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Environmental Assessment by Metallic Trace Elements of Gold Soils – Case of Chami (Dakhlet Nouadhibou, Mauritania)

El Hadi Sidi Mohamed, Hamoud Ahmed, Chakiri Said, El Hadi Hassan, Sabbar Mohamed Salem, Abdeina El Houssein, Baghdad Bouamar, Zerdeb Mohammed Amine, Vall Mohamed

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 6

239--249

EN

In the Inchiri region of northern Mauritania, the discovery of new artisanal methods for extracting gold has made the town of Chami a strategic location for gold miners and their mining operations. Despite the importance of this activity in the country’s economy, to the significant revenues it provides, it is still likely to have a negative impact on the various environmental compartments. The objective of this study was to assess the environmental impact of trace metal elements (ETM) from gold panning in the soils of Chami area. For this purpose, forty soil samples were collected during a field mission in May 2022. The geochemical analyses of the ETM (As, Co, Cr, Cu, Hg, Pb, Ni and Zn) were carried out at the ALS laboratory in Dublin, using the inductively coupled plasma - atomic emission spectroscopy (ICP-AES) technique. The results show that the concentrations of ETM in soils differ according to the sampling station and the considered metal. These concentrations sometimes exceed the normal thresholds. The average value of the pollution index is higher than 1, revealing soil contamination by several elements (As, Cu, Hg and Pb). The geo-accumulation index varying between 0 and 4 shows a medium to high soil pollution class. The correlation matrix obtained shows positive correlations between the studied elements, which suggest that they have the same anthropic origin. These results show an accumulation of metals in soils that can persist in the environment, especially Hg, the most toxic element that is easy to diffuse and change speciation, in addition to being capable of causing risks to the environment and human health.

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Assessment of Groundwater Contamination by Trace Metals in the Chami Gold Area (Mauritania)

El Hadi Sidi Mohamed, Hamoud Ahmed, Chakiri Said, El Hadi Hassan, Abdeina El Houssein, Sabbar Mohamed Salem, Baghdad Bouamar, Vall Mohamed, Zerdeb Mohammed Amine, Dahi Sidi Mohamed

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 7

139--147

EN

Artisanal gold mining in Chami is an important lever in the country economy, owing to the benefits it brings, but it is also likely to have a negative impact on various environmental compartments. Contamination of surface and ground water by trace metals elements (ETMs) was studied in the vicinity of the Chami gold processing center. The aim of the study was to assess the water contamination by trace metals (ETMs) in the town of Chami. Nine water samples (process and boreholes) were analyzed for (Co, Cr, Cu, Ni, Pb, Zn and Hg). The analysis was carried out by the DMA 80 technique for Hg at the ONISPA laboratory in Nouakchott and the other ETM at the Kenitra geosciences laboratory by the ICP-MS technique. The results of the analyses show that the ETM concentrations are high in process water samples and low in drilling water samples. Pollution indices and coefficients of variation indicate no contamination or anthropogenic traces in the borehole samples, but high levels of Hg and Ni in the process water. These results show the accumulation of metals in significant quantities in the process waters, especially Hg, proving that the waters of the mining waste basins at the Chami processing site are becoming sources of environmental pollution by mercury, which can be released into the environment by several pathways.

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Assessment of Heavy Metals Pollution in the Marine Sediments of the Lévrier Bay (Nouadhibou, Mauritania)

Yehdhih Maimouna, El Hadi Hassan, Baghdad Bouamar, Chakiri Saïd, Hamoud Ahmed, Zerdeb Amine, Moussa Karima

Ecological Engineering & Environmental Technology

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2022

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Vol. 23, iss. 5

84--90

EN

Geochemical study of twenty-seven marine sediments of the Levrier Bay used eleven heavy metals to display descriptive statistics and to assess the environmental impact of this industrial area. The analysis of eleven heavy metals (Pb, Zn, Cu, Ni, V, Cr, Co, Hg, Cd, As and Mo), major and other trace elements, were performed by ICP-MS. Pollution load Index (PLI) show low degree of contamination. Geochemical Index (Igeo) and enrichment Factor (EF) have been used to assess the environment quality at varied sites in sediments. Results display moderate concentrations for the most of elements excepted the As and Hg which often are upon the amount measured in the UCC baseline. The local presence Hg and As, limited to some sites of the area, allow to conclude that the sediments of the Lévrier Bay didn’t suffer from the human activities in the area.

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The meteorite fall near Boumdeid, Mauritania, from September 14, 2011

Buhl S., Toueirjenne C., Hofmann B., Laubenstein M., Wimmer K.

Meteorites

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2014

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Vol. 3, No. 1-2

5--18

EN

On the evening of September 14, 2011 at 21:00 GMT a bright bolide was observed by hundreds of eyewitnesses in the area north and west of the town of Kiffa, in the department of Assaba, in south Mauritania. A terminal fragmentation and sound phenomena were observed near the end point of the trajectory. At least one mass of 3.5 kg was observed to impact and recovered the morning after the fall near Boumdeid (or Bou Mdeid), around 60 km north of Kiffa. Subsequently a large number of eyewitness accounts were recorded and mapped by GPS. The present paper provides a scenario for the trajectory of the Boumdeid (2011) meteorite based on the available parameters and wind data at the relevant altitudes. In addition the paper presents the results of the mineralogical and chemical analysis of the recovered meteorite which is consistent with a classification as ordinary chondrite of type L6, shock stage S2, and a weathering grade of W0. Following its analysis and classification, the meteorite was published under the official name Boumdeid (2011) in Meteoritical Bulletin, no. 100, MAPS 49(8), (2014). Gamma ray spectroscopy was conducted 84 days after the fall and the detection of short-lived radionuclides such as 56Co and 46Sc confirmed the recency of the event. Derived from the data of 60Co, 54Mn and 22Na the approximate preatmospheric radius of the meteorite body was 10–20cm. The report is also intended to serve as a case example for post-event data recovery and trajectory reconstruction in areas not covered by sky-camera networks and with limited scientific infrastructure.