Science in Society Archive

Sex Hormones and City Life

Is it safe to douse cities with synthetic pheromones? Prof. Joe Cummins and Sam Burcher

Northern California is in the grip of a horrific aerial spray programme designed to eradicate an insect pest, Epiphyas postvittana, the light brown apple moth (LBAM). The LBAM is native to Australia and is also found in New Zealand, Hawaii, and the United Kingdom where it is not considered a significant pest [1]. However, the California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) have prescribed a $74.5 million pesticide plan using a synthetic insect sex hormone to eradicate the perceived threat to a number of plant species thought to be susceptible to attack by the LBAM.  These species may include the Californian cypress, oak and redwood trees, as well as ornamental and nursery plants; and a broad range of citrus, grapes, and deciduous fruit tree crops [2].

Botanist Daniel Harder, the executive Director of the Arboretum at UC Santa Cruz, visited New Zealand in 2007 to study the behaviour of the LBAM where its presence does not cause economically significant crop damage, or had a detrimental effect on native flora [3].  His research has led him to conclude that, “It is not such a nasty pest.  You’re not going to see a plant succumbing to the LBAM.” [1]. Furthermore, he says that there is no reason to believe that this moth will be any more of a problem in California than any other moth from the Torticidae family.  He is confident that earwigs, birds and spiders will eat the moth and its larvae and prevent the devastation envisaged by agricultural officials, and rejects the expensive, unnecessary spraying of a dozen urban communities in the coast and bay areas.  Jim Carey, a UC Davis entomology professor, says that the pesticide plan won’t work because the LBAM has been in California for at least thirty, if not fifty years, or more, and that the money would be better spent trying to contain the spread of the LBAM rather than eradicate it altogether.  UC Berkeley associate Professor of Agro-ecology Miguel Altieri agrees, and says that the fact that the moth is here doesn’t mean devastation.

Aerial pesticides sprayed over urban communities

A pheromone is a natural scent that an insect produces in very small quantities to communicate with a potential mate. In the case of the aerial spray, the pheromone works by confusing the male moth, which disrupts the mating cycle, thereby decreasing or eradicating the pest population. Several rounds of aerial spraying with ‘CheckMate LBAM-F’, and ‘CheckMate OLR-F’, have already blanketed Monterey and Santa Cruz counties in September through to November 2007 with the insect pheromone, and further sprays planned for June 2008 have been temporarily halted by the courts until after 17 August 2008 when test results from the spray formula are expected [4]. The counties of Alameda, Albany, Contra Costa, Marin, Santa Clara, San Mateo, San Francisco, Solano, and Oakland are fresh targets for the summer aerial spraying campaign in 2008.        The CDFA and USDA have identified the LBAM as a Class ‘A’ pest to obtain an “emergency exemption” from the California Environmental Protection Agency (EPA), and both claim that synthetic pheromones are not toxic to humans or to the environment.  However, a report from a Task Force set up by the city of Albany, California has provided evidence to the contrary [5].  The report states that, “Following the spraying in Monterey and Santa Cruz in 2007, there were more than 600 reports of health problems, including asthma-like attacks and difficulty breathing, chest pains, headaches, blurred vision, swollen glands, skins rashes, and feelings of chronic fatigue.”

The symptoms reported by Monterey and Santa Cruz residents are consistent with the known health effects of several of the ten ingredients found in the pheromone formula. Matthew Sluder of the Sustainable Health Institute [6] recently outlined his concerns to the Marin Country Agricultural officer and to the Integrated Pest Management Commission of two of CheckMate’s published ingredients [7]:

  • Butylated hydroxytoluene is mutagenic for mammalian somatic cells, also for bacteria and/or yeast. Repeated or prolonged exposure can produce organ damage and may be toxic to blood, central nervous system (CNS) and liver [8].
  • 2-hydroxy-4-n-octyloxybenzophenone is a xenochemical that binds to estrogen receptors in humans and animals.  Even small doses will signal specific biological action in the body. Prolonged disruption the endocrine system is a cause of breast cancer [9].

CheckMate OLR-F® also contains (E)-11-tetradecen-1-yl acetate and (Z)-11- tetradecen-1-yl acetate as the active ingredients (A.I.s); while CheckMate LBAM-F® and DISRUPT Micro-Flake®, contain in addition to (E)-11-tetradecen-1-yl acetate and (Z)-11- tetradecen-1-yl acetate, (E, E)-9,11- tetradecadien-1-yl acetate. All formulations include the ‘inert’ ingredients, Polymethylene Polyphenyl Isocyanate (PPI), Tricapryl Methyl Ammonium Chloride and 1, 2-benzisothiazolin-3-one [7]. The EPA’s claim that these chemicals are inert fails to disclose the fact that these substances are toxic.  Inert ingeredients are chemical formulations that accompany the main chemicals responsible for eradicating the pest, in this case the pheromones.

