Issues > June 1, 1998 (#54-55) > Environmental Factors in the Rise of Children's Cancer

Environmental Factors in the Rise of Children's Cancer

In the fall of 1988 in Minneapolis, Minnesota, 10-year-old Clinton Hill was diagnosed with a malignant brain tumor. Eleven months later, after two radical brain surgeries and debilitating treatments, Clinton, an avid environmentalist and founder of Kids for Saving Earth, was dead.

Clinton's parents agonized over what might have caused their son's death, and instinctively looked to environmental factors. "We had had the house sprayed for roaches and fleas every quarter," says Tessa Hill, "and we also used a lot of flea powder on the dogs ... and then Clinton got lice in school a few times." The school recommended lice shampoo and a spray that Tessa used on the bed pillows and carpets. Unknown to Tessa at the time, numerous studies have linked use of pesticide-based sprays and foggers in the home to childhood brain cancer. Did pesticides kill Clinton, or was it a genetic predisposition, a virus, diet, or some combination of these?

The Rise in Childhood Cancer

Such questions are increasingly being asked by government bodies like the Environmental Protection Agency (EPA) Office of Children's Health Protection, as they seek reasons for the rise in childhood cancer rates, climbing approximately 1% per year. The National Cancer Institute reports that some 8,500 U.S. children under age 15 are diagnosed with cancer each year, and a newborn's risk of contracting cancer is one in 600 by the age of 10. While survival rates for most childhood cancers have improved, cancer is the most common form of fatal childhood disease. "It's likely that environmental factors -- from a child's food to the substances she touches and the air she breathes -- are playing a significant role in the rise of childhood cancer," says Philip J. Landrigan, M.D.

Why Children?

Adult cancer rates in the U.S. declined an average 0.7% per year from 1990 to 1995, reversing a 17-year rise, the National Cancer Institute announced in March 1998. Why, then, did children's cancer rates rise during this same time? Proportionately, children consume more foods, drink more liquids, and take in more air than do adults, increasing their exposure to potentially carcinogenic contaminants. "Half of a lifetime's consumption of carcinogens from food is eaten by age five," says Harvey Karp, M.D., a pediatrician in Los Angeles. Children are also less able to metabolize and excrete most toxic substances, and their rapidly developing organ systems, especially the central nervous system and the brain, are highly susceptible to chemical interference, Dr. Landrigan says. Finally, their behavior, such as crawling on the floor, exposes them to different hazards than adults.

Nursing infants are exposed to known carcinogenic contaminants, such as dioxins, polychlorinated biphenyls (PCBs), and DDT and other pesticides, in their mothers' breast milk. Despite this, doctors advise that the benefits of breastfeeding, such as higher I.Q.s and stronger immune systems, outweigh the risks.

More problematic is prenatal exposure to contaminants in the womb. According to Frederica Perera, Dr.P.H., a professor at Columbia University who is studying the effects of air pollution on children and their mothers in Poland, carcinogens can pass through the placenta directly to the fetus. "We found that levels of genetic damage caused by carcinogens called polycylic aromatic hydrocarbons, or PAHs, produced by the burning of coal and fossil fuels, were somewhat higher in newborns than in their mothers," says Perera.

Types of Carcinogens

In addition to many pesticides, among the most potent carcinogens are tobacco smoke, including secondhand smoke, and petrochemical emissions, such as diesel fumes. A recent study in England of more than 20,000 children found an increased incidence of leukemia and other childhood cancers among those living near such facilities as oil refineries, automobile factories and body shops; steel mills, foundries and smelters; manufacturers of petroleum products; airports, railways and highways. Following are other documented instances of environmental exposures.

WATER POLLUTION: Drinking water contaminated by the industrial chemical trichloroethylene (as well as other solvents and heavy metals) was definitively linked to incidences of Acute Lymphoblastic Leukemia (ALL), the most common form of leukemia, in children living in Woburn, Massachusetts. As documented in Jonathan Harr's A Civil Action (Vintage Books, 1995), Woburn's leukemia rates rose to four times the national average between 1966 and 1986.

In 1995, the Environmental Working Group (EWG) found five commonly used weed killers (four of which are listed as probable or possible carcinogens by EPA), in the treated tap water of the Midwest, Louisiana and the Chesapeake Bay watershed. Lawrie Mott, M.S., a senior scientist with the Natural Resources Defense Council (NRDC) in San Francisco, advises that parents concerned about the safety of drinking water should first have their water tested by an independent lab, then use a water filter specifically designed to eliminate the contaminants found

PESTICIDES IN THE HOME AND IN FOOD: Children are being exposed to pesticides every day. A 1992 survey by the EPA found that an average of three to four pesticide products are stored in homes. EPA also found that over one million households still use products containing banned ingredients like DDT.

NRDC's Mott says, "There are more studies linking the use of pesticides in and around the home, and [pesticide-based] lice treatments, to childhood cancers than anything else." A 1987 study in the Journal of the National Cancer Institute showed that children exposed to pesticides in the home or garden are three to six times more likely to contract leukemia than children who were not exposed.

