Megacities in Asia - Essay Example

In Bangladesh, arsenic contamination of groundwater was first detected in 1993 and was later addressed by the government as a national disaster. Groundwater can get arsenic contamination sporadically either by industrial or natural means. The presence of arsenic complexes in soil contributes to its natural occurrence in groundwater due to the fact that it can easily be freed from the complexes. Owing to its high mobility in soil, once it is freed from the complexes, arsenic often results in the contamination of groundwater. Most of Bangladesh’s regions are made up of deltaic and alluvial sediments that contain pyrite, and they have also contributed to groundwater arsenic contamination. Oxidation causes arsenopyrite minerals to release arsenic. Further, when the water table is lowered by over-exploiting groundwater in irrigation procedures, more arsenic is released (Karim, 2000). The most likely remediation strategy to be implemented is the use of innovative alternative drinking water sources. Although restoring the natural flow of rivers and the level of groundwater would have been the ideal situation, the time implications in achieving such goals are not practical. Examples would include harvesting rainwater, pond sand filters, Ranney wells, and infiltration galleries. These methods are recommended because they are less costly than most of the proposed solutions. Secondly, they have the potential of providing drinking water for longer terms than the rest of the proposals. For example, harvesting rainwater may incur an initial cost of putting up the structures, but once that is done, no more expenses are expected. The same applies to ponds, which require minimum maintenance.