Tag Archives: Melanie Kah

Effects of soil contamination could be blunted with nanonutrients

An October 15, 2024 news item on phys.org highlights research into soil remediation, Note: A link has been removed,

One of the pressing problems that the world faces in the era of climate change is how to grow enough healthy food to meet the increasing global population, even as soil contamination rises. Research recently published in Nature Food by an international team of scientists led by the University of Massachusetts Amherst, Guangdong University of Technology, and Central South University of Forestry and Technology, has shown that nutrients on the nanometer scale can not only blunt some of the worst effects of heavy metal and metalloid contamination, but increase crop yields and nutrient content.

Caption: Nanomaterials can enter plants through above-ground tissues and root tissues. Soil rhizosphere microorganisms, soil particles, organic matter and rhizosphere deposits can also influence NM uptake in plants. Credit: 10.1038/s43016-024-01063-1 Courtesy of University of Massachusetts Amherst

An October 15, 2024 University of Massachusetts Amherst news release (also on EurekAlert), which originated the news item, describes the problem and the proposed solution, Note: Links have been removed,

“Much of the world’s arable soil is contaminated by heavy metals, like cadmium, lead and mercury, as well as metalloids, like arsenic and selenium,” says Baoshan Xing, University Distinguished Professor and director of the Stockbridge School of Agriculture at UMass Amherst. Xing, who is also the paper’s senior author, notes that such contamination puts severe stress on the ability to grow staple crops, which also affects the nutritional value of the crops that manage to survive. “We need to come up with solutions to reduce the heavy metals that wind up in our food,” says Xing, and one approach that has shown promise is the use of nutrients at nanoscale, or what he calls a “nano-enabled” agriculture.


The bulk fertilizers that you may be more familiar with are made up of large particles, which aren’t as readily absorbed by the crop. This means that farmers need to apply more, which then increases the levels of fertilizer runoff into streams, lakes and the ocean. However, crop nutrients at the nanometer scale can be specifically designed and mixed for particular crops, growing conditions and application methods, and engineered so that the target plant can most efficiently absorb the nutrients into its system, cutting down on the amount of fertilizer needed, keeping costs down and limiting runoff.

Though nanomaterials are already available on the agricultural market and have plenty of peer-reviewed science looking at their effect on the soil and crop growth, Xing and his colleagues’ research is the first comprehensive account of the effectiveness of nanomaterials as a class, with results that offer practical insights to help steer sustainable agriculture and global food safety.

“We collected data from 170 previous publications on the effectiveness of nanoparticles in reducing heavy metal and metalloid uptake,” says Chuanxin Ma, the paper’s co-lead author who completed his doctoral training at UMass Amherst’s Stockbridge School of Agriculture and is now a professor at China’s Guangdong University of Technology. “From those 170 papers, we collected 8,585 experimental observations of how plants respond to nanomaterials.”

The team then conducted a meta-analysis on this enormous trove of data, running it through a series of machine-learning models to quantify the effect of nanomaterials on crop growth and metal and metalloid uptake, before finally testing a flexible quantitative approach, known as the “IVIF-TOPSIS-EW method,” that can illuminate how to choose different types of nanomaterials according to a range of realistic agricultural scenarios.

The results show that nanomaterials are more effective than conventional fertilizers at mitigating the harmful effects of polluted soil (by 38.3%), can enhance crop yields (by 22.8%) and the nutritional value of those crops (by 30%), as well as combat plant stress (by 21.6%) due to metal and metalloid pollution. Nanomaterials also help increase soil enzymes and organic carbon, both of which help drive soil fertility.

“Of course, nanomaterials are not a silver bullet,” explains Xing. “They need to be applied in distinct ways based on the individual crop and soil.” Which is where the team’s IVIF-TOPSIS-EW method comes into play. “Our method can help policy makers choose the best course of action for their particular situation,” says Ma.

Yini Cao from Central South University of Forestry and Technology also contributed greatly to collecting and analyzing the data in this work.

This research was supported by the National Natural Science Foundation of China and the United States National Institute of Food and Agriculture (USDA).

