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.

Fact sheets (Chapter 12) 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 of the GDWQ. This chapter also includes background information on the approaches taken to derive guideline values and analytical achievability.

What is new?

In December 2021, chemical background documents were updated for asbestos, manganese, nickel and silver. A number of chemical background documents were also published in December 2020. Background documents for bentazone; chromium; iodine; microcystins; tetrachloroethene; and trichloroethene were revised. New background documents were prepared for anatoxin-a and analogues; cylindrospermopsins; and saxitoxins while a background document for organotins was developed, to replace the background document on dialkyltins. The recommendations in these publications, including any changes in guideline values, have been incorporated into the current edition of the GDWQ (4th edition incorporating the 1st  and 2nd  addenda), published in March 2022.

To view these chemical background documents, click on the corresponding chemical from the alphabetical list below.