Stricter Biocide Regulations Needed to Protect Dutch Water Quality, Say Water Authorities

The Union of Water Authorities (Unie van Waterschappen) is calling on the Dutch government to impose tougher regulations on biocides, citing their growing impact on surface water pollution. Although biocides are widely used by both consumers and professionals, for example in insect sprays, ant traps, and antifouling boat paints, their active substances often exceed environmental safety thresholds.

Unlike plant protection products, biocides receive limited regulatory attention. The discrepancy means that hazardous substances such as DEET, permethrin, and imidacloprid remain widely used, even though they are frequently detected in Dutch surface waters above legal limits. This undermines national efforts to meet the targets of the EU Water Framework Directive (WFD).

Overlapping Use of Hazardous Substances

Many active substances in biocides are also found in pesticides and veterinary medicines. Imidacloprid, for instance, is banned in agriculture but still permitted in pet treatments and household products. These inconsistencies pose ongoing risks to ecosystems and drinking water quality.

Water authorities argue that pollution is not solely caused by agriculture. Wastewater monitoring shows that many harmful substances reach waterways through urban wastewater systems, making biocides a major but underregulated contributor to chemical pollution.

Unified Substance Evaluation and Stricter Controls

To address the gap, the water authorities advocate a ‘one substance, one assessment’ approach. This would ensure that each active substance undergoes a single evaluation process, regardless of whether it is used in agriculture, biocides, or veterinary applications.

They propose that the Dutch Board for the Authorisation of Plant Protection Products and Biocides (Ctgb) should reassess any biocide consistently exceeding environmental limits. Additionally, provincial and municipal authorities should tighten usage rules in sensitive areas.

The Ministry of Infrastructure and Water Management, which is responsible for biocide policy, should also set a near-zero emission goal for biocides by 2030. This would align with ambitions already established for pesticides.

Improved Monitoring and Public Awareness

Currently, there is little data on the quantity and type of biocides used in the Netherlands. A national sales register is in development, but progress is slow. Authorities want the ministry to prioritise high-risk substances, particularly those most likely to enter water, be poorly monitored, or regularly breach safety norms.

Investment in analysis methods, lower detection thresholds, and a national biocide monitoring network, similar to the existing pesticide monitoring system, are also urgently needed. Public and political awareness must improve, especially among consumers and professionals using these products daily.