First, Do No Harm
First, Do No Harm

    A recent press release from the SYMVCD stated that the material sprayed into our air supposedly to control the vectors of West Nile virus was such a slight amount, less than 1 ounce per acre, that it could do no harm.  This would be quite in keeping with the famous medical ethic, "First, Do No Harm."  There's one slight problem however -- the statement is not quite accurate in its implications for total safety.  Vector control and public health officials have made the statement many times, including before the Sacramento City Council, as we discuss in The Safe-Dose Myth.  There is additional discussion of this important issue in Dose Considerations, and please note that "the dose makes the poison" is old dogma. 

Acute Effects Can Be Deadly:  One ounce of the pesticide can kill a small child.  Of course in order to kill the child outright that child would have to drink most of that ounce.  And it would seem very unlikely that a small child would manage to drink the entirety of the acre's worth of insecticide raining out of the air. There would be enough to kill two small children if it were painted over their skin, but it would be equally difficult to imagine two children covering themselves with an acre's worth of insecticide raining out of the air.  If that ounce were put in an inhaler it would kill several children, but raining out of the air for three days is nothing near the same.

    So it would seem unlikely that SYMVCD would be killing children outright with their aerial insecticide spray.  It is important to note, however, that pesticide safety testing is done on individual pesticides and not on the combination of pesticides to which we are all exposed.  They can have cumulative effects, as is noted by Dr. LeStourgeon of Vanderbilt University in The Safe-Dose Myth.  So, what if some of those small children had been fed avocado sandwiches at lunch?  Avocados are allowed to contain up to 6 ppm organophosphate insecticide often applied to commercial avocados.  What if they finished lunch with an apple that contained an equal portion of organochlorine insecticide and then had played in the front yard where mommy or daddy had sprayed glyphosate herbicide?  And what if they had recently developed allergic sensitivity to the household insecticides similar to the aerial spray?  What if those children were asthmatic?  And is drop-dead toxicity really the only possible harm? 

Sub-acute Effects Are Non-trivial:  There are in fact many sub-acute harms that could arise from exposure to the insecticide formula SYMVCD sprayed over the residential neighborhoods of Sacramento.  PB0, which constitutes 60% of the material, increases the toxic effects of a broad range of poisons the children might be exposed to aside from the pyrethrum in the aerial spray.  This includes the sub-acute effects of chronic exposure to all those same materials.  That means that the increase in cases of autism and ADD that are already occurring due to the exposure of children to organochlorine insecticides will only be increased.  PBO and pyrethrum are both known to induce asthma on chronic exposure which is already epidemic in area children.  That same PBO interferes with the enzymatic control of estrogen hormone.  Glyphosate herbicide mimics estrogen.  Pyrethrum also mimics estrogen.  And the synthetic pyrethroid chemicals have been shown to furnish the proliferation of breast cancer cell lines in the same fashion as hormone replacement therapy.  None of these diseases can be considered trivial or harmless.

Aerosolized Pesticides Can Trigger AsthmaThe California Department Of Health Services estimated the number of people in a recent year (2003) in Yolo County with asthma at 23,000 (17,000 adults and 6,000 children).  Along these lines Washington, DC officials noted the high asthma rate in their area and said that aerosolized pesticides can trigger asthma and aggravate respiratory conditions, even with broadcast aerosol applications of pesticides at night.  In addition to scientific research that demonstrates that adulticiding is not effective in slowing the transmission of WNv to humans, this health risk was a key reason behind the DC officials policy not to spray.

Pesticide Application Has Unintended Consequences:  There are a number of unintended consequences from pesticide spraying.  Pesticides can suppress the immune system, making it harder to fight off WNv infection.  Pesticides also kill the natural mosquito predators, some of whom have a much longer recovery period, and mosquitoes sprayed with pesticides can become more aggressive and bite more before they die.  And we certainly should try to discover if the use of pesticides contributes to the widespread colony collapse disorder in honeybee colonies, vital to many crops for their pollination.  Finally, we once again note that research has shown that the PBO in the current mix in 2005 doubled the toxicity of pesticides already existing in local creek sediments from general urban pesticide use. 

SYMVCD Still Has No Evidence of Efficacy:  When two other inconvenient details are considered the whole question of risk seems a moot point.  First, there is no conclusive evidence that this spray protocol does any more than a temporary slight reduction in the risk of acquiring West Nile virus.  Second, the risk of exposure to West Nile virus has been declining, as would be expected after first introduction, to a very much smaller number.  Last year (2010) there was less than one reported infection per hundred thousand population in Sacramento County.  This includes non symptomatic blood donors.  Note that in 2005 the rate was greater than 15 per 100,000.  It can be expected to decline to an even lower number in future seasons due to the increased rates of immunity in the bird population.  As much as those who sell insecticides would like you to believe that West Nile virus is the last great plague of the world, this is not so.  Any further expenditures on insecticidal spray are not just a waste of money but are an unnecessary risk to human health and the environment. 

    Note that SYMVCD had no evidence that aerial spraying was effective at slowing the transmission of WNv to humans when they sprayed Sacramento in the summer of 2005, and they still have no evidence.   Indeed, the situation is now even worse in that they are touting their fatally flawed 2005 experiment as evidence, showing at the very least that they either do not understand what constitutes solid evidence or they do not consider solid evidence to be important in developing public policy. With the extremely weak items they have offered as evidence, at the same time ignoring the scientific evidence to the contrary, concerned citizens must ask why this practice continues. 

Further References about Dose and Harm

•  Why the Adage 'the Dose Makes the Poison' Can Be Toxic to Corporate Chemicals Policy.
•  Does "the dose make the poison?"
•  Are all things poison? Rethinking safety standards for low doses of chemicals.
•  Time to Update Environmental Regulations: Should public health standards for endocrine-disrupting compounds be based upon sixteenth century dogma or modern endocrinology?
•  Dose Doesn’t Always Make Poison.