Abstract
Heavy metal pollution is one of the major global concerns which require urgent attention. Considering this, pot experiments were designed to assess the phyto-extraction ability of Zea mays and Brassica napus plants grown in soils irrigated with municipal wastewater and amended with varying levels of copper, lead and zinc at Faculty of agriculture, Gomal University, Dera Ismail Khan, Pakistan. In this study, four treatments such as tap water, municipal wastewater, 300 mg kg(-1) soil each of Cu, Pb and Zn (medium toxic), and 600 mg kg(-1) soil each of Cu, Pb and Zn (high toxic) were used in completely randomized design with three replications. The salt solutions of Cu (copper sulphate), Pb (lead acetate trihydrate) and Zn (zinc sulphate) were added as post-emergence application to the respective pots. The maize and brassica plants were harvested at 42 days of life, and uptake of heavy metals by shoot and root tissues were analyzed. In addition, the dry matter yield as affected by the various treatments was determined. Maize and brassica plants receiving wastewater accumulated maximum heavy metals and excelled the medium and high toxic solutions of 300 and 600 mg kg(-1) soil of each metal, respectively. Among plant organs, shoots of both Z mays and B. napus in general, accumulated two to four times more heavy metals compared to roots. Maize due to its vigorous growth accumulated two times more heavy metals than brassica. Apart from control, the dry matter yields were maximum in both maize and brassica plants treated with municipal wastewater followed by medium toxic metal solutions. However, high toxic metal solution revealed minimum dry matter yield in both crops. Results suggested that Zea mays and Brassica napus could be used as viable phyto-extractors for heavy metals.