Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
This original research article investigated the synergistic effects of Lavandula angustifolia (lavender) and a four-strain bacterial consortium on the bioremediation of a multi-contaminated soil collected from a former industrial site in Southern Italy. The aim was to assess whether combining plant-assisted remediation and bioaugmentation could more effectively reduce heavy metal contamination (specifically Zn, Sn, and Pb) and enhance soil quality compared to either approach alone. The experimental setup consisted of four microcosm treatments: unplanted and uninoculated control (HCS), planted with lavender (PLANT), bioaugmented with the bacterial consortium (BIOAUG), and a combined treatment (PLANT+BIOAUG). Over 90 days, researchers monitored soil physicochemical properties (pH, electrical conductivity, metal concentrations), plant growth, microbial abundance, and dehydrogenase activity and integrated these metrics using a Soil Quality Index (SQI) to evaluate the overall effectiveness of each remediation strategy. The study directly informs best practices for heavy metal tested and certified (HTMC) programs by providing empirical data on an integrated, sustainable remediation approach.
Who was studied?
The study utilized historically contaminated soil collected from a recognized contaminated site of national interest near Taranto, Southern Italy, affected by emissions from metallurgical and petrochemical industries. The soil displayed elevated levels of Zn, Sn, and Pb, exceeding Italian regulatory limits. The biological components included uniform Lavandula angustifolia plants sourced from a commercial nursery and a bacterial consortium comprised of Gordonia amicalis, Rhodococcus erythropolis, Acinetobacter puyangensis, and Acinetobacter tibetensis—strains selected for their heavy metal tolerance and bioremediation capacity. Each microcosm treatment was replicated, and all experiments were performed under controlled environmental conditions to ensure reproducibility and to reflect real-world contamination scenarios relevant to industrial and regulatory stakeholders.
Most important findings
| Critical Points | Details |
|---|---|
| Reduction of heavy metals | The combined PLANT+BIOAUG treatment achieved significant reductions in total lead (Pb) and tin (Sn) concentrations—44.7% and 66.9% respectively—over 90 days. Zinc (Zn) levels did not decrease significantly in any treatment. |
| Soil quality improvement | The Soil Quality Index (SQI) was highest in the PLANT+BIOAUG treatment (0.73), demonstrating a substantial enhancement in overall soil quality, integrating improvements in pH, microbial abundance, and metal reduction. |
| Microbial abundance | Microbial abundance increased significantly in the presence of lavender, especially in the PLANT+BIOAUG treatment, supporting the survival and proliferation of both the natural and inoculated microbial communities. |
| Dehydrogenase activity | The highest dehydrogenase activity (a marker of microbial metabolic activity) was observed in the PLANT treatment, indicating that lavender roots stimulate the indigenous microbial community more than when combined with bioaugmentation. |
| Plant uptake and metal stabilization | Metal accumulation was observed primarily in plant roots, with low translocation to leaves, reducing the risk of contaminants entering the food chain via aboveground biomass. This trait is especially relevant for HTMC certification. |
| Statistical validation | Multivariate analyses (PCA and PERMANOVA) confirmed that chemical and biological improvements were significantly associated with the combined plant-microbe treatment, reinforcing the robustness of the integrated approach. |
Key implications
The study demonstrates that integrating Lavandula angustifolia with a specialized bacterial consortium offers a scalable, eco-friendly strategy for heavy metal remediation in contaminated soils. This combined approach not only enhances the reduction of key toxic metals but also improves soil health, supports microbial diversity, and minimizes contaminant transfer to aboveground plant parts, directly aligning with the requirements of heavy metal tested and certified (HTMC) programs.
Citation
Cavone C, Rutigliano A, Cotugno P, Rolando L, De Carolis C, Barra Caracciolo A, Grenni P, Savino I, Bucci A, Naclerio G, et al. Synergistic Effects of Lavandula angustifolia and a Bacterial Consortium on Bioremediation of a Heavy Metal-Contaminated Soil. Plants. 2025;14:2734. doi:10.3390/plants14172734
Heavy metals are high-density elements that accumulate in the body and environment, disrupting biological processes. Lead, cadmium, arsenic, mercury, nickel, tin, aluminum, and chromium are of greatest concern due to persistence, bioaccumulation, and health risks, making them central to the HMTC program’s safety standards.
