Committee on Environment and Public Works
United States Senate
Tuesday, October 1, 2002
Mr. Chairman and Members of the Committee:
My name is Philip J. Landrigan, MD. I am a pediatrician, Chairman of the Department of Community and Preventive Medicine and Director of the Center for Children’s Health and the Environment of the Mount Sinai School of Medicine in New York City. A copy of my curriculum vitae is attached to my testimony.
I will focus my testimony on environmental threats to children’s health in America’s schools.
School is a place where children spend 5 to 8 hours per day, 5 days each week for 12 or more years of their lives. For our nation’s future, it is essential that schools provide our children a sound education and prepare them for future citizenship. It is also essential that our nation’s schools provide a safe haven for our children and contain an environment that is free from threats to children’s health.
Unfortunately, schools are not always free from environmental hazards. Pesticides, lead, and asbestos are three classes of hazardous chemical that have been found in America’s schools. These are chemicals that can cause disease, acute as well as chronic. They can interfere with children’s learning.
Fortunately, there exist well-studied, and proven techniques for dealing with these environmental hazards in schools and for minimizing the threats they pose to our children’s health. I shall review this information in my testimony.
Children’s Vulnerability to Environmental Toxins
Children are especially sensitive to environmental toxins. Pound for pound of body weight, children have greater exposure to pesticides because they drink more water, eat more food and breathe more air than adults. Two additional characteristics of children further magnify their exposures: 1) they live and play close to the floor; and 2) they constantly put their fingers into their mouths. Children’s metabolic pathways, especially in the first months after birth are immature. Generally they are less well able to metabolize, detoxify, and excrete toxicants than adults and thus are more vulnerable to them. Children are undergoing rapid growth and development, and their developmental processes are easily disrupted. Since children have more future years of life than most adults, they have more time to develop chronic diseases that may be triggered by early exposures
The Problem. Schools, with their cafeterias and lunches stored in lockers, provide an ideal indoor habitat for pests. According to cooperative extension services, common insects that inhabit school buildings include cockroaches, bees, wasps, ants, flies as well as rodents and birds.
Pesticides are widely used in schools to combat these pests. Pesticides are a diverse group of chemical compounds and they are among the classes of toxic chemicals most commonly encountered by children. Pesticides include insecticides, fungicides, herbicides, and rodenticides.
Pesticides have been shown to cause injury to human health, as well as damage the environment. The health effects include acute and persistent injury to the nervous system, lung damage, injury to the reproductive organs, dysfunction of the immune and endocrine systems, birth defects, and cancer. The principal classes of insecticides in use in the US are the organophosphates, carbamates, and pyrethroids. The organophosphates and carbamates are toxic to the nervous system and some of the pyrethroids are believed to be toxic to the reproductive system and disruptive to endocrine function.
A recent survey by Connecticut environmental researchers showed that schools in 13 of the 16 school districts in Connecticut were treated with pesticides on a monthly basis, even though they may not have needed it. Surveys in other states have similarly shown that 85 to 90 percent of school districts routinely apply pesticides, whether or not there is evidence of need. Pesticides used indoors included bendiocarb, chlorpyrifos, cyfluthrin, cypermethrin, pyrethrin, piperonyl butoxide, tralomethrin, and bromadiolone. In addition, seven school districts in Connecticut reported that townships were responsible for maintaining the athletic fields used by the schools; of these, 53 percent used herbicides, some of them known carcinogens.
The effects of pesticide poisoning on children can be acute and obvious, or chronic, cumulative, and subtle. The Consumer Product Safety Commission collects data on acute pesticide poisonings in the US, based on statistical sample of emergency rooms in 6,000 selected hospitals. From 1990 to 1992, an estimated 20,000 emergency room visits were the result of pesticide exposure. The incidence was disproportionately high among children, who accounted for 61% or more than 12,000 of these cases. Organophosphates were the class of compounds most frequently involved.
