Lawn & Garden Pesticides
Increase Rates of Serious Health Problems
Compilation of the Scientific Research
- by - January, 2016

Pesticides used on lawns include 3 types of chemicals - insecticides (for killing bugs) - herbicides (for killing weeds) - and fungicides (for killing fungus). All of these have been found to be harmful to human health. This pesticide toxicology section will address harmful effects of pesticides used on both lawns and golf-courses. Golf courses are a significant exposure source for people living near fairways and greens due to the frequent applications and large grass areas treated. All medical conditions below have been linked with lawn and garden pesticide use. Articles were acquired from the bound Index Medicus at University of Florida Shands Medical Library and through online searches through PubMed. Scroll down to view all studies. Links are are also provided to the original journal article.


Lawn Pesticides Increase Risk of Leukemia in Children

SOURCE: Journal of the National Cancer Institute, 79(1) July 1987
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Children who live in homes where indoor or outdoor pesticides are used face a far greater chance of developing leukemia (leukemia is a cancer in which exceptionally high levels of blood cells are formed in the blood). The study, published in July's 1987 issue of the Journal of the National Cancer Institute, studied 123 Los Angeles children with leukemia and 123 children without the malignancy. The results showed the children living in the pesticide treated homes had nearly 4 times greater risk of developing the disease. If the children lived in homes where pesticides were used in the garden as well, the risk of developing leukemia was 6.5 times greater. All of the children in the study were 10 years of age or younger.

Dr. John Peters
University of Southern California

Worrisome Immune System Weakening Found in People
Exposed to Common Weed Killer

SOURCE: Occupational and Environmental Medicine, Volume 53:583-585, 1996
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Although the weed killer 2,4-D is routinely used on golf-courses and lawns, in this study scientists measured the chemical's effects on 10 farmers who applied 2,4-D to their fields. Results showed a dramatic decrease in immune system function at 12 days after exposure and other effects lasting 2 months.

To get a baseline of immune system counts before spraying, all farmers had their blood drawn and tested for total white blood count, total lymphocytes, T-Cells, Natural Killer cells and Natural Killer activity. Tests were also conducted to measure how fast their lymphocytes would attack a foreign substance (called the PHA and ConA test). After spraying 2,4-D, the farmers were again tested for the same immune system parameters providing a clear before and after picture.

RESULTS: While their total white blood count remained the same before and after spraying (around 6,000 cells per cubic millimeter of blood), the farmers showed a significant 30% decrease in numbers of natural killer cells. (Natural Killer Cells are the first defense your body uses to attack viruses entering the body). Along with this, the ability of natural killer cells to "do their job" and attack other cells decreased by 50%. Another significant finding was that the ability of their lymphocytes to multiply (as when mounting an attack against a virus) was decreased by more than 50% during the 12 day period after spraying and was still decreased by about 25% two months after spraying. As no other types of pesticides were used by the farmers during the study, this provides important documentation on how 2,4-D can seriously weaken the immune system.

WHY THIS IS IMPORTANT: Your immune system protects you from bacteria as well as from viruses that cause the flu - pneumonia and even the common cold. It kills cancer cells and cancer patients with higher immune function have increased rates of remission. With this information in mind, it is certainly understandable that everyone should do whatever possible to have a stronger immune system.

While this study was conducted on farmers, who applied it once during the season, exposure to the same chemical also occurs to people (and neighbors) using chemical lawn applications and also to people living close to golf courses.

STOP SPRAYING COMMENT: Also, as the weakening of immune systems was found among people with normal immune systems at onset, we could expect to see more serious consequences among people who already have weak immune systems to begin with (such as the elderly and children). For example, a 50% reduction in natural killer cell function could be tolerated by someone with a healthy immune system, but could cause severe illness in someone who has low natural killer cell function to begin with. Also of concern, current EPA testing guidelines do not require chemical manufacturers to report detailed immune system effects such as those found here.

