HP9 Environmental Assessment, Environmental Toxicology
D137-140
1:20 PM - 5:20 PM, Thursday
() Comparing photo-induced cytotoxicity and genotoxicity of 6-aminochrysene and 5,6-chrysene-quinone.
Hwang, H.-M.1, Zhang, Y.1, Zeng, K.1, 1 Jackson State University, Jackson, Mississippi, U.S.A.
ABSTRACT- Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic environmental pollutants. Chrysene is one of the basic PAHs. The photoproduct mixture of 6-aminochrysene (6AC) was complex and its speciation was not reported. We hypothesize that 6AC becomes less toxic after photo-transformation. In this study, liquid chromatography coupled with mass spectrometer detector (LC-MS) was used to separate and identify the photoproduct mixture of 6AC. The main 6AC photoproducts identified include 5,6-chrysene-quinone (5,6-CQ) along with some minor products. The photo-induced cytotoxicity of 6AC and 5,6-CQ to heterotrophic bacteria in river water samples was assessed with spread plate method. In the presence or absence of UVA irradiation, cytotoxicity and genotoxicity of 6AC and 5,6-CQ to human skin cell line, HaCaT, were measured with FDA test and Comet Assay. Compared to the control, the bacteria viable count in river water samples treated with 6AC or 5,6-CQ were inhibited by 82% and 68% respectively after exposure to solar irradiation for 36 minutes. FDA test showed that HaCaT cell viability was decreased dose-dependently after exposure to UVA irradiation in both 6AC and 5,6-CQ groups with 6AC group having lower cell viability, indicating 5,6-CQ was less toxic. Comet assay showed that extent of DNA damage was dose-dependent after the combined UVA irradiation and 6AC treatment, while there was no detectable DNA damage in the 6AC group without UVA irradiation. In addition, no DNA damage was found in the 5,6-CQ groups with or without UVA exposure. Since natural bacteria assemblages and human skin cells were subjected to cytotoxicity and genotoxicity of 6AC under the test condition, the photo-induced toxicity of 6AC could significantly affect human health and cause adverse impact on biogeochemical cycling of organic contaminants. This research was supported by (1) NIH-SCORE S06GM08047 (to JSU) and (2) U.S. Department of the Army #DAAD 19-01-1-0733 (to JSU).
Key words: cytotoxicity, photo-induced, genotoxicity, 6-aminochrysene