The Problem with Pesticides
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What's the Problem with Pesticides? By Dr Sharyn Martin, PhD. June 2005
Pesticides have become a part of modern society. There are very few places where pesticides are not used in any form. Indeed those with chronic health conditions such as chemical sensitivity are having an extremely difficult time finding such places to live. The potential for frequent contact with pesticides is high and is resulting in overlapping, cumulative exposures to pesticides that are potentially causing ill health in the community. The evidence that people are being exposed to a range of different chemicals, including pesticides (old, new & banned), can be found in the Body Burden/Monitoring studies being performing in America. These studies are showing that a large number of chemicals (including pesticides) or their metabolites are being found in the human blood and urine.
Lawn, garden and household pesticides are used
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On Residential lawns & gardens,
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for Home pest infestations – wasps, cockroaches, ants,
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as Scabies & lice treatments,
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in Pet flea/tick collars & treatments,
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on Golf courses,
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for mosquito control in the urban environment,
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for weed control on Highway verges,
Railway Lines, -
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Public parks & gardens,
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Schools,
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Hospitals etc.
Agricultural pesticides are used
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on Farms,
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in Greenhouses & Orchards,
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and trace amounts maybe present in Farm produce and Food products.
Those pesticides used outdoors can be tracked into the house on shoes and clothing. For both househo
In addition pesticide residues can linger for hours, days and even months after application.
While for the large majority of the population pesticide exposure does not cause overt symptoms of pesticide poisoning, there are other subsets in the community who are more sensitive to their effects. These vulnerable groups include pregnant women, children, the elderly, allergy sufferers, those with asthma and other respiratory diseases, the chemically sensitive and the chronically ill. For children the risk is much higher due to factors such as their developing physiology, and longer life expectancy over which cancers & other chronic health problems can develop. For children there are critical windows when pesticide exposures are more harmful. Links have been made between low level intrauterine, early childhood and adolescent exposure to environmental agents (including pesticides) and neurotoxic effects, developmental delays and behavioural disorders. During adolescence and early adulthood when hormonal changes are at their peak the risks are also high.
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In Australia a lot of effort has been put into bringing the adverse reporting scheme (AERP- Ag) to fruition. It is only by accurate reporting that an evaluation of pesticide effects can be made and dealt with. But people cannot report what they do not know about and Drs cannot diagnosis what they do not know about. People may (or may not) go to the GP with non-specific symptoms such as flu-like feeling, rashes, fatigue etc and are not aware that these can be due to pesticide exposures. As many of the symptoms are non-specific it is only by precise differential diagnosis that the cause can be determined. Physicians must be able to recognise these effects when patients present so they can provide appropriate medical care & advice. Physicians are also crucial in prevention of adverse reactions through patient education .
Both the Ontario College of Family Physicians and Health Care Without Harm Organisation acknowledged that pesticide induced illness is often undiagnosed or misdiagnosed due to lack of early training of medical students of the effects of pesticides and other chemicals and human health.
HEALTH EFFECTS OF PESTICIDES:
Rather than citing numerous individual research studies I have selected a few review articles and large scale studies that are particularly relevant, and from which a generalised overview of the problem can be gained.
The Ontario College of Family Physicians completed a Systematic review of studies done from 1992 on pesticide health effects. “This systematic review of pesticide health effects was undertaken to help family physicians and their patients interpret the large body of literature in this area and make effective decisions about prevention efforts. These include patient education, identification of vulnerable groups, risk assessment, and clinical problem solving. We also identified areas where existing information is insufficient to inform clinical decision-making.”(OCFP, 2004). Ontario College of Family Physicians. Systematic Review of Pesticide Human Health Effects. 2004. www.ocfp.on.ca
Summary of Review findings
“The results of the systematic review do not help indicate which pesticides are particularly
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harmful. Exposure to all the commonly used pesticides — phenoxyherbicides, organophosphates, carbamates, and pyrethrins — has shown positive associations with adverse health effects. The literature does not support the concept that some pesticides are safer than others; it simply points to different health effects with different latency periods for the different classes.” (OCFP, 2004)
Health Care Without Harm http://www.noharm.org/ is an international coalition of hospital & health care systems, medical professionals, community groups, environmental health organisations & other groups. They have published a report on pesticides titled Healthy Hospitals, Controlling Pests without Harmful Pesticides. Kagan Owens, A 2003 Report By Beyond Pesticides - Health Care Without Harm. 2003. Their study found that - “Hospitals are intended to be places for health and healing. Yet the findings of a survey of top U.S. hospitals indicate that major hospitals in the U.S. are regularly using toxic pesticides. This puts the health of patients and staff at risk and raises questions about the safety of hospitals.” HCWH, 2003)
Summary of Health Care Without Harm review findings on the health effects of pesticides.
