Title: Netherlands (bio)monitoring data from different waterboards

Description:Three Excel files compile physico-chemical / pollution monitoring data and macrofauna monitoring data collected and curated by JP and RK from 18 Dutch water authorities (waterboards) as part of national and regional freshwater monitoring programs. The three Excel files are: Site code information:File “1_Site code table_Oginah et al GCB.xlsx”: Information on site codes and geographic locations, allowing to spatially link measured abiotic and biotic parameters. Physico-chemical / chemical pollution data:Files “2a/2b/2c_RuwChemie1/2/3_Physico-chemical_Pollution_1/2/3: Data are presented in three Excel files, related to limitations in Excel file size. Measurements of physico-chemical / chemical pollutant parameters are measured at the exact monitoring locations. These data were used to calculate the multi-substance Potentially Affected Fraction (msPAF), a toxic pressure indicator that reflects the combined impact of chemical mixtures on aquatic species. Macroinvertebrate data: File “3_macrofauna.xlsx”: Species composition and abundance data of aquatic macroinvertebrates sampled in Dutch surface waters. These data, collected using standardized national protocols, provide a basis for assessing biodiversity patterns and community responses. The dataset supports analyses exploring potential correlations between biodiversity metrics for the macroinvertebrates and the calculated msPAF values and the abiotic factors, to disentangle the multiple stressors that drive changes in freshwater biodiversity (with emphasis on the potential impacts of chemical pollution). It offers a robust resource for researchers studying ecotoxicological risk, ecosystem health, and the effects of various stressors in aquatic environments.