human health

What Is A Pesticide?

According to the Environmental Protection Agency (EPA), the government body that regulates pesticides in the U.S., a pesticide is any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest. Though often misunderstood to refer only to insecticides, the term pesticide also applies to herbicides, fungicides, and various other substances used to control pests. Pesticides also include plant regulators, defoliants and desiccants.

The Problem with Pesticides

Pesticides are the only toxic substances released intentionally into our environment to kill living things. This includes substances that kill weeds (herbicides), insects (insecticides), fungus (fungicides), rodents (rodenticides), and others.

The use of toxic pesticides to manage pest problems has become a common practice around the world. Pesticides are used almost everywhere -- not only in agricultural fields, but also in homes, parks, schools, buildings, forests, and roads. It is difficult to find somewhere where pesticides aren't used -- from the can of bug spray under the kitchen sink to the airplane crop dusting acres of farmland, our world is filled with pesticides. In addition, pesticides can be found in the air we breathe, the food we eat, and the water we drink.

When Rachel Carson wrote Silent Spring in 1962, she raised public awareness about the effects of pesticide use on our health and our environment. However, almost forty years after Carson drew attention to the health and environmental impacts of DDT, use of equally hazardous pesticides has only increased. And all the time there is more evidence surfacing that human exposure to pesticides is linked to health problems. For example, in May 2010, scientists from the University of Montreal and Harvard University released a study that found that exposure to pesticide residues on vegetables and fruit may double a child’s risk of attention deficit hyperactivity disorder (ADHD), a condition that can cause inattention, hyperactivity, and impulsivity in children.

Pesticides are used in our schools, parks, and public lands. Pesticides are sprayed on agricultural fields and wood lots. Pesticides can be found in our air, our food, our soil, our water and even in our breast milk.

Pesticides and Human Health

Pesticides have been linked to a wide range of human health hazards, ranging from short-term impacts such as headaches and nausea to chronic impacts like cancer, reproductive harm, and endocrine disruption.

Acute dangers - such as nerve, skin, and eye irritation and damage, headaches, dizziness, nausea, fatigue, and systemic poisoning - can sometimes be dramatic, and even occasionally fatal.

Chronic health effects may occur years after even minimal exposure to pesticides in the environment, or result from the pesticide residues which we ingest through our food and water. A July 2007 study conducted by researchers at the Public Health Institute, the California Department of Health Services, and the UC Berkeley School of Public Health found a sixfold increase in risk factor for autism spectrum disorders (ASD) for children of women who were exposed to organochlorine pesticides.

Pesticides can cause many types of cancer in humans. Some of the most prevalent forms include leukemia, non-Hodgkins lymphoma, brain, bone, breast, ovarian, prostate, testicular and liver cancers. In February 2009, the Agency for Toxic Substances and Disease Registry published a study that found that children who live in homes where their parents use pesticides are twice as likely to develop brain cancer versus those that live in residences in which no pesticides are used.

Studies by the National Cancer Institute found that American farmers, who in most respects are healthier than the population at large, had startling incidences of leukemia, Hodgkins disease, non-Hodgkins lymphoma, and many other forms of cancer.

There is also mounting evidence that exposure to pesticides disrupts the endocrine system, wreaking havoc with the complex regulation of hormones, the reproductive system, and embryonic development. Endocrine disruption can produce infertility and a variety of birth defects and developmental defects in offspring, including hormonal imbalance and incomplete sexual development, impaired brain development, behavioral disorders, and many others. Examples of known endocrine disrupting chemicals which are present in large quantities in our environment include DDT (which still persists in abundance more than 20 years after being banned in the U.S.), lindane, atrazine, carbaryl, parathion, and many others.

Multiple Chemical Sensitivity (MCS) is a medical condition characterized by the body's inability to tolerate relatively low exposure to chemicals. This condition, also referred to as Environmental Illness, is triggered by exposure to certain chemicals and/or environmental pollutants. Exposure to pesticides is a common way for individuals to develop MCS, and once the condition is present, pesticides are often a potent trigger for symptoms of the condition. The variety of these symptoms can be dizzying, including everything from cardiovascular problems to depression to muscle and joint pains. Over time, individuals suffering from MCS will begin to react adversely to substances that formerly did not affect them.

For individuals suffering from MCS, the only way to relieve their symptoms is to avoid those substances that trigger adverse reactions. For some individuals, this can mean almost complete isolation from the outside world.

Pesticides and Children

Children are particularly susceptible to the hazards associated with pesticide use. There is now considerable scientific evidence that the human brain is not fully formed until the age of 12, and childhood exposure to some of the most common pesticides on the market may greatly impact the development of the central nervous system. Children have more skin surface for their size than adults, absorb proportionally greater amounts of many substances through their lungs and intestinal tracts, and take in more air, food and water per pound than adults. Children have not developed their immune systems, nervous systems, or detoxifying mechanisms completely, leaving them less capable of fighting the introduction of toxic pesticides into their systems.

