Which sources contribute more to nitrosamines and their precursors in water resources: The natural or the anthropogenic?

This paper summarizes recent progress in identifying sources of nitrosamines (NAs) and their precursors in water resources. Natural sources include humic substances, microbial and algal metabolites, which will be exacerbated by natural disasters and extreme climate events. Anthropogenic sources include domestic wastewater, industrial wastewater and agricultural wastewater. Natural sources generally contribute a few to dozens of ng/L of precursors but provide minimal NAs, while anthropogenic sources provide a few to hundreds of ng/L of NAs and higher levels of precursors. These insights aid differentiation of natural vs. anthropogenic contributions, providing guidance for pollution control and sustainable management of water resources.