Mhlathuze Estuary constitutes one of the ecological most important estuaries in southern Africa and is regarded as an estuary of high conservation importance. The ongoing expansion of the adjacent industrialized Richards Bay Harbour increases the risk of metal pollution to the estuary. This study provides insight into the extent and sources of trace metal contamination using pollution indices and sediment quality guidelines and the effect on macrobenthic habitat quality. Sediment samples for sediment metal and macrobenthic analysis were collected quarterly during 2016–2017 at five sites in the estuary using a marine-grade Zabalocki grab. Metal concentrations were determined using an ICP-OES. Sediment metal concentrations were consistently highest in the subtidal mudflats and lowest in marine sand at the mouth of the estuary. Concentrations of all metals displayed significant differences between sites (P < 0.05). Pollution indices indicated moderate enrichment of Cr at all sites, although the mean pollution load index showed the estuary to be unpolluted. Comparison with sediment quality guidelines revealed that concentrations of Ni and Cr were potentially toxic to biota. Using multivariate analysis, metal concentrations appeared not to significantly affect the macrobenthic community. The multi-metric biotic index M-AMBI proved to be a robust tool in the habitat quality assessment of the estuary. The continuing use of M-AMBI as a biomonitoring tool for ecological management of the estuary is advocated.

中文翻译：

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南非夸祖鲁-纳塔尔省北部Mhlathuze河口沉积物中的痕量金属污染：对大型底栖动物群落的影响。

Mhlathuze河口是南部非洲最重要的生态河口之一，被视为具有高度保护意义的河口。毗邻的工业化理查兹湾港的不断扩建增加了河口金属污染的风险。这项研究使用污染指数和沉积物质量指南以及对大型底栖动物栖息地质量的影响，提供了对痕量金属污染程度和来源的见解。2016-2017年期间，使用海洋级Zabalocki抓斗每季度在河口的五个地点收集用于沉积物金属和大型底物分析的沉积物样本。使用ICP-OES测定金属浓度。在潮下带滩涂，沉积物金属的浓度始终是最高的，而在河口处的海洋沙中的沉积金属的浓度最低。P <0.05）。尽管平均污染负荷指数表明河口未被污染，但污染指数表明所有地点的铬含量均中等。与沉积物质量指南的比较表明，镍和铬的浓度对生物群有潜在的毒性。使用多变量分析，金属浓度似乎并未显着影响大型底栖动物群落。多指标生物指数M-AMBI被证明是河口栖息地质量评估的有力工具。提倡继续使用M-AMBI作为河口生态管理的生物监测工具。