Bioremediation for Sustainable Soil Health: Harnessing Phytochemicals for Remediation of Agrochemicals and Heavy Metal Contamination in Soil

Abstract

Background: Soil functions as a major sink for environmental pollutants, particularly heavy metals and agrochemicals released through agricultural and industrial activities. Recent research highlights the potential of plants, through their phytochemical constituents, to remediate contaminated soils. This study evaluated the remediation efficacy of crude methanolic extracts from Sida acuta, Senna alata, and Sacosephallous latifolius on soils contaminated with heavy metals and agrochemicals. Methods: Soil samples were artificially spiked with arsenic (As), cadmium (Cd), lead (Pb), zinc (Zn), and five agrochemicals (Cypermethrin, Terminator, DD-Force, Furan, and Rido). Crude extracts were prepared via maceration and methanolic fractionalization and applied to the contaminated soils. Heavy metal concentrations were determined using atomic absorption spectrometry (AAS), while agrochemical residues were analyzed using gas chromatography-mass spectrometry (GC-MS). Results: Heavy metal remediation (% reduction) followed distinct trends: Cd > As > Zn > Pb (S. acuta), Zn > Pb > Cd > As (S. alata), and Pb > Zn > As > Cd (S. latifolius). A total of 21 agrochemical compounds were detected, with 1,1'-biphenyl, 2,2',4 showing the highest concentration (38.06 mg/mL) from Terminator agrochemicals. All plants achieved bioaccumulation factor (BAF) values <1 for most metals, except for As (at 40 ppm) and Zn (at 10 ppm) in S. latifolius, where BAF >1. Additionally, three key agrochemical compounds showed notable concentration reductions following treatment with S. acuta and S. alata extracts. Conclusion: The findings demonstrated that the phytochemical-rich extracts of Sida acuta, Senna alata, and Sacosephallous latifolius hold strong potential for phytoremediation of heavy metals and persistent organic pollutants (POPs) in contaminated soils, supporting their use in sustainable soil recovery and environmental management strategies.