Recycled water use in irrigated crops

What it contains

EPA has a role in educating Victorians about the use of recycled water. We work with government partners, the water industry and academic institutions to understand and act on potential risks of harm to human health and the environment.

Background

Recycled water is a precious resource in our drying climate. As Victoria’s population grows, we need to make better use of recycled water and understand emerging and legacy contaminants.

Emerging contaminants are natural or man-made chemicals that may pose a risk to our health or the environment. These include things like pharmaceuticals and personal care products, pesticides, phthalates and industrial chemicals. They’re called ‘emerging’ because we are still learning about them – their presence, how they behave, and what effects they might have.

Some contaminants, like per-and polyfluorinated alkyl substances (PFAS) are especially persistent. PFAS do not easily break down in the environment. There are low levels of PFAS in soil, sediment, water, and animals across most of Victoria.

Our goal is to educate the public about these emerging contaminants and study their impact to ensure safe use of recycled water.

Our research

From 2022-2025, in collaboration with Department of Energy, Environment and Climate Action (DEECA) and CSIRO, EPA Victoria led a study on emerging contaminants in edible crops irrigated with recycled water.

The purpose of this research was to measure levels of emerging contaminants in two classes of recycled water – Class A and Class C – to determine whether contaminants are transferred from water to soil or taken up by crops.

This work aims to support Victoria’s broader water sector by improving understanding of potential environmental and public health risks associated with recycled water use.

The study involved six farms:

• Two using Class A recycled water to grow broccoli
• Two using Class C recycled water to grow pasture and,
• Two reference farms not using recycled water.

Sampling was carried out in 2023 and 2024, with water, soil and plant tissues collected and analysed from each site.

What we found

Of the thousands of chemicals, we screened for in irrigation water, soils and plants, targeted testing revealed 79 chemicals above the reporting limit.

The chemical profiles of the recycled water differed from water at the reference farms, but the plants had similar chemical profiles across all sites. These findings align with similar studies conducted globally.

Only 6 emerging contaminants were found in plants. This included common medications and pesticides, mostly in trace amounts. Some pharmaceuticals were also found in water used for irrigation at the reference sites and were similar to contaminants found in nearby rivers.

There were low levels of PFAS detected in water, soil and plants. There were no significant effects on crop health, soil, or water quality from using recycled water.

What this means

Our research showed that the presence of emerging contaminants in recycled water used for irrigation does not necessarily mean they are present in the plants. Despite the differences in the chemical composition of the recycled water compared to reference sites, the plant tissues from all sites were similar. Most chemicals in recycled water did not make it into crops, thanks to natural processes in soils and plants that break them down or block their uptake.

Our key findings are:

• Recycled water consistently contained a greater number and concentration of chemicals than reference water.
• Although emerging contaminants were present in water and in soil, our study found limited evidence that they moved into the edible parts of the plants.
• No impact of recycled water on crop health was observed. Differences in plant pigments and biomass appeared linked to crop maturity, not to irrigation source.
• Some pesticides were found in edible parts of the plants from the reference farms not using recycled water for irrigation, indicating on-farm sources (e.g. direct pesticide application).
• The reference farm irrigation water for broccoli contained PPCPs, suggesting other potential sources (e.g. river water).
• Concentrations of PFAS found in edible crops were generally low and with a low detection rate. As such they are unlikely to present a risk to human health.
• Based on this study, recycled water can be used for crop irrigation, if the quality of the water is regularly monitored, and use managed appropriately.
• Ongoing monitoring and the inclusion of more crop types and locations are recommended to refine risk assessments and management strategies.
  

These studies help us to better understand and manage any small risks, especially as recycled water use in farming grows. Using recycled water on farms is a sustainable option, helping to conserve drinking water supplies and support food production.

Next steps

EPA continues to work with partners to build state of knowledge and improve understanding of the effects of emerging contaminants to the environment, and to develop solutions. This includes an ARC-linkage project on fate of PFAS in biosolids-amended soils.