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Comparative Human Health Risk Analysis of Coastal Community Water and Waste Service Options
Citation:
Schoen, M., X. Xue, T. Hawkins, AND N. Ashbolt. Comparative Human Health Risk Analysis of Coastal Community Water and Waste Service Options. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 48(16):9728-9736, (2014).
Impact/Purpose:
For submission to peer-reviewed journal.
Description:
As a pilot approach to describe adverse human health effects from alternative decentralized community water systems compared to conventional centralized services (business-as-usual [BAU]), selected chemical and microbial hazards were assessed using disability adjusted life years (DALYs) as the common metric. The alternatives included: 1) composting toilets with septic system, 2) urine-diverting toilets with septic system, 3) low flush toilets with blackwater pressure sewer and on-site greywater treatment with non-potable reuse, and 4) alternative 3 with on-site rainwater treatment and use. Various pathogens (viral, bacterial, and protozoan) and chemicals (disinfection by-products [DBPs]) were used as reference hazards. The exposure pathways for BAU included ingestion of contaminated recreational water, ingestion of cross-connected sewage to drinking water, and exposures to DBPs from showering. The alternative systems included ingestion of treated greywater from garden irrigation, toilet flushing, and crop consumption; and ingestion of treated rainwater while showering. The pathways with the highest health impact included the ingestion of cross-connected drinking water and ingestion of recreational water contaminated by septic seepage. These were also among the most uncertain when characterizing input parameters, particularly the scale of the cross-connection event, and the removal of pathogens from groundwater transport of septic seepage. A comparison of the health burdens indicated potential health benefits by switching from BAU to decentralized water and wastewater systems.
