Investigating the public health risks of low impact development at residential, neighbourhood, and municipal levels

Abstract

Low Impact Developments (LIDs) employ a series of vegetative techniques to retain rainfall close to the origin. Although LIDs offer sustainable runoff management, these infrastructures can be considered a risk to public health due to the presence of pathogens in the runoff and human exposure to contaminated water held in and transported by LIDs. The objective of this study is to examine the disease burden from exposure to LIDs at the residential, neighbourhood, and municipal levels. The authors conducted a meta -analysis of literature on three water features: (1) harvested rainwater obtained from LIDs, (2) surface water, and (3) floodwater. A set of 32 studies were systematically selected to collect values of risks of infection and expressed as the disease burden , i.e. disability adjusted life years (DALYs). The results showed that the percentage of GI illness exceeding the health guidelines were high for harvested rainwater , i.e. 22% of annual disease burden exceeded the WHO guideline s (0.001 DALYs/1000 persons), and 2% exceeded the US EPA guideline s (5.75 DALYs/1000 bathers). Among the six exposures for harvested rainwater, exposure to spray irrigation, exceeded US EPA guidelines whereas ; five exposures , i.e. flushing, hosing, daily shower, spray irrigation , and children playing, surpassed the WHO guidelines. Considering LID treatment, the value s of annual disease burden from all the selected barriers were below US EPA guidelines however, these values exceeded the WHO guideline s for three barriers i.e. water plaza, grass swale, and open storage ponds. These findings provide a broader perspective of the disease burden associated with LIDs and emphasise to consider the type of exposure s and required treatment barrier s for developing LID infrastructures in urban areas.