Every year, millions of tonnes of treated sewage sludge (biosolids) are applied to agricultural lands across the UK as fertiliser. Although this practice helps recycle nutrients and builds soil organic matter, emerging research reveals a troubling hidden cost: unregulated pharmaceutical compounds that can fundamentally disrupt soil ecosystems.
The Scale of the Problem
Although pharmaceuticals have essential practical health applications, they enter our wastewater systems and natural environment through numerous routes. Ingested pharmaceuticals are eventually metabolised and excreted in urine and faeces. Washing off dermally applied creams or other products adds to this problem, alongside the disposal of unused medications down the toilet or sink [1]. Wastewater from hospitals and pharmaceutical manufacturing processes further add to the burden of these compounds in our waste systems [1].
When wastewater is treated, many pharmaceutical compounds end up in the solid sewage sludge that is treated to produce biosolids that are applied to agricultural land. Unfortunately, current outdated UK sewage sludge (use in agriculture) regulations focus only on certain metals, leaving pharmaceutical contamination completely unmonitored. This means that our soils have become inadvertent repositories for everything from antibiotics to hormonal medications, with research documenting a wide range of pharmaceuticals in biosolids applied to agricultural land [2], [3].
Widespread Environmental Impact
Pharmaceuticals are designed to modify biological functions, and these properties don’t disappear when they reach our soils and waterways. Sewage sludge application to land creates a direct pathway for pharmaceuticals to enter ecosystems and food chains, causing adverse effects on terrestrial and aquatic organisms. In aquatic systems, for example, hormonal medications disrupt reproduction in fish[4], while antibiotics fuel the development of antibiotic resistant bacteria [5].
One alarming consequence of pharmaceuticals in biosolids in the spread of antibiotic resistance genes. Long-term sewage sludge application increases these genes in soil environments [6], where they can transfer from environmental bacteria to human pathogens, creating serious public health risks. Meanwhile, crops grown on contaminated soils can take up and accumulate pharmaceutical compounds, potentially introducing them into the human food supply [7].
The contamination doesn’t stop at individual organisms. In fact, entire agricultural soil processes and ecosystem functions are being disrupted, threatening farmer livelihoods and the food production systems that we depend on.
Devastating Impacts on Soil Fungi
A research collaboration between the University of Leeds and the University of Sheffield has recently revealed some of the catastrophic effects of pharmaceuticals on soil fungi – the microscopic networks that underpin healthy ecosystems.
Soil fungi form intricate mycorrhizal partnerships with plant roots, facilitating nutrient exchange and enhancing plant resilience. The research [8] found that pharmaceutical exposure caused fungal networks to collapse, with soil arbuscular mycorrhizal (AM) fungi hyphal densities plummeting by 70% and beneficial root colonization dropping by 72-82%. Particularly concerning was that they found that the addition of anti-fungal pharmaceuticals could result in the complete shutdown of AM-mediated phosphorus acquisition.
A soil functional collapse such as this illustrates the threat that contaminated biosolids pose, both in terms of immediate crop nutrition and productivity, as well as long-term soil health.
Professor Laura Carter, who led the research team, explains to Fidra that “As our use of pharmaceuticals continues to increase, it is crucial that we assess the environmental behaviour of contaminants following their inadvertent release into agricultural environments. We know very little about the impacts of pharmaceuticals on soils and wider agroecosystems that we depend on for food production.”
The UK Falls Behind: A Growing International Divide
While the UK maintains outdated regulations and environmental protection measures that ignore pharmaceutical contamination, other countries are taking action. The EU’s updated Urban Wastewater Treatment Directive, which came into force in January 2025, requires member states to begin efforts to monitor and remove specific micropollutants, commonly found in pharmaceuticals, from wastewaters [9].
The new EU regulations, where quaternary wastewater treatment to remove micropollutants is being phased in with a deadline of 2045, also introduce the ‘polluter pays’ principle, requiring companies that produce pharmaceuticals and cosmetics to cover at least 80% of these additional treatment costs. It is hoped that this will shift the burden away from water companies and encourage industries to reduce the use and disposal of environmentally harmful pharmaceuticals. There are also new monitoring requirements for microplastics and PFAS under the stricter EU directive rules.
