Faber, MSmit, CE2025-10-152025-10-152025-10-1310.21945/RIVM-2025-0051https://rivm.openrepository.com/handle/10029/655713<p>Benzotriazoles are chemical substances that are widely used in industrial cooling water systems to prevent corrosion. They are also present in antifreeze and dishwasher tablets. These substances are emitted to surface waters through industrial and household discharges.<br><br>The national task force to address emerging substances (Dutch: werkgroep Aanpak Opkomende Stoffen) would like more information on the environmental impact of these discharges.<br>In response, the Ministry of Infrastructure and Water Management (I&W) commissioned RIVM to derive environmental risk limits for this group of substances.<br>Benzotriazoles include hundreds of different compounds. RIVM selected eight of them for which research has demonstrated widespread use. Some of these eight substances are comparable in terms of chemical structure, environmental behaviour and effects. In this case, the derived risk limits apply to the sum of the respective benzotriazoles. This report therefore includes risk limits for four benzotriazoles (or groups of benzotriazoles): 1H-benzotriazole and sodium 1H-benzotriazolide, methylbenzotriazoles, hydroxybenzotriazole and sodium 5-N-butyltriazole.<br><br>The risk limits in this report are scientific advisory values. Based on the present research, the Ministry of I&W may decide to set quality standards for benzotriazoles in surface water. An indicative water quality standard for 1H-benzotriazole is already in force. RIVM has collected more information that enables derivation of a more reliable value, which may replace the current indicative standard.</p>application/pdfenReport2025-10-15