“Pesticides are hazardous chemicals designed to kill or repel insects, plants, and animals that are undesirable or that threaten human health. Many of them contain volatile compounds that contribute to poor indoor air quality. In addition to killing pests and beneficial organisms, in humans pesticides can exacerbate asthma and cause other acute adverse effects including nausea, headaches, rashes, and dizziness. Many pesticides are also linked to chronic effects, such as cancer, birth defects, neurological and reproductive disorders, and development of chemical sensitivities.” (HCWH, 2003)
RISK FACTORS AND VULNERABLE GROUPS
There are numerous risk factors for any individual that will determine the extent of adverse effects from a pesticide exposure. Risk factors vary widely among individuals, toxicants and diseases. Individual risk factors include, When exposed (in utero, young, older, early childhood), Age, Gender, Amount of exposure, What other toxicants they are exposed to, Lifestyle factors, Individual susceptibility/ genetic variations, Occupational exposure, etc. (OCFP, 2004; HCWH, 2003.)
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There are also vulnerable groups for whom these risk factors are even more important. This may be due to their occupation, physiology, health status or developmental stage of life.
At risk groups include, Women of childbearing age, Children, Elderly, Farmers, Pesticide applicators, Professional gardeners, Home owners with lawns &/or gardens, Floriculturists, Greenhouse workers, Chemically Sensitive, Individuals with Genetic variations that lead to increased susceptibility. (OCFP, 2004).
Children are even more susceptible to toxicants than adults. Apart from their developing physiology that is more sensitive to toxicant effects they are potentially exposed to more pesticides. They can accumulate more pesticides due to exposures via the placenta & breast milk; in foods (as children eat proportionately more than adults compared to body weight); via Indoor & outdoor pesticide application of homes & schools that can lead to exposure by playing on floors, treated lawns & play areas, handling treated pets; or by spray drift or farm work that can expose children to agricultural chemicals. Associations have been made been parental occupational exposure and an increased risk of birth defects and intrauterine growth retardation.
INDIVIDUAL SUSCEPTIBILITY AND BIOMARKERS
Environmental Health Perspectives is a fully peer-reviewed monthly publication of the National Institute of Environmental Health Sciences ( NIEHS ), the Public Health Service, U.S. Department of Health and Human Services, and is a forum for the examination, discussion, and dissemination of news, scientific research, and ideas relating to issues and advances in environmental health. The EHP Toxicogenomics issue, Vol 111, No 11, August, 2003 highlighted the advances in Biomarker research. These studies are elucidating some of the mechanisms behind individual susceptibility to pharmaceuticals and environmental agents. The Environmental Genome Project is studying individual genetic differences and how they can influence disease risk from environmental agents. (EHP Toxicogenomics, 2003, V111, No11. August 2003). EHP homepage EHP Online
Single Nucleotide Polymorphisms (SNP’s) for example are thought to be important in determining disease susceptibility and the group is resequencing > 200 environmentally
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responsive genes for the purpose of identifying potential SNP’s. Some people are more sensitive to insecticides & possibly nerve agents because of genetic variability in the gene that regulates production of paraoxonase-1 (PON1). [PON1 oxidises lipids, metabolises Organophosphate Pesticides & activates or inactivates medications including statins, glucocorticoids & antibiotics.]
Metabonomics (metabolic profiling) studies biofluids & tissues to determine metabolites present both in homeostasis and when an organism is affected by factors such as environmental exposures. These studies are looking for information about metabolic pathways, novel biomarkers, how metabolites interact with genes and proteins as well as with environmental, nutritional & lifestyle factors. This will determine the phenotypic expression of individual genetic variations.
Toxicoproteomics the use of protein expression analysis techniques to discover biomarkers that reflect toxicant exposure or environmental disease. Profiling of protein changes over the course of pretoxic, toxic and recovery stages of chemical exposure may eventually link the protein expression patterns of multiple organ systems involved in toxicant action.
SYMPTOMS AND CHRONIC HEALTH PROBLEMS RELATED TO PESTICIDE EXPOSURE
Typical symptoms found to arise following an acute exposure to pesticides include nausea, dizziness, headache, aching joints, mental disorientation, intractable migraine headaches, inability to concentrate, vomiting, convulsions, skin irritations, flu-like symptoms & asthma-like problems.
Chronic health effects include cancer (children & adults), birth defects, genetic damage, neurological, psychological & behavioural effects, blood disorders, chemical sensitivities, reproductive effects & abnormalities in liver, kidney & immune system function. These chronic health effects can develop following either an acute poisoning or low level exposure over a period of time. (OCFP, 2004; HCWH, 2003, Body Burden, 2003)
IS THERE EVIDENCE THAT HUMANS ARE ACCUMULATING PESTICIDES AND OTHER CHEMICALS IN BODY TISSUES.