Acute high-dose exposure to organophosphate pesticides inhibits the enzyme acetylcholinesterase in the nervous system, leading to a spectrum of cholinergic symptoms, including lacrimation, abdominal cramps, vomiting, diarrhea, miosis, and profuse sweating. The more severe cases progress to respiratory arrest and death. Studies in animals indicate that the young are more susceptible than adults to this acute neurotoxic syndrome, probably because the young are less able to detoxify and excrete organophosphates.
Concern about the chronic effects of pesticides focuses on two particular areas: subclinical neurotoxicity and disruption of endocrine function. The notion of the possible “subclinical toxicity” of pesticides has gained increasing attention in recent years. This term denotes the idea that relatively low-dose exposure to certain chemicals, pesticides among them, may harm various organ systems without producing acute symptoms or being evident in a standard clinical examination. The concept arose from studies of children exposed to relatively low levels of lead who were found to have suffered loss of intelligence and altered behavior even in the absence of clinically detectable symptoms. The underlying premise is that there exists a continuum of toxicity in which clinically apparent effects have asymptomatic, subclinical counterparts. It is important to note that these subclinical changes represent truly harmful outcomes and are not merely homeostatic or physiological “adjustments” to the presence of pesticides.
Recent findings on the developmental toxicity of chlorpyrifos in animals illustrate the potential of pesticides to produce subclinical neurotoxicity in infants and children. The mechanism of chlorpyrifos-induced neurotoxicity appears to involve injury to the adenylyl cyclase cascade, a system in brain cells that mediates cholinergic as well as adrenergic signals. Even at low doses of exposure, insufficient to compromise survival or growth, chlorpyrifos was found to “produce cellular deficits in the developing brain that could contribute to behavioral abnormalities.
Because these animal data are so recent, studies of the developmental toxicity of chlorpyrifos in human infants have not yet been conducted. However, the animal data raise the concern that chlorpyrifos may not be the only organophosphate pesticide that could be a developmental toxicant in humans. The potential for such toxicity may be substantial in urban communities, where chlropyrifos is heavily applied in closed apartments.
On the basis of these findings, the EPA recently issued a ruling that bans the sue of chlorpyrifos in schools, parks, and day-care settings and that prohibits and phases out nearly all residential use. Preventing developmental disability in children was the major reason for this ruling. But many other similar organophosphate remain on the market and are used in schools.
The potential of pesticides to disrupt endocrine function has been recognized for nearly four decades, ever since the 1962 publication of Rachel Carson’s Silent Spring. Carson’s work showed that eagles and ospreys who had been heavily exposed to DDT had suffered disrupted estrogen cycles. As a result, these two predatory species at the top of the food chain were producing thin-shelled, nonviable eggs. Carson’s work, along with the desire to prevent the bald eagle from becoming extinct, prompted the EPA to ban DDT in the early 1970s.
Recent concern about the endocrine toxicity of pesticides in humans has focused especially on the pyrethroids, a class of insecticides widely used as substitutes for chlorpyrifos and other organophosphate and carbamate pesticides. Pyrethroids have been used in pediatric practice to control body lice and scabies instead of more toxic agents such as lindane, and their acute toxicity is generally low. However, hormonal activity has been reported for certain pyrethroids in laboratory systems, suggesting that their capacity to affect hormonal and reproductive development in children should be investigated further.
The Solution. The control of pests in schools does not require heavy, preventive sprayings of toxic pesticides that can be harmful to children. The approach to pest management that is preferred by public health professionals is Integrated Pest Management (IPM). This concept calls for an approach that relies on a thorough knowledge of each pest and use of least-toxic, common-sense methods of keeping pests under control. The best, least-toxic way to control pests is to prevent them from ever infesting an area in the first place-make sure they cannot get in, deny them access to food and water, and make the building uninhabitable. The IPM approach to cockroach control begins with eliminating the things that are attractive to them: take away their water sources by repairing leaky pipes and faucets, and treat areas that have condensation on them; wipe out their travel plans by repairing cracks and crevices with caulk; and take away their food sources by cleaning countertops and cooking surfaces. In IPM, chemical pesticides are used only as the strategy of last resort. I highly recommend that school districts contact their local cooperative extension program to see if they have IPM advice for pests in the district’s region.
