Bergeson & Campbell, P.C. serves small, medium, and large pesticide product registrants and other stakeholders in the agricultural and biocidal sectors, in virtually every aspect of pesticide law, policy, science, and regulation.

By Lynn L. Bergeson and Carla N. Hutton

On August 26, 2019, the National Institute of Environmental Health Sciences (NIEHS) announced that the results of an NIEHS-funded study show that graphene could provide alternatives to chemicals in insect repellant and protective clothing.  The study, “Mosquito Bite Prevention through Graphene Barrier Layers,” was published in the Proceedings of the National Academy of Sciences.  According to the abstract, the researchers hypothesized that graphene films may provide mosquito bite protection for light, fiber-based fabrics.  The researchers investigated the fundamental interactions between graphene-based films and the mosquito species Aedes aegypti through a combination of live mosquito experiments, needle penetration force measurements, and mathematical modeling of mechanical puncture phenomena.  The abstract states that “the results show that graphene or graphene oxide nanosheet films in the dry state are highly effective at suppressing mosquito biting behavior on live human skin.  Surprisingly, behavioral assays indicate that the primary mechanism is not mechanical puncture resistance, but rather interference with host chemosensing.”  The researchers propose that the interference is “a molecular barrier effect that prevents Aedes from detecting skin-associated molecular attractants trapped beneath the graphene films and thus prevents the initiation of biting behavior.”  According to the abstract, placing water or human sweat on the external film surface circumvents the molecular barrier effect.  In this scenario, the abstract states, “pristine graphene films continue to protect through puncture resistance -- a mechanical barrier effect -- while graphene oxide films absorb the water and convert to mechanically soft hydrogels that become nonprotective.”


 

By Lynn L. Bergeson and Carla N. Hutton

 

On May 19, 2015, the U.S. Environmental Protection Agency (EPA) announced that it issued a conditional registration for a nanosilver-containing antimicrobial pesticide product named “NSPW-L30SS,” or “Nanosilva.”  This is the second nanosilver registration issued by EPA and reflects the Agency’s growing expertise in addressing, processing, and approving nanopesticide registration applications.  According to EPA, the product will be used as a non-food-contact preservative to protect plastics and textiles from odor- and stain-causing bacteria, fungi, mold, and mildew.  Items to be treated include household items, electronics, sports gear, hospital equipment, bathroom fixtures, and accessories. EPA based its decision “on its evaluation of the hazard of nanosilver after reviewing exposure data and other information on nanosilver from the applicant, as well as data from the scientific literature.”  EPA states that these data show that treated plastics and textiles release “exceedingly small amounts of silver.”  Based on this evaluation, EPA “determined that NSPW-L30SS will not cause unreasonable adverse effects on people, including children, or the environment and that it would be beneficial because it will introduce less silver into the environment than competing products.”  EPA notes that it is requiring the company “to generate additional data to refine the Agency’s exposure estimates.”  According to EPA, it will post a response to comments received on its 2013 proposed registration decision document, as well as the current decision document, in the rulemaking docket.