Bioscience Evidence 2024, Vol.14, No.4, 154-160 http://bioscipublisher.com/index.php/be 154 Research Report Open Access Phytoremediation of Soil Contaminated with Lead (Pb) and Zinc (Zn) Using Chromolaena odorata(L.) under Greenhouse Condition O. M. Ajayi , O. Kekere Department of Pant Science and Biotechnology, Adekunle Ajasin University, P.M.B. 01, Akungba-Akoko, Ondo State, Nigeria Co-corresponding emails: otito.kekere@aaua.edu.ng; oluwaferanmiajayi2@gmail.com Bioscience Evidence, 2024, Vol.14, No.4 doi: 10.5376/be.2024.14.0017 Received: 29 Jun., 2024 Accepted: 22 Jul., 2024 Published: 13 Aug., 2024 Copyright © 2024 Ajayi and Kekere, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Ajayi O.M., and Kekere O., 2024, Phytoremediation of soil contaminated with lead (Pb) and zinc (Zn) using Chromolaena odorata (L.) under greenhouse condition, Bioscience Evidence, 14(4): 154-160 (doi: 10.5376/be.2024.14.0017) Abstract Phytoremediation is gaining popularity worldwide for its cost-effectiveness and environmentally friendly approach to removal of heavy metals from soil. This study investigated potential of weed, Chromolaena odorata (L.), in remediating soil contaminated with lead (Pb) and zinc (Zn). The experiment involved growing C. odorata as potted plants in soil with varying concentrations (0-100 mg/kg) of Pb and Zn. The survival of the seedlings was not affected by either heavy metal. Compared to the control, there was no significant effect of Pb on number of leaves at 20-60 mg/kg but significantly increased it at 80-100 mg/kg. Zn significantly reduced number of leaves at all the concentrations applied. Pb did not significantly affect stem girth while Zn led to its significant reduction at 60-100 mg/kg. Pb had no significant effect on leaf area except at 80 mg/kg where there was an increase, while it was not significantly affected by Zn. The metals decreased root length without statistical difference from the control while number of roots was not affected. Fresh and dry weight values of plant parts were higher under contamination than the control. This was significant at 80-100 mg/kg for leaf and stem, and at 80 mg/kg for root. The plant was more tolerant to Pb than Zn in growth. There were significantly higher concentrations of metals in plant parts of those grown in metal contaminated soil than the control. C. odoratais a potential candidate for phytoremediation of soil contaminated with Pb and Zn, and can survive up to 100 mg/kg. Keywords Siam weed; Heavy metals; Soil; Pollution; Remediation 1 Introduction The soil, recognized as a vital ecosystem, assumes critical roles in sustaining life, contributing to food production, climate regulation, and supplying raw materials essential for various human activities (Atagana, 2011; Ayesa et al., 2018). Despite its paramount importance, the integrity of the global soil environment faces formidable challenges due to escalating human activities that induce pollution (FAO, 2015a, http://www.fao.org/3/a-i4324e.pdf; FAO, 2015b, http://www.fao.org/3/a-i4965e.pdf; FAO, 2015c). Soil pollution, arising from the direct or indirect discharge of extraneous substances, poses significant threats to the delicate balance of living resources, human health, and environmental well-being (Masindi and Muedi, 2018). The cumulative impact of industrial and mining activities as well as some agricultural practices exacerbates soil pollution, with heavy metals assuming a predominant role as major culprits in this environmental challenge (EEA, 2014, https://www.eea.europa.eu/data-and-maps/indicators/progress-in-management-of-contaminated-sites/progress-inmanagement-ofcontaminated-1; Cetin, 2016; Sandeep et al., 2019). With the rapid development of economy and society, a variety of heavy metals contaminate soil which threatens the environment and public health (Lambert et al., 2012; Kapoor et al., 2021). Many of such metals including Pb and Zn are widely distributed, and persist long-term in soil environment. Soil contamination by heavy metals leads to decreasing availability of farmland as they negatively affect plant growth as well as crop yield (Yahaghi et al., 2019; Madhu and Sadagopan, 2020; Khan et al., 2023; Rashid et al., 2023). Besides, the metals may be accumulated into edible and non-edible parts of plants. Surveys have shown that continuous consumption of concentrations of heavy metals through foodstuffs lead to large accumulations of the metals in the kidney and liver of humans causing disruption of numerous body processes, leading to cardiovascular, nervous, kidney and bone diseases (Angon et al., 2024). Specifically, taking very high doses of Zn is likely unsafe and might cause stomach pain, vomiting, and many other problems. Single doses of 10-30 grams of zinc can be fatal (Herawati,
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