Screening of organic chemicals in surface water of the North River by high resolution mass spectrometry

Wide use of various chemicals has resulted in water pollution, which has become a global environmental concern. So far limited information is available on what chemicals in our water. Here we investigated the occurrence and profiles of organic chemicals in the North River, South China by applying non-target screening analysis with high resolution mass spectrometry. A total of 402 organic chemicals belonging to eleven categories were identified in the North River, with notable presence of industrial chemicals, pharmaceuticals and pesticides. Among these detected chemicals, over half of the tentatively identified compounds were rarely reported in the surface water, with a few compounds, e.g., sisomicin, simeton, 2-methyl-4,6-dinitrophenol, xanthurenic acid and indole-3-carboxylic acid that have never been documented in the North River before, while the metabolites like 4-acetamidoantipyrine were also observed. The maximum concentration of the identified chemicals in the North River was above 300 ng/L (Sulfamonomethoxine). Principle component analysis results of the obtained dataset showed significant seasonal distribution, which could be linked to variations in wastewater discharge, river dilution and anthropogenic activities such as pesticide spray. Agricultural activities in the upper reaches led to detection of various pesticides in the river basin, especially in the wet season. The findings from this study demonstrated the widespread presence of chemicals in our waterway, and further retrospective analysis would reveal more information about chemicals of emerging concern.