What question did this study set out to answer?

The study aims to evaluate the effectiveness of Ricinus communis L. in remediating zinc and cadmium from contaminated soils using spent mushroom substrate and citric acid.

January 23, 2026

Spent mushroom substrate and citric acid promote the remediation of zinc and cadmium polluted soil by in situ Ricinus communis L . phytoremediation

Key Points

The study aims to evaluate the effectiveness of Ricinus communis L. in remediating zinc and cadmium from contaminated soils using spent mushroom substrate and citric acid.
Field evaluation of Ricinus communis L. for phytoremediation in contaminated soils.
Application of spent mushroom substrate and citric acid to assess their effects on plant biomass and heavy metal extraction.
Statistical analysis was performed using one-way ANOVA with Tukey's HSD to analyze biomass and metal extraction rates.
Total biomass of plants increased significantly to 164.70 g with SMS and 162.80 g with CA+SMS compared to 77.38 g in the control.
Total zinc extraction increased by 114.86% with SMS and 104.89% with CA+SMS; total cadmium extraction increased by 112.80% and 99.22%, respectively.
Cadmium bioconcentration factors remained above 1, while zinc bioconcentration factors were below 0.33.
CA+SMS treatment enhanced soil enzyme activities, notably catalase, up to 1.98 mL 0.1 mol L-1 KMnO4 g-1 h-1.

Abstract

Heavy metal contamination of agricultural soils, particularly by zinc (Zn) and cadmium (Cd), threatens food security and ecosystem health. This study evaluated the in situ phytoremediation potential of Ricinus communis L. in Zn- and Cd-contaminated field soils amended with citric acid (CA), spent mushroom substrate (SMS), and their combination (CA+SMS). Across contamination levels, SMS and CA+SMS significantly increased total biomass to 164.70 ± 5.61 and 162.80 ± 4.11 g per plant, respectively, compared with 77.38 ± 3.40 g in the unamended control (one-way ANOVA with Tukey's HSD, p p 1 across all treatments, whereas Zn BCF remained -1 KMnO4 g-1 h-1). SMS maintained seed oil content (∼ 55.71 ± 1.78%). Overall, R. communis is a high-biomass, metal-tolerant candidate for field phytoremediation, and CA+SMS is a practical, low-cost strategy that enhances plant uptake while promoting metal sequestration into less labile reducible/oxidizable/residual fractions relative to exchangeable/carbonate-bound pools.

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Spent mushroom substrate and citric acid promote the remediation of zinc and cadmium polluted soil by in situ Ricinus communis L . phytoremediation

Key Points

Abstract

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