Registration of the synthetic pheromones themselves seems to be a dangerously cursory process, in which data relating to toxicity, mutagenicity, allergenicity or teratogenicity may be waived if the substance is a member of a well characterized chemical group in the major OECD countries including the United States [10]. In general, the registration of the synthetic pheromones seems to be slipshod and inadequate.

A recent study on CheckMate LBAM-F® by the Aquatic Toxicology Laboratory at UC confirms the danger of aerial application [11] particularly from the ‘inert’ microcapsules ranging in size from approximately 10 microns to 190 microns.  According to the American Lung Association (ALA) [12] microcapsules in the region of 10 microns come under the category of ‘Particle Pollution’  defined by the ALA as a combination of fine solids and aerosols that are suspended in the air we breathe and are small enough to lodge deep in the lungs where they can do serious damage. Particle Pollution is well documented for its adverse effects on short and long term health, including the increased severity of asthma attacks in children, damage to the small airways of the lungs and dying from lung cancer, respiratory and cardiovascular causes. Children and the elderly are most at risk from these ingredients.

Severe reactions ignored

One eleven month old infant called Jack had such a severe reaction after the first aerial spraying in Monterey that his father Air Force Major Tim Wilcox called a military doctor [13]. The boy was hospitalized on three occasions and stopped breathing on one occasion.  The previously healthy child spent his first birthday on medication and oxygen and is now permanently on medication. Major Wilcox’s letters and complaints to the state about the possible bad reaction to the spraying were ignored. CDFA spokesman Steve Lyle said his agency had received 330 complaints of spray-related illness but he downplayed the news, insisting that “the agencies with the jurisdiction to review the product have told us it’s safe to use.... and the CheckMate products were unlikely the cause of the illnesses reported.” California’s Governor Arnold Schwarzenegger supports the urban spraying liquid and backs the CDFA’s position on the spray being safe [7]. 

California State’s official emergency exemption under Section 18 of the Federal Insecticide, Fungicide and Rodenticide Act has allowed CheckMate LBAM-F, and CheckMate OLR-F to bypass the normal vetting processes to assess safety under California law. This effectively allows a substance that has not been thoroughly tested to be used in urban areas, and despite the manufacturer Suterra LLC of Bend, Oregan admission that “long term studies on the active ingredients have not been done” [14].  Further aerial onslaughts of the LBAM are to be coupled with “complementary techniques” such as ground treatments and foliar sprays of Bacillus thuringiensis (bt) [2], a bacterium known to have adverse health effects on human and animal populations (see More Illnesses Linked to Bt Crops [15]. It also infects open sores or abrasions of people with weak immune systems from age, HIV infection, or from treatment for autoimmune diseases [16]. Spinosad is a natural insecticide obtained from bacteria (synthetic Spinosad derivatives are also available) that is to be applied to areas of LBAM infestation. Even though Spinosad is approved for organic production, laboratory experiments showed that it was harmful to honeybees and bumblebees. Later experiments showed that dried residues of the natural insecticide are not harmful to bees [17]. But as the bees are already stressed and threatened by colony collapse disorder (CCD) see Saving the Honeybee Through Organic Farming [18] it is advisable to apply the natural insecticide, if at all, only at night when bees are not foraging.

Elephants are white mice

In modern toxicology the adverse effects of pesticides is evaluated by exposing test animals and carefully evaluating the impact of the pesticide. Most testing is done with either rats or mice. In the case of the Lepidopteran (moth) pheromones, there is clear evidence that pheromones similar if not identical to those delivered from the air in California are active in inducing aggression and sexual arousal in the African elephant. The female elephant excretes the pheromone in her urine and the smell of that urine arouses male elephants [19, 20, and 21]. The elephants should be regarded as the white mice, as their response is relevant, not only to elephants that might be in the Bay Area but a large array of mammals including humans. Male sexual aggression should be considered a marker and evaluated from police records in the communities sprayed with insect pheromone from the air.

Both vertebrate and invertebrate animals are influenced by pheromones similar to those sprayed in California. Higher primates and humans have retained many of the genes specifying pheromone receptors of ‘lower’ vertebrates as inactive pseudo-genes, though humans have retained active pheromone receptor genes as well [22, 23]. The safety of a synthetic cockroach sex pheromone was questioned when it was found to be toxic to human cells [24]. It would be prudent to presume all synthetic pheromones toxic to humans until fully evaluated for toxicity and unintended behaviour modification. Olfaction and pheromones are well documented to be a part of human behaviour [25, 26].