Here’s a link to and a citation for the paper,

Engineered nanomaterials reduce metal(loid) accumulation and enhance staple food production for sustainable agriculture by Yini Cao, Chuanxin Ma, Jason C. White, Yuchi Cao, Fan Zhang, Ran Tong, Hao Yu, Yi Hao, Wende Yan, Melanie Kah & Baoshan Xing. Nature Food volume 5, pages 951–962 (2024) DOI: https://doi.org/10.1038/s43016-024-01063-1 Published: 11 October 2024 Issue Date: November 2024

This paper is behind a paywall.

Nano-pesticides or nanopesticides or nano pesticides

It’s the spelling that’s driving me nuts. In the last year it seems to have gotten quite higgledy piggledy and so we have this salad of one word, two words, and hyphenated words for anything  prepended by nano.  I hope it settles soon but in the meantime, here’s an Aug. 12, 2013 news item on Azonano concerning nano-pesticides,

Research is urgently needed to evaluate the risks and benefits of nano-pesticides to human and environmental health. Melanie Kah and Thilo Hofmann from the Department of Environmental Geosciences of the University of Vienna recently performed an extensive analysis of this emerging field of research.

The results were published June 6th in the internationally recognised journal “Critical Reviews in Environmental Science and Technology”. The study presents the current scientific state of art on nano-pesticides and identifies direction priorities for future research.

The University of Vienna June 20, 2012  press release, which originated the news item (I’ll explain the one year gap later in this posting), describes some of the concerns raised in the study,

Nano-pesticides encompass a great variety of products, some of which are already on the market. The application of nano-pesticides would be the only intentional diffuse input of large quantities of engineered nano-particles into the environment. Innovation always results in both drawbacks and benefits for human and environmental health. Nano-pesticides may reduce environmental contamination through the reduction in pesticide application rates and reduced losses. However, nano-pesticides may also create new kinds of contamination of soils and waterways due to enhanced transport, longer persistence and higher toxicity.

The current level of knowledge does not allow a fair assessment of the advantages and disadvantages that will result from the use of nano-pesticides. As a prerequisite for such assessment, a better understanding of the fate and effect of nano-pesticides after their application is required. The suitability of current regulations should also be analyzed so that refinements can be implemented if needed. Research on nano-pesticides is therefore a priority for preserving the quality of both the food chain and the environment.

Here’s a link to and a citation for the paper,

Nano-pesticides: state of knowledge, environmental fate and exposure modeling: Melanie Kah, Sabine Beulke, Karen Tiede and Thilo Hofmann. Critical Reviews of Environmental Science and Technology, Volume 43, Issue 16, 2013 , pages 1823-1867 DOI: 10.1080/10643389.2012.671750

http://www.tandfonline.com/doi/abs/10.1080/10643389.2012.671750

There was a 2012 version of this paper posted, which was when the press release was originally written and posted at the University of Vienna website, but June 2013 is when the paper was officially published. It is behind a paywall but thankfully one of the authors, Melanie Kah, gave Katy Edgington an interview about the study for Edgington’s June 26, 2012 article on scienceomega.com,

“Although some research is ongoing, one application that is fairly well-developed involves the injection of nanoscale zero-valent iron particles into groundwater to degrade certain contaminants. This is an example of something that is still under development but which is already being applied, as the technique is currently in use on a large scale in the United States.” [says Kah]

A project is underway in the department which aims to help make the technique more widely applicable, and another – at the complete opposite end of the scale in terms of its development – is looking at a potential application for carbon nanotubes.

“People have suggested that carbon nanotubes could be used to replace activated carbon, the material used worldwide to decontaminate water,” clarified Dr Kah. “It is suggested that carbon nanotubes have different properties which will complement activated carbon, but this is only at the laboratory scale so far.”

It is important to steer clear of making broad generalisations about the risks and benefits of nanopesticides as compared to conventional pesticides, Dr Kah emphasised. They cannot be considered as a single entity; rather each case must be taken on its own merits.

In their review of the literature on the topic, the authors also discuss how the adequacy of existing legislation and regulation may be affected in light of the development of nanopesticides in various forms.

“I think it is far too early to propose any amendments to the current regulation,” Dr Kah stated. “It appears from our analysis that a lot of nanopesticides would be well covered by the European regulation on plant protection products because this regulation is very thorough; indeed it is probably the strictest in the world.”

I imagine that since the initial publication of the paper and the interview, there may have been a few changes to the paper and refinements to Kah’s ideas but the Edgington article does provides some interesting insight, especially if you don’t have access to the paper.