Nursing - Cadmium, Mercury, Pesticides: Environmental Chemicals of Concern

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Cadmium, Mercury, Pesticides: Environmental Chemicals of Concern

Ilena Rose

2005-07-24, 12:32 pm

Cadmium, Mercury, Pesticides: Environmental Chemicals of Concern

ATLANTA, Georgia, July 22, 2005 (ENS) - A decline in exposure to
secondhand smoke and continued decreases in children’s blood lead
levels represent the good news from a new report on human exposure to
environmental chemicals by the Centers for Disease Control (CDC). But
chemicals such as cadmium, mercury and insecticides were found in the
bodies of test subjects at levels that could be causing health
problems, agency officials said.

National reports on human exposure to environmental chemicals have
been issued by the CDC every two years since 1999. For this year’s
report, issued Thursday, CDC’s Environmental Health Laboratory
measured 148 chemicals or their breakdown products in blood or urine.

Of the chemicals tested, 38 have never been measured before in the
U.S. population.

Dr. Julie Gerberding is director of the Centers for Disease Control
and Prevention in Atlanta. (Photo courtesy NIH)
“This is the most extensive assessment ever of Americans’ exposure to
environmental chemicals; it shows we’re making tremendous progress,
and that’s good news,” said CDC Director Dr. Julie Gerberding. "It
really provides a giant step forward in our ability to understand the
relationship between exposures to various chemicals and potential
human health effects."
Commenting on the report Thursday, House Democratic Leader Nancy
Pelosi said the funding for CDC's Environmental Health Lab to conduct
these studies was well spent. "The report will assist researchers in
determining whether these exposures are contributing to birth defects,
cancer, asthma, Alzheimer's and Parkinson's diseases, and other health
problems," she said.

“Exposure to secondhand smoke continues to plummet and blood lead
levels in children are way down," Dr. Gerberding said. "However, many
challenges remain."

Cadmium, a metal primarily associated with exposure to cigarettes
through tobacco use, is one of those challenges. About five percent of
the population of adults 20 years and older, had cadmium levels in
their urine that were close to the point at which there was concern
for health effects, Gerberding said.

Finding cadmium of this level indicates a need for further research,
she said.

Smoking cigarettes are associated with elevated levels of cadmium in
the urine. (Photo courtesy Office of the Kentucky Attorney General)
Recent studies have shown that urine levels of cadmium as low as one
microgram per gram of creatinine may be associated with subtle kidney
injury and an increased risk for low bone mineral density, said the
CDC.
The samples for this report were collected from 2,400 people who
participated in CDC's National Health and Nutrition Examination Survey
(NHANES) from 1999 to 2002. NHANES is an ongoing national health
survey of the general U.S. population. The report provides exposure
data on the U.S. population by age, sex, and race or ethnicity.

Health experts determined that exposure to secondhand smoke is
decreasing when they looked at levels of a chemical called cotinine, a
marker of exposure to secondhand smoke in nonsmokers.

Compared with median cotinine levels for 1988-1991, median levels
measured from 1999-2002 have decreased 68 percent in children, 69
percent in adolescents, and about 75 percent in adults.

Still, some people are at greater risk. The new report shows that
non-Hispanic blacks have levels twice as high as those of non-Hispanic
whites or Mexican Americans, and children’s levels are twice as high
as adults’ levels.

New data on blood lead levels in children aged one to five years show
that for 1999 to 2002, 1.6 percent of those children had elevated
blood lead levels. The levels of lead in their blood were 10
micrograms per deciliter or greater – the CDC blood lead level of
concern.

While this percentage has decreased from 4.4 percent in the early
1990s, Dr. Jim Pirkle, deputy director for science at CDC’s
Environmental Health Laboratory, said 1.6 percent still means too many
children are being damaged by lead in their blood.

“Lowering blood lead levels in children is one of the major
environmental health accomplishments of the past 30 years," Dr. Pirkle
said. However, CDC is still concerned about exposure to lead from
lead-based paint and lead-contaminated house dust, soil and consumer
products."

“There is no safe blood lead level in children," he said. "Children
are best protected by controlling or eliminating lead sources before
they are exposed.”

Dr. Gerberding says the decrease in blood lead levels is due partly to
the replacement of leaded gasoline with unleaded. "I think really
speaks to the removal of lead from gasoline, which was one of the
major correlates of this reduction but also the lead abatement
programs and other steps, being able to screen, treat and protect
children from lead exposure," she said.

Tenement children are at risk of lead exposure from old paint and
lead-laden dust. (Photo courtesy Battelle)
Mercury is poses a health risk for 5.7 percent of women tested, the
report shows.
The report provides information about exposure to methyl mercury,
found in fish and shellfish. Methyl mercury is formed when metallic
mercury enters the air or water from mining ore deposits, burning coal
and waste, and from manufacturing plants. Methylmercury may be formed
in water and soil by small organisms called bacteria. Methylmercury
builds up in the tissues of fish.

