Using Modified Minerals to Clean Soil and Boost Marigold Metal Uptake

Greg Howard
4th May, 2024

Using Modified Minerals to Clean Soil and Boost Marigold Metal Uptake

Pot marigold (Calendula officinalis)

Photographer: Sonia Parsons

Key Findings

  • Researchers at the University of Zanjan found that modified diatomite reduces heavy metal uptake by plants
  • Using 10% modified diatomite decreased lead and copper in plants by 91%, chromium by 78%, and nickel by 79%
  • Modified diatomite also boosted soil nutrients, improving plant growth and health
The contamination of soil with heavy metals is a critical environmental issue that threatens ecosystems and human health. Heavy metals such as lead (Pb), zinc (Zn), chromium (Cr), nickel (Ni), and copper (Cu) often enter the soil through industrial activities and can be harmful if they enter the food chain. To address this problem, researchers have been exploring various methods for removing or stabilizing these toxic elements in soils. A recent study conducted by the University of Zanjan[1] has made significant strides in this field by utilizing modified diatomite, a naturally occurring compound, in conjunction with the cultivation of Calendula officinalis, a plant known for its ability to accumulate heavy metals. The study aimed to assess the effectiveness of modified diatomite in reducing the bioavailability of heavy metals in soil, thereby preventing their uptake by plants. Diatomite, a sedimentary rock composed of the fossilized remains of diatoms, has been previously modified to enhance its ability to immobilize potential toxic elements (PTEs)[2]. The modification process increases the electronegativity, surface area, and pore volume of diatomite, which in turn improves its capacity to bind with heavy metals. In this study, researchers applied varying concentrations of modified diatomite to contaminated soils and monitored the levels of heavy metals in both the soils and the tissues of Calendula officinalis grown in these soils. The results were promising, showing a significant reduction in the bioaccumulation of heavy metals, except for Zn, in the treated soils. Specifically, using 10% modified diatomite led to a 91% decrease in Pb and Cu, 78% in Cr, and 79% in Ni concentration in the plants compared to the control group. Interestingly, the study also found that the application of modified diatomite improved the nutrient profile of the soil. This was evidenced by an increase in the uptake of key nutrients like phosphorus (P) and potassium (K) in the plants. These enhancements in soil fertility correlated with improved growth characteristics of Calendula officinalis, including increased shoot and root height as well as fresh and dry weight of the shoots. The findings from the University of Zanjan's research align with earlier studies that have demonstrated the potential of natural and modified inorganic compounds in soil remediation. For instance, a study[3] highlighted the effectiveness of phytoremediation, where plants are used to harvest heavy metals from soils. The current research takes this a step further by combining phytoremediation with an advanced soil amendment technique, thereby potentially overcoming some of the limitations of traditional phytoremediation methods. Another related study[4] investigated the use of vermiculite, a clay mineral, to reduce the uptake of metal pollutants by plants. The addition of vermiculite to contaminated soils was found to significantly reduce the bioavailability of metals to plants like lettuce and spinach. The current study's use of modified diatomite could be seen as an extension of this approach, providing an alternative amendment that can stabilize heavy metals in soils. In conclusion, the study from the University of Zanjan presents a compelling case for the use of modified diatomite as a soil amendment to stabilize heavy metals and improve soil health. By reducing the bioavailability of heavy metals and enhancing nutrient uptake, this method offers a dual benefit to both the environment and agriculture. These findings contribute to the growing body of research on sustainable and cost-effective solutions for remediating contaminated soils, with the potential to significantly impact ecological restoration and sustainable agricultural practices in areas affected by industrial pollution.

AgricultureEnvironmentPlant Science

References

Main Study

1) Modified diatomite for soil remediation and its implications for heavy metal absorption in Calendula officinalis.

Published 3rd May, 2024

https://doi.org/10.1186/s12870-024-05068-7

Related Studies

2) Modified natural diatomite and its enhanced immobilization of lead, copper and cadmium in simulated contaminated soils.

https://doi.org/10.1016/j.jhazmat.2015.02.052

3) Phytoremediation strategies for soils contaminated with heavy metals: Modifications and future perspectives.

https://doi.org/10.1016/j.chemosphere.2016.12.116

4) Accumulation of heavy metals from contaminated soil to plants and evaluation of soil remediation by vermiculite.

https://doi.org/10.1016/j.chemosphere.2010.10.028


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