Nonylphenol ethoxylates and their metabolites in sewage treatment plants and rivers of Tianjin, China

Nonylphenol polyethoxylates (NPnEO) and nonylphenol (NP) have provoked much environmental concern because of their weak estrogenic activities. We monitored NPnEO and their metabolites in rivers in Tianjin and in a sewage treatment plant of Tianjin monthly for 1 year. The total concentrations of NPnEO and NP in influent, up to 47.2 μg L−1 in August, were higher in summer than in other seasons. During the 12 months survey, NP was accumulated in most effluent samples with a mean value of 2.92 μg L−1. The average concentrations of nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO) and nonylphenol triethoxylate (NP3EO) in effluents were 1.26, 1.53 and 1.06 μg L−1, which corresponds to percent removals of 75%, 60% and 62%, respectively. In rivers of Tianjin, NP2EO and nonylphenoxyethoxy acetic acid (NP2EC) exhibited the highest concentrations in the surface water, up to 1.38 and 9.59 μg L−1, respectively. The pollution of nonylphenolic substances in sediments of Haihe River belongs to moderate or severe level in the world, with the total concentration between 4.1 and 9.9 μg g−1, dry weight.