Department of Occupational and Environmental Medicine, Linkoping, Sweden
Epidemiology Unit, Lazio Regional Health Authority, Rome, Italy
Local Health Unit, Tarquinia, Italy

Natural Killer Cells Weakened by Weed Killer Atrazine

SOURCE: Toxicology & Applied Pharmacology, Volume 221(2):179-188, June 1, 2007
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Atrazine is one of the most common pesticides used to kill broad-leaf weeds in agriculture and on lawns. After being applied to a lawn, homeowners can be exposed through either direct contact or evaporation that continues for hours and days after application.

Natural Killer cells in humans perform a critical role in eliminating viruses from the body before they cause noticeable infection in the person. In other words, you can thank your natural killer cells for killing viruses hours after entering the body. Natural killer cells work by identifying a virus or cancer cell and then injecting toxic granules into the cell to kill it before the viruses or cancer can spread. Failure of natural killer cells to be successful in this early stage allows viruses (or cancers) to grow faster and to larger numbers.

Of the many chemicals now being found to weaken natural killer cell function, the weed killer atrazine can now be added to the list. Scientists at the Department of Microbiology at West Virginia University found that atrazine reduced the ability of natural killer cells to kill virus infected cells by blocking the release of their "toxic granules" payload into virus infected cells.

Department of Microbiology, Immunology and Cell Biology,
West Virginia University, Morgantown, WV 26506, USA

Brain Cell Function Changes from Atrazine

SOURCE: Environmental Health Perspectives, Volume 113(6):708-15, June, 2005
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Atrazine is a common weed killer and has been shown to be toxic to hormonal systems in females and the reproductive tract in males. Because of the way that atrazine affects the hormonal system, scientists also believed atrazine could cause significant damage to the brain.

In this study, male rats exposed chronically to 5 or 10 mg/kg of atrazine in the diet for 6 months exhibited persistent hyperactivity and altered behavioral responsivity to amphetamine. They found that atrazine exposure could in fact produce neurotoxicity in dopaminergic systems that are critical to the mediation of movement as well as cognition and executive function. Therefore, atrazine may be an environmental risk factor contributing to dopaminergic system disorders, underscoring the need for further investigation of its mechanism(s) of action and corresponding assessment of its associated human health risks.

Environmental and Occupational Health Sciences Institute
Department of Environmental and Occupational Medicine
Robert Wood Johnson Medical School,
University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey

Hyperactivity from Triazole Fungicides

SOURCE: Toxicology Letters, Volume84(3):115-9, March, 1996
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Fungicides are used on golf courses and lawns for control of various fungi. Previous work by the authors found that the fungicide "triadimefon" affects the central nervous system and causes hyperactivity in rats.

This study was done to determine if the same effect occurred after exposure to other triazole fungicides. The researchers set up dose-effect situations in which adult male rats were exposed to 14 different fungicides. Hyperactivity was measured for 2 hours in figure-eight mazes. Results indicated that only the fungicides triadimefon and triadimenol were able to induce hyperactivity. Triadimenol is a primary metabolite of triadimefon.

According to EPA's registration of these pesticides (see archive), the chemical will no longer be used on food (except pineapple) and residential lawns. However, it can still be used on golf courses. The above EPA fact sheet states these two chemicals are neurotoxic and classified as a "possible human carcinogen."

Environmental and Occupational Health Sciences Institute
Department of Environmental and Occupational Medicine
Robert Wood Johnson Medical School,
University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey












Common Turf Fungicides include:
azoxystrobin boscalid captan chloroneb chlorothalonil ethazole fenarimol fludioxonil mancozeb mefenoxam myclobutanil iprodione fosetyl-aluminum polyoxin D Mmyclobutanil (potassium phosphite) propiconazole pyraclostrobin tebuconazole thiram thiophanate-methyl triadimefon trifloxystrobin vinclozolin

Herbicides include - atrazine 2,4-D glyphosphate paraquat benefin balan bensulide tetasan dithiopyr ethofumesate metolachlor oryzaliln oxadiazon pendimethalin prodiamine barracade prodiamine pronamide simazine

isoxaben ethofumesate metoachlor

BINGO - MCPA - triclopyr - dicamba mecroprop quinclorac pyraflufen ethyl trifloxysulfuron

lawn insecticides - cabaryl - methiocarb acephate trichlorfon fipronil bifenthrin cyfluthrin cypermethrin permethrin dinotefuran imidacloprid thiamethoxam spinosad docofol