The Ishiagu area is a water scarce region and has played host to mining activities for more than four decades. Mining-related activities have become a threat to potable water supply in the area. This paper is an attem...The Ishiagu area is a water scarce region and has played host to mining activities for more than four decades. Mining-related activities have become a threat to potable water supply in the area. This paper is an attempt to show the extent of this threat and in particular, investigate the regional groundwater occurrence and flow pattem based on GPS, water well and geological data. This basin- wide model can be used for further groundwater assess- ment, pollution control and contaminant management. Groundwater occurs between 2.4 and 9 m in the Lekwesi- Lokpaukwu area; 1.5-3.7 m in the Ndi-Ugbugbor-Ayaragu axis and 1.2-4.6 m in the Ishiagu area. Recharge areas include the Leru-Amaubiri-Lekwesi sandstone hills and the Ihetutu-Ugwuajirija mine field. While the ultimate sink of contamiants is the Ivo River system, other discharge axis is the Ishiagu-Ayaragu axis and the Ogwor Ndi- Ugbugbor zone. An unconfined and a confined （〉 10） circulation groundwater system was inferred, and flow model reveals that a large part of Ishiag-Ayaragu and Ndi- Ugbugbor part of the study area suffer polluted recharge from the Pb/Zn mining area. Groundwater was also subjected to hierarchical cluster analysis and the existence of 3-4 hydrological regimes, which revealed： Unpolluted recharge areas, areas affected by polluted recharge, a deep water and shallow water circulation and mine effluents.展开更多
The Ivo River Basin of south-eastern Nigeria is a water scarce and mining region, which suffers from water scarcity. The influence of mining activities on the quality of the Ivo River and its capacity for community wa...The Ivo River Basin of south-eastern Nigeria is a water scarce and mining region, which suffers from water scarcity. The influence of mining activities on the quality of the Ivo River and its capacity for community water supply was investigated. Also the efficacy of TDS-Eh graph in explaining water quality was presented. Results indicated that the TDS-Eh graph highlights subtle chemical relationships which control water quality and provide a simple but generic pollution index for rapid water quality assessment. It was also discovered that the Ivo River could become an adequate alternative to groundwater as a source of rural water supply in the study area with an estimated average daily discharge of 6726000L and a rural population of less than 200000 persons. The Ivo River meets the WHO drinking water standards in 20 physico- chemical water quality parameters （pH, temperature, conductivity, turbidity, salinity, TDS, Eh, alkalinity, chloride, nitrate, sulfate, phosphate, calcium, magnesium, iron, manganese, zinc, lead and cadmium） analyzed and can therefore （with little treatment） provide up to 133.4% of average community water demand and 83.8% of maximum community water demand. The. impact of mining on Ivo River quality was found to have been moderated by the presence of carbonate rocks which may have enhanced the precipitation of heavy metals from the river.展开更多
文摘The Ishiagu area is a water scarce region and has played host to mining activities for more than four decades. Mining-related activities have become a threat to potable water supply in the area. This paper is an attempt to show the extent of this threat and in particular, investigate the regional groundwater occurrence and flow pattem based on GPS, water well and geological data. This basin- wide model can be used for further groundwater assess- ment, pollution control and contaminant management. Groundwater occurs between 2.4 and 9 m in the Lekwesi- Lokpaukwu area; 1.5-3.7 m in the Ndi-Ugbugbor-Ayaragu axis and 1.2-4.6 m in the Ishiagu area. Recharge areas include the Leru-Amaubiri-Lekwesi sandstone hills and the Ihetutu-Ugwuajirija mine field. While the ultimate sink of contamiants is the Ivo River system, other discharge axis is the Ishiagu-Ayaragu axis and the Ogwor Ndi- Ugbugbor zone. An unconfined and a confined （〉 10） circulation groundwater system was inferred, and flow model reveals that a large part of Ishiag-Ayaragu and Ndi- Ugbugbor part of the study area suffer polluted recharge from the Pb/Zn mining area. Groundwater was also subjected to hierarchical cluster analysis and the existence of 3-4 hydrological regimes, which revealed： Unpolluted recharge areas, areas affected by polluted recharge, a deep water and shallow water circulation and mine effluents.
文摘The Ivo River Basin of south-eastern Nigeria is a water scarce and mining region, which suffers from water scarcity. The influence of mining activities on the quality of the Ivo River and its capacity for community water supply was investigated. Also the efficacy of TDS-Eh graph in explaining water quality was presented. Results indicated that the TDS-Eh graph highlights subtle chemical relationships which control water quality and provide a simple but generic pollution index for rapid water quality assessment. It was also discovered that the Ivo River could become an adequate alternative to groundwater as a source of rural water supply in the study area with an estimated average daily discharge of 6726000L and a rural population of less than 200000 persons. The Ivo River meets the WHO drinking water standards in 20 physico- chemical water quality parameters （pH, temperature, conductivity, turbidity, salinity, TDS, Eh, alkalinity, chloride, nitrate, sulfate, phosphate, calcium, magnesium, iron, manganese, zinc, lead and cadmium） analyzed and can therefore （with little treatment） provide up to 133.4% of average community water demand and 83.8% of maximum community water demand. The. impact of mining on Ivo River quality was found to have been moderated by the presence of carbonate rocks which may have enhanced the precipitation of heavy metals from the river.
