Characterization Of Persistent Halogenated Organic Pollutants And Heavy Metal Pollution In Fish From The Laibin Of The Xijiang River

The Xijiang River is the main river of the Pearl River Basin in Guangxi and is rich in fish resources,providing food and production raw materials for humans.However,the discharge of chemical by-products from industrial and agricultural production and use around the river affects its water quality,resulting in the enrichment of pollutants in the water body by fish through ingestion,respiration and dermal contact,and their transfer to the human body along the food chain.In order to understand the contamination of persistent halogenated organic pollutants(HOPs)and heavy metals in fish muscle in this water,this paper selects nine common food fish species(Cirrhinus molitorella,Ctenopharyngodon idella,Cyprinus carpio,Squaliobarbus curriculus,Ptychidio jordani,Carassius auratus,Silurus asotus,Tachysurus fulvidraco,Channa argus)in the Laibin of the Xijiang River as the study objects,detects the content of pollutants in their muscles,analyses the enrichment characteristics of each pollutant,calculates the ecological contamination level and assesses the potential health risk level of food fish.The study provides theoretical data for fish environmental biology.The results of the study are as follows:(1)The results showed that the concentrations of OCPs,PCBs and PBDEs in the muscles of nine fish species ranged from 8.94 to 43.32 ng/g ww,1.22 to 4.09 ng/g ww and >0.01 to 0.13 ng/g ww,respectively,using gas chromatography-mass spectrometry(GC-MS).The inductively coupled plasma mass spectrometer(ICP-MS)was used to determine the levels of six heavy metals in the muscle of nine fish species in the order of Zn>Cu>Cd>Pb>Cr>Ni,with concentrations ranging from 4.48 to74.70 mg/kg,0.38 to 4.12 mg/kg,ND to 1.69 mg/kg,ND to 0.85 mg/kg,ND to 1.79mg/kg and ND to 0.40 mg/kg,respectively.(2)Characterization of the composition of homologous compounds of persistent halogenated organic pollutants in fish muscle showed that hexachlorocyclohexane(HCHs)and endrin accounted for the largest proportion of organochlorine pesticides,31.59% and 35.84% respectively,and β-HCH accounted for 42.10% of the HCHs.Hexa-CBs makes the largest contribution to PCBs,accounting for 64.89% of the total,followed by Penta-CBs>Deca-CBs>Tetra-CBs>Hexa-CBs.PBDEs were distributed differently among the nine fish species,with BDE 154 accounting for the largest share at 53.05%.(3)OCPs and PCBs have high residues in carnivorous fish and PBDEs have high residues in herbivorous fish when analysed in terms of different food types.More OCPs,PCBs and PBDEs remain in demersal fish than in pelagic fish.The results of the one-way ANOVA for heavy metals showed that there was no significant difference(P>0.05)in the heavy metal content in fish of different feeding habits and different habitats,and the highest enrichment capacity for Cr,Cd and Ni was found in Ptychidio jordani.(4)The results of the food safety evaluation of persistent halogenated organic pollutants showed that daily consumption of fish in the Laibin section of the Xijiang River did not pose a health risk to local residents.The results of the evaluation of the food safety of heavy metals showed that the actual weekly intake of six heavy metals did not exceed 14.00% of the PTWI ratio,which was much lower than the standard value,and none of them posed any consumption risk.