Study On Water Quality Criteria Of 2,2’,4,4’-tetrabromodiphenyl Ether (BDE-47) In Bohai Bay

Polybrominated diphenyl ethers（PBDEs）are common brominated flame retardants,which are commonly used in polymer foams,building materials,and plastics,etc.PBDEs are semi-volatile,highly toxic,bioaccumulative,and persistent,and are emerging persistent organic pollutants（POPs）.2,2’,4,4’-tetrabromodiphenyl ether（BDE-47）is one of the most common PBDEs detected in the environment due to its high lipophilicity and long half-life.In recent years,it has been widely distributed in China’s offshore waters.BDE-47 can be transported and accumulated through food webs,resulting in certain toxicity to marine aquatic organisms,even ultimately affecting marine ecosystems.The Bohai Sea is the only semi-closed inland sea in China,and Bohai Bay is one of the three major Bays.BDE-47 can enter the water ecosystem of Bohai Bay from the discharge of industrial wastewater and domestic sewage in the urban agglomerations around Bohai Bay.Therefore,it is necessary to carry out research on Water Quality Criteria（WQC）for the protection of aquatic organisms from pollutants BDE-47 in Bohai Bay,but there are few reports.Therefore,in view of the blank research of regional seawater water quality criteria in China,this paper serves the battle of comprehensive treatment of Bohai Bay,carries out the research of BDE-47 seawater water quality criteria in Bohai Bay,in order to clarify the pollution situation of Bohai Bay water body,and combines the investigation of Bohai Bay pollution status,so as to provide guidance and reference for the reduction of pollutants in Bohai Bay.（1）The acute and chronic toxicity data of BDE-47 to aquatic organisms in Bohai Bay were screened,and the acute toxicity tests of BDE-47 on eight dominant species in Bohai Bay and the chronic toxicity tests of two species were supplemented.The 96 h-50%of lethal concentration(96 h-LC₅₀)of Psetta maxima,Takifugu rubripes,Fenneropenaeus chinensis,Sinonovacula constricta,and Sinonovacula constricta,were 44.44μg/L,387.20μg/L,44.01μg/L,69.65μg/L,and 120.22μg/L,respectively.The 48 h-LC₅₀ of Acartia bifilosa,Brachionus plicatilis were 340.66μg/L and 411.06μg/L,and the 96 h-50%of effective concentration(96 h-EC₅₀)of Skeletonema costatum was 14.43μg/L.The order of toxicity sensitivity of aquatic organisms to BDE-47 were Skeletonema costatum>Fenneropenaeus chinensis>Psetta maxima>Argopecten irradians>Sinonovacula constricta>Acartia bifilosa>Takifugu rubripes>Brachionus plicatilis.Chronic toxicity test showed that 21 d-no observed effect concentration（21 d-NOEC）of Takifugu rubripes was 5.00μg/L,8 d-NOEC of Brachionus plicatilis was 20.00μg/L.（2）Considering the methodological guidelines of different countries,a three-level protection framework for aquatic organisms in Bohai Bay is established:short-term seawater quality criteria（S-SWQC）,long-term seawater quality criteria（L-SWQC）,and serious risk concentration for the ecosystem(SRC_eco).The acute toxicity data of genera were used to derive S-SWQC,and the SSD method was adopted for the derivation.At the same time,the minimum data quantities requirements are as follows:when the amount of data is small,the data quantities requirements are derived by referring to the freshwater quality criteria of China,and at least five aquatic organisms of three nutritional levels are satisfied.L-SWQC is recommended to refer to the AA＿QS derived by the EU,including seawater quality criteria,sediment criteria,the secondary poisoning water quality criteria,and the adverse health effects upon ingestion of fishery products water quality criteria.The SRC_eco uses the model extrapolation or assessment factor method according to the amount of data.（3）Finally,based on the toxicity data of BDE-47 to marine aquatic organisms in Bohai Bay,S-SWQC,L-SWQC,and SRC_eco were derived as 9.20μg/L,0.25μg/L,and 3.65μg/L,respectively,this provides data reference and support for the revision of water quality standard in China in the future.