NANOTECHNOLOGY: Food and Pesticides
Albert Jefferson
Hosea Immanuel
Derek Lee
Introduction
Nanomaterials have always been in food naturally. Natural processes used to
make cheese, produce nano-scale particles. With the advancements in nanotechnology,
we now have the ability to create artificial nanoparticles that are in many, many products
including the food we eat. According to Jeffery Card, a toxicology expert at Intertek, a
multinational safety consultancy that works extensively in the nanotech area, says “The
possibilities seem endless, think of nanoscale filters to remove bacteria from milk and
other beverages without boiling, or nanosensors to detect and alert consumers to
pathogens or spoiled food”. “Some groups are even attempting ‘molecular food
manufacturing’,” he adds.
One of these artificial nanomaterials is titanium dioxide. Titanium dioxide is used in
paints, plastic, cosmetics and even in the icing on some of your glazed donuts[1]. According to
Lori Stryker, B.SC., B.H.Ec., B.Ed.; “titanium dioxide is the subject of new controversy, yet it is
a substance as old as the earth itself. It is one of the top fifty compounds produce worldwide, it is
a white, opaque and naturally-occurring mineral found in two main forms: rutile and anatase.
This mineral can be found in many products ranging from paint to food to cosmetics. Concerns
have arisen from studies that have pointed to titanium dioxide as a carcinogen and
photocatalyst.”[2]
In relation to food, the area we want to discuss is the use of pesticides. Pesticides are
tools of chemical or biological origin which we use to control, kill or mitigate unwanted nuisance
or hazardous pests such as insects, bacteria, fungi, weeds, mites and rodents. Pesticides are
necessary in killing the pests that otherwise would eat food crops or subject the crops to disease.
Organophosphorous pesticides (OPs) are the most commonly used type of pesticide.
These are organic compounds that contain carbon-phosphorous bonds. They are used as a
pesticide because they attack the nervous system of pests. In the nervous system, there is an
enzyme called acetyl-cholinesterase that helps regulate neurotransmitter signals.[3] The chemical
essentially kills the pests by suffocating them. When humans or other animals come in contact
with it, it can have similar effects on the nervous system if it is in a strong enough concentration.
How Pesticides Can Be Cleaned Up
Since pesticides can have significant impact on the health of people, animals, and the
environment, figuring out how to find and measure these chemicals has a lot of focus. Many
methods of detection have been or are being used, such as: gas or liquid chromatography, solid-
phase micro extraction, supercritical fluid extraction, accelerated solvent extraction, pressurized
liquid extraction, and microwave-assisted extraction.[4]
The new method we want to focus on is the emerging use of nano-magnetic materials to
cleanup organophosphorous pesticides (OPs). These are materials that can be manipulated using
a magnetic field. The purpose of utilizing this property in a nanoparticle is that by applying a
magnetic field, they are easy to separate from other material. The magnetic particle being used is
Fe3O4.
The benefit of using nanoparticles is that surface modifications can be done to change the
properties of them to work differently in a way that we want them to. In our case, we want
something that can absorb pesticide compounds and then allow them to be extracted. C18 SPE
(solid-phase extraction) is a well-known technique for cleaning up OPs. C18 was chosen as the
functional group of Fe3O4 particles to create Fe3O4-C18 composite nanoparticles. Ideally, what
we get is the magnetic properties of Fe3O4 and the cleanup properties of C18.
How This Method Was Experimented
The magnetic nanoparticles are prepared by reacting FeSO4+7H2O with Fe2(SO4)3 and
NaOH to precipitate Fe3O4. The Fe3O4 particles are then chemically modified by reacting Fe3O4
with C18-SiCl3 to make the Fe3O4-C18 composite particles. The reaction conditions (pH,
temperature, and amount of time the reaction takes place) are important and determines the size
of the particles. The pH, temperature, and amount of time the reaction takes place. The sizes of
the particles desired are 5-10 nm.
To study the effectiveness of the particles at cleaning up pesticides, samples of food such
as cabbage are spiked with an OP and were allowed to soak in for a period of time. Then the
pesticide is extracted through a centrifuge process. With the pesticide in a solution extract, three
approaches were done using the Fe3O4-C18 composite materials to compare the effectiveness of
the cleanup procedures.
In the first cleanup approach, the OP extract and the composite nanoparticles are made
into a mixture in a beaker. The composite nanoparticles would hopefully bind with the OPs. The
nanoparticles are then separated from the solution under a magnetic field and they are analyzed
using gas chromatography to determine to composition of the particles at the end. This is the
simplest of the three approaches.
In the second approach, the nanoparticles are put into a special cartridge to be used for
solid-phase extraction (SPE). In the process of SPE, compounds are dissolved in a solution and
are then separated from other compounds through washing with solvents. In addition to SPE
process, a magnetic field is applied.
The third approach is similar to the second approach but used common commercial C18
material already being used as a cleanup method, instead of the composite nanoparticles.
Comparing the effectiveness of the three cleanup approaches in removing OPs, approach
one and two are similar to the common C18 material approach: each being between around 8090% effective.
The process of adhesion of OPs to the magnetic nanoparticles works so that when a
magnetic field is applied, OPs can be trapped by the nanoparticles. When the magnetic field is
withdrawn, OPs can easily escape from the nanoparticles and be rinsed off. The magnetic
nanoparticles can also be recovered and recycled. So in the work studied, magnetic Fe3O4-C18
composite nanoparticles are comparable with common C18 materials for cleanup of OPs, but the
procedure is faster and easier.[4]
Pros
In some parts of the world, pests are more destructive and harder to control. For
example, the Middle East and Northern Africa both have locust plagues that totally consume
harvests and leave people behind starving. Australia has had a share of problems controlling its
locust and grasshopper plagues. [5] They have used pesticides with much success.
