Immune System Weakened by Pesticides

Interleukin I Damaged by Pesticides
Researchers at the Department of Biology at the Virginia Polytechnic Institute and State University, Blacksburg Virginia have conducted several studies on the ability of the pesticide aldicarb to alter immune system function. Groups of test animals were injected with small amounts of water containing various levels of the pesticide at .1, 1, 10, 100 and 1000 parts per million. Their results showed that all pesticide groups experienced a reduction in the ability of macrophages (a type of white blood cell) to stimulate proper function of helper T-cells. The scientists stated that all evidence suggested that the pesticide damaged the ability of the macrophages to produce interleukin-1. Macrophages normally produce interleukin-1 after coming in contact with a virus or other antigen. The interleukin-1 then starts the production of interleukin-2 which then begins the proliferation of immune system cells called T-cells.

Cancer Killing Ability Weakened in Macrophages
Other studies of aldicarb reported in the 1989 Bulletin of Environmental Contamination and Toxicology found the pesticide also decreases the ability of macrophages to kill cancer cells, however, aldicarb did not weaken the ability of natural killer cells to attack cancer cells.

Potatoes Routinely Contain Highly Toxic Pesticide
The pesticide aldicarb has also been found in food sources. A 1987 analysis of over 28 samples of potatoes by the Florida Department of Agriculture from major grocery store chains, including Winn Dixie and Publix, found that aldicarb was present in 57% of the potatoes sampled at levels averaging close to 60 parts per billion. This information coupled with the previous research on the dangers of aldicarb raises serious concern regarding the long term consumption of commercially grown potatoes and its effects upon the immune system.

Respiratory Infections Higher in Pesticide Workers
As many as 16 million people may be allergic to commonly used pesticides according to Dr. Russell Jaffe, director of a biotechnology laboratory in Resten, Virginia. Pesticides can enter the body not only from water and food sources, but also from inhalation from home or yard applications.

A study was done to determine the frequency of infections in 85 workers exposed to organophosphate pesticides in their workplace. The workers were also examined for several other functions of their immune system. The study, published in the 1984 journal Clinical Immunology and Immunopathology, found more than twice the frequency of infections in the pesticide workers. The infections were mainly localized in the upper respiratory tract. The study also found a "marked impairment" of what is called neutrophil chemotaxis. (Chemotaxis is a test which measures how well neutrophils are attracted to a particular problem area in the body).

Although not a direct immune system study, the National Cancer Institute published a 1985 report that Florida pesticide workers employed for 20 or more years faced nearly a 3 times greater risk of developing lung cancer and twice the risk for developing brain cancer. Keep in mind that it is your immune system that removes cancer cells that have begun growing in the body.

Child Cancer Linked to Home Pesticides
Approximately 90% of Florida homes have regular indoor pesticide treatments to help control roaches and insects. A 1987 study conducted by Dr. John Peters at the University of California, and reported in the Journal of the National Cancer Institute, found that children exposed to regular home pesticide applications had approximately 3 and one-half times greater risk of developing leukemia. If the children were exposed to outdoor pesticides as well they had nearly 6 times increased risk for leukemia.

Autoimmune Problems Caused by 2 Pesticides
EPA finally banned the use of the pesticide chlordane in 1988, but not until the chemical had contaminated tens of thousands of homes and caused a flood of health problems. Chlordane was used from the 1950’s through the 1980’s to prevent termite problems in homes for many years. It has only been since 1988 that the EPA finally banned its use because of increasing reports of health problems and home contamination.

Dr. Allen Broughton and Roberta Madison studied 21 patients at the Department of Health Science at California State University. The patients included 3 individuals also exposed to the more common organophosphate pesticides - a 40 year old female who was exposed to Dursban/Vapona at her pet shop, a 33 year old male who was exposed to Dursban for 14 months while treating cattle and a 62 year old female who was exposed to malathion from the aerial spraying of crops. Each patient first had a flu-like illness followed by chronic health complaints including fatigue, malaise, headaches, loss of memory, difficulty with task, muscle and joint pain. The study was not conducted immediately after the exposure, thereby it was measuring long term and not short term effects. Although the results found no difference in total number of white blood cells and lymphocytes, it did find there was a large increase in what are called "autoantibodies" in the pesticide exposed patients (remember, autoantibodies are malfunctioning antibodies that are attacking healthy tissue by mistake). In fact, autoantibodies were found against five organ systems. Out of eleven patients tested, nine had antimyelin autoantibodies directed against peripheral myelin. (Mylelin is the insulation covering that surrounds all nerves and must remain intact for proper nerve transmission.

The researchers concluded by stating,

"the presence of autoantibodies suggests that chlordane exposure has caused injury to the myelin sheath." The myelin must remain intact for proper nerve function. The researchers also stated, ".....perhaps the autoimmunity is the basis for their chronic health problems."

Common Home Pesticide Lowers Blood Counts
The pesticide chlordane is being detected in the majority of homes tested and is considered a health risk in many U.S. homes. Chlordane was used regularly as a termite preventive for over 30 years, finally being banned in 1988, but unfortunately, not before contaminating millions upon millions of U.S. homes.

