TASTE AND ODOR THRESHOLD CONCENTRATIONS OF POTENTIAL POTABLE WATER CONTAMINANTS

Taste and odour complaints from consumers are a major problem for supp liers of drinking water. Small quantities of chemicals, either natural ly present in raw water or from industrial sources, or even produced d uring water treatment, can affect the organoleptic properties of drink ing water. Taste and odour threshold concentrations in water were dete rmined for 59 potential drinking water contaminants, including pestici des, phenol, chlorinated phenolic compounds and anisoles, geosmin, 2-m ethyl-isoborneol and aluminium sulphate. Panels comprising a minimum o f six specially selected and trained assessors were used. Taste and od our threshold concentrations are presented as geometric means as well as the lowest detected concentration; in addition, descriptors are rep orted. Threshold concentrations are also compared with health-based li mits established by the United States Environmental Protection Agency, and drinking water guideline values recommended by the World Health O rganisation. The results indicated that there was no correlation betwe en organoleptic effects of drinking water contaminants and their toxic ity. Chemicals with the lowest taste and odour threshold values includ ed chemicals such as geosmin, 2-methyl-isoborneol and similar microbia l metabolites, and chlorinated phenols and anisoles.