Childhood Cancer Risks and Pesticides

[Guest guest]

Another study by the National Cancer Institute of 3,827 Florida Pest Control

Operators found they had approximately twice the normal rate of brain

cancer. Dr. Jack Leiss and Savitz reported in the 1995 American

Journal of Public Health of several studies showing pesticide exposure

increases risks for childhood cancer. This included one study which found

over twice the risk of brain cancer for children exposed to household

insecticide extermination. Also reported was research by Dr. Ellen of

children with brain cancer under 10 years of age. This study found children

with brain cancer had 6.2 times greater exposure to certain pesticides. A

1987 study by the University of Southern California found children exposed

to home and lawn pesticide use had a 6.5 times increased risk of developing

leukemia.

One of the strongest links of pesticides causing child cancer comes from

research of children developing neuroblastoma after their homes were treated

with the pesticide chlordane. Researchers at the U.S. Occupational Safety

and Health Administration in Washington, D.C. reported of 5 cases of child

neuroblastoma which were suspected to have occurred following chlordane

treatment in or around the home. In one case, a 3 year 9 month old boy

developed neuroblastoma after his family moved into a new home. Two years

prior to the child's birth and also when he was two years old, the house was

treated for termite infestation with chlordane. This report also discussed

other cancers following chlordane treatment, which included 3 cases of

aplastic anemia and 3 cases of leukemia. 25 other cases of cancers were

reported elsewhere following chlordane home exposure. Many of these cases

have moved into litigation.

Another study appearing in the 1981 journal CANCER, detected high levels of

chlordane in 13 children with cancer. Researchers have stated that chlordane

is a high risk chemical for brain cancer because it is a fat soluble

compound and therefore has the potential to accumulate in the brain.

In regards to the so called safety tests conducted by chemical companies on

pesticides, there is unfortunately no consideration given to the fact that

the developing fetus has been reported to be 50 times more vulnerable to the

harm of cancer causing chemicals. Also, the EPA does not take into account

that a newborn child does not develop an efficient blood brain barrier until

at least one year after birth. The blood brain barrier functions to keep

toxic substances out of the brain and is believed to be the reason why

epilepsy is shown to be an increased risk factor for developing brain

cancer, as epileptic patients have been found to have lower blood brain

barrier function.

One reason scientists are still extremely concerned about chlordane is the

fact that although its use was stopped in the U.S. in April of 1988,

chlordane is such an extremely persistent pesticide that it is still being

detected in the air of homes today. In fact, tests of over 1000 homes

performed by the U.S. Air Force and other agencies have come to the

conclusion that approximately 75% of all homes built before 1988 are

contaminated with chlordane and that 6-7% are suspected of being over the

maximum safe levels set by the National Academy of Sciences. This is such a

large number of homes that toxicologist Dr. Epstein stated in a major

medical journal that, " A national program for monitoring all homes treated

is urgently needed to detect persistent contamination. " Dr. Cassidy, a

chlordane research toxicologist in Texas, stated that the chlordane

contamination problem is of such magnitude nationally that it is, " causing

more harm than that caused by cigarette smoking. " This is a very strong

statement, but one that I certainly agree and brings to reality the

magnitude of the problem.

Next we need to look at the research explaining how and why pesticides can

be increasing the risk of child cancers. The explanations now show that

pesticides are able to cause at least two biological changes in the body

that enable cancer to grow. First, pesticides have shown the ability to

damage our DNA and genetic structure and the second is that pesticides are

now being found to seriously weaken the human immune system. All of us

develop cancer cells on a regular basis and it is our immune system which

literally attacks and removes these cancer cells from our body.

Regarding children with neuroblastoma, there have been several studies done

finding these children frequently have damage to the end of what is called

chromosome number 1. Scientists believe this part of the chromosome may be

responsible for suppressing tumor growth or controlling cell growth. This

genetic damage is not observed in other cells in these children.

Children with neuroblastoma are being found to have defects in the part of

their immune system which removes cancer from the body. For instance, it was

found by researchers at the University of Hamburg, Germany, that the blood

of normal healthy people contains antibodies called IgM which seek out and

destroy neuroblastoma cells. However, in a test of 11 people with

neuroblastoma, none had properly working IgM antibodies. Other parts of the

immune system which have been found to attack neuroblastoma and cancer cells

are our cells called natural killer cells and macrophages. In studies of

macrophages and cancer, conducted by the Department of Pediatrics,

University of Arkansas for Medical Sciences, it was found that exposure to

chlordane literally paralyzed the ability of macrophages to search and

destroy cancer cells. Certainly, this raises legitimate questions to the

role of chlordane and other pesticides in and around homes of children with

cancer. It is also of concern, that the two counties showing the highest

rates of childhood cancer, St. Lucie and Indian River, are the same two

counties with the highest proportion of the area devoted to growing citrus.

Although there are many chemicals a child can be exposed to which can damage

his/her chromosome structure, we need to first investigate chemicals the

child may have been exposed to on a repeated basis. Therefore, our

researchers must look at pesticides which may have been applied inside or

around the homes (such as chlordane) as well as pesticides that may have

been used in agriculture in the nearby area.