Some exposure pathways are significant for children due to their habits. Children spend more time playing outdoors than adults. Also, they play in soil and standing water found in fields, empty lots, and near canals which may contain pesticides or industrial waste. Per pound of body weight a child ingests more food, drinks more water, and inhales more air than an adult. So exposure to dangerous substances translates into higher doses for children under the same exposure scenario as adults.
Some drugs elicit an odd response in children when compared to the average adult.
Typically these drugs sedate adults, in many children they have been known to cause hyperactivity. Other disturbing effects of common drugs include significant effects on learning and behavior after the chronic intake of Phenobarbital . Permanent staining of teeth caused by tetracycline deposits. Stunting of growth by corticosteroid therapy. And, compared to adults, high risk of liver toxicity from valproic acid .