Wai me taiao
Water & environment
We investigate water quality, identify contamination sources, and develop resources to better manage waterways, the surrounding environment, and potential risks to public health.
About
At PHF Science we understand the health of our water is critical to the health of our people. E ora ana te wai. Water is life.
We look at the relationship between drinking water, surface water, stormwater and wastewater, to understand how it affects, and is affected by, the health of our main water source, groundwater.Â
We detect and monitor threats to our water, including the impact of climate change, while exploring sustainable solutions to protect vital water sources and manage waste products. Our focus is on improving te mauri o te wai so we can all trust the quality of the water we drink, play in and use every day.Â
Find out more about our specialist and research areas in the links above, and our team and services below.
Resource recovery from wastewater by directing microbial metabolism toward production of value-added biochemicals
01 Mar, 2025
Dynamic oxygen fluctuations in activated sludge were investigated to enhance valuable biochemical production during wastewater treatment. Batch experiments compared constant aeration with rapid cycling between oxygen-rich and oxygen-poor states.
Reducing uncertainty of groundwater redox predictions at national scale, for decision making and policy
04 Dec, 2024
Understanding hydrogeochemical heterogeneity, associated with natural nitrate attenuation, is an integral part of implementing integrated land and water management on a regional or national scale. Redox conditions are a key indicator of naturally occurring denitrification in the groundwater environment, and often used to inform spatial planning and targeted regulation.
Reporting population size in wastewater-based epidemiology: A scoping review
25 Nov, 2024
Knowledge of the number of people present in a catchment is fundamental for the assessment of spatio-temporal trends in wastewater-based epidemiology (WBE). Accurately estimating the number of people connected to wastewater catchments is challenging however, because populations are dynamic.
Diversity of free-living amoebae in New Zealand groundwater and their ability to feed on Legionella pneumophila
07 Aug, 2024
Free-living amoebae (FLA) are common in both natural and engineered freshwater ecosystems. They play important roles in biofilm control and contaminant removal through the predation of bacteria and other taxa. Bacterial predation by FLA is also thought to contribute to pathogen dispersal and infectious disease transmission in freshwater environments via the egestion of viable bacteria.
Metagenomic evaluation of bacteria in drinking water using full-length 16S rRNA amplicons
30 Jul, 2024
Escherichia coli and total coliforms are important tools for identifying potential faecal contamination in drinking water. However, metagenomics offers a powerful approach for delving deeper into a bacterial community when E. coli or total coliforms are detected. Metagenomics can identify microbes native to water systems,
Soil conditions are a more important determinant of microbial community composition and functional potential than neighboring plant diversity
21 Jun, 2024
Replanting is an important tool for ecological recovery. Management strategies, such as planting areas with monocultures or species mixtures, have implications for restoration success.
Evaluation of the suitability of selected contaminants for wastewater-based surveillance at the border
11 Jun, 2024
Wastewater-based surveillance (WBS) is a useful tool for non-invasively screening arrivals at the New Zealand border en masse for a range of different biological and non-biological contaminants. A previous report prepared for the Ministry of Health assessed the logistics of conducting WBS at New Zealand’s international airports, including sampling directly from inbound international aircraft and from airport wastewater networks. This current report extends this assessment by evaluating a wide range of different contaminants for their suitability for WBS.
A method for the extraction of microplastics from solid biowastes including biosolids, compost, and soil for analysis by µ-FTIR
03 Jun, 2024
Few methods exist detailing the extraction of microplastics from organic matrices. A validated method for the successful extraction of microplastics from solid biowastes including biosolids, compost, and soil for spectroscopic analysis by micro-Fourier transform infrared spectroscopy (µ-FTIR) was developed.
Uncoupled: investigating the lack of correlation between the transcription of putative plastic-degrading genes in the global ocean microbiome and marine plastic pollution
15 May, 2024
Plastic pollution is a severe threat to marine ecosystems. While some microbial enzymes can degrade certain plastics, the ability of the global ocean microbiome to break down diverse environmental plastics remains limited.
Testing methods to estimate population size for wastewater treatment plants using census data: Implications for wastewater-based epidemiology
20 Apr, 2024
In wastewater-based epidemiology (WBE), wastewater loads are commonly reported as a per capita value. Census population counts are often used to obtain a population size to normalise wastewater loads. However, the methods used to calculate the population size of wastewater treatment plants (WWTPs) from census data are rarely reported in the WBE literature.