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Body Burden Studies:
Body Burden Programs are providing direct measurement of environmental chemicals, their primary metabolites or reaction products (such as DNA adducts) in blood or urine of American individuals. These studies are showing that a large number of chemicals are being found in the human body – blood and urine. The concentration at which, or mixture of substances at which, adverse health effects develop will vary depending on an individual’s susceptibility to their effects.
US Based National Report on Human Exposure: Environmental Working Group Body Burden Information
US CDC National Centre Environmental Health Monitoring Program: www.cdc.gov/nceh/trackin g Environmental Public Health Tracking
US CDC. NCEH. 2nd NHEXAS report Exposure Report
WHY IS THE OPINION THAT PESTICIDE HEALTH EFFECTS ARE LOW?
“Pesticide poisonings are frequently misdiagnosed or unrecognized, largely because most health care providers receive minimal training in environmental illnesses and few people know when they have been exposed to a pesticide.” (HCWH, 2003)
“We also identified areas where existing information is insufficient to inform clinical decision-making.” (OCFP, 2004)
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The conclusion drawn from these reviews is that there is a problem that needs to be addressed and further studied. Patients trust their family doctor as a source of information on environmental questions and can more effectively communicate the risks associated with pesticide use. Clinicians need more information about the issues in order to best diagnose, advise and treat patients.
“Very few of our patients willingly expose themselves to harmful chemicals, but information about pesticide health effects is not common knowledge, and we are in an excellent position to make it so. Strong one-to-one messages from health care providers about the potential harm from pesticide exposure are an effective way to inform our patients. The evidence for harm is strong, and just as the public became aware of the health risks of smoking over decades of education, we now have an important role in heightening awareness of the risks of pesticide exposure.” (OCFP, 2004).
With the wide range of commonly used home and garden pesticide products associated with health effects, the authors felt that the message to patients should focus on reduction of exposure to ALL pesticides. (OCFP, 2004)
EXAMPLE OF WHAT IS BEING DONE IN AMERICA
OCFP Recommendations to Physicians
Educate patients to the potential health effects of pesticides and promote awareness of ways in which to avoid or minimise exposure to chemical hazards in the home, community & workplace. Supply information on organic methods of lawn & garden care and indoor pest control, educate patients about the high skin absorption of pesticides and the need for adequate personal protection equipment (gloves, glasses, mask/respirator etc) when using pesticides.
US National Environmental Education & Training Foundation (NEETF):
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NEETF have published the National Strategies for Health Care Providers: Pesticides Initiative Implementation Plan. This aim of this plan is to improve prevention, recognition & management of pesticide poisonings by increasing education of physicians, nurses and other health care providers about pesticides,
National Institute Environmental Health Services (NIEHS): During the 90’s provided grants for medical schools to develop academic curricula for environmental/occupational undergraduates and post graduate medical education. www.aoec.o rg Education Resources. The page http://www.aoec.org/CEEM/CEEM_courses.html lists the courses offered at various US Health Education Centres.
THE USAGE OF PESTICIDES IN AUSTRALIA.
The following table uses Australian Pesticide Usage data from Pesticide Use in Australia, 2002. A review undertaken by the Australian Academy of Technological Sciences & Engineering. This study reviewed agricultural pesticides use only and did not take into account the amount used for lawn, garden and household pesticides. The amounts today may be higher again as the data for this review is now five years old.
Pesticide Volume Increase/Decrease over 1996 to 1999
Most common chemical used in this Pesticide category
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Amount Used per annum
1999 DATA
Herbicides
Down 2%
Glyophosate
15,000 tonnes
Atrazine & simazine
3,000 tonnes
Plant cell growth disruptors phenoxys,
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benzoic acids & pyridines (2,4-D & derivatives & MCPA)
> 1,000 tonnes
Insecticides
Up 40%
OP’s (parathion methyl, chlorpyriphos, dimethoate, profenos, & diazinon)
5,000 tonnes
Carbamates (Acetyl choline esterase inhibitors – Metham sodium most common used)
3,000 tonees
GABA-gated chloride channel antagonists (Endosulfan
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[acyclodiene OC], Fipronil)
500 tonnes
Pyrethroids & Pyrethrins (compromising of ~ 20 chemicals)
200 tonnes
Fungicides
Up 46%
Mancozeb (dithiocarbamate) and Captan (cyclic imide)
> 3,000 tonnes
Plant Growth Regulators
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Up 7%
Ethephon (ethylene generator)
> 500 tonnes
While the usage of herbicides in Australia was down 2% over the 1996 to 1999 time period, the volume of herbicides used is higher than for all the other categories. Glyophosate usage is at least 5 times higher than for any other pesticide. Round up, active ingredient Glyophosate, also contains a number of other ‘inert ingredients’. The inerts themselves are associated with a range of acute effects including eye irritation, nausea, diarrhea, skin and respiratory reactions. According to the California Department of Pesticide Regulation, glyophosate ranks first among herbicides as a cause of pesticide related illness in people in California. Health Care Without Harm, 2003.
