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.
Background
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.
Expected end-product(s)
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.