# UNSW study screens 47 chemicals in biosolids and flags several that may persist in farmland soil

- Published: 2026-11-12 23:16 UTC
- Section: Planet › Ecology & recycling
- Tags: biosolids on farmland, treated sewage sludge, chemicals persistence in soil, PFAS in biosolids, carbamazepine, triclosan, environmental screening assessment, wastewater treatment plants
- URL: https://realtech.media/news/rt-1b1788cc0b03f8430c9ffd22_unsw_study_screens/

**A UNSW Sydney review of existing studies screened 47 chemicals in biosolids and found several that may persist in soil for months or years.**

![UNSW study screens 47 chemicals in biosolids and flags several that may persist in farmland soil](https://realtech.media/media/2026/11/d9b6339de401eee6.jpg)
*USDAgov, Wikimedia Commons, Public domain*

Engineers at UNSW Sydney have screened 47 chemicals detected in biosolids, the treated sewage sludge applied to farmland, to identify those that may need closer monitoring, according to miragenews.com. [1] The study, published in the Journal of Hazardous Materials, was led by researchers at the Water Research Laboratory at UNSW. [1] About 80% of biosolids produced in Australia are reused on farmland as a source of nutrients and organic matter. [1]

## How the screening was done

The team ran no new field experiments. They combined findings from existing studies to ask where a chemical goes after biosolids are applied, how long it remains in the environment, and whether concentrations reported in biosolids could matter for plants and animals. [1] The 47 substances include pharmaceuticals, personal care ingredients, industrial chemicals and hormones. They are a small selection of the hundreds detected in biosolids. [1]

Reported concentrations were compared with existing benchmarks for effects on organisms such as algae and small aquatic animals. According to the authors, this is a conservative screening tool, not a measure of human exposure or of food safety. [1]

## Chemicals that may persist in soil

Several chemicals could persist in soil for months or even years: some per- and polyfluoroalkyl substances (PFAS), the medicine carbamazepine, the antimicrobials triclocarban and triclosan, and the fragrance chemicals galaxolide and tonalide. [1] Some compounds stay in soil, while others dissolve and may move into groundwater or waterways. Persistent chemicals have more opportunity to accumulate if biosolids are applied repeatedly. [1]

Concentrations also varied considerably between wastewater treatment plants, which the authors say supports site-specific monitoring. [1] The study does not show that the chemicals cause harm on farms, that food grown with biosolids is unsafe, or that people are exposed to harmful levels. [1]

Professor Denis O'Carroll said that if particular contaminants prove to be a concern, options include changing the design or operation of treatment plants, altering how biosolids are applied, and reducing the use of those chemicals at source. [1] The researchers say further work testing actual biosolids and soils under local conditions is needed. [1]

## Sources

1. [miragenews.com](https://www.miragenews.com/research-examines-chemicals-that-may-persist-in-1772110/)
2. [Phys.org](https://phys.org/news/2026-11-chemicals-sewage-based-fertilizer-persist.html)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-1b1788cc0b03f8430c9ffd22_unsw_study_screens/