While our European neighbours have begun to explore and invest in solutions, pharmaceutical contamination of UK agricultural soils and waterbodies continues through the ongoing agricultural use of contaminated biosolids alongside discharges of contaminated wastewater into waterways, including controversial sewage overflows.
A Path Forward
The UK Government’s current approach fails to protect soils from pharmaceutical contaminants and Fidra, alongside other concerned stakeholders, are urgently calling for change. For example, the recent Cunliffe Independent Water Review acknowledges these risks and calls for the list of contaminants monitored in biosolids to be reviewed and updated.
The evidence is clear: contaminated sewage sludge is polluting agricultural land with severe consequences for the health of soils and the wider environment. It’s time for the UK Government to stop this contamination and take steps to protect our soil and wider ecosystems, farm businesses, and public health.
References
[1] “Pharmaceuticals in the Environment – One Health Breakthrough Partnership.” Accessed: Aug. 21, 2025. [Online]. Available: https://ohbp.org/our-work/pharmaceuticals-in-the-environment/
[2] J. Martín, C. Mejías, J. L. Santos, I. Aparicio, and E. Alonso, “Pharmaceuticals and Their Main Metabolites in Treated Sewage Sludge and Sludge-Amended Soil: Availability and Sorption Behaviour,” Molecules 2021, Vol. 26, Page 5910, vol. 26, no. 19, p. 5910, Sep. 2021, doi: 10.3390/MOLECULES26195910.
[3] N. Pérez-Lemus, R. López-Serna, S. I. Pérez-Elvira, and E. Barrado, “Analysis of 60 pharmaceuticals and personal care products in sewage sludge by ultra-high performance liquid chromatography and tandem mass spectroscopy,” Microchemical Journal, vol. 175, p. 107148, Apr. 2022, doi: 10.1016/J.MICROC.2021.107148.
[4] K. Fent, “Effects of Pharmaceuticals on Aquatic Organisms,” Pharmaceuticals in the Environment, pp. 175–203, Oct. 2008, doi: 10.1007/978-3-540-74664-5_12.
[5] R. Murray, Y. C. Tien, A. Scott, and E. Topp, “The impact of municipal sewage sludge stabilization processes on the abundance, field persistence, and transmission of antibiotic resistant bacteria and antibiotic resistance genes to vegetables at harvest,” Science of The Total Environment, vol. 651, pp. 1680–1687, Feb. 2019, doi: 10.1016/J.SCITOTENV.2018.10.030.
[6] Q. Chen, X. An, H. Li, J. Su, Y. Ma, and Y. G. Zhu, “Long-term field application of sewage sludge increases the abundance of antibiotic resistance genes in soil,” Environ Int, vol. 92–93, pp. 1–10, Jul. 2016, doi: 10.1016/J.ENVINT.2016.03.026.
[7] W. Bolesta, M. Głodniok, and K. Styszko, “From Sewage Sludge to the Soil—Transfer of Pharmaceuticals: A Review,” International Journal of Environmental Research and Public Health 2022, Vol. 19, Page 10246, vol. 19, no. 16, p. 10246, Aug. 2022, doi: 10.3390/IJERPH191610246.
[8] E. K. Durant, K. J. Field, J. B. Sallach, S. Moeskjær, A. Williams, and L. J. Carter, “Azole antifungal contaminants disrupt mycorrhizal function and risk agricultural sustainability,” Plants, People, Planet, 2025, doi: 10.1002/PPP3.70068.
[9] “Revised EU Wastewater Directive: A Milestone for Pollution Control and Public Health – One Health Breakthrough Partnership.” Accessed: Aug. 21, 2025. [Online]. Available: https://ohbp.org/2024/11/08/revised-eu-wastewater-directive-a-milestone-for-pollution-control-and-public-health/