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- Gårdestedt, Caroline, et al.
(författare)
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Zinc in Soils, Crops, and Meals in the Niger Inland Delta, Mali
- 2009
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Ingår i: Ambio. - 0044-7447 .- 1654-7209. ; 38:6, s. 334-338
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Tidskriftsartikel (refereegranskat)abstract
- Zinc deficiency is a problem in developing countries and not least so in Africa. This concerns both agriculture and human food provision. Zinc deficiency in soils may severely decrease yields, whereas insufficient zinc in food intake primarily affects the immune defense, notably in children. The present investigation concerned zinc availability in soils, crops, and food in the Niger inland delta in Mali. Agricultural soils are largely deficient in plant-available zinc, however, soils in close vicinity to habitation show elevated zinc concentrations. The zinc concentrations in crops are low; in rice, they are about half of reference ranges. Zinc intake assessed from a number of sampled meals was about half the recommended requirement. When zinc concentration is higher phytate was also high, which made the zinc less available. In spite of a recorded sufficient intake of iron, anemia is common and is most likely because of the high phytate concentration in the cereal-dominated diet. Increasing zinc and iron availability would be possible through the use of malting, fermentation, and soaking in food preparation. Finally, in the long run, any trace element deficiency, especially that of zinc in agricultural soils needs to be amended by addition of appropriate amounts in commercial fertilizers.
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| 2. |
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| 3. |
- Jacks, Birgitta, et al.
(författare)
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Zinc deficiency in the Niger inland delta, Mali
- 2007
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Ingår i: Annals of Nutrition and Metabolism. - : KARGER. - 0250-6807 .- 1421-9697. ; 51, s. 223-223
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 4. |
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| 5. |
- Balfors, Berit, et al.
(författare)
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Contamination of water resources in Takwa mining area of Ghana : Linking technical, social-economic and gender dimensions
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ghana is Africa’s second largest producer of gold with gold deposits in western part of the country. There are seven large-scale mines and 168 small-scale mining concessions valid in the region. Wassa West District is an important mining area, with Tarkwa as administrative capital. In recent years, the area has been exposed to lead, cadmium, arsenic, mercury and cyanide. Both small and large-scale mining industries have reportedly contaminated rivers, streams, dug wells and boreholes with heavy metals such as lead, cadmium, arsenic, mercury and cyanide. There has been significant adverse impact upon health, economy, and social life that may be felt differently by women and men, raising the question of sustainable access to safe water as a millennium development goal (MDG) in the area. A multi-disciplinary approach was adopted in the project with distinct work components on the technical as well as on social, gender and policy aspects. It also aimed to suggest integrated strategies to address the problem so as to ensure achievement of the MDGs. Based upon a field study in 37 local communities coupled with water and sediment analysis from the area, the research indicated the existence of not only higher levels of metal contaminants in local water resources in Tarkwa area, particularlymanganese and iron, but also arsenic and aluminium in some wells. However, water resources, particularly groundwater is currently safe for human consumption but the spillages of cyanide and other effluents into surface streams have health and ecological implications. Levels of mercury in stream sediments are high with a clear risk of methylation of the mercury and transfer in the food chain via fish to humans. Regarding the impact of mining, it was found that for women who are the primary domestic water managers, contamination of local water sources has forced them to fetch water from greater distances, and livelihoods are hampered due to the fish loss through cyanide spillages in streams. Another finding was the lack of trust and rising water conflicts between mining authorities and the local communities. Regarding the policy aspects underlying the problem, it was found that there is a lack of coordination between the 3 policy areas, namely, rural water supply, mining, and environmental impact assessment (EIA) and environmental protection to the detriment of women as water users and domestic water managers. While impact of mining is increasingly seen as an issue of human rights violation, little is being done to strengthen participatory approaches especially involving women in rural water supply programs. The detailed analysis of the EIA regulations reveals that most mining have not undertaken any comprehensive EIA guiding their operations. A number of recommendations have emerged from the integrated perspective attempted to be developed through this research. These include a need for further in-depth explorations on the situation of contamination in groundwater and surface waters as well as stream sediments in the area; the need to resolve the situations of water conflicts between the local communities and the mining authorities by promoting greater public participation; and the need to minimize the gaps between the three related policy frameworks. Also, there is a necessity to strengthen environmental compliance on part of the mining companies so as to uphold the quality of water resources in the area.
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| 6. |
- Bhattacharya, Aparajita, et al.
(författare)
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Environmental assessment of abandoned mine tailings in Adak, Vasterbotten district (northern Sweden)
- 2006
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Ingår i: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 21:10, s. 1760-1780
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Tidskriftsartikel (refereegranskat)abstract
- Sulfide-rich mine tailings in Adak that are exposed to weathering cause acid mine drainage characterized by low PH (2-4) and high SO4 (UP to 800 mg L-1). Surface water, sediment and soil samples collected in this study contain higher concentrations of As, Cu, Fe and Zn, compared to the target and/or intervention limits set by international regulatory agencies. In particular, high As concentrations in water (up to 2900 mu g L- 1) and sediment (up to 900 mg kg(-1)) are of concern. There is large variability in trace element concentrations, implying that both physical (grain size) and chemical factors (pH, secondary phases as sulfides, Al-oxides or clay minerals) play an important role in their distribution. The low PH keeps the trace elements dissolved, and they are transported farther downstream. Trace element partition coefficients are low (log K-d = 0.3-4.3), and saturation indices calculated with PHREEQC are < 0 for common oxide and sulfidic minerals. The sediment and soil samples indicate an enhanced pollution index (up to 17), and high enrichment factors for trace elements (As up to 38,300; Zn up to 800). Finally, leaves collected from different plant types indicate bioaccumulation of several elements (As, Al, Cu, Fe and Zn). However, some of the plants growing in this area (e.g., Salix, Equisetum) are generally resistant to metal toxicity, and hence, liming and phytoremediation could be considered as potential on-site remediation methods.
