Pollution Characteristics And Risk Assessment Of Organotin In Eastern Coastal Ports Of China

Organotin compounds（OTCs）are metal organic compounds combining tin and carbon,and are also one of endocrine disrupting substances.Since the middle of last century,OTCs have been gradually applied in Marine antifouling coatings and gradually polluted the Marine environment,which is considered to be one of the most toxic substances introduced into the Marine environment by human beings so far.In 2011,China formally entered into force of the International Convention for the Control of Harmful Anti-Fouling Systems on Ships（AFS）formulated by the International Maritime Organization（IMO）.However,due to the rapid development of Chinese ports and ocean transportation at the end of the last century,as well as the characteristics of OTCs that are not easily degraded in sediments for a long time,China’s coastal areas have been plagued by OTCs.In order to comprehensively understand the pollution status of OTCs in ports along the east coast of China,and to investigate its ecological risks and risks to human health,this study targeted coastal sediments and Marine organisms（including nearly 20 species of mollusks,crustaceans and fish）in the adjacent waters of typical ports along the east Coast of China.The concentrations of six organotin compounds,including tributyltin（TBT）,dibutyltin（DBT）,monobutyltin（MBT）,triphenyltin（TPh T）,diphenyltin（DPh T）and monophenyltin（MPh T）,were determined using gas phase triple quadrupole tandem mass spectrometer（GC-MS/MS）.The results show that the concentration ofΣOTCs in the coastal sediments of east China ports ranges from 6.7 to 39 ng Sn g^-1dry weight（dw）,with an average concentration of 14 ng Sn g^-1dw.OTCs were detected in all Marine organisms in the vicinity with concentrations ranging from 0.81 to 2900 ng Sn g^-1dw,with an average concentration of 130 ng Sn g^-1dw.There are two major categories of phenyltin（Ph Ts:MPh T,DPh T and TPh T）and butyltin（BTs:MBT,DBT and TBT）.The coastal sediment is mainly polluted by BTs,and the contribution rate is 35%～100%,and the average contribution rate is 77%.Ph Ts dominated the OTCs of Marine organisms in the waters near each port,contributing 51%to 87%with an average contribution level of 71%.From the perspective of space,OTCs pollution is more serious in the southern sea area,that is,near the southeast coastal port group.Compared with other regions in the world,the OTCs of coastal sediments in eastern ports of China are at a lower level,and the average OTCs pollution level of marine organisms in nearby waters is at a moderate level.OTCs pollution in ports along the east coast of China comes from a variety of sources,including historical residues and agricultural pesticide use.In addition,the main reason for the decrease of BTs pollution may be the effective of AFS convention with China to control and manage TBT antifouling coatings.Ph Ts pollution increased and the Southeast Coastal Port Group was higher,which may be related to pesticide use and other factors,but the specific relationship with agricultural development needs to be further studied and traced.Based on China’s eastern coastal port of coastal sediments of TBT and TPh T residue levels in ecological risk assessment,according to the coastal marine Sediments Quality Guidelines（SQG）of the Netherlands National Institute for Coastal and Marine Management（RIKZ）,the Bohai Bay Port Group and the Southeast Coastal Port Group in the east coast of China may have certain ecological risks.The health risk assessment based on exposure to OTCs by eating seafood showed that some marine organisms near ports in eastern China may have potential risks to human health,mainly concentrated in the waters near ports in southeastern China.For marine organisms types,mollusks are at higher risk than crustaceans and fish.For different groups of people,seafood consumption poses the greatest risk to children,followed by teenagers and adults.TPh T residue level in marine organisms is the highest,and its contribution to human risk is up to 66%.However,TBT with low residue level is second only to TPh T in its contribution to human risk due to its toxic effects,reaching 14%.Therefore,it is necessary to continuously monitor the pollution of BTs and Ph Ts in the east coast of China and its adjacent waters in the future,especially the Southeast Coastal Port Group,and take some measures to protect the marine ecosystem and human health.