Nitrate and drinking water from private wells: Will there be an epidemic of cancers of the digestive tract, urinary bladder and thyroid?

Abstract

Purpose: To estimate the nitrate levels in private wells located in different parts of Enugu and discuss the future health implications following chronic ingestion of well water.
Materials and Methods: The map of Enugu was used to divide the city into many 25 units, using grid lines 1 cm apart. Cluster sampling method was used to collect samples. These samples were sent to two laboratories for estimation of nitrate levels. The people drawing water from the different wells were interviewed to determine what they used the water for.
Result: The subjects who were interviewed said they ingested the water. The nitrate levels found in these wells (median value of 31 mg/L) were  significantly higher than the internationally accepted levels of nitrate in water for ingestion, (P < 0.0001).
Conclusion: High nitrate levels drinking water is dangerous to health and can cause methemoglobinemia in children. It may also increase cancer risk in adults because nitrate is endogenously reduced to nitrite and subsequent nitrosation reactions give rise to N‑nitroso compounds (NOCs), which are highly carcinogenic and can act systemically.

Key words: Cancer, contamination, nitrates, private wells