There are three types of water pollutant: microbiological, chemical and physical. Although chemical pollution is recognized as being of concern, exposure to microbiological agents poses the greatest threat to health. The risk of infection from waterborne pathogens, including protozoa and viruses, is likely to increase as polluted and/or limited groundwater resources lead to a shift towards extracting drinking-water from surface water, which is more vulnerable to contamination. Poor hygiene in regions suffering economic and political instability is exacerbating these microbial threats.
The Australian Cooperative Research Centre for Water Quality and Treatment is funding a major project to investigate the effects on cancer growth of algal toxins in drinking water.