Abstract
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 μg/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 μg/L; 2.90 ± 2.77 μg/L; 2.89 ± 2.15 μg/L; and 2.25 ± 0.96 μg/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.
Acknowledgment
This research was supported by the National Science Council, Taiwan, and grant number NSC95-2211-E-020-026.
Notes
∗Standard deviation.
∗LN: Lognormal distribution (mean, standard deviation), shift indicate mean value shift from zero for optimal fitting.
∗∗N: Normal distribution (mean, standard deviation).