Risikovurdering av plantevernmidler i vann. Kumulativ risiko ut fra målinger i Program for jord- og vannovervåking (JOVA-programmet) i perioden 2011- 2018

Sammendrag

Summary: Monitoring of agricultural streams in Norway through the JOVA program reveals that 75% of water samples containing pesticides include multiple substances simultaneously. Despite low concentrations—often below NOEC and EC50 thresholds—combined effects may still pose risks to aquatic life. Several EU initiatives, including SPRINT, SOLUTIONS and PARC, stress the need for improved risk assessment methodologies that account for mixture toxicity and also a robust approach for identifying the drivers of observed toxicity effects in the environment. To address this, the study presented here demonstrates the use of NIVA’s Risk Assessment database (RAdb) tool for cumulative risk prediction based on JOVA monitoring data (2011–2018). While overall risk levels were generally below concern thresholds, certain pesticides—such as insecticides (e.g., alpha-cypermethrin, imidacloprid), fungicides (e.g., azoxystrobin), and herbicides (e.g., simazine)—were linked to episodic risks for specific aquatic organisms. The approach used here enables a risk assessment of relevant mixtures to specific aquatic organisms, as compared to the current approach in the JOVA-program based on a conservative approach assessing the toxicity to the most sensitive organism for each individual chemical in a complex mixture. The report further adress the need for cross-sectoral collaboration and harmonized monitoring and data use across regulatory frameworks. This should be further explored in a Norwegian context to allow for a more holistic approach to assess and fulfil national and international environmental goals.