Groundwater pollution on the Zambian copperbelt: deciphering the source and the risk. Sci Total Environ

School of Geography and the Environment, Oxford University, Oxford OX1 3TB, UK.
Science of The Total Environment (Impact Factor: 4.1). 08/2004; 327(1-3):17-30. DOI: 10.1016/j.scitotenv.2003.08.028
Source: PubMed


The protection of groundwater resources is of great importance in many semi-arid and sub-tropical environments. The Copperbelt of Zambia is one such environment and due to the high proportion of tailings impoundments, residue heaps, high-density informal settlements and extensive sulfidic ore deposits in the region, its groundwater resources are under threat of anthropogenic or geogenic pollution. One such pollutant plume is investigated in this study, to determine its origin, rate of progression and the environmental and health risk it poses. Geological and geochemical investigation strongly suggests an upslope tailings impoundment as the source of contaminants, with the edge of the pollution plume lying 500-700 m downstream of the impoundment. Although cobalt, nickel and zinc concentrations were elevated within the polluted groundwater, the concentrations are low as a result of sulfide precipitation and adsorption within the aquifer, and meets guidelines for drinking water quality. Attenuation of heavy metals is linked to tailings dam and aquifer pH, with the high buffering capacity of each implying that these processes of attenuation are likely to continue removing harmful metals from the aquifer. Thus, it appears unlikely that the contaminated groundwater will present a major environmental risk at this site. However, tailings impoundments are widespread throughout the Copperbelt: sites with low tailings dam buffer capacity and in catchments on crystalline bedrock geology, groundwater pollution through tailings dam leachate may liberate high concentrations of heavy metals into the shallow groundwater, potentially posing a serious human health risk to the communities using the water resources and an environmental risk to the downstream ecosystems.

Download full-text


Available from: Mark George New, Jun 06, 2014
    • "Of the 152 shallow wells tested for total coliforms , 60 had 0 CFU / 100 ml , indicating minimal subsurface interaction between shallow wells and nearby pit latrines . The shallow well results for total coliforms in this study may be the ' best case scenario ' , due to the potentially deleterious impact of increased overland runoff during the wet season , and the ability for surface contaminants to be transported into shallow groundwater ( Wright , 1986 ; von der Heyden & New , 2004 ) . Conversely , it may be expected that a dilution effect occurs during the wet season , reducing contamination . "
    [Show abstract] [Hide abstract]
    ABSTRACT: Many informal communities within urban areas in sub-Saharan Africa are heavily reliant on shallow hand-dug wells for water, but these are vulnerable to contamination from a range of sources. This paper assesses the heavy metal contamination and total coliform risk of unprotected shallow wells in Ndola, Zambia – a city struggling with contaminated surface waters from both bacteriological and potential mining waste products. One hundred and twenty three shallow wells were sampled across the Ndola, and these encompassed the three main lithologies of the city. All wells lacked an internal casing, however, some wells did have covers and/or pavements surrounding the wells, albeit of dubious efficacy. Despite the lack of protection, the quality of water used abstracted from these wells generally met the World Health (WHO) guidelines for heavy metals (with the exception of Al) and total coliforms (although, this was highly variable). The quality of shallow well water varied across Ndola relative to the underlying geology, where total recoverable concentrations were typically lowest in granite-gneiss. Dissolved load concentrations were lowest in dolomite-limestone, highlighting the role of aquifer geology in acting as a buffer against metal toxicity. Our study illustrates that shallow wells, within the appropriate geological units, may provide a safe and reliable source of drinking water. Well protection is, however, needed to ensure that the proliferation of shallow well use does not lead to regional degradation of the groundwater resource. There is an immediate need to invest in promoting internal well casing during the construction of shallow wells, concomitant with investment and education into protecting wells at the surface, despite the current relatively low level of contamination in wells without protection.
    Applied Geography 02/2015; 57:80-90. DOI:10.1016/j.apgeog.2014.12.010 · 3.08 Impact Factor
  • Source
    • "Mining and processing activities are known to emit a variety of metals, metalloids and heavy metals to the environment (Mining Minerals and Sustainable Development, 2001; Stüben et al., 2001; Von der Heyden and New, 2004). These often result in elevated concentrations of persistent chemicals such as arsenic, cadmium, cobalt, copper and lead in the surrounding environment (Bidone et al., 2001; Coelho et al., 2007; Panday et al., 2007). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Copper mining contributes to increased concentrations of metals in the environment, thereby increasing the risk of metals exposure to populations living in and around mining areas. This study investigated environmental and toenail metals concentrations of non-occupational human exposure to metals in 39 copper-mining town residents and 47 non-mining town residents in Zambia. Elevated environmental concentrations were found in samples collected from the mining town residents. Toenail concentrations of cobalt (GM 1.39mg/kg), copper (GM 132mg/kg), lead (21.41mg/kg) selenium (GM 0.38mg/kg) and zinc (GM 113mg/kg) were significantly higher in the mining area and these metals have previously been associated with copper mining. Residence in the mining area, drinking water, dust and soil metals concentrations were the most important contributors to toenail metals concentrations. Further work is required to establish the specific pathways of exposure and the health risks of elevated metals concentrations in the copper mining area.
    International journal of hygiene and environmental health 03/2013; 217(1). DOI:10.1016/j.ijheh.2013.03.011 · 3.83 Impact Factor
  • Source
    • "The pollution of water with heavy metals has been of great concern, due to their toxic nature and other adverse effects (Davis et al. 2003; Von der Heyden & New 2004; Pandey et al. 2007). Among the most toxic heavy metals, cadmium is known to cause renal dysfunction, bone degeneration, lung inefficiency, liver damage and hypertension in humans. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work the removal potential on Cd(2+ ) by the non-living Egeria densa biomass has been studied. The influence of the metal solution pH, the plant drying and the metal solution temperature, and biosorbent grain size was previously studied in batch systems. The cadmium adsorption rate has increased when the pH was increasing, but at pH 5, the cadmium precipitation has begun to occur, avoiding such high pH values in other tests. The cadmium removal was around 70% at 30 degrees C biomass dried and solution temperatures, assuming as the best temperature conditions. No significant influence was observed in cadmium removal due to the grain size effect. The biosorption kinetic data were well fitted by a pseudo-second order model. The equilibrium time in experiments was around 45 min with a 70% Cd removal. The equilibrium data at pH 5 were described rather better by the Langmuir isotherm than the Freundlich one, with an adsorption rate and maximum metal content values of 0.40 L g(-1) and 1.28 meq g(-1), respectively, for Langmuir model. The kinetic parameter values are near to other biosorbents, indicating that the macrophytes E. densa could be used as biosorbent material in industrial effluent treatment system.
    Water Science & Technology 02/2009; 60(2):293-300. DOI:10.2166/wst.2009.178 · 1.11 Impact Factor
Show more