Chemical hazards in drinking water - N-nitrosodimethylamine (NDMA)
Rolling revision of the WHO Guidelines for Drinking-water Quality
NDMA is included in the plan of work of the rolling revision of the WHO Guidelines for Drinking-water Quality.
N-Nitrosodimethylamine, or NDMA, can be formed during the treatment of drinking-water. Concentrations of NDMA in drinking-water up to 40 ng/litre have been measured, although lower concentrations are more common. NDMA is clearly carcinogenic, with a strong likelihood that the mode of action for the induction of tumours involves direct interaction with genetic material.
Background document and summary statement, for publication in the second addendum to the third edition; addition of NDMA to Table 8.25, for second addendum.
Progress to date
As NDMA clearly satisfies one of the criteria for inclusion in the Guidelines for Drinking-water Quality as outlined in the Policies and Procedures Manual (“evidence for occurrence in drinking-water, combined with evidence of actual or potential toxicity”), the Guidelines for Drinking-water Quality Working Group meeting (Geneva, 2004) agreed that NDMA should be added to the rolling revision for consideration at the next meeting. The Guidelines for Drinking-water Quality Working Group meeting (Geneva, 2005) agreed to prepare a background document for publication in the second addendum.
The Guidelines for Drinking-water Quality Working Group meeting (Geneva, 2006) requested that the document be sent for review with a specific question regarding the validity of the use of an animal-to-human adjustment factor.
The background document and summary statement are now available.