• Everyday plastic products release trilli

    From ScienceDaily@1:317/3 to All on Wednesday, April 20, 2022 22:30:48
    Everyday plastic products release trillions of microscopic particles
    into water

    Date:
    April 20, 2022
    Source:
    National Institute of Standards and Technology (NIST)
    Summary:
    Plastics surround us, whether it's the grocery bags we use at
    the supermarket or household items such as shampoo and detergent
    bottles.

    Plastics don't exist only as large objects, but also as microscopic
    particles that are released from these larger products. These
    microscopic plastics can end up in the environment, and they can
    be ingested into our bodies.



    FULL STORY ========================================================================== Plastics surround us, whether it's the grocery bags we use at
    the supermarket or household items such as shampoo and detergent
    bottles. Plastics don't exist only as large objects, but also as
    microscopic particles that are released from these larger products. These microscopic plastics can end up in the environment, and they can be
    ingested into our bodies.


    ==========================================================================
    Now, researchers at the National Institute of Standards and Technology
    (NIST) have analyzed a couple of widely used consumer products to better understand these microscopic plastics. They found that when the plastic products are exposed to hot water, they release trillions of nanoparticles
    per liter into the water.

    The NIST researchers published their findings in the scientific journal Environmental Science and Technology.

    "The main takeaway here is that there are plastic particles wherever
    we look.

    There are a lot of them. Trillions per liter. We don't know if those have
    bad health effects on people or animals. We just have a high confidence
    that they're there," said NIST chemist Christopher Zangmeister.

    There are many different types of plastic materials, but they are all
    made up of polymers, natural or human-made substances composed of
    large molecules linked together. Scientists have found microscopic
    particles from these larger plastics in the oceans and many other
    environments. Researchers categorize them into two groups: micro-
    and nanoplastics.

    Microplastics are generally considered smaller than 5 millimeters in
    length and could be seen by the naked eye, while nanoplastics are smaller
    than one millionth of a meter (one micrometer) and most can't even be
    seen with a standard microscope. Recent studies have shown some consumer products that hold liquids or interact with them, such as polypropylene
    (PP) baby bottles and nylon plastic tea bags, release these plastic
    particles into the surrounding water.



    ==========================================================================
    In their study, the NIST researchers looked at two types of commercial
    plastic products: food-grade nylon bags, such as baking liners --
    clear plastic sheets placed in baking pans to create a nonstick surface
    that prevents moisture loss -- and single-use hot beverage cups, such as
    coffee cups. The beverage cups they analyzed were coated with low-density polyethylene (LDPE), a soft flexible plastic film often used as a liner.

    The LDPE-lined beverage cups were exposed to water at 100 degrees Celsius
    (212 degrees Fahrenheit) for 20 minutes.

    To analyze the nanoparticles released from these plastic products,
    the researchers first needed to determine how to detect them. "Imagine
    having a cup of water in a generic to-go coffee cup. It could have many billions of particles, and we would need to figure out how to find these nanoplastics. It's like finding a needle in a haystack," Zangmeister said.

    So, he and his colleagues had to use a new approach. "We used a way of
    taking the water that's in the cup, spraying it out into a fine mist,
    and drying the mist and all that's left within the solution," said
    Zangmeister. Through this process, the nanoparticles are isolated from
    the rest of the solution.

    The technique itself has previously been used to detect tiny particles
    in the atmosphere. "So, we're not reinventing the wheel but applying it
    to a new area," said Zangmeister.



    ========================================================================== After the mist was dried, the nanoparticles in it were sorted by their
    size and charge. Researchers could then specify a particular size, for
    example nanoparticles around 100 nanometers, and pass them into a particle counter. The nanoparticles were exposed to a hot vapor of butanol, a
    type of alcohol, then cooled down rapidly. As the alcohol condensed,
    the particles swelled from the size of nanometers to micrometers,
    making them much more detectable. This process is automated and run by
    a computer program, which counts the particles.

    Researchers could also identify the chemical composition of the
    nanoparticles by placing them on a surface and observing them
    with techniques known as scanning electron microscopy, which takes high-resolution images of a sample using a beam of high-energy electrons,
    and Fourier-transform infrared spectroscopy, a technique that captures
    the infrared-light spectrum of a gas, solid or liquid.

    All these techniques used together provided a fuller picture of the size
    and composition of the nanoparticles.

    In their analysis and observations, the researchers found that the average
    size of the nanoparticles was between 30 nanometers and 80 nanometers,
    with few above 200 nanometers. Additionally, the concentration of
    nanoparticles released into hot water from food-grade nylon was seven
    times higher compared with the single-use beverage cups.

    "In the last decade scientists have found plastics wherever we looked in
    the environment. People have looked at snow in Antarctica, the bottom of glacial lakes, and found microplastics bigger than about 100 nanometers, meaning they were likely not small enough to enter a cell and cause
    physical problems," said Zangmeister.

    "Our study is different because these nanoparticles are really small and
    a big deal because they could get inside of a cell, possibly disrupting
    its function," said Zangmeister, who also stressed that no one has
    determined that would be the case.

    The U.S Food and Drug Administration (FDA) regulates the plastics that
    touch the food we eat or the water we drink. The agency has standards and safety measures in place to determine what's safe. The FDA's researchers
    run rigorous tests on these plastics and measure how much plastic mass
    is lost when exposed to hot water. For example, the FDA has determined
    that food grade nylon (such as that used in tea bags) can safely lose
    up to 1% of its mass under high- temperature conditions. In the NIST
    study using their new technique, the researchers found one tenth of a
    percent of the mass was lost, which is significantly below current FDA
    limits for what's considered safe.

    Zangmeister noted there isn't a commonly used test for measuring LDPE
    that is released into water from samples like coffee cups, but there
    are tests for nylon plastics. The findings from this study could help
    in efforts to develop such tests. In the meantime, Zangmeister and his
    team have analyzed additional consumer products and materials, such as
    fabrics, cotton polyester, plastic bags and water stored in plastic pipes.

    The findings from this study, combined with those from the other types
    of materials analyzed, will open new avenues of research in this area
    going forward. "Most of the studies on this topic are written toward
    educating fellow scientists. This paper will do both: educate scientists
    and perform public outreach," said Zangmeister.


    ========================================================================== Story Source: Materials provided by National_Institute_of_Standards_and_Technology_(NIST).

    Note: Content may be edited for style and length.


    ========================================================================== Related Multimedia:
    * Nanoparticles_found_in_single_use_beverage_cups ========================================================================== Journal Reference:
    1. Christopher D. Zangmeister, James G. Radney, Kurt D. Benkstein, Berc
    Kalanyan. Common Single-Use Consumer Plastic Products Release
    Trillions of Sub-100 nm Nanoparticles per Liter into Water during
    Normal Use.

    Environmental Science & Technology, 2022; DOI:
    10.1021/acs.est.1c06768 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/04/220420133533.htm

    --- up 7 weeks, 2 days, 10 hours, 51 minutes
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)