Monitoring of 1300 organic micro-pollutants in surface waters from Tianjin, North China

• First systematic investigation of 1300 chemicals in surface waters, China.
• 227 Organic micro-pollutants were found.
• Benzothiazoles, 2-naphthol and metformin were detected with high concentrations.
• Principal components analysis identified 4 factors for contamination origin.
• This comprehensive analytical method is a useful tool for environmental survey.

In spite of the quantities and species of chemicals dramatically increased with rapid economic growth in China in the last decade, the focus of environmental research was mainly on limited number of priority pollutants. Therefore, to elucidate environmental pollution by organic micro-pollutants, this work was conducted as the first systematic survey on the occurrence of 1300 substances in 20 surface water samples of Tianjin, North China, selected as a representative area of China. The results showed the presence of 227 chemicals. The most relevant compounds in terms of frequency of detection and median concentration were bis(2-ethylhexyl) phthalate (100%; 0.26 μg L−1), siduron (100%; 0.20 μg L−1), lidocaine (100%; 96 ng L−1), antipyrine (100%; 76 ng L−1), caffeine (95%; 0.28 μg L−1), cotinine (95%; 0.20 μg L−1), phenanthrene (95%; 0.17 μg L−1), metformin (90%; 0.61 μg L−1), diethyl phthalate (90%; 0.19 μg L−1), quinoxaline-2-carboxylic acid (90%; 0.14 μg L−1), 2-(methylthio)-benzothiazole (85%; 0.11 μg L−1) and anthraquinone (85%; 54 ng L−1). Cluster analysis discriminated three highly polluted sites from others based on data similarity. Principle component analysis identified four factors, corresponding to industrial wastewater, domestic discharge, tire production and atmospheric deposition, accounting for 78% of the total variance in the water monitoring data set. This work provides a wide reconnaissance on broad spectrum of organic micro-contaminants in surface waters in China, which indicates that the aquatic environment in China has been polluted by a large number of chemicals.