Variation, correlation, and toxicity of phenolic endocrine-disrupting compounds in surface water

This study investigated the variation in toxicity of phenolic endocrine-disrupting compounds (EDCs) and determined the correlation between their concentrations. All twenty-four samples acquired from a polluted river contained five phenolic EDCs. The EDC nonylphenol (NP) concentration was found to be the highest (4.26 +/- 2.74 mu g/L) in the river water. In addition the concentrations of nonylphenol diethoxylate, (NP2EO), octylphenol (OP), nonylphenol monoethoxylate (NP1EO), and bisphenol A (BPA) were 1.58 +/- 1.37 mu g/L; 2.90 +/- 2.77 mu g/L; 2.89 +/- 2.15 mu g/L; and 2.25 +/- 0.96 mu g/L, respectively. Concentrations of NP, NP1EO, and OP were significantly greater in the daytime than in the nighttime samples. Furthermore, concentrations of NP, NP1EO, and NP2EO showed a strong correlation due to similar parent compounds while BPA and OP did not. NP1EO had the highest risk to aquatic organisms (hazard quotient, HQ = 26.3) and BPA the lowest (HQ = 2.24). The accumulative HQ sum (hazard index, HI) was 81.3 within all the samples. The HI was 110.3 in the daytime samples. This was 97% higher than in the nighttime HI (56.3), which suggested daytime anthropogenic discharges were an important source of toxicity to aquatic organisms.