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Zeolites improve crop growth in soil contaminated by industrial waste and heavy metals

Daviid Williams

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Soils that have been contaminated with heavy metals are not optimal for pretty much any kind of crop. However, a new study revealed that making one simple change could turn things around. Researchers from the Agricultural University of Tirana have discovered that the simple addition of natural zeolite can serve as an effective method for the remediation of heavy metal-contaminated soils. They found different rates of changes depending on the rates of zeolite, but overall it appeared that the results were mostly positive. They have published the details of their research in the Albanian Journal of Agricultural Sciences.

Soils that have been exposed to and contaminated with heavy metals can give rise to similarly contaminated plants. As such, these types of soils pose a great threat to human health. Typical cases of heavy metal contamination are seen as dangerous for the higher risk of exposure to materials such as arsenic, cadmium, lead, and mercury. Based on many previous studies, these kinds of heavy metals have a number of adverse effects on human health, so they need to be avoided at all costs.

In most cases, the best way to avoid the negative effects of soils that have been contaminated with heavy metals is by opting to grow your own crops on your own land. Land which contains soils that you control and that which you can monitor for possible heavy metal contamination. Of course, that’s not always a possible course of action. So what’s the next best thing that you can do? Soil remediation comes to mind.

Although there are a number of known methods of remediation for contaminated or unhealthy soil, the researchers tried to test the efficacy of adding natural zeolites in particular to see if it had any effect, whether it be positive or negative. What they found after gathering their data for analysis is that zeolites can improve the condition of soils, to the point that plants even grow a little bit further than they’re expected to.

In case you aren’t familiar with them, zeolites are a large group of land-based minerals that can be described as microporous, and officially consisting of hydrated aluminosilicates of barium, calcium, potassium, and sodium. They are commonly found as secondary minerals in cavities in basic volcanic rocks, and are often used as commercially available adsorbents and catalysts.

This particular research study focused on the growth of ryegrass (Lolium multiflorum L.) based on varying rates of zeolite in heavy metal-contaminated soils. According to the researchers, they found the lowest germination performance in the sample of soil with the highest zeolite application rate of 10 percent, which could be due to the effect of zeolite on electrical conductivity of the experimental soil. It also resulted in a significant increase of plant height in the second cutting for that particular batch.

Meanwhile, plant root and shoot dry weight also increased based on the amount of zeolite application, going up as the rate went higher through the following rates: 0, 1.25, 2.5, 5, and 10.

Due to the results of the experiments, the researchers concluded that the application of zeolite can be an effective plant growth regulator in soils that have been contaminated with heavy metals. What’s interesting is that zeolites have been found to contain certain heavy metals themselves. All zeolites contain lead, and they are largely made of inorganic aluminum. This research shows that while zeolites may be questionable when ingested, they can offer a number of environmental that shouldn’t be ignored or overlooked. All they need is proper application in order to be effective.

Read more on the latest ways of soil remediation in

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