Toxicological risks of Acid Bordeaux B on duckweed and the plant potential for effective remediation of dye-polluted waters.

In the present study, the ability of duckweed (Lemna minor L.) in the decolorization of Acid Bordeaux B (ABB), as an aminoazo benzene dye, from polluted waters was evaluated. It was found that the rise of temperature and enhancement of the plant initial weight led to increasing the dye removal efficiency, but raising the initial dye concentration and pH reduced it. However, in the optimum conditions, the plant exhibited a considerable potential for the phytoremediation of ABB by 94%. The comparison of the experimental dye removal efficiency with its predicted amounts from ANN (R2 = 0.99) showed that ANN supplied the appropriate predictive performance. Inhibition of the plant growth and reduction of the chlorophyll (Chl) a, b, and a+b content (around 26%, 32.4%, and 28.6%, respectively) after plant treatment with 40 mg/L of ABB confirmed its toxic effects on the plant in high concentrations. Antioxidant enzyme activities and contents of malondialdehyde, phenol, and flavonoids were also raised by the augmentation of the ABB concentration. As a result of the ABB biodegradation pathway, seven intermediate compounds were identified using GC-MS analysis.