Impact of Past Mining Activity on the Quality of Water and Soil in the High Moulouya Valley (Morocco)

Abstract

Physical and chemical properties and the total content of potentially toxic metals (PTMs) in waters and soils were studied from the High Moulouya Valley (Morocco) in order to assess the impact of the past mining activity on their quality and to lay the foundations of a potential reclamation of the area. Surface water and groundwater samples were collected from the Moulouya River and mine pit lakes; tailings and soils were sampled inside and outside the mine sites of Ze < da, Mibladen, and Aouli. Both waters and soils were alkaline, due to the limestone environment, and contained Pb and Zn as main metallic contaminants. Pollution levels were highest within the Mibladen mining site, and soil pollution was mainly restricted to the areas where activities of metal concentration were carried out. Tailings and soils from these areas besides Pb and Zn were also polluted by As, Cd, and Cu showing clay fraction highly enriched in metal contaminants. At the time of study, all soils and wastes (including the highly polluted tailings) were in advanced stage of spontaneous herbaceous and arbustive revegetation. It is concluded that, in the High Moulouya Valley, the processes governing PTM transfer from the element-rich sites to the nearby environment are strongly influenced by pH, carbonate content, and semi-arid climate reducing metal mobility from the mining waste impoundments by dissolution. The transfer by wind and water erosion of metal-enriched fine waste particles is likely to be a much more important vector for metal dispersion. In this perspective, among a range of land remediation techniques available, natural and oriented revegetation could represent a low-cost and possible permanent solution

Geochemical background of potentially toxic trace elements in soils of the historic copper mining area: a case study from Miedzianka Mt., Holy Cross Mountains, south-central Poland

“…In most soil samples the Cr concentrations were lower than the world median content of this element which is estimated to be 54 mg kg -1 (KabataPendias and Mukherjee 2007). The relatively low Cr contents (16-60 mg kg -1 ) were reported from the post-mining soils from the High Moulouya Valley in Morocco (Iavazzo et al 2012). The high Spearman's correlation coefficient values were found in the examined soils for Cr and Ni (0.88), Zn (0.81) and U (0.80) ( Table 6).…”

“…The raised levels of Mn, 1446-4153 mg kg -1 , were found in surface soils (A-horizon) in the abandoned Miguel Vacas copper mine in SE Portugal (Abreu et al 2008b). Similarly, high Mn concentrations in post-mining soils (400-4520 mg kg -1 ) were reported from the High Moulouya Valley, Morocco (Iavazzo et al 2012). …”

“…For example, the Cu concentrations in the range of 17-225 mg kg -1 were found in the abandoned mercury mining area in northern Spain (Loredo et al 2006). Similarly, the contents of this metal ranged from 13 to (Iavazzo et al 2012). Much higher Cu levels in surface soils (70-2231 mg kg -1 ) were reported from the abandoned Miguel Vacas copper mine in SE Portugal (Abreu et al 2008b) or other post-mining areas, where Cu ores were extracted, e.g.…”

“…Likewise, high Zn levels (53-211 mg kg -1 ) were found in surface soils (horizon-A) of the abandoned Miguel Vacas Cu mine in SE Portugal (Abreu et al 2008b) and soils of different post-mining areas, for example, 31-835 mg kg -1 in France (Camizuli et al 2014), 46-215 mg kg -1 in northern Spain (Loredo et al 2006) or 28-3660 mg kg -1 in the abandoned Cu mines in the Sudetes Mts SW Poland (Karczewska et al 2006). Extremely high Zn concentrations (46-182,000 mg kg -1 ) were reported in soils from the High Moulouya Valley in Morocco (Iavazzo et al 2012) and from San Luis Potosi in Mexico (26-6270 mg kg -1 ) (Razo et al 2004). …”

Copper changes the yield and cadmium/zinc accumulation and cellular distribution in the cadmium/zinc hyperaccumulator Sedum plumbizincicola

“…Mixed and multiple contamination of soils by metals can result from industrial and mining activities and agricultural practices such as land application of contaminated sewage sludges and usually involves several contaminants [1,2]. Phytoremediation using hyperaccumulator plants to remove contaminants from soils is an environmentally friendly and relatively inexpensive technique [3][4][5].…”