Identifying the sources of nitrate contamination of groundwater in an agricultural area (Haean basin, Korea) using isotope and microbial community analyses

摘要: Abstract An integrated study based on hydrogeochemical, microbiological and dual isotopic approaches for nitrate sulfate was conducted to elucidate sources biogeochemical reactions governing groundwater contaminants in different seasons under land use a basin of Korea. The the area is comprised forests (58.0%), vegetable fields (27.6%), rice paddy (11.4%) others (3.0%). concentrations NO3–N SO42 − were highest with 4.2–15.2 mg L− 1 1.6–19.7 mg L− 1 respectively, whereas ranged from 0 10.7 mg L− 1 ~ 15 mg L− 1. Groundwater high > 10 mg L− 1 had δ15N–NO3− values ranging 5.2 5.9‰ δ18O between 2.7 4.6‰ suggesting that mineralized soil organic matter amended by fertilizer additions. Elevated δ34S–SO42 − 1 6‰ aquifers indicated mixture atmospheric deposition, mineralization synthetic fertilizers source sulfate. δ18O–NO3− δ18O–SO42 − samples collected denitrification bacterial reduction are actively occurring removing groundwater. This supported occurrences denitrifying reducing bacteria as evidenced 16S rRNA pyrosequencing analysis. shows isotope techniques combined microbial data can be powerful tool identification processes affecting NO3− areas intensive agricultural use.