Abstract This study assesses trace metals and macro benthic fauna in a dumping area for dredged material in the continental shelf of Guanabara Bay (Rio de Janeiro), southeast Brazil. Sampling of the study area was made after the last dredging of Rio de Janeiro, in 2017, removing 2.9 × 106 m3 of sediments that were disposed at a recurrent dumping site. The trace metals Cu, Zn, Pb, Cr and Ni exhibited a pattern of increasing concentrations towards the disposal site. Geoaccumulation index (NIgeo) and pollution load index (PLI) classified the dumping area as extremely polluted. The benthic macrofauna was composed by Nemertinea, Nematoda, Sipuncula, Annelida-Polychaeta, Mollusca, Crustacea, Brachiopoda and Echinodermata groups. The central station at the dumping site presented a single taxon Corbula patagonica. The benthic diversity decreased towards the disposal site, as observed by richness and diversity indexes that were markedly different among stations. Results presented preliminary data of trace metals in the dumping area revealing severe pollution in the continental shelf of Guanabara bay. Dumping of dredged material seems to negatively affect the macrobenthic community in the study area since richness and diversity increase with distance from the central spot.

中文翻译：

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疏浚沉积物倾倒对热带城市化河口附近大陆架微量金属浓度和宏观底栖组合的影响

摘要 本研究评估了巴西东南部瓜纳巴拉湾（里约热内卢）大陆架疏浚材料倾倒区的痕量金属和大型底栖动物群。2017 年里约热内卢最后一次疏浚后，对研究区进行了采样，清除了 2.9 × 106 m3 的沉积物，这些沉积物被丢弃在一个经常性的倾倒场。痕量金属 Cu、Zn、Pb、Cr 和 Ni 表现出向处置场所浓度增加的模式。地累积指数 (NIgeo) 和污染负荷指数 (PLI) 将倾倒区归类为极度污染。底栖大型动物由Nemertinea、线虫类、Sipuncula、环节动物-多毛类、软体类、甲壳类、腕足类和棘皮动物类组成。倾倒地点的中心站展示了一个单一的分类群 Corbula patagonica。底栖多样性向处置地点下降，正如各站之间显着不同的丰富度和多样性指数所观察到的那样。结果显示了倾倒区中痕量金属的初步数据，揭示了瓜纳巴拉湾大陆架的严重污染。疏浚材料的倾倒似乎对研究区的大型底栖动物群落产生负面影响，因为丰富度和多样性随着距中心点的距离而增加。