SUMMARY
Current status of groundwater pollution in Hµ Néi area
NguyÔn V¨n §¶n, NguyÔn ThÞ Dung
The water supplied in Hµ Néi is based mainly on groundwater. The exploitation of groundwater for living and industrial use in Hµ Néi has been beginning since 1909 with increasing amount. The abstracted water amount is 100,000m3/day in 60’s, 200,000 m3/day in 70’s, 300,000 m3/day in 80’s, 400,000 m3/day in 90’s, and over 500,000 m3/day in present time. It is estimated that in 2010 the abstracted amount will be 1,000,000 m3/day. The abstraction with large amount of groundwater causes negative impacts, such as lowering of water level, expansion of area of depression cone, land subsidence and groundwater pollution.
The groundwater pollution occurs both in the Holocene aquifer (upper aquifer) and Pleistocene aquifer (lower aquifer - production aquifer). The pollutant elements are detected like nitrogen component, microorganisms, organic matter, toxic elements: arsenic, mercury… The pollution by nitrogen components has been studied since 90’s. The studied results showed that the main contaminant is ammoni (NH4+), contributing in large area with high concentration. The polluted area and concentration of pollutants are increasing with time.