Residues And Risk Assessment Of Persistent Organic Pollutants In Main Cultured Shellfish From Shandong Coastal Area

The widespread existence of persistent organic pollutants?POPs?in environment and biology and their great harm to ecosystem and human health have attracted great attention from all countries over the world.POPs residue analysis technology,pollution monitoring and control have become research hotspots which scholars are concerned about.In order to find out the pollution situation of shellfish in Shandong coastal area,residue levels,distribution characteristics,risk assessment and sources of pollution organochlorine pesticides?OCPs?,polychlorinated biphenyls?PCBs?and polycyclic aromatic hydrocarbons?PAHs?were analyzed in cultured shellfish.The main research contents and results are as follows:1.Establishment of detection methods for persistent organic pollutants residues in shel fishA gas chromatography–electron capture detector?GC–ECD?method for the simultaneous determinatio n of 8 OCPs and 7 PCBs residues in shellfish was established.The samples were extracted with acetone,and the extracts were purified by gel permeation chromatography?GPC?and solid phase extraction?SPE?.External standard method was uesd for quantitative analysis.The results showed that the limit of quantification?LOQ?of ?–666?PCB101?p,p'–DDE?PCB118?p,p'–DDD?PCB153?PCB138 and PCB180 were 1.0 ?g/kg,LOQ??–666?PCB28 and PCB52?were 1.5 ?g/kg,LOQ??–666??–666 and o,p'–DDT?were 1.3 ?g/kg,then p,p'–DDT was 2.0 ?g/kg.The detection limits was 0.3⁰.8 ?g/kg.15 POPs have a good linear relationship in the concentration range of 1.00¹00 ?g/L,the correlation coefficient is greater tha n 0.995 0,and the average recoveries range from 60.1% to 111% with relative standard deviation?RSD?from 1.7%⁹.8%.The method has good accuracy and precision,and is suitable for simultaneous determination of 8 organochlorine pesticides and 7 polychlorinated biphenyls residues in marine shel fish.The pretreatment method for the determination of 16 polycyclic aromatic hydrocarbon residues?PAHs?in marine shellfish was optimized.The sample was purified by silica gel column and rinsed by n–hexane,then target compounds were eluted by 15 m L of n–hexane–dichloromethane?1:1,V/V?mixture eluent and analyzed by gas chromatography– mass spectrometry?GC – MS?coupled with HP – 5ms capillary column in selected ion monitoring?SIM?and quantified by internal standard method.Under the optimized conditions,good separation of 16 substances and good linear correlation in the range of 2⁵00 ?g/L was achieved?r?0.998 6?.The average recoveries was 84.1%¹19% with RSD between 0.44% and 12%.The method has easy operation,good reproducibility,high recovery rate and good accuracy and precision,which meets the requirements of residue analysis.2.Pollution characteristics and risk assessment of organochlorine pesticides and polychlorinated biphenyls in main cultured shel fish from Shandong coastal areaThe residues of hexachlorocyclohexane?HCHs?,dichlorodiphenyl trichloroethane?DDTs?and PCBs were n.d.–17.6 ?g/kg,2.68–66.7 ?g/kg and n.d.–36.8 ?g/kg?wet weight?.Spatial distribution studies have shown that OCPs and PCBs have relatively high detection values in more developed industries.Seasonal distribution studies indicate that OCPs and PCB residues have generally increased from April to October 2017.The exposure risk index?ERI?and cancer risk index?CRI?are 0–3.07×10^{– 3} and 0–1.22×10^{– 6},which indicates that the OCPs and PCBs residues do not exist the expose risk,and the cancer risks are at acceptable level.3.Residue characteristics,risk assessment and source analysis of polycyclic aromatic hydrocarbons in main cultured shel fish from Shandong coastal areaThe pollution of polycyclic aromatic hydrocarbons was common among the shellfish samples investigated.The mainly components detected in 16 PAHs was 2⁴ rings with the highest detection rates of Naphthalene?NA?and fluorene?FLU?,then high molecular weight PAHs?5⁶ rings?were not detected.Spatial distribution stud ies showed high PAHs content level exist in developed area such as ports and shipping industrial area.Seasonal distribution studies showed that PAHs residue in 9 stations had increased from April to October 2018.The results of risk assessment indicated that the exposure risk index of polycyclic aromatic hydrocarbons in human body health in Shandong coastal shellfish was much less than 1,which was a acceptable range and had no effect on health;the incremental lifetime cancer risk?ILCR?of all shellfish samples was less than 10?– 4?,which indicates no significant cancer risk.The source of PAHs in shellfish was analyzed by ratio method and principal component analysis?PCA?.The results of the ratio analysis indicated that the PAHs in the cultured shellfish from Shandong province came from a mixed source of petroleum sources and pyrolysis sources,and mainly from pyrolysis sources based on the combustion process of fossil fuels.The results of PAHs pollution sources obtained by PCA are consistent with results of ratio method.