Specialist services
Specialist services
We provide health authorities, local and central government, industry and communities with scientific advice and expertise on the management of drinking water, groundwater, recreational water and wastewater. Please contact us to explore if our expertise can help your organisation.
Microbial Risk Assessment (MRA) tool
About
The Microbial Risk Assessment (MRA) tool provides an objective and transparent basis for consent decision-making on land use applications and their impact on drinking water supplies.
Protecting our drinking water from potential microbial contamination is critical for regional councils. An effective approach to assessing the risks posed by land use activities in close proximity to protected drinking water zones is needed in order to make informed consent decisions. PHF Science experts are working alongside GNS and Environment Canterbury on a new model for microbial risk assessment of land use on drinking water supplies.
Groundwater modellers, hydrologists and microbiologists at PHF Science and GNS, along with Environment Canterbury (ECan), developed the Microbial Risk Assessment (MRA) tool to provide a more objective and transparent basis for consent decision-making on land use applications. This risk assessment tool involves modelling potential microbial contamination of groundwater supplies from land use activities such as community and on-site wastewater management systems, pastoral farming, wildfowl, stormwater systems, and animal effluent/manure application within ‘source protection zones’ – areas of protection around drinking water sources.Â
The MRA tool includes a range of soil and groundwater system types found throughout Aotearoa New Zealand, modelling various permeabilities, topographies, recharge rates, hydraulic gradients, and lithologies. The tool also includes four climate types for modelling, representing relevant regions of the country.Â
This MRA tool offers two significant improvements over the existing guidelines: improved inputs and improved risk modelling. It considers more input types, including additional land-use activities, multiple on-site wastewater management systems, and supply wells that are pumped at different rates. This improves the usefulness and application of the model as well as the risk model accuracy. In addition, the MRA also provides additional information and visualisation of uncertainty to assist in understanding trade-offs in risk with different separation distances and land use activities. Instead of evaluating at only a 95% confidence level, the entire spectrum of risks can be considered, from very risk averse setting at 99%, to more risk tolerant applications.
Benefits to land users and regional councils
The MRA benefits both land users and regional councils by providing greater guidance and certainty to stakeholders, reducing variation in assessment quality, assisting in consent processing, and avoiding duplication of effort in developing methods by individual regional councils.
The team is now building a user interface that will allow easy access and adoption of the MRA, assisting planners throughout Aotearoa New Zealand – and potentially beyond.
Get in touch
For questions about the tool, how to use it and what the benefits are; or to collaborate, share knowledge or develop partnerships projects in the groundwater or water quality space, get in touch with the groundwater team.
Water Quality
Waterborne outbreak investigations
PHF Science water scientists can identify a range of waterborne pathogens within a water sample and can link the bacteria to those found in another source such as cattle, sheep or poultry. Using sequencing facilities on-site we can determine the complete picture of microbes present in a water sample and the impact of activities, such as discharges, on the health of the microbial community present.
Tracking faecal sources
When waterways become contaminated with faeces, identifying the source of the pollution is an important part of the contamination management strategy. PHF Science has a range of molecular and chemical techniques that help to identify sources of faecal contamination of water, whether they are from farms, domestic or feral animals, humans or birds. For example, if an initial test indicates high levels of E. coli, we undertake one or more assays from our ‘toolbox’ of methods. We then develop a strategy for determining the most efficient way to identify the likely faecal contamination source, which includes a ‘decision tree’ outlining the steps to obtaining the most relevant information for the least financial outlay. We have an excellent record of helping local government staff with water management responsibilities to manage and reduce water pollution levels.
Surface water assessments
Our experts can assess the quality of surface and recreational waters and determine the cause of water pollution, including differentiating between sources of pollution. Our work includes developing monitoring and reporting programmes, applying bacterial and viral tracers to mark and follow effluent plumes, and conducting microbial risk assessments on discharges.
Drinking water standards and safety
About
We advise clients on the quality of their drinking water, report to the Ministry of Health on compliance with drinking water standards, assist with the management of large water quality datasets, and help develop resources to address public health risks associated with water supplies.
