High-frequency NO3? isotope (δ15N, δ18O) patterns in groundwater recharge reveal that short-term land use and climatic changes influence nitrate contamination trends

摘要

Poultry manure is the primary source of nitrate (NO3?) exceedances in the transboundary Abbotsford-Sumas aquifer (Canada-USA) based on synoptic surveys two decades apart, but serious questions remained about seasonal and spatial aspects of agricultural nitrate fluxes to the aquifer to help better focus remediation efforts. We conducted over 700 monthly δ15N and δ18O of nitrate assays, focusing on newly recharged groundwater (