Background, Research and More

Benefits of Banning Pesticides and Moving to Organic Practices

  • After the Canadian Province of Ontario banned the use of toxic pesticides, a government report found a staggering decline in herbicide concentrations. Median concentrations for herbicides 2,4-D, dicamba, and MCPP, commonly used by both private individuals and lawn care professionals, declined by 81%, 83%, and 71% respectively.

  • Research from the University of Maryland finds that mowing at the proper height alone can reduce weed and diseases by 50 to 80% in tall fescue grass, a variety used throughout Maine.
  • A 2010 report by Grassroots Environmental Education found that once established, a natural/organic turf management program can result in savings of greater than 25% when compared to the conventional approach.

Hazards to Children and Human Health

  • A 2017 study in the International Journal of Cancer links residential use of pesticides to a 1.4x increased risk of a child developing a brain tumor before the age of 15.

  • A 2015 study in Environmental Health found that children between ages 8 and 15 that had detectable levels of commonly used pyrethroid insecticides in their urine were twice as likely to have ADHD as children who did not have the chemical in their bodies, with boys exhibiting a stronger correlation than girls.

  • A 2004 study in Children’s Health found that infants exposed to herbicides within their first year of life are 4.5 times more likely to develop asthma by the age of five.

  • In 2012 the American Academy of Pediatrics (AAP) called for local governments to reduce children’s exposure to pesticides. AAP wrote that scientific evidence “…demonstrates associations between early life exposure to pesticides and pediatric cancers, decreased cognitive function, and behavioral problems.”

  • A 2015 study in Pediatrics found that residential use and exposure to herbicides during childhood increases the risk of leukemia by 26%.

  • Of the 30 most commonly used lawn pesticides, 16 are possible and/or known carcinogens, 17  have the potential to disrupt the endocrine (hormonal) system, 21 are linked to reproductive effects and sexual dysfunction, 12 have been linked to birth defects, 14 are neurotoxic, 25 can cause kidney or liver damage, and 26 are sensitizers and/or irritants, as outlined in this Beyond Pesticides Factsheet.

Dangers to Pets

Impacts to Water Quality and Soil Health

Synthetic and high nitrogen fertilizers can disrupt the nutrient balance of the soil, accelerate turf growth, increase the need for mowing, and contribute to thatch buildup. Synthetic pesticides harm the microorganisms, beneficial insects and earthworms, that are essential to maintaining healthy soil, and therefore healthy turf.

Numerous empirical studies have documented adverse impacts to aquatic ecosystems from the use of synthetic pesticides, summarized at this South Portland Stormwater Runoff and Pesticides workshop.

  • Sampling conducted by Friend of Casco Bay has detected the presence of the herbicides 2,4-D, dicamba, chlopyralid, MCPA, and MCPP, the synthetic pyrethroid insecticides bifenthrin and sumithrin, and the fungicides propiconazole and chlorothalonil in sediment or outflow.
  • The 2008 President’s Cancer Panel Report on Reducing Environmental Cancer Risk notes that “Fertilizers, herbicides, and pesticides used for residential and other landscaping purposes (e.g., parks, golf courses), in some cases the same as those used on farms, represent a considerable component of water contamination because they seep into groundwater and runoff into streams, rivers, and other drinking water supplies.” The report adds that, “in addition, individuals can be exposed to these chemicals by swimming in or eating seafood from contaminated bodies of water.”

  • A 2015 study in Scientific Reports found that the use of glyphosate (Roundup) reduced activity and reproduction in earthworms, and led to increased soil nitrate and phosphate concentrations, pointing to increased risk of these nutrients leaching into local streams, lakes, and groundwater.

  • A 2014 study in Soil Biology and Chemistry found that earthworms on conventionally managed land spent significant energy detoxifying pesticides, leading to smaller and fewer worms when compared to organically managed land.  

Threats to Pollinators and other Wildlife  

  • Of the 30 most commonly used lawn pesticides, 22 are toxic to birds, 29 are toxic to bees, and all 30 are toxic to fish and aquatic organisms, as outlined in this Beyond Pesticides Factsheet.  

  • A 2016 study in Scientific Reports found that systemic insecticides such as neonicotinoids can be taken up by nearby plants and exuded in the pollen, nectar, and dew droplets honey bees and other pollinators feed on.

  • In 2017 an international group of scientists reiterated earlier warnings that widely used systemic insecticides, including neonicotinoids and fipronil often used in residential lawns, are poisons, “and the chronic damage caused can include: impaired sense of smell or memory; reduced fecundity; altered feeding behavior and reduced food intake including reduced foraging in bees; altered tunneling behavior in earthworms; difficulty in flight and increased susceptibility to disease.”

Issues with EPA’s existing pesticide regulations