A rural household uses a sanitary pit latrine located 15 metres from its hand pump. Residents complain of gastrointestinal illness. The most likely mechanism of groundwater contamination in this scenario is:
- A Volatilisation of faecal gases re-entering the well
- B Leaching of nitrates only, which do not cause gastrointestinal disease
- C Direct hydraulic connection through a fractured laterite layer
- D Horizontal travel of pathogens through saturated soil beyond the 10-metre safe zone ✓
Explanation
Safe separation between a latrine and a water source is recommended at a minimum of 15 metres (some guidelines cite 10 metres for ordinary soil, more for fissured strata) to allow natural filtration, die-off of pathogens, and attenuation of bacteria and viruses through the unsaturated zone. Gastrointestinal illness in this context points to faecal-oral transmission via contaminated groundwater, consistent with horizontal pathogen travel through soil. Option B wrongly excludes pathogen risk. Option C is a special geological condition not indicated in the stem. Option A is not a recognised contamination pathway.
Reference: Park's Textbook of Preventive and Social Medicine / Wagner and Lanoix, Excreta Disposal for Rural Areas, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.