Chemicals in AmericansBy George Grow
This is the VOA Special English SCIENCE REPORT.
American health officials have produced a scientific report about environmental chemicals found in average Americans. It is the most detailed study of such chemicals in the general population. The Centers for Disease Control and Prevention released the report. C-D-C officials say the report is an important tool for scientists and policymakers.
The findings are based on a technology known as biomonitoring. Biomonitoring permits scientists to measure chemicals in a person's blood and waste fluid. In the past, scientists measured chemicals in air, water or soil to estimate chemical exposures in people.
The new study examined the blood and urine from three-thousand-eight-hundred adults and children. It found small amounts of twenty-seven environmental chemicals. The chemicals include metals, products to kill insects and substances found in plastics.
Officials say the presence of a chemical does not necessarily mean that it will cause disease. They say additional studies are required to show if the levels reported are a cause for concern.
A few of the chemicals were measured in earlier studies. Levels of two of them -- tobacco smoke and lead -- have decreased sharply in the past ten years.
For example, cotinine in the body measures the amount of cigarette smoke in a person's environment. Cotinine levels among Americans who do not smoke decreased more than seventy-five percent since Nineteen-Ninety-One. The decrease suggests that efforts to ban smoking in public buildings have helped reduce exposure to what is called second-hand smoke. Second-hand smoke is known to cause cancer.
The study also found that lead levels in the blood continue to decrease among most American children. Even low levels of lead can cause brain damage.
Scientists say one surprise was the high level of man-made compounds called phthalates. Phthalates are used to make plastics, toys and products used on the skin. Scientists say laboratory rats fed large amounts of the substance have had birth defects and reproductive problems.
C-D-C officials say their goal is to expand the study to provide information about one-hundred chemicals. They also want to find out how these chemicals affect health.
This VOA Special English SCIENCE REPORT was written by George Grow.