Tackling chemical pollution of freshwater: The need for a strategic approach

Currently, not a single English river is in good chemical status, as defined by the handful of chemicals covered by regulatory standards, and many of the chemicals found in our fresh and coastal waters are persistent, bioaccumulative and toxic, impacting upon aquatic life, raising implications for human health and requiring costly treatment to remove. The importance of this issue was recognised within the Independent Water Commission (Cunliffe) report of summer 2025 that highlighted the threat posed by forever chemicals, microplastics, sewage sludge and more.

The recent Water White Paper, however, is notably light on an approach to addressing chemical pollution of our aquatic environments, offering no tangible commitments and missing the opportunity to develop a roadmap or strategy. Moreover, the government’s recent PFAS action plan offers little in comparison to its European counterpart, despite it noting the huge economic benefits of a PFAS free market. But there are several key actions government can readily take to address chemical pollution to realise not only environmental benefits, but public health and economic ones too.

Chief amongst these is the need to control chemical pollution at source before it is released into the environment when removal is so much harder and costly. This was recognised by the Cunliffe report that recommended that the government consider “legislative changes to drive a more coherent approach to ‘pre-pipe’ solutions to stop pollutants ... entering the system”. Achieving this will require phasing-out harmful chemicals except for the most essential uses, the use of (genuinely) less-harmful substitutes, and the adoption of the precautionary principle where evidence is incomplete. Control at source is closely linked to the regulation and authorisation of chemicals but, unfortunately, there is plenty of clear evidence of a divergence between the UK (with the exception of Northern Ireland) and the EU REACH chemical regulatory regimes over recent years.

This divergence is apparent in other ways too; the European Commission’s recent revision of the Urban Wastewater Treatment Directive, for example, now extends treatment requirements to smaller plants and communities whilst the producers of pharmaceuticals and cosmetics – one of the main sources of micropollutants in urban wastewater – will need to contribute to the costs of treatment in alignment with the ‘polluter pays’ principle. So, where does this leave wastewater treatment in the UK? Despite the recent and long overdue attention on sewer overflows, a substantial proportion of the UK’s wastewater treatment plants, particularly smaller rural ones, still deploy no more than secondary treatment, whereby many pollutants are discharged to rivers and coastal waters in partially treated effluent.

The contrast with developments across the EU may soon also extend to acceptable levels of certain chemicals in the aquatic environment. The European Commission is proposing to extend the number of Water Framework Directive ‘Priority Substances’, i.e., those chemicals of greatest concern, from the current 45, to 70 and is proposing stricter standards, based on ecotoxicological research, for several of them. These include PFAS forever chemicals, bisphenol-A, a known endocrine disrupting chemical, imidacloprid, a neonicotinoid pesticide and several pharmaceuticals.

The European Commission is now into its 4th iteration of the Watch List, the mechanism by which the EU legislation on water pollution is kept up to date, by gathering evidence from surface waters on contaminants of emerging concern. The latest list contains twelve pollutants, including pesticides and pharmaceuticals, a sunscreen agent, and an antioxidant used in tyres, the impacts of which have been identified as having the possibility for widespread concern for the environment and human health. Whilst the Environment Agency’s Prioritisation and Early Warning System (PEWS) does scan for a number of emerging contaminants, it is only for those that are pre-targeted and the data arising is far from accessible. But, more pointedly, how often has it led to any tangible action?

But credit where it is due, the government has recently announced that the EU is to be the only other jurisdiction the UK will recognise chemicals approvals from and the recent PFAS Action Plan hints at a closer future EU alignment. But the challenge extends beyond divergence - Resource constraints mean that regulatory monitoring of chemicals in the UK is limited both in time and space and not designed to either discriminate a particular source nor enable emissions to be quantified, which can preclude identification and targeting of the most effective mitigation measures. In contrast, a growing number of academic studies, sometimes in collaboration with NGOs, are building a substantial evidence base, homing in on a particular chemical and/or isolating and quantifying a source such as road runoff pollution. This additional evidence needs to be brought to bear and become part of the waterbody programme of measures. For this to be achieved, all this chemicals data needs to be integrated and made freely accessible such that all stakeholders have a common understanding of the issues and can work collaboratively to identify priorities and take action.

So, in addition to the urgent need to address divergence with the EU, we also need to see a much better resourced monitoring programme for chemicals right across our environment, supported by a national data platform, accessible and understandable by all. But there’s more that can be done…

Even with a greater focus on control at source, we will still continue to see the emission of chemicals to the environment. In this regard there is potential for nature-based solutions (NbS) to play a much greater role in their attenuation, in both rural and urban environments, including for wastewater treatment. A growing body of research is quantifying the efficacy of NbS in this regard, with promising results.

Support, including incentives, to farmers is needed to ensure that pesticides are used in a sustainable and optimal manner, providing benefits for the farm business and the environment and supporting the (modest) goals of the Pesticides National Action Plan (NAP). Without this, the NAP will remain simply aspirational.

We also need greater public awareness of the issue to encourage more sustainable use and disposal of chemicals from our homes, gardens and businesses. This encompasses medicines, including antibiotics; few people are aware that unwanted drugs can be returned to a pharmacy rather than being disposed of inappropriately (e.g. by flushing them away) where they lead to detrimental impacts upon aquatic life and can contribute to antimicrobial resistance. The England-wide Catchment Based Approach partnerships provide a mechanism to undertake such community engagement.

Finally, wouldn’t it make sense to capture all these actions, and more, within a chemicals strategy that sets out a longer-term integrated plan of action with associated goals?