Register of recognised laboratories for New Zealand
To demonstrate compliance with the New Zealand Drinking-Water Standards, water suppliers need to monitor the quality of their drinking water by taking water samples and having them analysed. The Ministry of Health requires all such testing to be performed by laboratories that have appropriate skills and quality assurance procedures and to be registered.
The Register of Recognised Laboratories for New Zealand is prepared annually by PHF Science for the Ministry of Health and provides easily accessible information about the laboratories that have been assessed by IANZ and found to comply with either ISO 17025 or the Ministry of Health Level 2 Criteria analytical laboratories.
The register includes information such as the name of the laboratory, its contact details, and certified methods for determinants the laboratory can test for.
Drinking water supply and quality
With backgrounds in public health, microbiology, environmental radioactivity and chemistry, our scientists help clients to understand the quality of their drinking water and the implications of that quality for water treatment.
Our clients benefit from our direct involvement in preparing New Zealand’s drinking-water standards. Our responsibility to provide the Ministry of Health with annual reports of compliance with those standards, means we can advise clients on interpreting the standards and the next steps required for compliance, as well as help develop resources to address public health risks associated with water supplies.
In addition, we help those clients with major water-related responsibilities to manage large water-supply and water-quality datasets. With more than a decade’s experience in summarising and reporting on such datasets, we can help clients make sense and benefit from the data.
Household water supplies: the selection, operation and maintenance of individual household water supplies
03 Nov, 2021
This booklet gives information about the supply of safe drinking water to households that are not connected to town water supplies. It includes information on water sources, storage and treatment. It should be read in conjunction with the Guidelines for Drinking-water Quality Management for New Zealand, published by the Ministry of Health. (Go to https://www.health.govt.nz/publication/guidelines-drinking-water-quality-management-new-zealand)
Public health risk assessment of sewage disposal by onsite wastewater treatment and disposal systems in the Darfield and Kirwee Communities
03 Jun, 2014
This report was undertaken to provide the Ministry of Health with information to better understand the public health risk associated with the onsite treatment and disposal of sewage in Selwyn.
Risks to public health from emerging organic contaminants in the New Zealand aquatic environment
10 Apr, 2018
This report was prepared for the Ministry of Health to consolidate New Zealand data on emerging organic contaminants in wastewater and the receiving environment, and assess the risks to public health of this.
Faecal Source Tracking in the Avon River, Christchurch March-May 2009
Testing & Analysis
Testing & analysis services
We detect and identify a range of waterborne pathogens as well as identifying their source and contaminant pathways.
News
Testing plane sewage at border can help detect disease
04 April 2025
News
PHF Science drinking water project receives $8 million from NZ’s largest science fund
18 October 2024
News
Growing evidence linking plastics to serious health risk
07 October 2024
News
Understanding the risk of acute gastrointestinal disease from contaminated drinking water
26 September 2024
Insight
Small plastics, big consequences: the impact of microplastics on Aotearoa
24 June 2024
News
Microplastics in Aotearoa New Zealand: local sources and broad impacts
24 May 2024
News
Symposium to highlight success of world-leading Kiwi microplastic research
13 May 2024
News
Let’s commit to reducing plastic pollution this Earth Day
22 April 2024
Case Study
Microbial Risk Assessment of land use on drinking water supplies
13 June 2023
News
Leading the charge in checking our waters are safe for swimming
30 May 2023
Experts in the area
Experts in Water & Environment
Allanah Kenny
Scientist
Angela Baschieri
Science Leader, Climate Health Impacts
Angela Cornelius
Senior Scientist
Annette Bolton
Science Leader
Beverley Horn
Senior Scientist
Brent Gilpin
Technical lead/Team leader
Helena Rattray-Te Mana
Scientist
Isabelle Pattis
Senior Scientist
Jo Chapman
Senior Scientist
Liping Pang
Science Leader
Louise Weaver
Science Leader
Maria Hepi
Senior Scientist
Maxie Christison
Quality Director – Health and Environment
Megan Devane
Senior Scientist
Olga Pantos
Senior Scientist
Phil Abraham
Principal Technician
Richard Sutton
Groundwater Team Senior Technician
Sarah Nelson
Senior Scientist
Theo Sarris
Water and Environment Group Manager and Senior Science Leader
Virginia (Jinny) Baker
Senior Scientist