基于氧化逆境标志物的北部湾潮间带沉积物有机污染程度综合评价

利用综合生物标志物响应(IBR)指数对北部湾潮间带沉积环境中多氯联苯(PCBs)、石油烃(TPH)、壬基酚(NP) 和苯并芘(Ba]P)的综合污染水平进行评价。在9个站位采集波纹巴非蛤(Paphia undulata)和沉积物样品,测定沉积物和生物软组织中有机污染物含量,同时对鳃、内脏中与细胞防御系统有关的各7种标志物(包括还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)、谷胱甘肽过氧化物酶(GPx)、过氧化氢酶(CAT)等)进行分析。利用相关性分析法筛选出对1~2种有机污染物响应敏感的生物标志物共8种,分别为内脏中的GPx、GSH、GSSG、CAT和鳃中的GPx、GSH、GSSG、CAT。以筛选的8种生物标志物为基础, 9个站位IBR指数范围为0.27~1.48,其中站位S2(湛江市乐民镇码头)、站位S9(湛江市江洪码头)的IBR较小,显示污染程度最轻;站位S4(防城港西湾)、站位S3(钦州湾老人沙浅滩) IBR较高,显示生物体因有机污染产生氧化逆境。不同站位的IBR值与污染源分布、化学污染物分析结果基本一致,表明该方法可用于北部湾潮间带沉积物有机污染程度的综合评价。

Organic contamination assessment of Beibu Gulf intertidal zone with IBR index based on biomarkers of oxidative stress

Integrated Biomarker Response (IBR) index was used for accessing the integrated quality impacted by four organic contaminants, total petroleum hydrocarbon (TPH), polychlorinated biphenyls (PCBs), Nonylphenol (NP) and Benzo(a)pyrene (Ba]P) in the intertidal sediment of Beibu Bay. Bivalves Paphia undulata and sediments were collected from 9 sites. Contents of the organic contaminants were analyzed in the sediment and soft tissue samples. Seven biomarkers related to cellular defense systems including reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GPx), catalase (CAT), etc. in the hepatic tissues and gills of bivalves were also quantified respectively. According to correlation analysis, eight biomarkers were selected for calculating IBR value because of their significant response to one or two pollutants in the sediment and bivalve tissues. They were GPx, GSH, GSSG, CAT in the hepatic tissues and GPx, GSH, GSSG, CAT in the gills. The IBR index of 9 sampling sites ranged from 0.27 to 1.48. Higher IBR values at site S4 in the western Fangchenggang Bay and S9 in Laorensha tidal-flat of Qinzhou Bay indicated a situation of oxidative stress in bivalves induced by organic pollutants. on the contrary, site S2 in Lemin Port and S3 in Jianghong Port of Zhanjiang City had lower IBR values indicating little pollution situation. The IBR index data agreed with chemical determination profiles and distribution of contamination sources. Therefore, this method will offer a promising potential for the integrated assessment of organic contamination in intertidal sediment of Beibu Gulf.