Effects of Malachite Green Contaminated Water on Production of Pak Choy and Chinese Convolvulus

Malachite green is used in industries and aquaculture and disposed in the effluents. In this study, effects of malachite green on growth of Brassica chinensis and Ipomoea aquatica were studied in order to evaluate possibility of using dye-contaminated wastewater for irrigation. Seedlings of the plants were grown in growing material and watered with tap water containing malachite green at the concentrations of 0 (control), 1, 2, 10, and 20 mg/L for 21 days. At harvest, number of leaf and shoot and root dry weight of all plants were measured. For both species, biomass values of treated plants were similar to the control (dry weight were 0.6-1.0 and 1.1-1.7 g/plant for B. chinensis and I. aquatica, respectively) and B. chinensis was more sensitive to contaminant compared to I. aquatica. There was no sign of MG and leucomalachite green detected in root and shoot tissues of plants treated with MG at 20 mg/L, tested by TLC. After plant harvest, toxicity of the growing material was tested on mung beans. Percent germination (83-97%), seedling fresh weight (0.3-0.5 g/plant), and shoot length (11-12.5 cm) were similar to the control indicating that contaminant in growing material did not pose detrimental effect on mung beans. Based on these results, the water contaminated with low concentration of MG may serve as fertirrigation water to compensate water shortage. 