Risk assessment of trace metals in Mefou River sediments, West-Africa

Abstract

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.

Magnetic susceptibility and heavy metal contents in sediments of Riam Kiwa, Riam Kanan and Martapura rivers, Kalimantan Selatan province, Indonesia

“…The high Fe content of the sediments in these rivers is due to their being in a volcanic area, which has a very high Fe content; the bedrock is very high. The average Zn content in this study's sediment samples was also lower when compared to sediments from the Krueng River, Aceh, Indonesia [ 24 ]; Citarum River, West Java, Indonesia [ 22 ]; Zijiang River, Hunan, China [ 53 ]; Xiangjiang River, Hunan, China [ 54 ]; Vaigai River, Tamilnadu, India [ 52 ]; Mefou River sediments, West-Africa [ 55 ]; Gardon of Ales River, France [ 56 ]; and Gorges River, Australia [ 57 ]. The Mn content of the sediment samples in this study was higher than that of the Zijiang River in Hunan, China [ 53 ], the Halda River in Bangladesh [ 58 ], and the Chenab River in Pakistan [ 59 ].…”

Environmental Geochemistry and Fractionation of Cadmium Metal in Surficial Bottom Sediments and Water of the Nile River, Egypt

“…This index assesses the potential risk to the ecology of one or more constituents [ 61 ]. When the prospective ecological risk factor and the toxicity response coefficient were taken into account, Er reflected the sensitivity of the biological community.…”

“…When the prospective ecological risk factor and the toxicity response coefficient were taken into account, Er reflected the sensitivity of the biological community. The Er is calculated as follows: where is the contamination factor, is the toxicity response coefficient of each element (Cd = 30) [ 61 , 62 ] and Er is the ecological risk factor of each element [ 63 ]. Er values were categorized as follows Er <40 is low pollution, 40 < Er < 80 moderate potential risk, 80 < Er < 160 high potential risk, 160 < Er < 320 very high potential risk, and Er > 320 dangerous [ 57 ].…”