AWWA WQTC60579

The current regulatory framework often relies on the results of the health effect studies conducted on individual compounds, which is responsible, in part, for the bias towards a contaminant-by-contaminant approach (i.e., individual regulatory levels of what constitutes "safe"). One limitation of the individual constituent approach is that it does not view drinking water as the complex "soup" of constituents (e.g., minerals, microbes, byproducts, etc.) that it actually is. While many constituents (regulated and unregulated) are monitored by water utilities, currently health effects information are available for a limited number of these. One alternative approach for gaining insight as to improving the healthfulness of water that already meets regulatory standards is to assess the risk of the entire mixture. This more holistic approach would guide efforts focused on the reduction of total risks rather than the reduction of any particular risk. A risk index method that calculates the values for cancer, non-cancer and microbiological endpoints has been developed (though subject to many limitations). Emerging contaminants (e.g., NDMA, perchlorate, endocrine disruptors) need to be considered as well. This paper focuses on the analysis method for the cancer endpoint. Includes 4 references, table.