Other studies suggest a possible link between parental exposures to pesticides at their jobs prior to and during pregnancy and an increased risk of of brain cancer, leukemia, Wilms' tumor and Ewing's sarcoma (malignant kidney cancer) in their children. A number of studies also show that children exposed to "no-pest" strips and garden and household pesticides may have an increased risk of brain cancer and leukemia.

Compounding these exposures are pesticides in our food supply. The EWG warns in a January 1998 report that, every day, more than one million children age five and under eat an unsafe dose of organo-phosphate pesticides.

RADIATION: Exposure to ionizing radiation is an established cause of childhood (and adult) cancers. Post-Chernobyl studies show a dramatic increase in thyroid cancer among exposed children. And children treated for cancer with radiation at an early age have developed secondary bone, breast and skin cancers. Low doses of ionizing radiation, received from diagnostic x-rays, particularly in the last trimester of pregnancy, have also been shown to increase the risk of childhood cancer.

The largest source of naturally-occurring ionizing radiation is radon, an odorless radioactive gas that is a byproduct of of the decay of uranium and radium, and is found in most types of soil and rocks. In February 1998, the National Research Council announced that radon is the second greatest cause of lung cancer after smoking. Radon gas may seep into homes through cracks in basements and foundations, and may also dissolve in drinking water.

Ultraviolet (UV) rays from the sun are another kind of radiation. Dr. Richard Rivlin, program director of the Clinical Nutrition Research Unit at Memorial Sloan-Kettering Cancer Center, cautions that, "as the Earth's protective ozone layer gets depleted, more harmful UV radiation will enter the Earth's atmosphere, increasing the risk of skin and possibly other cancers."

Cancer clusters have been found in some neighborhoods close to electric power facilities, but it is difficult to determine whether other environmental factors also were contributors. Some studies suggest a link exists between exposure to electromagnetic fields (EMFs) and leukemia and brain cancers in children. But other studies have found no connection.

The National Institute of Environmental Health Science (NIEHS) suggests prudent avoidance.

AIR POLLUTION: In 1995, 18 million American children under the age of 10 lived in areas that failed to meet federal air quality standards. A common air pollutant, both indoors and out, is benzene, a known carcinogen emitted from gas stations, oil refineries, chemical and rubber plants, and diesel-powered vehicles. Many glues and epoxies contain benzene and benzene derivatives, and it is present in cigarette smoke, as well. Other carcinogenic air pollutants include heavy metals from smelters and dioxins from waste incinerators and pulp and paper mills.

Air pollution indoors, where most of us spend 90% of our time, poses another risk. Plywood, particleboard, and many paints, carpets, curtains, cotton and synthetic garments are treated with formaldehyde, a probable carcinogen, and other volatile organic chemicals (VOCs), both of which are slowly released as vapors from products over time. In addition, most dry cleaners still use perchloroethylene, or "perc," a solvent classified as a probable human carcinogen. Tobacco smoke is responsible for approximately 3,000 lung cancer deaths annually in American nonsmokers, according to the EPA.

What is Being Done to Protect Children's Health?

In 1996, Congress passed the Food Quality Protection Act (FQPA) to ensure that pesticide tolerances in foods were determined with children's special vulnerability in mind. In April 1997, President Clinton signed an executive order instructing federal agencies to consider children's health when setting exposure standards for contaminants in air, water and food. Together, EPA and NIEHS plan to spend $10 million annually to research environmental risks to children's health. But they're up against a chemical industry with global sales of $1.56 trillion in 1995.

In fact, EPA has made very little progress in implementing the "kid-protective" provisions of the FQPA. NRDC reported in April 1998 that pesticide data specific to children is severely lacking, and locates problems in EPA's pesticide testing requirements which produce these data gaps.

In addition, "Thousands of new chemicals are added to the environment each year without adequate, if any, toxicity data. The studies are done by corporations, so they are less credible," says Dr. Karp. A 1998 Environmental Defense Fund report, "Toxic Ignorance," found that the public lacks access to data on the basic health effects of the majority of synthetic chemicals.

Rather than wait for government agencies to act, we can do a lot right now to protect ourselves and our children, such as choosing organic foods. After their 5-year-old daughter Colette died from Wilms' tumor in 1991, Nancy Chuda and her husband Jim started the Children's Health and Environmental Coalition (CHEC). Chuda advocates organic agriculture because, she says, in addition to reducing our exposure to synthetic pesticides, it helps prevent harmful chemicals from contaminating our water, air and soil.

We can also stop buying and using home products containing toxic chemicals, helping to end their production by reducing demand. "You don't need them," says Chuda. We can become more active in protecting the environment. Today, Tessa Hill runs Kids for Saving Earth, the nonprofit environmental group her son Clinton started.

Alix Fano is the author of Lethal Laws: Animal Testing, Human Health & Environ-mental Policy (St. Martin's Press, 1998)