Water sanitation hygiene

Chemical hazards in drinking-water

The World Health Organization’s (WHO) Guidelines for drinking-water quality (GDWQ) cover a broad range of chemicals that can affect drinking-water quality. However, not all chemicals included in the GDWQ will be relevant within a country.

Facts sheets (Chapter 12) [PDF, 667Kb] are included in the GDWQ and comprehensive review documents are available for many individual chemicals. For many of these chemicals, guideline values are derived. These background documents may be accessed through the following alphabetical index of chemicals.

Guidance on management approaches for chemicals is presented in Chapter 8 [pdf, 296Kb] of the GDWQ. This chapter also includes background information on the approaches taken to derive guideline values and analytical achievability.

Whats new?

WHO has recently published new or revised background documents for selected chemical hazards in drinking-water, which inform the development of the first addendum to the fourth edition of the GDWQ.

These chemicals include: barium; bentazone; chlorine dioxide, chlorate and chlorite; dichlorvos; dicofol; diquat; lead; MCPA; nitrate and nitrite; and perchlorate. To view the new chemical background documents, click on the corresponding chemical from the alphabetical list below.

Other publications of interest:

Chemical safety of drinking-water: Assessing priorities for risk management

Protecting groundwater for health: Managing the quality of drinking-water sources

Protecting surface water for health: Identifying, assessing and managing drinking-water quality risks in surface water catchments

Water safety planning resources.