Study On The Distribution Characteristics And Sources Of Heavy Metals And Polycyclic Aromatic Hydrocarbons In Apostichopus Japonicus Culture Pond

This study used Apostichopus japonicus as main cultural species. According tothe complementary characteristics of different types of ecological niches and habits,filter feeders of scallop Chlamys farreri, omnivorous shrimp and sea cucumber werematched.After comparing and analyzing the different contents of typical contaminantsin different polyculture systems between living organisms and between livingorganisms and their environment, then trying to explore the sources,migration processand pathway of typical contaminants for cutting off the transfer of the typicalcontaminants in sea cucumber aquaculture ponds. The results could provide scientificbasis for establishing a clean, efficient and healthy breeding patterns and resolving thefood safety issues. The main results were presented as the following:1. Study on the effect of co-culture of scallop Chlamys farreri in Apostichopusjaponicus pond on the heavy metal concentrationsThe present study compared the concentration of typical heavy metals （Cu, Pb,Cd, As, Mn, Cr, Hg） in the tissue of sea cucumber Apostichopus japonicus, totalparticulate matter and sediment before and after removing the scallop Chlamys farreriin the sea cucumber-scallop polyculture system and analyzed the impact of theco-culture of filter-feeding scallop with sea cucumber on the changes in theconcentrations of heavy metals. The results showed that the contents of Mn and Asincreased significantly during the entire experiment period. The contents of Cd, Cr,Cu and Hg were relatively higher in juvenile sea cucumber. However, it decreasedgradually and eventually stabilized with the extension of cultivation period. Thecontents of Hg and Pb were obviously affected by the co-culture of scallop, and itincreased significantly after the removal of scallop. The results showed that polyculture system combining sea cucumber and scallop reduced the contents of Hgand Pb in total particulate matter. The contents of Hg and Pb were positivelycorrelated, indicating their characteristics of homologous source. The correlationanalysis on the heavy metal contents between sea cucumber, sediment and totalparticulate matter showed that the content of Hg in sea cucumber was positivelycorrelated with that in total particulate matter and sediment （P <0.05）.2. Study on the heavy metal distribution characteristics in Polycultural System ofApostichopus japonicus with Penaeus chinensis and the ecological assessmentThe present study compared the concentration of typical heavy metals （Cu, Pb,Cd, As, Mn, Cr, Hg, Zn） in the tissue of sea cucumber, Penaeus chinensis, totalparticulate matter and sediment in the sea cucumber monoculture pond andApostichopus japonicus-Penaeus chinensis polyculture pond, and variations ofparticulate organic matter and loss on igniation, then analyzed the impact of theco-culture of Penaeus chinensis with sea cucumber on the changes of the seacucumber cultured environment. The results showed that the concentration of Cu, Asand Mn of sea cucumber were the same trend in monoculture pond and polyculturepond, besides, the concentration of Cu and As of sea cucumber in polyculture pondwere lower than that in monoculture pond.The contants of total praticulate matter andparticulate organic matter in polyculture pond were significantly lower than that inmonoculture pond, it showed that co-culture of Penaeus chinensis with sea cucumbercould effectively improve the culture water environment.Besides, the content andvarious trend of heavy metal in total particular matter were different in monoculturepond and polycultur pond. The concentration of Cr, Mn, and Hg in total particularmatter decreased after polyculturing Penaeus chinensis. The content of organic matterin surface sediment firstly decreased and then increased and polyculture pond washigher than monoculture pond. The correlation analysis on the heavy metal contentsand loss on igniation （LOI） in surface sediment showed that LOI was positivelycorrelated with the contents of Cd, Zn, Pb and Mn.3. Study on the Polycyclic Aromatic Hydrocarbons distribution characteristics inPolycultural System of Apostichopus japonicus with Chlamys farreri The concentriation of sixteen respentative Polycyclic Aromatic Hydrocarbons（PAHs） in Apostichopus japonicus, Chlamys farreri, surface sediments, totalparticulate matter were analyzed by Soxhlet extraction and GC/MS technology. Thepotential sources of PAHs were discussed using isomeric ratios of pairedcompounds such as and Benzo（a）anthracene/（Benzo（a）anthracene+Chrysene）,Fluoranthene/（Fluoranthene+Pyrene）,Pyrene/Benzo（a）pyrene,LMW/HMW.Theresults showed that samples contained fifteen PAHs except Dibenzo（a,h）anthracene.The contents of PAHs oder is following: total particulate matter＞Chlamys farrerifece＞Chlamys farreri＞Apostichopus japonicus＞surface sediment.The abundance of low ring with high ring components were less than one. The typesof PAHs found in the the samples were mainly4⁶ring PAHs. The concentriation ofPAHs of Apostichopus japonicus were affected by both Chlamys farreri fece andsurface sediment in polyculture system. The review showed that the main sources ofPAHs in sanmples were pyrolysis such as combustion of coal, oil and tail gas.4. Study on heavy metal contaminations and the sources of Pb pollution using stableisotope technique in Jinghai BayIn this study, the contents of typical heavy metal contaminants （Cu, Hg, Pb, Zn,Mn, Cd, Cr, As） in serface sediment matter and total particulate matter in Rongchengcity Jinghai Bay were detected using atomic absorption spectrometer. The heavymetal pollution degree of serface sediment in Jinghai Bay was assessed according tonational marine sediment quality.The potent ecological risk （PER） of heavy metals tomarine ecosystem in arrears of Jinghai Bay was assessed using PER factors and riskindices.The results shows that the contents of heavy metals and PER were low,surface sediments correspond to the first class of the sediment quality standardsexcept that the contents of Cu and Zn in S2and Cd in S3, S4, S5and S6correspond tothe second class of the sediment quality standards.The heavy metals PER order isfollowing: Zn＜Cr＜Pb＜Cu＜As＜Hg＜Cd.The contents of heavy metals in serfacesediment matter and total particulate matter were hightest at S2, and they graduallydeclined with the increase of near-shore distance. The correlation analysis on the losson ignition and kinds of heavy metals showed that loss on ignition was positively correlated with Cu, Cr, Pb, Zn, Mn, Hg and As in serface sediment matter. Stableisotope technique was used to search for the main source of Pb contamination insurface sediments and total particulate matter. The results showed that the ratio of208Pb/204Pb,²⁰⁷Pb/204Pb,206Pb/204Pb,208Pb/206Pb and206Pb/²⁰⁷Pb in surface sedimentsand total particulate matter had no significant difference, but ratio of208Pb/204Pb,²⁰⁷Pb/204Pb,206Pb/204Pb and206Pb/²⁰⁷Pb in surface sediments was bigger. The ratio of206Pb/²⁰⁷Pb was lowest in site S2and contrary to the lead concentration. The Pbcontamination was caused mainly by human activities such as industrial dischargesand leaded gasoline.