Paper Contents
Abstract
Heavy metal contamination of agricultural land is detrimental to food safety, ecosystem and human health. This study assessed the impact of heavy metal contamination on phenological parameters of lettuce (Lactuca sativa) and amaranthus (Amaranthusviridis) under greenhouse condition. Plants were grown in soil contaminated with varying concentrations (10, 20 and 30 mgkg) of lead (Pb), Copper (Cu), and Nickel (Ni). Completely randomized design with three replicates was used for the experiment. The phenological parameters (leaf number, plant height, leaf length, and stem diameter) were measured at 3 days, 2 weeks, and 3 weeks after sowing. The results revealed that heavy metal exposure significantly (P5%) affected the phenological traits of both plant species. Amaranthus recording the highest leaf number under Pb (9.331.53 at 30 mgkg) followed by Cu (8.002.00cm at 20 mgkg 2WAS) while the least (2.001.10cm) was found with Cu also at 10 mgkg, 3DAS. The highest (6.330.58cm) and least (2.200.26cm) plant height for lettuce were recorded Ni and Cu (30 and 10mgk) at 3WAS and 3DAS respectively. Stem diameter was highest under Ni (5.671.15 cm) with Amaranthus at 30mgkg and lowest (1.270.46cm) in Lettuce at 10mgkg at 3WAS and 3DAS respectively, as compared to the control.The findings suggest that low-moderate heavy metal concentrations possessed the growth and developmental effects on the plants examined.Key words: Lead, Nickel, Phenological parameters, Lettuce, Amaranths, and Heavy metals1.0 INTRODUCTIONSoil contamination by heavy metals has emerged as a critical environmental issue due to rapid industrialization, urban expansion, and the intensive use of agrochemicals (Khan et al., 2015). These pollutants such as lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu), and chromium (Cr) are not biodegradable and tend to persist in the environment, posing serious threats to food safety, soil health, and human well being (Alloway, 2013; Khan et al., 2015). Heavy metal pollution has emerged due to anthropogenic activity which is the prime cause of pollution, primarily due to mining the metal, smelting, foundries, and other industries that are metal-based, leaching of metals from different sources such as landfills, waste dumps, excretion, livestock and chicken manure, runoffs, automobiles and roadwork (Ranald, 2021).Metals such as lead (Pb), copper (Cu), and nickel (Ni) are persistent, non-biodegradable, and toxic when accumulated in food crops, posing risks to human health (Alloway, 2013).Conventional remediation methods, including excavation and chemical treatments, are often costly and ecologically disruptive, prompting interest in more sustainable alternatives such as phytoremediation (Khan et al., 2015). Phytoremediationthe use of plants to remove or stabilize contaminantsoffers a sustainable alternative to costly conventional remediation approaches (Ali et al., 2013). Leafy vegetables such as lettuce (Lactuca sativa) and amaranthus (Amaranthus viridis) are promising phytoremediators because of their rapid growth, high biomass, and reported ability to accumulate heavy metals (Cui et al., 2004; Muchuweti et al., 2006). However, comparative data on their growth responses under Pb, Cu, and Ni stress remain limited, particularly in Nigeria. This study thus, assessed the effects of Cu, Pb, and Ni on the phenological traits of lettuce and amaranthus under greenhouse conditions to determine their phytoremediation potential.
Copyright
Copyright © 2025 Mustapha Abubakar. This is an open access article distributed under the Creative Commons Attribution License.