In an unpublished study by the makers or chlordane (Velsicol Inc.), and reported by Dr. David Ozonoff Boston University School of Public Health (Teratogenesis, Carcinogenesis, and Mutagenesis 7:527-540, 1987 ), it was reported that inhalation of the pesticide chlordane by monkeys, over a dose range from 100 to 1,000 ug/m3 for a 90 day period, induced a statistically significant incidence of leukopenia (low white blood cell counts) and thromobocytopenia with effects seen even at the lowest dose tested (Huntingdon Research Laboratories: "Chlordane" A Ninety-Day Inhalation Toxicity Study in the Rat and the Monkey." Unpublished report to the Velsicol Company, June 1984.) Although approximately 75% of homes built before 1988 are routinely being found to contain air levels of the pesticide chlordane, a study by Dr. Richard Fenske at Rutgers University in New Jersey found a startling 34% homes built before 1982 contain air chlordane levels over the safety limit of 5 micrograms per cubic meter of air, set by the National Academy of Sciences. There is no definite data on the number of homes in the United States that have been treated with chlordane, however, in 1987 the National Pest Control Association estimated that 1.5 million homes per year were treated for termite control (8) get Birth Defect Book for reference...... Taking information from several studies regarding chlordane being found in homes today, it could be estimated that 100-185 million U.S. residents are breathing chlordane in their homes daily and 10-20 million U.S. residents could be living in homes where the indoor air levels of chlordane are exceeding the recommended safe limits set by the National Academy of Sciences (set at 5 micrograms per cubic meter). Once the scale of this problem is brought to the publics’ attention, it should dwarf the concerns previously generated by formaldehyde and radon. In a review of the chlordane home contamination problem and its link to childhood cancers and blood disorders, Dr. David Ozonooff, of the Boston University School of Public Health stated, "a national program for monitoring all homes treated is urgently needed to detect persistent contamination (9)." Because of the importance of understanding the extent of exposure of the population to air levels of pesticides, the first section below summarizes the research on air levels of pesticides in buildings.

The Majority of U.S. Homes Emit Pesticide Vapors
A common misconception among the public is that pesticides used for termite or insect control are safe once applied and do not find their way into the breathable air space of the home.  In fact, the long term exposure of home and building occupants to the evaporation of these chemicals has been found to continue in some cases for many decades after application and has resulted in the permanent evacuation of some buildings. Below is a summary of studies assessing air levels of common pesticides in homes. Although pesticides are tested for many health effects such as cancer, skin irritation, fatality risk, and major birth defects, they are currently not required to be tested for subtle neurological effects such as with memory, learning problems or effects upon behavior.

Home Indoor Air Pesticide Contamination Summary

Flea Home Treatments Cause Illegally High Air Pesticide Levels
Applying common flea pesticide treatments to carpets results in illegally high air pesticide levels in homes which lasts for over 24 hours after application. This was the conclusion of research conducted by Dr. Richard A. Fenske, Assistant Professor at Rutgers University.

Tests were conducted by applying the common pesticide Chlorpyrifos (Dursban) for flea treatment by a licensed Pest Control Applicator to three rooms of an unoccupied apartment in New Jersey in June, 1987. Air sampling equipment was installed above the floor at the levels expected for an adult sitting in a chair and that of an infant. After application, samples were taken at 30 minutes, 1 hour, 1.5 hours, 3 hours, 5 hours, 7 hours and 24 hours. Results showed that at 5 hours post application, indoor air levels of the pesticide was nearly twice above the legal limit in homes with ventilation (an open window) and over 6 times above the legal limit at 7 hours where windows were closed. Levels at the infant breathing zone was nearly 10 times above the legal limit at 7 hours and over 3 times the legal limit even after 24 hours.

These results show it is incorrect when Pesticide Applicators state it is safe to return home several hours after application. In fact, levels at 7 hours were 3-5 times higher than the 1.5 hour level.

In conclusion the researchers stated,

"Despite uncertainties in exposure/absorption estimates and toxicological interpretation, the dose values derived in this study raise a public health concern. Broadcast applications and possibly total release aerosol/fogging applications of acutely toxic insecticides may result in dermal and respiratory exposures sufficient to cause measurable toxicological responses in infants.

Dr. Richard A. Fenske, Ph.D., MPH, Kathleen G. Black, MPH, Kenneth P. Elkner, MS
Department of Environmental Sciences and Graduate Program in Public Health, Rutgers University
American Journal Public Health, 80(6):689-693, 1990

School Poisoning from Pesticides
Chlordane exposure is always of great concern because, unlike other pesticides that diminish after weeks or months, chlordane can continue outgassing for over 30 years and is one reason why it was banned.

Students and teachers at Andrew Jackson Junior High School in West Virginia were complaining for four years about persistent fatigue, headaches, respiratory problems, nausea and numbness in limbs. The school was finally shut down in May 1989 when NIOSH investigators found chlordane levels 11 times higher than the National Academy of Sciences Evacuation limit. Not only has chlordane been found to cause defects in immune function, but very small levels of chlordane have also been found to cause abnormal liver function tests and subtle neurological problems from concentration problems to depression.
Form more information on the chlordane problem visit our chlordane information site.

Other Research on Pesticides Affecting the Immune System by the World Resources Institute