Assessment of the effectiveness of open defecation free system on the incidence of faecal contamination on environment through microbial source tracking

Abstract The aim of this study was to assess the effectiveness of open defecation free (ODF) system on the incidence of faecal contamination on environment (water, soil and food mediums). The magnitude of contamination of environmental medium of ODF and non-open defecation free (n-ODF) villages by faecal indicator bacteria (FIB) in three states of India, was investigated. The FIB positive samples were further processed to determine the source of faecal contamination using Bacteroidale molecular markers for human (HuBac). The matrix of relative risk (RR) due to FIB and HuBaC contamination was developed to assess the effectiveness of ODF interventions. When compared to ODF villages, the RR of faecal contamination in n-ODF villages was estimated 11.25 times more likely in groundwater, 2.68 times more likely in household storage drinking water, 2.71 times more likely in piped water supplies, 1.13 times more likely in soil and 1.48 times more likely in food. The RR of faecal contamination traceable to humans was estimated 12.66, 2.48, 2.40, 1.10 and 2.16 times more likely in n-ODF villages as compared to ODF villages in cases of groundwater, household storage drinking water, piped water supplies, soil and food respectively. The risk assessment matrix designed in present study can be useful towards evaluation of the performance of ODF missions being implemented in many developing countries to achieve sanitation and hygiene objectives in accordance to the target 6.2 of Sustainable Development Goals 2030.