深圳西部海域河流入海口沉积物酸可挥发性硫、同步提取重金属分布特征与生物毒性评价

摘要

The horizontal and vertical distributions of acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) in the sediment from seven estuaries along the Shenzhen coast were studied. The potential risks of heavy metals to benthic organisms in the sediment were also preliminary evaluated. The concentration of AVS in the surface sediment ranged from 0.54 to 24.17μmol·g-1 with an average of 10.74μmol·g-1. The sediment concentration of AVS in the Shenzhen River estuary was the lowest, and that in the Houhai River estuary was the highest. The spatial distribution of AVS was in the order of Houhai River estuary>Xixiang River estuary>Xinzhen River estuary>Dasha River estuary>Tiegang Reservoir estuary>Fuyong River estuary>Shenzhen River estuary. The concentration ofΣSEM was between 5.58 to 32.18μmol·g-1 with an average of 15.63μmol·g-1. The concentration ofΣSEM in the Dasha River estuary was the lowest, and that in the Fuyong River estuary was the highest. The spatial distribution ofΣSEM was in the order of Tiegang Reservoir estuary>Shenzhen River estuary>Fuyong River estuary>Xinzhen River estuary>Xixiang River estuary>Houhai River estuary>Dasha River estuary. The spatial distributions of AVS and SEMs were consistent. The vertical diversification of AVS increased at first and then decreased, which was similar toΣSEM. The TOC (total organic carbon), particle size and pH were significantly correlated with AVS in the sediment. We found that high organic matter content, large particle size and high pH were favorable to the formation of AVS in the study area. Based on the analysis of the potential risks to benthic organisms, theΣSEM/AVS、(ΣSEM-AVS) and (ΣSEM-AVS)/foc in the surface sediment ranged from 0.77 to 8.93, from-5.58 to 16.85 and from-244.30 to 2071.65μmol·g-1, respectively. However,ΣSEM/AVS, (ΣSEM-AVS) and (ΣSEM-AVS)/foc in the core sediments ranged from 0.38 to 8.93, from-19.69 to 36.05 and from-1278.27 to 2391.28μmol·g-1, respectively. High toxic effects were concentrated in the heavy metals in the estuaries of the Fuyong River, Tiegang Reservoir and Shenzhen River. Attention should be paid to strengthen the heavy metal pollution monitored in these three estuaries.%对深圳西部海域7个河流入海口沉积物中酸可挥发性硫化物(AVS)和同步可提取重金属(SEM)的区域和垂直分布特征进行了研究,对沉积物重金属的潜在生物毒性进行初步评价。结果表明：深圳西部海域河流入海口沉积物 AVS 的含量范围为0.54~24.17μmol·g-1之间,平均为10.74μmol·g-1,分布规律为后海河河口>西乡河河口>新圳河河口>大沙河河口>铁岗水库洪排口>福永河河口>深圳河河口；ΣSEM 含量范围为5.58~32.18μmol·g-1之间,平均值为15.63μmol·g-1,分布规律为铁岗水库洪排口>深圳河河口>福永河河口>新圳河河口>西乡河河口>后海河河口>大沙河河口。ΣSEM垂直分布规律与AVS相似,都有先增高后降低趋势；沉积物中AVS与沉积物有机碳(TOC)、粒度以及溶出液pH呈显著性相关,河口区沉积物有机质含量越高、粒度越大、pH越高越有利于AVS生成；对沉积物进行重金属生物毒性效应分析,表层沉积物中(ΣSEM/AVS)、(ΣSEM-AVS)和(ΣSEM-AVS)/foc 值(foc 为有机碳百分含量)的变化范围分别为0.77~8.93、–5.58~16.85μmol·g-1和-244.30~2071.65μmol·g-1,而柱状沉积物中(ΣSEM/AVS)、(ΣSEM-AVS)和(ΣSEM-AVS)/foc值的变化范围分别为0.38~8.93、-19.69~36.05μmol·g-1和-1278.27~2931.28μmol·g-1。其中,福永河河口、铁岗水库洪排口和深圳河河口沉积物重金属表现为高生物毒性效应,应加强重金属污染监控。