PHILADELPHIA – When it comes to environmental health hazards, children are canaries in the coal shaft.
That’s because children are not just scaled-down adults. "Children are a lot more vulnerable to environmental hazards than adults," Dr. Jerome A. Paulson said at a conference sponsored by the Mid-Atlantic Center for Children's Health and the Environment. Factors behind the increased vulnerability include their small mass for a given dose of food or water contamination, increased transdermal absorption due to thinner skin and increased surface-area-to-mass ratio, more hand-to-mouth activity, more time spent on the ground, higher relative minute ventilation, and a longer window of exposure due to their longer life expectancy compared with adults, said Dr. Paulson, a pediatrician at George Washington University and director of the Mid-Atlantic Center for Children’s Health and the Environment in Washington, D.C.
Children, like adults, face an ever-growing list of potential environmental hazards. Here are some of the newer additions to Dr. Paulson’s list of concerns:
• Organophosphates. This pesticide class that includes malathion has been implicated in causing adverse neurodevelopmental effects. A 2004 report linked infant exposure to decrements in memory, attention, motor tasks, and behavior ( Environ. Health Perspect. 2004;112:46-51 ). A report last year linked detectable levels of organophosphates in children aged 8-15 years with an increased risk for attention-deficit/hyperactivity disorder ( Pediatrics 2010;125:e1270-7 ).
• Pyrethrins. This pesticide class has grown more popular as health concerns cut sales of other pesticides. Since 2000, calls to poison control centers and visits to health facilities due to exposure to pyrethrins and the related pyrethroids steadily increased ( J. Med. Toxicol. 2007;3:94-9 ). Pyrethrins are commonly accepted as safe for children, and are in head lice products, but their long-term neurologic effects have not been thoroughly evaluated.
• Bisphenol A (BPA). Until recently, BPA was widely used as a hardener agent in plastics, although originally it was developed as a synthetic estrogen. This led to concerns about its impact on endocrinologic function and reproduction, as well as effects on metabolism and neurodevelopment ( Environ. Health Perspect. 2009;117:1945-52 ; Curr. Opin. Pediatr. 2011;23:233-9 ).
• Phthalates. This widely used plasticizer softens plastics, but also appears in a huge variety of other products including packaging, cosmetics, lotions, vinyl flooring, and fragrances. Classified as endocrine-disrupting chemicals, results from preliminary studies suggest possible effects on reproduction, a possible role as an allergen, and possible carcinogenic effects, but more study is needed ( J. Med. Toxicol. 2006;2:126-35 ).
• Manganese. This metal in gasoline and industrial waste that can appear in air, water, and soil has been linked with impaired development in infants and toddlers and low IQ scores in children aged 11-13 years ( Lancet 2006;368:2167-78 ).
• Arsenic. A classic heavy metal toxin that causes multi-organ system injury, it can cause neurotoxicity at chronic, low levels, producing impaired verbal IQ scores and memory ( Neurotoxicology 2006;27:210-6 ).
• Global Climate Change. This was called by Dr. Paulson "the single most important environmental health threat to children today because it impacts every single child." It is a cause of air pollution, severe weather, vector-borne infectious diseases, floods, draughts, malnutrition, and so on.
Dr. Paulson said that he had no relevant financial disclosures.