Many of the activities that children engage in - playing in the grass, putting objects into their mouth and even playing on carpet - increase their exposure to toxic pesticides. The combination of likely increased exposure to pesticides and lack of bodily development to combat the toxic effects of pesticides means that children are suffering disproportionately from their impacts.

Pesticides and the Environment

Since the publication of Rachel Carson’s landmark 1962 book Silent Spring, the impacts of pesticides on the environment have been well known. Pesticides are toxic to living organisms. Some can accumulate in water systems, pollute the air, and in some cases have other dramatic environmental effects. Scientists are discovering new threats to the environment that are equally disturbing.

Pesticide use can damage agricultural land by harming beneficial insect species, soil microorganisms, and worms which naturally limit pest populations and maintain soil health;

Weakening plant root systems and immune systems;

Reducing concentrations of essential plant nutrients in the soil such nitrogen and phosphorous.

The Myth of Safety: A Failed Regulatory System

Despite what government agencies and corporations tell you, pesticide products currently on the market are not safe, even when they are used legally. There are many flaws in the way that pesticides are registered and in our political process that allows corporations to influence pesticide policy to allow the continued use of their poisonous products.

Even if we know that a pesticide causes severe health and environmental impacts, including cancer and genetic damage, it may still be allowed for use. The EPA may determine that a cancer-causing chemical may be used despite its public health hazard if its "economic, social or environmental" benefits are deemed greater than its risk. According to the US EPA, more than 70 active ingredients known to cause cancer in animal tests are allowed for use.
Although industry tests for a wide range of environmental and health impacts, the vast majority of pesticides currently on the market have not been fully tested.

Pesticides often contain inert ingredients in addition to the active ingredients that are designed to kill the target pest. Unfortunately, the public is not provided information about what inert ingredients are included in pesticides in most cases.

At least 382 of the chemicals that the U.S. EPA lists as inert ingredients were once or are currently also registered as pesticide active ingredients. This means that the public is kept in the dark about the contents of pesticide products that may be hazardous. Among the ingredients that are listed as both inert and active ingredients are chloropicrin, which has been linked to asthma and pulmonary edema, and chlorothanonil, a probable human carcinogen.

The Solution to Pesticides

We need to make our food, our air, our water, and our soil free from toxic chemicals.

The real solution to our pest and weed problems lies in non-toxic and cultural methods of agriculture, not in pulling the pesticide trigger. Organically grown foods and sustainable methods of pest control are key to our families’ health and the health of the environment.

Better testing. State and federal agencies should require stricter independent testing, including testing of synergistic effects of pesticides. Pesticides known or suspected of causing human health problems should be phased out.

Protect our children. Because our children are the most vulnerable population to pesticides, pesticide use should be prohibited in places where our children live and play, including schools, parks, and playgrounds. Require strict non-toxic pest management programs for such places.

Pesticide Use Reduction. Provide technical assistance to farmers, local governments, businesses, and homeowners on non-toxic alternatives to pesticide use. This includes alternatives to nuisance spraying for mosquitoes and controlling West Nile virus and other pest problems.

Prohibit pollution of our water and poisoning of our communities. Ensure that aerial pesticide use does not pollute our waterways through strict rules governing spraying and buffer zones that prevent the harmful effects of drift. Prohibit the use of pesticides for purely aesthetic reasons. Prevent pesticide applications to water bodies, instead using non-chemical methods of managing aquatic invasive weeds.

Right to know. Provide free and universal notification to residents about pesticide use, including who is using chemicals, where, when, how, what pesticides are being used, and why.

Protect workers. Provide protection to workers and farmers to prevent acute and chronic pesticide poisoning. TAC

EPA Pesticide Registration: Our Safety in the Balance? by Dr. Michael Surgan, Chief Scientist in the Environmental Protection Bureau of the NY State Attorney General's Office.

Health effects of pesticides:

Pesticides Literature Review by the Ontario College of Family Physicians

Cancer health effects of pesticides.  National Center for Biotechnology Information by KL Bassil - ‎2007 - ‎Cited by 139 - ‎Related articles.   OBJECTIVE. To review literature documenting associations between pesticide use and cancer. ..... Toronto, Ont: Ontario College of Family Physicians; 2004.

Non-cancer health effects of pesticides.  Systematic review and implications for family doctors by M Sanborn - ‎2007 - ‎Cited by 86 - ‎Related articles

Generations at Risk from Greater Boston Physicians for Social Responsibility and Massachusetts Public Interest Research Group (MASSPIRG) Education Fund

Environmental Threats to Healthy Aging from Greater Boston Physicians for Social Responsibility

Season of conception tied to birth defect risk.  Reuters, 2009

Prenatal pesticide exposure linked with lower IQ.  Reuters, 2011

Epigenetics and Pesticide

Epigenetics is the study of heritable changes in gene expression that occur without a change in the DNA sequence. Several epigenetic mechanisms, including DNA methylation, histone modifications and microRNA expression, can be triggered by environmental factors. Current evidence indicates that epigenetic modifications may mediate pesticide effects on human health.