Study On The Hydroxylated Metabolites And Transmitting Characteristics Of Polychlorinated Biphenyls (PCB101) In Crucian Carp (Carassius Auratus)

Polychlorinated biphenyls?PCBs?are one of the first group 12 persistent organic pollutants which were prohibited by the Stockholm Convention in 2001,can be released into the aquatic environment through a verity of ways,and exposed in water and sediment,aquatic organisms were susceptible to be polluted.Hydroxylated PCBs?OH-PCBs?and methyl sulfonated PCBs?MeSO₂-PCBs?are main metabolites of PCBs in organisms which are nominated as the second generated persistent environmental pollutants.These pollutants can be bioaccumulated in organisms and biomagnified in the food chain due to their lipophilic properties,and may have toxic effects involved with endocrine disruption in aquatic organisms,lead to consequent quality and safety problems of aquatic products,and have attracted sustained attention in worldwide.In China,there is a lack of studies on the types,distribution and accumulation characteristics of hydroxylated metabolites of PCBs in aquatic organisms,as well as their distribution and transmitting characteristics in the environment,in particular,the typical PCBs pollution area has become a protential danger to the environment and aquatic products safety.Taking crucian carp as the model organism,PCB101 as the parent compound,the crucian carp was exposed to PCB101 by intraperitoneal injection for 30 days.The metabolites of PCB101 were identified and analyzed by GC/MS/MS to confirm the types and structures of PCB101 metabolites in crucian carp,and the distribution and accumulation characteristics of PCB101 and its metabolites in crucian carp were studied as well.The main research results were as follows:?1?The gas chromatography?GC-?ECD?method was established to determine 10OH-PCBs in aquaculture sediment.Before extracting with n-hexane,the sediment amples were adjusted to pH 3.0 with HCl?6 mol/L?.In order to remove the interference materials,silica gel column was used for purification,and the proportion and elution volume of the cleaning solvent were studied simultaneously.After the silica gel column was washed,target compounds were eluted with n-hexane/ethyl acetate?1:1V/V?,the eluent was proceed with silylation derivatization after concentrating under N₂.And the target compounds were finally determined by GC-?ECD.It was confirmed that the cleaning solvent was n-hexane/ethyl acetate?98:2 V/V?with a elution volume of5mL;The limit of detection is 4.00?g/kg,and the limit of quantitation is 8.00?g/kg;At the spiked level of 4.00,8.00,20.0?g/kg,the average recoveries of 10 OH-PCBs ranged from 72.4%to 94.0%,RSD ranged from 1.73%to 9.87%,and this method is used for the analysis of 10 OH-PCBs in aquaculture sediment from Taihu lake.In conclusion,the method can be used for trace analysis of OH-PCBs in aquaculture sediment.?2?A simultaneous identification method was developed to determine PCB101 and its hydroxylated,methoxylated and methyl sulfonated metabolites in fishery product samples with gas chromatography?GC-?ECD?in this paper.PCBs are a group of most ubiquitous persistent organic pollutants in the environment.This is the first time that both parent compound and three types of metabolites have been detected simultaneously in fishery products.Taken muscle tissue of crucian crap as the research matrix,several operational parameters were investigated and optimized,including the kind of extracting solvent,the volume of concentrated sulfuric acid for lipid removal from the extract,the eluting procedure and the volume of eluent of solid phase extraction which was used for clean-up.Under the optimum conditions,linearity of the method was in the range of 2.5-100 ng/mL,with correlation coefficients?R²?>0.9961,the limit of detection was 2.00?g/kg,the limit of quantitation was 5.00?g/kg.The spiked recoveries of six target compounds in crucian carp muscles were achieved ranged from84.4%to 104%,and RSD between 4.02%and 8.75%.The proposed method has been successfully applied to analyze fishery product samples from local market and marine organisms collected from East China Sea.And the existence of PCB metabolites was found in samples collected from the East China Sea for the first time.The research result has beneficial effect on providing data support for further study of the nvironmental behavior and biological transmitting characteristics of PCBs.Meanwhile,it is valuable for the research to reveal the real polluted level of PCBs in environment.?3?The metabolites of PCB101 in crucian carp were identified in this study for the first time.Taking crucian carp as the model organism,PCB101 as the parent compound,the crucian carp was exposed to PCB101 by intraperitoneal injection for 30 days.The metabolites of PCB101 were identified and analyzed by GC/MS/MS to confirm the types and structures of PCB101 metabolites in crucian carp,and the distribution and accumulation characteristics of PCB101 and its metabolites in crucian carp were studied as well.The results showed that PCB101 could be metabolited to three types of metabolites in crucian carp at least,including hydroxylated,methoxylated and methyl sulfonated PCB101.The major hydroxylated metabolites identified in most tissues such as liver,bile,blood and muscle were 3-OH-PCB101 and 4-OH-PCB101,in the blood,3-OH-PCB101 showed a higher accumulation advantage than 4-OH-PCB101,the accumulation concentration of 4-OH-PCB101 in liver and bile was slightly higher than that of 3-OH-PCB101.The main methyl sulfonated metabolites identified in gallbladder,blood and brain were 3-MeSO₂-PCB101 and 4-MeSO₂-PCB101,compared with3-MeSO₂-PCB101,4-MeSO₂-PCB101 has a wider tissue distribution characteristic and slightly higher accumulation concentration.Meanwhile,the main methoxylated metabolite identified in liver,bile,blood and spleen of crucian carp was4-MeSO₂-PCB101.And the accumulation concentration of PCB101 in different of crucian carp showed a similar trend with time.?4?The contents of 10 OH-PCBs in soil,water,sediment,fish,shrimp and crab and other environmental and biological samples in typical PCBs contaminated areas were determined.The distribution and transfer characteristics of PCBs in environmental and biological samples have been preliminarily explored.Low chlorinated OH-PCBs may be easily distributed and transferred between environmental media and aquatic organisms.High chlorinated OH-PCBs may be tended to metabolized and accumulated in aquatic organisms,and distributed and transfered through the food chain in the aquatic environment.Historical remains and current new sources of PCBs,its hydroxylated second generation pollutants produced by biological metabolism,microbial degradation and abiotic reactions,will pose potential safety risks to the environment and aquatic organisms.It is helpful to understand the transformation and metabolism mechanisms in fishery products by identifying the types and structures of metabolites of PCB101 in crucian carp,as well as the characteristics of tissue distribution and accumulation.It is of great significance to identify potential pollution hazards of parent compounds and their metabolites on aquatic products and ensure the quality and safety of aquatic products.The study of the distribution and transmitting characteristics of OH-PCBs in the environment of typical PCBs polluted areas and aquatic biological samples,which is beneficial to prewarn the problem of fishery products safety originated from OH-PCBs.And it will be helpful to reveal the real polluted level of PCBs in environment and organisms.And it is important for the exploration of the final existing forms of PCBs in environment.