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| 9. |
- Bhattacharya, Prosun, et al.
(författare)
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Distribution and mobility of arsenic in the Rio Dulce alluvial aquifers in Santiago del Estero Province, Argentina
- 2006
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 358:1-3, s. 97-120
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Tidskriftsartikel (refereegranskat)abstract
- Factors controlling arsenic (As) mobilization in the aquifers of the Rio Dulce alluvial cone were investigated. Groundwater analyses show severe As contamination (average concentration of 743 mu g/L) from geogenic sources, but spatial variability of As concentration is considerable. Sequential leaching of sediment samples from unsaturated zone using de-ionised water, bicarbonate, acetate, and oxalate extracted As to different extents. Sediment oxalate extraction showed that Al and Mn oxide and hydroxides are more abundant than Fe oxides and hydroxides, in spite of similar total Fe, Mn, and Al concentrations in the sediment. Speciation calculations performed for saturated zone samples indicated that Fe and Al oxides and hydroxides are stable in groundwater, suggesting that As adsorption processes may be to some extent controlled by the presence of Fe and Al mineral phases. Principal Component Analysis (PCA) showed that As is related to F, V, Mo, B, Si, most likely due to their common origin in volcanic ash. This suggests the volcanic ash as the probable source of groundwater As. Locally, elevated pH values linked to carbonate dissolution, cation exchange, and dissolution of silicates promote release of adsorbed As. Another factor contributing to the release of As locally may be the input of organic matter from excessive irrigation. The conceptual model of As release includes: i) As influx from dissolution of volcanic glass in volcanic ash, ii) adsorption of As on the surface of Fe and Al mineral phases in relatively low pH zones, and iii) high mobility of As in high pH zones. Future work should be focused on the determination of mineralogical forms of As in volcanic ash and on detailed investigation on factors controlling As mobility.
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| 10. |
- Bhattacharya, Prosun, et al.
(författare)
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Groundwater characteristics in the shallow aquifers of Huhhot region in Inner Mongolia, PR China : Implications on the mobilisation of arsenic
- 2006
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Ingår i: Natural Arsenic in Groundwaters of Latin America. ; , s. 11-12
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Elevated arsenic (As) concentration ingroundwater is becoming a worldwide problem. In Huhhot Alluvial Basin (HAB) in Inner Mongolia, People’s Republic ofChina, a population of over a million isexposed to severe health risk due to theconsumption of groundwater with high Asconcentration. In some arsenic seriouslyaffected areas, As concentration reach 1491µg L-1, 149 times over WHO’s drinkingwater guideline value for As and exceed theChinese drinking water standard by a factorof 30 times. Due to the acute shortage ofsafe water supply and inefficient watermanagement system, people are compelledto drink groundwater with high As concentration. Long period ingestion of water withhigh As concentration have lead to chronicarsenic poisoning among the residents ofthe region. This present work deals with thehydrogeochemical characterisation of thegroundwater of the shallow alluvial aquifers and their implications on the chemistryand its relation to the mechanism of Asmobilization in the HAB.Groundwater samples were collected during October 2003, from 29 sites in the village of Tie Men Jing, located about 100 kmfrom Inner Mongolia’s capital Huhhot. ThepH, redox potential (Eh), temperature andelectrical conductivity were measured atsites while major ions, trace elements including As total and As (III) were analyzedin laboratories at the Royal Institute ofTechnology and Stockholm University inSweden. Groundwater is generally neutralto alkaline and the pH varies from 6.67 to8.7. The redox potential (Eh) lies between74 and 669 mV. The electrical conductivity(EC) range varies from 581 to 5200 µS cm-1. Temperature ranges from 9.1 to 13.5 °C.Depths of wells are from 4 m to 75 m.Groundwater is mostly of Na-Mg-HCO3-Cl-type and dominated by HCO3-and Cl-asthe predominant anions. The concentrationsof SO42-range between 0.3 and 172.8 mg L-1and there is a trend of decreasing sulfateconcentrations with increase in well depth.The levels of NO3-were lower than theWHO´s guideline value of 50 mg L-1in 27wells. These high NO3-concentrations could have been caused by anthropogeniccontamination due to the sanitation practices.The PO43-concentration ranges between 0.04to 2.6 mg L-1.Total As concentration ranged from belowdetect limit (5.2 µg L-1) to 141 µg L-1. In 28of the investigated wells, As levels exceededWHO’s guideline value 10 µg L-1and 17wells exceeded Chinese standard 50 µg L-1.Among the 42 groundwater samples of theshallow aquifers only three complied withthe WHO drinking water guideline value forAs. The dominant species in the groundwaterwas As (III). In the 29 wells of Tie MenJing, the concentration of Fe and Mn –exceeded the WHO’s guideline value by afactor of 10.The aquifers are composed of Quaternary(mainly Holocene) fluvial and lacustrinesediments. High As occurring in anaerobicgroundwater in low-lying areas is associatedwith high concenrations of dissolved Fe andMn. Improved water supply system, employment new water and energy resources,poverty fighting and expertise cooperationare recommended to solve Huhhot basinrural area’s drinking water problem.
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