The effectiveness of selected microbial and chemical indicators to detect sewer leakage impacts on urban groundwater quality

Sewer and stormwater pipe leakage can lead to the degradation of urban groundwater quality. This groundwater may be subsequently used for public water supply and so the resulting water treatment and public health consequences can be serious. To understand the impact of sewer exfiltration on groundwater quality, suitable indicators need to be sampled and analysed for. This study examined potential sewer-derived inorganic and microbial parameters in the UK city of Doncaster. Sulphite reducing clostridia, faecal streptococci and boron were all detected in groundwater with reductions compared with sewer values ranging from 1 to 6 orders of magnitude for the former two, to 1 to 2 orders of magnitude decrease for boron. The correlation between these two different indicator types suggests that groundwater quality is being adversely affected by sewer leakage in the study area. The employment of several and varied indicators can better demonstrate the effect than use of single parameters.