Chemical Exposure and ADHD

Health Writer

There's no denying that the number of ADHD diagnoses continues to rise. According to the U.S. Centers for Disease Control and Prevention (CDC), two million more children were diagnosed in 2012-2012 than in 2003-2004. Some of this rise has been attributed to a better understanding of ADHD and a more informed public. In other words, the rise is not because more children have ADHD than before, it is because it is better recognized. While this is true, it isn't necessarily the only reason.

Neurotoxins are chemicals and other toxic substances that target the nervous system. According to research conducted by Harvard School of Public Health and the Icahn School of Medicine at Mount Sinai, there are around 12 industrial chemicals that are considered developmental neurotoxins, that is, they can cause damage to the young, developing brain, either during pregnancy or in early life. In 2006, the research team identified five chemicals that can lead to developmental difficulties, including ADHD and autism: lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene. Since that time, they have identified six more: manganese, fluoride, chlorpyrifos (pesticide), dichlorodiphenyltrichloroethane (pesticide), tetrachloroethylene(solvent), and the polybrominated diphenyl ethers (flame retardant).

Researchers believe that exposure to these, and possibly other, neurotoxins might be contributing to the increase in diagnoses of ADHD and autism. They found:

  • Exposure to manganese in drinking water in Bangladesh was associated with reduced math scores and in Quebec it was correlated with hyperactivity and diminished intellectual functioning
  • Exposure to fluoride in drinking water in China might contribute to lower overall IQ scores
  • Exposure to solvents in pregnant women might increase the risk of hyperactivity and aggressive behavior
  • Exposure to certain pesticides was correlated with slowed brain growth in utero and neurobehavioral deficits even at age 7
  • Certain herbicides and fungicides have been linked to neurodevelopmental deficits in children
  • Prenatal exposure to flame retardants is linked to neurodevelopmental deficits in children

Typically, discovery of the toxic nature of chemicals occurs first at the adult level, mostly in occupational exposures, such as lead. In this instance, workers became ill and after years of testing, steps were taken to limit exposure. But this process can take decades. to move from "being toxic to adults" to "causing developmental problems in children." Today, we know that pregnant women and children should not be exposed to lead and that lead poisoning can cause developmental delays, behavior problems and lower IQ scores.

The global community currently operates under the "it is safe until proven otherwise" and requires absolute proof before anything is done about a potentially toxic chemical. That means that chemicals are used in industrial settings as well as found in certain common occupations, such as hairdressing, hospital settings and cleaners can continue to be used, despite incidental evidence they are harmful. Some harmful pesticides which have been banned in countries like the United States are still used in poorer nations around the world.

The researchers have proposed new methods of assessing chemicals used in industrial and workplace settings and would like to see testing of existing and new chemicals mandatory. They propose the creation of an international clearinghouse so that information about the toxicity of chemicals can be shared around the world. They suggest that the philosophy of save until proven otherwise be discontinued and chemicals tested for neurotoxicity before being used and they suggest that the stringent "absolute" proof be replaced with more lenient and flexible standards of proof. These changes, they believe, will improve the health and welfare of our children.

The CDC recommends the following steps to reduce your exposure to chemicals:

  • When remodeling your home, check for hazardous materials such as lead and asbestos. You can check with your local permit office or contact your local health department for water and dust testing. If you have dangerous substances, contact a professional for safe removal.
  • Use natural cleaning products such as vinegar to remove mildew and grease, lemon juice as a deodorizer and glass cleaner, baking soda as an all purpose cleaner and olive oil to polish wood furniture.
  • When working with chemicals, such as paints, paint thinners or gasoline, wear a mask, gloves and goggles.
  • Wash fresh fruits and vegetables before you eat them.
  • Use care when using pesticides and herbicides in your garden. Be sure to read labels carefully and do not apply right before or after a heavy rainfall. Always wash off your hands and equipment after applying these chemicals.
  • Wear protective equipment if your work involves being in contact with chemical fumes, dust, fibers or in direct contact with chemicals. If you don't have protective gear such as gloves, masks and goggles, ask your employer to supply them.
  • Shower and wash your clothes immediately after work.
  • Read labels and instructions for any chemicals you use at home and work.

Chemicals are all around you. You can't avoid all chemicals but you can work to reduce your exposure. Be aware of chemicals you use on an everyday basis. Hobbies such as some crafts, furniture restoration and painting require the use of chemicals. Take the appropriate care to limit your exposure and always keep chemicals out of reach of children and away from pregnant women.

To read the complete study: Neurobehavioral Effects of Developmental Toxicity