations of Σ18 PAHs,which is related to the planning of the industrial park.In the industrial park,the amount of PAHs adsorbed on the surface of the pine needles is greater than that in the soil.Low-ring PAHs are mostly present in the atmosphere,while medium-and high-ring PAHs are mostly present in the soil.According to the correlation analysis,there is a strong correlation betweenΣ18PAHs and low and medium-ring PAHs in the atmosphere and soil.(4)The concentration of Σ18PAHs in soil is much smaller than the concentration of Σ18PAHs adsorbed on the surface of pine needles.According to the equation for equivalent concentrations of toxicity factors and the lifetime carcinogenic risk model,the combined contamination of soil and pine needles showed a seasonal trend of winter > summer > spring > autumn in all four seasons.The lifetime carcinogenic risk of the industrial park was in the potential risk area in all seasons,with the contribution of the ingestion pathway in the order ILCR(oral)> ILCR(respiratory)> ILCR(dermal).The contents of Σ18PAHs in soil and pine needles in two oil industrial parks attached to the Karamay Oilfield were detected and analyzed.It was found that in all seasons,the content of Σ18PAHs adsorbed on the surface of pine needles was much larger than that in soil,reaching a moderate pollution level,and the content of PAHs in soil reached a light pollution level.The hazard of PAHs in soil and pine needles to human body in four seasons mainly showed a seasonal change of winter > summer > autumn > spring,and the hazard of PAHs to human body and environment in industrial park mainly came from the atmosphere,and reached the threshold of potential carcinogenic risk(10-6 < ILCR < 10-4)in all four seasons,and the carcinogenic risk pathway was mainly oral,which should be paid attention to and prevented.