Sylvie Désirée Noa Tang, Armel Zacharie Ekoa Bessa, Thérèse Raïssa Messina, Vincent Laurent Onana, Paul-Désiré Ndjigui
Department of Biological Sciences, Higher Teacher Training School, University of Yaoundé I, Cameroon.
Department of Earth Sciences, Faculty of Science, University of Yaoundé I, Cameroon.
Heliyon. 2021 Dec 14;7(12):e08606. doi: 10.1016/j.heliyon.2021.e08606. eCollection 2021 Dec.
This study focuses on risk assessment of Cr, V, Ni, Co, Pb, Cu, and Zn in the Mefou River sediments located at Yaoundé, West-Africa. Sediment samples were collected from five stations in the downstream of the Mefou River, which drains the urban area of Yaoundé between latitudes 3°30' and 3°58' North and longitudes 11°20' and 11°40' East. The geochemistry data were analyzed statistically and the pollution indices were calculated in order to identify and estimate the sources of metal contamination in the Mefou River sediments. The results obtained show that the average concentrations of trace metals are almost higher than those of the upper continental crust (UCC) and the metal average in the Simbock Lake cores. However, the concentrations of Ni, Cu, Pb, and Zn in sediments located in most urbanized sites are lower than those of the UCC and the average of Simbock Lake sediments. The pollution indices such as enrichment factor (EF), geo-accumulation index (Igeo), and pollution load index (PLI) showed that trace metals were mainly influenced by human sources, except for Pb, Cu, and Zn, which stemmed from natural sources. The sediments of the Mefou River would therefore be affected with low to moderate pollution levels. The low values of potential ecological risk (RI: 22.36-41.53) suggest a low potential ecological risk effect. The multivariate statistical analysis indicates that Ni, Cu, Pb, Co, and Zn have been derived mainly from natural sources, while V and Cr would partially derive from human activities. The results of this research can be a reference for trace metal pollution along an African urbanized river corridor. This can be considered as an act of prevention of urban watercourses in Cameroon and in other parts of the world, especially in major African urban metropolis.
本研究聚焦于位于西非雅温得的梅富河沉积物中铬、钒、镍、钴、铅、铜和锌的风险评估。沉积物样本采自梅富河下游的五个站点，该河流经雅温得市区，位于北纬3°30'至3°58'、东经11°20'至11°40'之间。对地球化学数据进行了统计分析，并计算了污染指数，以识别和估算梅富河沉积物中金属污染的来源。所得结果表明，痕量金属的平均浓度几乎高于上地壳（UCC）和辛博克湖岩芯中的金属平均浓度。然而，大多数城市化站点沉积物中的镍、铜、铅和锌浓度低于UCC和辛博克湖沉积物的平均值。诸如富集因子（EF）、地累积指数（Igeo）和污染负荷指数（PLI）等污染指数表明，痕量金属主要受人为源影响，但铅、铜和锌源于自然源。因此，梅富河的沉积物受到的污染程度为低到中度。潜在生态风险较低的值（RI：22.36 - 41.53）表明潜在生态风险效应较低。多元统计分析表明，镍、铜、铅、钴和锌主要源自自然源，而钒和铬部分源自人类活动。本研究结果可为非洲城市化河流走廊沿线的痕量金属污染提供参考。这可被视为喀麦隆及世界其他地区，尤其是非洲主要城市大都市预防城市水道污染的一项举措。
