Decomposition of DNA Staining Agent Ethidium Bromide by Gamma Irradiation: Conditions, Kinetics, By-products, Biological Activity, and Removal from Wastewater

In this study, the removal of Eth-Br from aqueous solutions by gamma irradiation has been fully investigated. Gamma irradiation was capable of achieving a near complete removal of Eth-Br in neutral and non-buffered aqueous solutions at an absorbed dose of 15 kGy. Various experimental conditions were studied and showed that the removal efficiency is not diminished. The addition of hydrogen peroxide (2%) to the irradiated solutions reduced the D50 and D90 by 50%. Modeling Eth-Br decomposition showed that the reaction followed pseudo first-order kinetics and reaches at least 90% removal under all experimental conditions. TOC and HPLC measurements confirmed that Eth-Br is fully mineralized when the absorbed dose reaches 15 kGy. The biological activity of Eth-Br after irradiation treatment was investigated with synthetic DNA and natural DNA. The biological activity of Eth-Br was deactivated at an absorbed dose as low as 5 kGy. Toxicity measurement with E-coli bacteria also confirmed that the absorbed dose of 5 kGy was sufficient to remove Eth-Br toxicity.Graphical abstract
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research