Dear editor,We must know the source of water we use as a safety precaution. These water sources share several characteristics, although they can be very different. They utilise water from local aquifers, similar to underground lakes. Aquifers are formed where water, which has passed through the soil from the surface, reaches an impermeable layer and collects. These underground water sources tend to be stable and the water can take months or even years to reach them from the surface. The stratum, through which the water passes, will determine the final raw water characteristics. Although less susceptible to seasonal variations, these borehole sources can have their own treatment issues. Water from aquifers is often high in iron and manganese; this is due to the lower pH often found in these waters. Both iron and manganese have a distinctive taste noticeable at low concentrations in water. Limits for the levels of both of these metals in private drinking water are set at 200µg/l iron and 50µg/l manganese. Although the two water sources share several characteristics, well water sources tend to be more susceptible to changes in the local environment and microbiological contamination. The stability of a borehole water source for example, makes it preferable for use as a private water supply. Anybody who uses a natural untreated water source for the provision of his or her drinking water should confirm that it is a safe supply through regular testing. KIMISAGARA
