Uptake, accumulation, and degradation of dibutyl phthalate by three wetland plants

Abstract

The uptake and degradation mechanisms of dibutyl phthalate (DBP) by three wetland plants, namely Lythrum salicaria, Thalia dealbata, and Canna indica, were studied using hydroponics. The results revealed that exposure to DBP at 0.5 mg/L had no significant effect on the growth of L. salicaria and C. indica but inhibited the growth of T. dealbata. After 28 days, DBP concentrations in the roots of L. salicaria, T. dealbata, and C. indica were 8.74, 5.67, and 5.46 mg/kg, respectively, compared to 2.03–3.95 mg/kg in stems and leaves. Mono-n-butyl phthalate concentrations in L. salicaria tissues were significantly higher than those in the other two plants at 23.1, 15.0, and 13.6 mg/kg in roots, stems, and leaves, respectively. The roots of L. salicaria also had the highest concentration of phthalic acid, reaching 2.45 mg/kg. Carboxylesterase, polyphenol oxidase, and superoxide dismutase may be the primary enzymes involved in DBP degradation in wetland plants. The activities of these three enzymes exhibited significant changes in plant tissues. The findings suggest L. salicaria as a potent plant for phytoremediation and use in constructed wetlands for the treatment of DBP-contaminated wastewater. HIGHLIGHTS The uptake and degradation mechanisms of DBP by three common wetland plants were investigated by the hydroponic experiment.; The uptake and degradation capacities of DBP were higher in L. salicaria, which could well resist the oxidative damage caused by DBP and degrade it under the effect of enzymes.; L. salicaria can be used as a potential plant for DBP removal in phytoremediation and the constructed wetland.;

Keywords

• dibutyl phthalate
• enzyme activity
• hydroponics
• wetland plant