Identifying The Origin Of Petroleum Pollutants In Surface Water And Multivariate Statistical Analysis Of Oil Fingerprint

Petroleum is a common environmental pollutant with complex composition and potential harmful effects of carcinogenic,teratogenic and mutagenicity.It was a limiting factor for some rivers to meet the Class III standard for surface water.Studying petroleum pollution sources and their identification techniques was of great significance for emergency traceability and refined control management of oil pollutants in surface water environment.In this study,encrypted and monitored the water quality of Hangzhou Tang River and Changshan River in Jiaxing City.In addition,studied the spatial distribution and time variation of petroleum pollutants in the waters of Hangzhou Tang River and Changshan River,and researched the effects on gas stations,oil depots,wharfs,rainfall runoff and main tributaries.At the same time,light diesel samples from 9 water stations were collected from the rivers with high concentrations of petroleum pollutants detected in the two rivers,and conducted oil fingerprints and their multivariate statistical identification studies.The quality diesel oil was subjected to weathering experiments to study the weathering characteristics of n-alkanes and polycyclic aromatic hydrocarbons?PAHs?.The specific conclusions are as follows:?1?The concentration of petroleum pollutants in the monitoring sections of Hangzhou Tang River and Changshan River decreased year by year,but the fluctuations were large and did not show obvious seasonal changes.It was not able to reach the Class III water quality standard of surface water.The results of the encryption monitoring showed that the oil pollution of the two rivers were mainly concentrated in the section of Xishuangqiao to Longfeng Bridge and the section of Changshan River Entrance to Shuangxi Bridge Water Plant.?2?Most of the water stations in the water stations,terminals and all the oil depots had higher concentrations of petroleum pollutants than the upstream water bodies,indicated that the water stations,terminals and oil depots were important sources of petroleum pollutants in the river;Rainfall runoff did not show significant impact on the concentration of petroleum pollutants in the two rivers.The tributaries near some industrial parks had certain effects on the petroleum pollutants in the two rivers.The ship itself also had a certain impact on the petroleum pollutants in Hangzhou Tang and Changshan River.?3?The petroleum pollutants in the river are mainly light diesel oil.The source of light diesel oil couldnot be identified by GC-MS fingerprinting.However,based on the GC-MS spectrum,extracted the characteristic ratios of n-alkanes and PAHs could be preliminary identification.Combined with the multivariate statistical method of principal component analysis and cluster analysis,the characteristic ratios of oil fingerprint was analyzed,which could realize the fine identification of light diesel oil,and divided the oil fingerprints of 9 light diesel into 6 categories.?4?The results of weathering characteristics of oil fingerprints showed that the weathering resistance of n-alkanes components in petroleum pollutants increases with the increase of carbon number.The characteristic ratios C₁₇/Pr and C₁₈/Ph were greatly affected by weathering,Pr/Ph was less affected by weathering,and(C₁₉+C₂₀)/(C₂₁+C₂₂)and CPI were basically not affected by weathering;The anti-weathering ability of the PAHs components were stronger than that of n-alkanes.The characteristic ratios C₃-D/C₃-C,C₃-P/C₃-C,and?P/?D were greatly affected by weathering,and were not suitable for oil fingerprint identification after weathering,while C₃-D/C₃-P,C₂-D/C₂-P,C₁-D/C₁-P were less affected by weathering and could be used for oil fingerprint identification after short-term weathering.?5?With the initial concentration of petroleum pollutants in surface water is less than 0.5 mg/L,all characteristic ratios were unstable and unfeasible for the identification of oil origin.With the initial oil concentrations of 1.0 mg/L or higher,however,the characteristic ratios of C₁₇/Pr and C₁₈/Ph could be used for identifying oil origin when the weathering was within five days,while the characteristic ratios of Pr/Ph,(C₁₉+C₂₀)/(C₂₁+C₂₂),and CPI were less affected and could be used for oil fingerprint identification regardless of the weathering time.