According to  the California Department of Pesticide  Regulation (CDPR) US EPA states that “Based on low toxicity in animal testing, and expected low exposures to humans, no risk to human health is expected from the use of these pheromones. During more than 10 years of use of lepidopteran pheromones, no adverse effects have been reported. The safety record for lepidopteran pheromones has allowed the Agency to conclude that consumption of food containing residues of the pheromones presents no risk. ... Adverse effects on non target organisms (mammals, birds, and aquatic organisms) are not expected because these pheromones are released in very small amounts to the environment and act on a select group of insects.” For that reason little motoring of non-target effects was undertaken even though the toxicity of the pheromone to invertebrate organisms and fish was noted by CDPR.  The ‘inert ingredients’, were of no toxicological concern according to CDPR [27]. However, had they examined the actual; ‘inert’ ingredients’ they would have observed that more than on such ingredient posed a risk to human health.

Sex hormone makes manufacturer millions

The “organic biopesticides” market is specifically designed to target organic farmers in the US and Canada who can use Bt and pheromones on the premise that it is based on natural substances without losing their organic status. The biopesticides market is currently a small fraction of the overall $30 billion pesticides industry.  By 2010, it is estimated to be worth $1 billion [28].  It is also estimated that each aerial spray of CheckMate LBAM-F and CheckMate OLR-F® is worth $3 million paid directly to the manufacturer Suterra LLC [9].  Initially the US EPA did not approve biopesticide use, but they appear to have slipped through the regulatory net along with GM crops. Health Canada, the federal department responsible for helping Canadians maintain and improve their health has approved the aerial spraying of a Bt formula Foray 48b to control the Gipsy Moth (Lymantria dispar).  The manufacturer Valent BioSciences’ material safety data sheet [29] states that the “inert ingredients – identity withheld as a Trade Secret” are not known to be absorbed by the skin, or cause inhalation or ingestion problems.  The same sheet warns that Foray 48b could possibly irritate target organs, skin, eyes and respiratory tract and goggles and overalls should be used when in contact with it. In West Auckland, New Zealand, an urban population was subject to aerial spray of Bt Foray 48b for moth eradication during cycles of 2-3 weeks for over 2 years.  This was part of multimillion dollar aerial spray campaign between 1996 and 2004 in New Zealand.  A ‘People’s Inquiry’ set up by those whose health was adversely affected by the spray has received support from the independent Ombudsman [30].

There is major concern for the welfare not just of humans and animals, not just for bees, but also for butterflies, and particularly bats, all which are major pollinators of food crops and natural insect predators. Bats are now under significant threat from pesticides [31].

Organic farmers told chemical treatment safe

Ground treatments with Bt, and Spinosad may be utilized in conjunction with aerial pheromone spraying in areas in California where moth larvae have been detected [32]. Bt (Bacillus thuringiensis) kills insects by forming a protein crystal that the bugs ingest. The proteins rip through the innards of insects that go through a worm stage, said Olav Messerschmidt, executive director of the Biopesticide Industry Alliance [28].  The formulations of these products are approved for use on organic crops in the USA, Canada and elsewhere. This has encouraged use by organic farmers and growers in California, who are also told by the National Organic Program (NOP) that they support the combined synthetic pheromone and bt treatment. However, it transpires that the California Certified Organic Farmers (CCOF) has not researched or read, or been provided with any information on CheckMate other than from the NOP or the CDFA. Peggy Miers, the Executive Director of the CCOF said “We are not a health organization and we are not an environment organization, our mission is organic and other organizations will address the health aspects… and environmental aspects. Our needs are to address the needs of our members and the organic marketplace.” [33].

Most opponents of aerial spraying hesitate to question the safety of the pheromones, yet they agree that the additives to the spray mixture (above) are well known to cause the kinds of symptoms observed in Monterey and Santa Cruz [4]. The Californian Alliance to Stop the Spray (CASS) and the Environment and Human Rights Advisory highlight twenty three human rights violations of internationally accepted codes of ethics by the enforced spraying programme that may incur liabilities for the CDPR [34].

CDPR assurances unreliable - synthetic pheromones lack adequate study

It appears that the CDPR has not been entirely honest in expressing their opinion of the aerial spray mixture. They seem to have neglected the well documented toxicity of some spray additives. This has resulted in the reluctance to fully evaluate the impact of the aerial spray on a very large population exposed to the spray. The evidence on the toxicity of the spray additives was clear while the toxicity of the synthetic pheromones is not yet thoroughly studied. There is a growing body of evidence indicating that the synthetic insect pheromones may also be active in mammals and probably in humans. In the fullness of time, it is likely that the synthetic insect hormones will be seen to have behavioural and cellular impacts on vertebrates and humans. Presently, these impacts have been documented in a few cases, but the field is advancing rapidly. Meanwhile, bureaucrats are using the absence of evidence as evidence of the absence of harm.

Article first published 16/05/08


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