Pesticide use in urban and agricultural areas
“There are about 50,000 farms, plant nurseries, government agencies, local authorities, sports clubs and commercial pesticide applicators that use pesticides on a commercial scale in NSW. These entities are estimated to make a minimum of between 600,000 and 900,000 separate pesticide applications each year. This is divided into 250,000 to 500,000 applications in the agricultural, farming, forestry, sporting and public sectors, and 380,000 applications by urban pest controllers and fumigators Data provided by ABS (1996) shows that in 1991–92, over 700,000 L of herbicide, insecticide and fungicide were collectively applied to between 3.3 million and 4.5 million hectares of land in NSW.” NSW EPA, 2001.
NSW EPA. 2001. Regulatory Impact Statement and Proposed Pesticide Amendment Regulation 2000.
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These volumes are likely to have increased again over the last 9 years. The numbers of applications and volume of pesticides used are likely to be higher again in states such as Queensland where mosquito infestations are a large problem. Aerial and ground application of mosquito pesticide treatments occur on a regular basis in densely populated urban areas. Mosquito control treatments use a range of different insecticides such as organophosphates (malathion), Insect Growth Regulators (Methoprene), Pyrethin based products and biologicals such as Bti.
Data from the National Registration Authority for Agricultural and Veterinary Chemicals (NRA 1999) shows that the value of pesticide sales in Australia in 1998 exceeded $1.5 billion, of which $1.26 billion was for sales of herbicides, insecticides and fungicides for agricultural and commercial use. The remaining $0.24 billion would correspond to that sold for domestic household use, representing 16% of pesticide sales in Australia.
HEALTH EFFECTS IN AUSTRALIA:
An example of a pesticide affected cluster community occurring in Australia can be found in the 1996 Preliminary Report of the Health Impact of Pesticides on Affected Persons in the Gunnedah Community. By Fragar et al 1996. Australian Centre for Agricultural Health & Safety Moree. This study found that Cotton Pesticides associated with rhinitis, asthma and headache.
In NSW during the 1996 to 1999 period 917 serious pesticide incidents requiring investigation were reported to the NSW EPA. Of these 100 were wilful misuse, 363 involved aerial applicators and urban pest controllers, and the remaining 450 involved reports of spray drift, health safety, odour concerns, residue violations or complaints about baiting. Workers compensation data for NSW shows approximately 20 claims per year for pesticide injury. The NSW EPA report states that this is likely to significantly under represent pesticide injury as not all cases are covered by Workers compensation and not all people affected will necessarily present at a public hospital. NSW EPA, 2001.
The health care costs of chronic diseases and disabilities in Australia is not known but the Collaborative on Health and Environment (CHE) http://www.cheforhealth.org/ estimated that the economic cost of chronic diseases and disabilities excess $325 billion yearly in health costs
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and lost productivity in the US.
It is not only health care costs to take into consideration. In NSW three shearers suffering from organophosphate poisoning were awarded nearly $700,000 in compensation from their former employer. The shearer’s suffered symptoms such as headaches, rashes, itching, stomach symptoms and, for two of the shearers, diarrhea.(NSW EPA, 2001).
THE FUTURE AND THE PROBLEMS
There is a multitude of other studies, government and non government organisations, research institutes & websites on this topic. For toxicological studies to provide any meaningful data, the conditions under which any substance is tested must be tightly controlled in order for it to be reproducible and to give any statistical analysis credibility. Humans in everyday life do not conform to these tight controls. For any medical study, variables are difficult to manage and human control groups are not as genetically stable and identical as in animal studies (especially those using mice and rats). For these reasons any potential adverse health effects in humans (with enormous variations) will not be evident until the substance is on the market and in use. And because of this same variability it can also be expected that there are a variety of health effects of varying intensity within a population. GP’s are likely to be the first to see any emerging health problems. But if basic medical training does not provide adequate coverage in medical courses they will be unable to recognise it and provide appropriate advise and treatment.
References:
(OCFP, 2004) Ontario College of Family Physicians. Systematic Review of Pesticide Human Health Effects. 2004. www.ocfp.on.ca
(HCWH, 2003)/span>Healthy Hospitals, Controlling Pests without Harmful Pesticides. Kagan Owens, A Report By Beyond Pesticides - Health Care Without Harm. 2003. http://www.noharm. org/
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(Body Burden, 2003) Environmental Working Group Report - Body Burden, J Houlihan, R Wiles, K Thayer & S Gray, Jan 2003. www.ewg.org
NSW EPA. 2001. Regulatory Impact Statement and Proposed Pesticide Amendment Regulation 2000.
Pesticide Action Network North America: http://www.panna.org/
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