Researchers are working with nano pesticides to understand the implications for public
health. Scientists from the Oregon State University and the European Union believe that it
should be possible to design nano pesticides that work better and and/or safer. Stacey Harper, an
assistant professor of nanotoxicology at Oregon State University says, “Unlike some other
applications of nanotechnology, which are further along in development, applications for
pesticides are in their infancy” [6]. “There are risks and a lot of uncertainties, however, so we
need to understand exactly what’s going on, what a particular nanoparticle might do, and work to
eliminate use of any that does pose dangers.” They mentioned that designing pesticides at the
nano level allows them better control the delivery of active ingredients, have less environmental
drift, create formulations that will most effectively reach the desired pest, and perhaps have
better protection for agricultural workers.[6] Their goal is to be able to do more with less. They
say that although pesticides are compounds that have already been rigorously tested and
regulated, they are trying to encourage manufacturers to label all the specific ingredients and to
do testing in the same way humans would be exposed in the real world. Cooperation from the
government, industry, academic and the public will be critical in order to tackle the confusion
and uncertainty about nano pesticides.
Food is one of our basic necessities. It’s inevitable that technological advances will come
that change our food to make it better. Nanotechnology comes in as the latest way to look at how
to make our food more available and protected, more nutritionally enriched, stronger, last longer,
and more desirable to eat.
Cons for Nanopesticides
Pesticides can be harmful to humans because they are designed to kill. Children and pets
are more vulnerable to run into or consume them. The environment is at risk when it absorbs
unneeded and unwanted pesticides. Valuable plants and animals may very well be the untargeted
consumers.
A new study by scientists at the University of Missouri College of Agriculture, Food and
Natural Resources is shedding light on the persistence of nanopesticides in our food.
Researchers focused their attention on silver nanoparticles (nanosilver), a substance that has been
linked to environmental harm, bacterial resistance and not fully understood impacts on human
health. The last decade has witnessed a large influx in the use of nanotechnology in consumer
products, including food, clothing, cosmetics, fertilizers and pesticides. The growth of this
technology has elicited strong reactions from scientists across the globe, with many asserting that
further research is needed to evaluate the potential impacts of these novel substances. Mengshi
Lin, PH.D, associate professor at the University of Missouri (MU) and co-author of the study
states: “More than 1,000 products on the market are nanotechnology-based products. This is a
concern because we do not know the toxicity of nanoparticles. Our goal is to detect, identify and
quantify these nanoparticles in food and food products and study their toxicity as soon as
possible.” [7]
Research has been extremely active over the past few years to develop new pesticides
products based on nanotechnology. Thilo Hofmann, dean elected at the Faculty of Geosciences,
Geography and Astronomy of the University of Vienna states “ Nano-pesticides research is
emerging at high speed at the agrochemical labs, however, this topic has not reached public
awareness or state authorities so far, nor are any products available at the market. Since those
nano-pesticides have new or enhanced properties, this will change in the near future and will
inevitably result in both new risks and new benefits to human and environmental health”.[8]
Works Cited
1. Cressey, Daniel. "Nanotechnology Offers Small Food for Thought." The Guardian. N.p.,
n.d. Web. 17 Nov. 2013. <http://www.theguardian.com/what-is-nano/nanotechnologysmall-food-for-thought>.
2. Stryker, Lori. "Titanium Dioxide: Toxic or Safe?" Organic Make-Up Company. N.p., n.d.
Web. 17 Nov. 2013. <http://www.organicmakeup.ca/CA/titaniumdioxide.asp>.
3. "Case Study: Organophosphorus Pesticides." ChemicalBodyBurden.org. N.p., n.d. Web.
17 Nov. 2013. <http://www.chemicalbodyburden.org/cs_organophos.htm>.
4. Hao-Yu, Shen, et al. "Preparation Of Fe3o4-C18 Nano-Magnetic Composite Materials
And Their Cleanup Properties For Organophosphorous Pesticides." Analytical &
Bioanalytical Chemistry 387.6 (2007): 2227-2237. Academic Search Premier. Web. 17
Nov. 2013.
5. "What Can We Use to Control Locusts? - Ask an Expert." ABC Science. N.p., 17 Aug.
2010. Web. 17 Nov. 2013.
<http://www.abc.net.au/science/articles/2010/08/25/2992887.htm>.
6. Stauth, David. "New Approaches Needed to Gauge Safety of Nanotech-based Pesticides."
Oregon State University News & Research Communications. N.p., 04 Oct. 2010. Web.
18 Nov. 2013. <http://oregonstate.edu/ua/ncs/archives/2010/oct/new-approaches-neededgauge-safety-nanotech-based-pesticides>.
7. Beans, Laura. "Toxic Pesticide Nanoparticles Found to Persist in Food." EcoWatch. N.p.,
27 Aug. 2013. Web. 17 Nov. 2013. <http://ecowatch.com/2013/08/27/toxic-pesticidenanoparticles-in-food/>.
8. "Nano-pesticides: Solution or Threat for a Cleaner and Greener Agriculture?" Institute of
Nanotechnology. N.p., 9 Aug. 2013. Web. 17 Nov. 2013.
<http://www.nano.org.uk/news/1893/>.