A legislative approach that has proven successful in several states in reducing children’s pesticides exposures in schools is a legally mandated requirement that school districts provide parents advance notification of any planned application of pesticides. This approach has been adopted into law in Connecticut. Another sensible approach would be to develop a list of the most toxic pesticides and ban them from school premises.
· Lead Paint
The Problem. Lead is a toxic metal that can damage the kidneys, heart, and gastrointestinal system and can lead to brain damage in children. Granted, severe cases of lead poisoning have become less common in this country as medical treatment and efforts at prevention have become more sophisticated. However, we still need to be concerned because even low levels of lead can damage the developing brain and nervous system of a child. Studies have shown that children with even small amounts of lead in their blood have more difficulty learning and have lower intelligence quotients (IQ) than children without lead in their blood. In addition to affecting intelligence, lead poisoning may also cause behavioral problems, including a shortened attention span. The effects of lead poisoning (which are permanent) can occur silently and may often cause no symptoms.
The Solution. If lead paint is present, schools should call their local or state health department to find out what steps need to be taken to insure that children are not at risk for lead poisoning. Even if lead paint is not chipping or peeling, it can still pose a risk to children.
· Lead in Drinking Water
The Problem. In many older schools, drinking water is contaminated by lead because these schools have lead pipes in their plumbing. Some schools also have lead solder in their plumbing (lead solder was banned from use by the federal government in 1986). When water sits in contact with lead pipes or lead solder overnight, over a weekend, or during school vacations, it is possible for lead from the plumbing system to leach into the drinking water. Lead has also been found in some types of water fountains. Since childhood lead poisoning results from a child’s cumulative exposure to lead from many sources in the environment, it is important to eliminate lead from every possible source in the environment, including water.
The Solution. The EPA has published guidelines to prevent lead poisoning. Under these guidelines, schools are required to test their water in a prescribed fashion and in accordance with EPA guidelines. If lead is detected in the water, the source must be identified and removed.
· Asbestos in Schools
The Problem. Asbestos is a mineral that has been used in schools for heat insulation and for acoustic purposes. Since the 1920s, billions of tons of asbestos have been used in homes, schools, and public buildings in the United States. The heaviest use of asbestos occurred in buildings built in the 1950s and 1960s. In the 1970s, the use of asbestos rapidly declined as the health hazards of asbestos became better known. Such hazards include lung cancer and malignant mesothelioma (a cancer of the chest and abdomen lining). These cancers occur years after inhaling asbestos fibers. Lung cancer can occur 10 to 30 years after exposure to asbestos fibers, while mesothelioma generally occur 20 to 50 years after exposure.
The Solution. If asbestos is in poor condition, with apparent flaking and friability, it needs to be removed by a licensed, certified asbestos removal expert. If the asbestos is in good condition, with no flaking or cracking, it is better to leave it alone, and a commonly used approach is to put physical barriers between it and children, while continuing to monitor its condition on a regular basis. Under the EPA’s Asbestos Hazard Emergency Response Act (AHERA), schools are inspected and asbestos removed, according to carefully developed regulations.
Our children are our future. Our responsibility as the elder members of our society is to care for our children, protect their health, and guide them to successful adulthood.
The protection of children against toxic chemicals in the environment poses a major challenge to modern society. Hundreds of new chemicals are developed every year and released into the environment, and many of these chemicals are untested for their toxic effects on children. Thus, the extent of children’s exposures to environmental chemicals will almost certainly continue to increase: The problem is not going away. The challenge, therefore, is to design policies that will protect children against environmental toxins and will allow our children to grow, develop, and reach maturity without incurring neurologic impairment, immune dysfunction, reproductive damage, or increased risk of cancer as a consequence of toxic environmental exposures.
The hearing that you have convened today represents a spectacular opportunity to build policies that will meet this challenge. I commend you on having convened the hearing.