不同老化方式的浒苔生物炭对养殖底泥中复合污染物的修复研究

PAHs and heavy-metal polluted aquaculture sediment remediation using different-aged Enteromorpha biochar

为控制养殖底泥中重金属和PAHs等污染物的迁移性并降低其生物累积,从而保障水产品的质量安全,在探究热解对成品浒苔生物炭多环芳烃(PAHs)含量影响的基础上,进一步探讨了不同方法老化生物炭对养殖底泥中复合污染物稳定效果的影响。将制得的浒苔生物炭热解后分别进行自然老化及冻融循环老化,再以3%的比例投入到待修复的底泥中,以菲律宾蛤仔为生物指示物评估生物炭的修复效果。结果表明,热解后浒苔生物炭中PAHs的含量下降86%,达到了《European Biochar Certificate》使用标准;3%老化生物炭添加后重金属和PAHs的生物累积浓度均有下降,且自然老化的修复效果明显优于冻融循环老化,前者实验结束后,菲律宾蛤仔体内累积的重金属Cu、Pb、Cd、Cr和PAHs浓度分别下降了30%、41%、53%、43%和28%,且蛤仔的食用非致癌风险和致癌风险分别下降了42%和35%。因此,自然老化浒苔生物炭的添加不仅对底泥中的复合污染物有良好的稳定化效果,同时有助于提升水产品的质量,并保障消费者人体健康。

To control the migration of heavy metals and polycyclic aromatic hydrocarbons(PAHs)in the aquaculture sediment reduce their bioaccumulation,and ensure the quality and safety of aquatic products,this study investigated the effects of different aging methods on the immobilization of combined pollution in sediments based on the effects of pyrolysis on the content of PAHs in Enteromorpha biochar.The pyrolysis of the produced Enteromorpha biochar was followed by spontaneous aging and freeze–thaw cycle aging.A total of 3%of the biochar was added to the contaminated aquaculture sediment.The remediation effect of biochar was evaluated using clams(R.philippinarum)as biological indicators.The results showed that after pyrolysis,the content of PAHs in Enteromorpha biochar decreased by 86%,which reached the European Biochar Certificate standard.After adding 3%-aged biochar,the bioaccumulation concentration of heavy metals and PAHs decreased and the immobilization effect of spontaneous aging was significantly better than that of freeze-thaw cycle aging.The concentrations of heavy metals(Cu,Pb,Cd,and Cr)and PAHs in the R.philippinarum decreased by 30%,41%,53%,43%,and 28%,respectively.The non-carcinogenic and carcinogenic risks of R.philippinarum decreased by 42%and 35%,respectively.Therefore,the addition of Enteromorpha biochar after spontaneous aging not only had an acceptable stabilizing effect on the composite pollutants in the sediment but also improved the quality of aquatic products,thus protecting the health of consumers.