湛江红树林湿地沉积物中PCBs污染特征研究

Pollution Characteristics and Ecological Risk Assessment of Polychlorinated Biphenyls(PCBs)in Mangrove Sediments in Zhanjiang

作为中国面积最大的红树林生态系统,湛江红树林沉积物中PCBs(多氯联苯)污染特征及其来源尚不明确。2018年5月,通过采集湛江红树林保护区12个位点的表层沉积物,利用气相色谱质谱联用仪测定样品中PCBs质量分数,并根据沉积物质量指南(SQGs)标准对其进行生态风险评估。结果显示,湛江红树林湿地表层沉积物中共检测出11种PCBs,其质量分数范围为0~18.302 ng/g,平均质量分数为(5.858±1.614)ng/g,其中PCB157的质量分数水平最高,达1.639 ng/g。与国内外其他红树林地区相比,湛江红树林湿地沉积物中PCBs质量分数处于中等偏低水平。湛江红树林湿地检出的PCBs主要为高氯同系物,可能主要源于工业废气、饲料生产和使用、船舶油漆脱落。生态风险评估结果表明,湛江红树林湿地沉积物中暂不存在PCBs的生态风险,但在今后生产活动中需加强防护,避免生态风险等级的升高。该研究揭示了湛江红树林表层沉积物中PCBs的污染特征、污染来源与潜在生态风险,为湛江红树林的生态环境保护及污染控制提供了依据。

As the largest mangrove ecosystem in China,the pollution characteristics and sources of PCBs(polychlorinated biphenyls)in mangrove sediments in Zhanjiang are not clear.The surface sediments of 12 sampling sites in Zhanjiang Mangrove Reserve were collected in August,2018.All samples were determined by Gas chromatography-mass spectrometry(GC/MS)and the ecological risk assessment was conducted by sediment quality guidelines(SQGs).The results showed that a total of 11 homologues of PCBs were detected in the surface sediments of the Zhanjiang mangrove wetland,the content of PCBs ranged from 0 to 18.302 ng/g,the mean value was(5.858±1.614)ng/g,and PCB157 accouted for the highest proportion with mean value of 1.639 ng/g.Compared with other mangrove sediments in domestic and foreign mangroves wetlands,the content of PCBs in the mangrove sediments were in the medium to low level.PCBs homologues in Zhanjiang were mainly composed of high-chlorine homologues,and they would be mainly derived from the Industrial Waste Gas,feed production and use,ship paint peeling.The results of ecological risk indicated that there had nearly no ecological risk of PCBs in the man⁃grove sediments in Zhanjiang,while protection should be strengthened in future to avoid the increase of ecological risk lev⁃el.To provide basis for ecological environment protection and pollution control of mangroves in Zhanjiang.