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LBAM Spray Delivered via Plastic Microcapsules
The product that the CDFA plans to spray over the San Francisco Bay Area in 2008 will be delivered via tiny, plastic microcapsules -- in addition to other ingredients in the spray. (Read more here about the proposed aerial spraying plan.)
The microcapsules time release the product into the environment. And the microcapsule itself breaks down over 30 days. The product to be used will be identical to or similar to Checkmate, the Suterra-manufactured pesticide used in Santa Cruz and Monterey counties in 2007.
What the CDFA Claims
The California Department of Agriculture claims this is safe method of applying the pesticide. The CDFA suggests that the majority of plastic microcapsules are too large to be inhaled into lung tissue -- that the concentration of particles tiny enough to be inhaled is a small part of the total volume of product. Because of these claims, the CDFA says that inhalation studies of the product were not necessary before the aerial spraying they conducted over Monterey and Santa Cruz counties.
What Scientists Have Found:
In an April 2008 report, Dr. Dennis Knepp and Dr. Jeff Haferman refuted the CDFA's claims, showing that a large percentage of the capsules in Checkmate are 10 micrometers or less in size -- particles characterized as "PM10." A particle of this size is approximately one-third the width of a human hair.
In Knepp's and Haferman's calculations, the concentration of microcapsules small enough to reach deep lung tissue was greater than what the CDFA claims. And this larger concentration of PM10 is, in their words, "very disturbing."
The concentration of PM10 is an important measure since particles designated as such pose significant health and inhalation hazards.
An EPA fact sheet on particle pollution at the September 11 World Trade Center site confirms the hazards of PM10 particles: "These particles pose the greatest health concern because they can pass through the nose and throat and get into the lungs."
The EPA goes on to say:
Certain sensitive populations . . . are susceptible to more serious symptoms, including cough, phlegm, wheezing, shortness of breath, bronchitis, increased asthma attacks, and aggravation of lung or heart disease.
The sensitive individuals listed include people with asthma or respiratory problems, children, the elderly, smokers, and those with cardiovascular disease.
The EPA fact sheet does not list individuals with chemical sensitivity, also an important concern when it comes to any blanket application of chemicals. And, of course, none of the CDFA's claims can be reassuring for anyone who is sensitive or allergic to particular components of the capsule or the spray. Since the particles/capsules are designed to remain in the environment and break down over time, concerned individuals cannot simply leave the area when the spraying occurs.
CBS 5 ran an excellent investigative report on the PM10 issue, suggesting that volume-based studies like the ones cited by the CDFA are flawed in that they do not give an accurate representation of the numbers of PM10 particles in any given volume. Watch a video of Anna Werner's report here:
Scientists Refute CDFA's Claims of Microcapsule Safety
Composition of Microcapsule - Polyurea Polymer
Of some concern is the composition of the microcapsule. The capsule material is identified as a cross linked polyurea polymer (in CDFA documents). This polymer is "commonly used in manufacturing of plastics such as polyurethane foam production, waterproofing, insulation, and micro encapsulation agent for pesticides."
In an LBAM Fact Sheet prepared by Roy Upton, Daniel Harder and Thomas Dadant, the breakdown product of the polyurea polymer, urea (as well as other ingredients in the Checkmate spray) has been linked to "harmful algal blooms (HABs) also known as red tides."
A dramatic red tide occurred after the aerial sprayings in Monterey and Santa Cruz counties and it was this red tide, in fact, that was blamed for the dead seabirds found on the shoreline after the spray.** Research has linked urea to the occurrence of harmful algal blooms. This press release from UCSC (University of California at Santa Cruz) says that urea as a source of pollution is "generally ignored by state and federal environmental agencies" and "contributes to growth of potentially toxic blooms of a common phytoplankton species."
** In a report compiled by Roy Upton, the dead birds are described as covered with an unidentified waxy substance which inhibited the natural water-proofing and insulation of their feathers