Host: The Japanese Society of Toxicology
The discharge of industrial wastewater in the Bohai Bay area causes potential pollution to the Bohai Sea. To evaluate the pollution of polycyclic aromatic hydrocarbons (PAH), sludge samples were collected from a factory in Bohai Bay, and samples were extracted by ethanol for biological monitoring and chemical detection. The zebrafish embryos/larvae were exposed to sludge extract samples (SE) and PHAs (fluorene, phenanthrene, and pyrene), which used as positive controls from 4 hours post-fertilization (hpf) until observations. Similar to PAHs, SE increased the mortality and inhibited the hatching rate of zebrafish embryos/larvae at 72 hpf (P < 0.05). Interestingly, we also found that SE caused a dose-dependent inhibition of pigmentation intensity in zebrafish eyes at 36 hpf (P < 0.05). TPO, Dio2, and Thrβ mRNA expression were down-regulated and Dio3 mRNA was induced by SE at 120 hpf. The results of chemical analysis showed that the main pollutants were fluorene, phenanthrene, fluoranthene, pyrene, and other PAHs, which were consistent with biological assessment methods. The above results suggest that the pigment intensity of zebrafish eyes can also be used as an initial biological assessment of PAH pollution in Bohai bay.
