Abstract
The chronic problems of water quality and sanitation experienced by some of the South Asia countries were complicated by the year 2004 tsunami. Therefore this research study was aiming to study the post-tsunami and further health risks imposed on the aquifers in some of the affected areas, by carrying out a systematic well surveillance study, with the objective of providing medium to long term guidelines for the recovery and protection of groundwater quality. A field based sanitary surveillance programme was carried out in the Maldives islands and Sri Lanka, using the World Health Organization’s (1997) water surveillance methodology. The water quality investigation focused principally on the 44 C thermo-tolerant (faecal) coliform (FC) counts, conductivity and temperature, which were measured during the field work. Findings from the surveillance study imply that well water salinization is dependent on population density, rate of well water exploitation, amount of rainfall recharge, width of the island, tidal pressure waves and natural disasters such as tsunami. Rate of recovery of the well water salinization post-tsunami is dependent on the level of tsunami impact, recharge to aquifer from rainfall and from nearby fresh surface water, and, level of well water exploitation, post-tsunami. The sanitary survey form of the WHO (1997) surveillance methodology had to be modified to take account of the extreme vulnerability of the study areas. It was demonstrated that, under the very vulnerable hydro-geological conditions of this study, where on-site sanitation systems are practiced in close proximity to wells. and all other observable sanitary hazards occur, the combined risk analysis (of the sanitary survey observations together with the faecal coliform counts) was not useful in identifying hazards and hence prioritizing remedial action to improve the microbial quality of well water. In this scenario, the provision of more efficient sanitation systems is the foremost remedial action required to be carried out, prior to assessing other sanitary hazards to the water resource and supply, to improve the water quality. In terms of medium to long term strategies, the further treatment of septic tank effluents, by tile field filters, was identified as the single, most important intervention required to protect the shallow aquifers from faecal contamination. Target 17 of the UN MDGs will not be met until water safety plans, which include improving sanitation technologies performance and making fundamental changes to the surveillance methodology of WHO (1997), are implemented.