A study released by the central government has found that villages that are not yet open defecation-free (non-ODF) is 12 times more likely than ODF villages to carry the risk of faecal contamination of groundwater. The study, carried out by UNICEF, looked at the environmental impact of the Swachh Bharat Mission in 12 ODF and 12 non-ODF villages in three states — West Bengal, Odisha and Bihar — and was based on 725 samples of water, soil, and food. The overall findings were that non-ODF villages are:
* 12.7 times more likely to have their groundwater sources contaminated (from contaminants traceable to humans alone)
* 2.40 times more likely to have their piped water contaminated
* 2.48 times more likely to have their household water (stored) contaminated
* 1.1 times more likely to have their soil contaminated
* 2.16 times more likely to have food contaminated and 2.48 times more likely to have household drinking water contaminated
Among the three states, the levels were the worst in Bihar where non-ODF villages showed 35.7 times higher groundwater contamination than ODF villages, as compared to 6.6 times higher in West Bengal and 5.3 times higher in Odisha. For piped water, the relative risk of contamination (non-ODF to ODF) was 1.33 times more in Bihar, 2.73 times more in West Bengal and 1.50 times more in Odisha. For household water (stored), the relative risk was 2.74 times more in Bihar, 4.14 times more in West Bengal and 1.44 times more in Odisha.
For soil, the relative risk of faecal contamination traceable to humans, in non-ODF villages as compared to ODF villages, was 1.21 times more in Bihar, 1.39 times more in West Bengal and 0.89 times more in Odisha. And for food, the relative risk was 6.67 times more in Bihar; 8.47 times more in West Bengal and 1.14 times more in Odisha.
In its interpretation of the variations observed among states, the UNICEF report stated that in Odisha, the sudden onset of rain during sampling resulted in decreased impact. It said this indicates that systems for solid and liquid waste management, including faecal sludge management and drainage need improvement to realise the full benefits of residing in ODF environments.