Phytoremediation potential of sunn hemp for carbaryl-contaminated soil

Abstract

Phytoremediation of pesticide residue has been an efficient method for the removal of soil contaminants. This research examined the ability of sunn hemp to remove carbaryl residue in carbaryl-contaminated soil from the field. The sunn hemp plants were grown in soil contaminated with carbaryl that had been spiked at 73.5 and 147.25 mg/kg for 0, 4, 8, and 12 days. The results showed that in a soil pot system, sunn hemp could significantly increase shoot length (1.9-fold) and leaf number (1.9-fold) at a carbaryl concentration of 147.25 and 73.5 mg/kg, respectively, from day 4 to day 12 of cultivation. Although the plant could grow, carbaryl toxicity caused a significant decrease in the total chlorophyll (2.8-fold) and carotenoid (3.5-fold) contents when exposed to the high carbaryl concentration of 147.25 mg/kg from day 4 to day 12 of cultivation. Notably, carbaryl removal in the soil containing carbaryl at 73.5 and 147.25 mg/kg achieved residual levels of 0.0–3.8 mg/kg in the soil containing sunn hemp after cultivation for 4, 8, and 12 days. Carbaryl could be accumulated in the leaves (0.00–0.30 mg/kg) and roots (0.12–4.44 mg/kg) of sunn hemp grown in contaminated soil after 12 days of cultivation. Carbaryl could be degraded to 1-naphthol in the soil and plant. The results confirmed that sunn hemp could enhance carbaryl removal from contaminated soil based on phytoaccumulation and possible phytodegradation abilities.