Micropollutant concentrations in the Holtemme River (LC-HRMS direct injection, October 2021)

This dataset contains measured concentrations of 505 micropollutants in surface water samples collected from seven sites along the Holtemme River, Saxony-Anhalt, Germany, in October 2021. The analysis was performed using Liquid Chromatography coupled to High-Resolution Mass Spectrometry (LC-HRMS) with a direct injection (DI) methodology, following a matrix-matched calibration approach. A total of 126 compounds were detected across 478 measurements (one per compound-site combination). The sampling sites represent a gradient of chemical exposure along the river, capturing the impacts of two major wastewater treatment plant (WWTP) discharges. Detection frequency increases sharply downstream of WWTP outfalls, with the highest detection rates at the site immediately following the Halberstadt WWTP (21.6% detection rate). Upstream reference sites show minimal chemical occurrence (~1-5% detection), whereas the integrative downstream site captures cumulative signals from multiple pollution sources. Each measurement includes comprehensive chemical metadata (CAS number, InChI Key, SMILES notation), functional classification (primary/secondary/tertiary use categories), and toxicological information (mode of action, molecular targets). Analytical quality is characterized through method-specific detection limits (MDL) and quantification method codes (MZQ for quantitative; TF for screening). This dataset supports chemical occurrence studies, mixture risk assessment, structure-activity relationship analysis, and integration with complementary transcriptomic data from wild Gammarus pulex populations in the same river system. Data Format: Tab-separated values (TSV), 478 rows × 17 columnsCompounds Detected: 126 of 505 screenedSampling Period: October 2021