***Update: NSF/ANSI 60 has been revised. The current version is NSF/ANSI 60-2019.***
As we have discussed in the past, NSF International, an ANSI-accredited standards developing organization, has published several standards for the health effects of drinking water systems, addressing the criteria for promoting sanitation and protection of public health in relation to the unequivocally vital resource. These standards are:
NSF/ANSI 61-2017 – Drinking water system components – Health effects (you can read more about this in our post on Drinking Water System Components Health Effects)
NSF/ANSI 53-2017 – Drinking water treatment units – Health effects (you can read more about this in our post on Drinking Water Treatment Units Health Effects)
NSF/ANSI 60-2016 – Drinking water treatment chemicals – Health effects confronts a key issue with the treatment of water. While natural water is often not potable, the treatment performed to purify it must be conducted with care to prevent chemicals from residing within the treated public water source at harmful concentrations. The standard establishes minimum health effects guidelines for the chemicals, the chemical contaminants, and the impurities that are directly added to drinking water from drinking water treatment chemicals.
These treatment chemicals are intended to be present within the finished, potable water, but some others that will not be present are included as well. A strong concern present within NSF/ANSI 60-2016 is that treatment chemicals do not exceed their single product allowable concentration (SPAC), or “maximum concentration of a contaminant in drinking water that a single product is allowed to contribute”. For meeting this need, direct additives should be evaluated and tested in accordance with Annexes A and B of the document, and the SPAC of a contaminant should be calculated as outlined in Annex A.
The chemicals covered by NSF/ANSI 60-2016 serve different purposes during the treatment of water, including coagulation and flocculation chemicals, softening, precipitation, sequestering, pH adjustment, and corrosion/scale control chemicals, disinfection and oxidation chemicals, miscellaneous treatment chemicals, and miscellaneous water supply chemicals.
The standard includes numerous chemicals used for varying purposes in water treatment, but any that it excludes are not to be interpreted as incompatible with its guidance. As stated in the document, chemicals not specifically referenced “shall be acceptable provided they meet the requirements of this Standard”.
Just to give some examples, chemicals mentioned in NSF/ANSI 60-2016 include:
Coagulation and flocculation: bentonite, aluminum chloride
Corrosion and scale control: phosphoric acid, monopotassium orthophosphate
pH adjustment: magnesium hydroxide, magnesium oxide
Disinfection and oxidation: anhydrous ammonia, chlorine
Miscellaneous treatment: calcium fluoride (fluoridation), copper sulfate (algicide)
Furthermore, NSF/ANSI 60-2016 gives manufacturer guidelines for labeling and related considerations.
Annex C of NSF/ANSI 60-2016 is a major addendum to the standard, and it lists the normative drinking water criteria for different substances that can be used under the standard’s guidance, compiling the information from different sources.