OIA Ref: CAS-01737-M7Z3Q1
05 July 2023
Athina Andonatou
[FYI request #23191 email]
Tēnā koe Athina
Request for information on level of Atrazine in drinking water Thank you for your email dated 20 June 2023 requesting information under the Official Information
Act 1982 (OIA) relating to atrazine in drinking water.
Response:
Role of Taumata Arowai as the water services regulator
1. Taumata Arowai became the water services regulator on 15 November 2021 when the
responsibility for regulating drinking water transferred from Manatū Hauora – Ministry of Health
to Taumata Arowai with the commencement of the Water Services Act 2021 (the Act).
2. Our role as the water services regulator does not involve approving the use or application of
hazardous substances that may affect drinking water. Te Mana Rauhī Taiao – Environmental
Protection Authority (EPA) is responsible for the approval and setting of controls for hazardous
substances in New Zealand. As such, Taumata Arowai does not regulate or make decisions relating
to the risks and benefits of atrazine or other herbicides.
Setting Maximum Acceptable Values for substances in drinking water through the Drinking Water
Standards 2022
3. Taumata Arowai contributed to the development of the Drinking Water Standards for New
Zealand 2022 (Standards), including administering a public consultation process.1 The Standards
set the maximum acceptable value (MAV) for various substances in drinking water. The Standards
are generally based on guideline levels set by the World Health Organisation (WHO). The MAVs
are scientifically derived values that allow drinking water suppliers to manage risk based on
scientific evidence. For chemicals like atrazine, the WHO sets these values to assess the risk to
health of a person consuming two litres of water a day over a lifetime.
4. The MAV for atrazine and its metabolites (substances formed as atrazine breaks down) included
in the Standards is currently 0.1 mg/L. This value is adopted following the WHO guidelines. A
summary of how this value was arrived at by the WHO can be found in here:
•
atrazine-fact-sheet-2022.pdf (who.int).
5. The guideline values set by the WHO can change when more information about a substance
allows a more accurate assessment of the health risk. The previous MAV for atrazine of
0.002mg/L was based on previous WHO guidelines. The WHO reassessed the risk from atrazine
and its metabolites in drinking water in 2011.2
1 See the Water Services (Drinking Water Standards for New Zealand) Regulations 2022, available at
www.legislation.govt.nz
2 World Health Organisation, 2011, Atrazine and Its Metabolites in Drinking-wate
r Microsoft Word - Fourth
Edition Atrazine Final Jan 2011.doc (who.int)
6. The current Standards reflect the updated WHO guidelines. No additional analysis of the effects of
atrazine in drinking water was carried out during the Standards setting process.
7. Atrazine is a potential hazard in source waters (a waterbody from which water is abstracted for
use in a drinking water supply). The Act requires drinking water suppliers to have drinking water
safety plans that identify potential hazards (such as atrazine) and ensure that they are managed,
controlled, or eliminated in drinking water.3 The Act also requires that suppliers share information
about source water risks and hazards with relevant local authorities.4
8. The Ministry of Health is the lead policy agency in this area. It continues to monitor advice from
the WHO and the approaches taken by other international jurisdictions in relation to drinking
water standards.
Monitoring chemicals in drinking water catchments
9. The last part of your request refers to the Parliamentary Commissioner for the Environment’s
(PCE) March 2022 report
Knowing what’s out there: Regulating the environmental fate of
chemicals and an associated media release.
10. Taumata Arowai was not consulted in the development of the PCE report. We do not know
whether atrazine is included in the group of chemicals referred to in the passage from the PCE
media release that you have quoted (noting the quoted text does not appear in the body of the
report, so is presumably a summary comment).
11. What we can tell you, is that the Act and the Drinking Water Quality Assurance Rules (DWQAR)
that Taumata Arowai has made under it now require much more significant monitoring of source
water by drinking water suppliers than was previously the case. Drinking water suppliers are
required to have plans which address drinking water safety and source water risk management.
Broadly, these plans require drinking water suppliers to:
a. identify any hazards (including emerging or potential hazards),
b. assess risks associated with those hazards, and
c. identify how those risks will be managed, controlled, monitored, or eliminated.
12. Drinking water suppliers are also required to monitor a number of specific determinands
according to the scale, complexity, and risk of drinking water supplies as per the DWQAR. Atrazine
is not specifically mentioned in the DWQAR, however, the broader legislative requirements cover
the hazard and risks presented by atrazine. If it was identified as present (or potentially present in
the future) in source water for a drinking water supply, we would expect ongoing monitoring and
testing to be addressed in a supply’s drinking water safety plan.
13. There are many chemicals potentially used in a drinking water catchment, and it is difficult for
drinking water suppliers to monitor every individual chemical. Hence a risk-based approach is
considered where drinking water suppliers are required to identify any hazards in catchments.
Right to complain:
You have the right, by way of complaint to the Ombudsman under s 28(3) of the OIA, to seek an
investigation and review of this response. Information about how to make a complaint is available at
www.ombudsman.parliament.nz or freephone 0800 802 602.
Ngā mihi
Ray McMillan
Head of Regulatory
3 Water Services Act 2021, sections 31 and 43.
4 Water Services Act 2021, section 45.
