Abstract: Groundwater is a major source of water, meeting the domestic water needs of more than 70% of Africa's population. Although prized for its relatively good quality compared with surface water, groundwater is increasingly subjected to multiple sources of pollution. Long thought to be the solution to increasing agricultural production and achieving food self-sufficiency, agricultural inputs are now being pointed out in Burkina Faso as a major source of water pollution. However, few studies exist showing the contribution of agricultural inputs to groundwater pollution. The aim of this study is to show the impact of the use of agricultural inputs on groundwater quality: the case of the Boulbi valley rice-growing area in Burkina Faso, West Africa. Soil properties were measured using a double-ring infiltrometer and Harmonized World Soil Database. Groundwater recharge was assessed by Thornthwaite’s equation. The DRASTIC, GOD and SI methods were applied to map the valley’s vulnerability. Fertilizers and phytochemicals were recorded by surveys. A sampling of surface and groundwater was done in 32 locations and the chemical characteristics (pH, EC, NO3-, SO42-, PO42- and K+) confronted with the vulnerability indices. Results show that the soils were predominantly clay (41%), silt (37%) and silty sand (22%). Twenty types of phytochemicals were used, among which 35% were composed of the controversial glyphosate (denounced as carcinogenic) and 30% made with paraquat chloride also accused of being responsible for several self-poisoning. All the three methods pointed to a low vulnerability risk, partly because of the purification role of clay. The average pH is 8.2 ± 0.4, explaining the low-rice yield (<4.0 tons/ha), in spite of fertilizer use. Although the risk assessment rendered non-alarming situation, preventive measures about health and environment need to be taken.
Abstract: Groundwater is a major source of water, meeting the domestic water needs of more than 70% of Africa's population. Although prized for its relatively good quality compared with surface water, groundwater is increasingly subjected to multiple sources of pollution. Long thought to be the solution to increasing agricultural production and achieving foo...Show More
Abstract: Access to safe drinking water and the wide spread of water-borne diseases are major challenges in Sub-Saharan Africa and Madagascar. Based on this, a water purification models has been developed which can use on a local scale. It consists of an intermittent biosand filter amended with oyster shell powders designed from local materials. The performance of the filter was evaluated through physicochemical and bacteriological analyses using standardized methods on raw polluted well water with previously determined initial D0 characteristics. The effectiveness of the designed filter was assessed and a filtration operation was carried out over a monitoring period of 13 days (D13) prior to 7 days of acclimatization of the system. With a filtration rate of 0.75l/h-1, there is a very strong reduction in turbidity from 35.59NTU to 0 NTU and in BOD5 from 125mg/l to 2mg/l. More so, bacteriological analyses reveal a progressive and complete decrease from D0 to D13 of fecal coliforms from 9000 CFU/100ml to 0 CFU/100ml; total coliforms from 6,000 CFU/100 ml to 0 CFU/100 ml and fecal streptococci from 10,800 CFU/100 ml to 0 CFU/100 ml. Compared to the classic ceramic filter, no significant difference in the Duncan test is reported for the highlighted parameters. This filter presents potential among other water treatment methods at the local scale for reducing the risks of water-borne diseases and achieving Sustainable Development Goal 6 in developing countries.
Abstract: Access to safe drinking water and the wide spread of water-borne diseases are major challenges in Sub-Saharan Africa and Madagascar. Based on this, a water purification models has been developed which can use on a local scale. It consists of an intermittent biosand filter amended with oyster shell powders designed from local materials. The performa...Show More