Mercury levels above 58 micrograms, millionths of a gram, are
associated with neurodevelopmental effects in the fetus, the CDC
report states

"No women in the survey had mercury levels that approached this
concentration," Dr. Gerberding said, "but we do see that a small
percentage of women, about 5.7 percent of women had levels within a
factor of ten of what has been defined as the health threshold
effect."

Mercury's harmful effects that may be passed from the mother to the
fetus include brain damage, mental retardation, incoordination,
blindness, seizures, and inability to speak, according to the federal
Agency for Toxic Substances, which operates under CDC jurisdiction.
Children poisoned by mercury may develop problems of their nervous and
digestive systems, and kidney damage.

For the first time, the CDC studied the effect of organochlorine based
pesticides and other pesticides known as pyrethroids.

Organochlorine pesticides like Aldrin and Endrin and Dieldrin, used in
the United States for decades, were mostly eliminated from use in the
late 1980s. Dr. Gerberding said the exposure report shows that since
these chemicals have no longer been used as pesticides, they have been
"virtually eliminated" from the human population.

"So over time there's been a decay, the pesticides have been
eliminated from our environment and people are no longer experiencing
any potential risk from exposure to them," she said.

The pyrethroids are insecticides that are found in almost any product
that we would use today when we go to the store to buy an insect
agent, Gerberding explained. "We have been able to measure five of
these for the first time ever in the United States population."

"What we know is that because they're used so ubiquitously, there is
widespread exposure to them and our exposure report bears this out,"
the CDC director said. "So we have a reason now to look further to see
if there are any health effects from these exposures."

"We have no evidence of that at this point in time, but, again, now
that we've documented that not only are they being used in the
environment, but they can be measured in the blood of people in that
environment, it's our responsibility to take this to the next step and
to work with our scientific partners to assess what if any health
effects are a consequence of this, Dr. Gerberding said.

Spraying insecticide on lettuce (Photo courtesy UC Berkeley)
CropLife America, which represents the nation’s crop protection
industry, was quick to point out the CDC conclusion that the reason so
many chemicals are detect in blood is because today's tests are so
technically sophisticated.
CropLife agreed with the CDC conclusion that, “Just because people
have an environmental chemical in their blood or urine does not mean
that the chemical causes disease…Small amounts may be of no health
consequence, whereas larger amounts may cause adverse health effects.”

Pesticides are the most intensely researched, tested and regulated
chemicals in the United States, the industry group said, and in
addition, we need them. "The benefits of having safe, affordable and
nutritious fruits and vegetables are well documented and the proper
use of pesticides ensures these benefits to all Americans," CropLife
said.

"Pesticides and pest management products also help safeguard public
health by controlling or eliminating pests that cause disease and
property damage," said CropLife. "They reduce waterborne and
insect-transmitted diseases such as Lyme disease and West Nile virus
and protect homes and gardens from damage from termites and other
pests."

For the first time, the CDC tested for a family of compounds called
phthalates, used to soften vinyl plastics and in cosmetics such as
nail polish.

Phthlates were identified as problem chemicals in the mid-nineties by
Greenpeace, which campaigned against them for years to the ridicule of
the plastics industry. But now some convincing scientific studies are
in and earlier this month six phthlates were banned across the
European Union.

"These compounds are associated with plastics and vinyl, they come in
a variety of chemical variations," said Dr. Gerberding, "and in this
report our scientists were able to refine the ability to separate out
the various phthalates and to look at them with much more precision
individually than ever before."

"I think this is going to really help us refine our ability to study
the relationship, if any, between phthalate exposure and potential
immunologic and other toxicities," she said.

As the report was released, the Washington, DC research and advocacy
organization Environmental Working Group (EWG) asked the agency to
begin testing the umbilical cord blood of newborn babies.

EWG also sent letters to 20 top chemical manufacturers asking them to
release any internal tests to determine whether their products pollute
babies.

The letters follow an investigative report that EWG released last week
commissioning laboratory tests of 10 umbilical cord blood samples for
the most extensive array of industrial chemicals, pesticides and other
pollutants ever studied in newborns.

EWG found that the babies averaged 200 contaminants in their blood,
including mercury, fire retardants, pesticides and the Teflon
production chemical PFOA. In total, the babies' blood contained 287
chemicals, including 209 never before detected in cord blood. The
study is available at www.ewg.org/reports/bodyburden2.

"Chemical exposures during childhood can be far more harmful than
those later in life. Our cord blood findings above all raise the need
for testing that ensures the safety of the widespread exposures we've
documented that begin even before birth," Jane Houlihan, EWG's vice
president for research, said.

"CDC is uniquely positioned and funded to respond to this need through
its national body burden testing program, but CDC cannot test for all
80,000 industrial chemicals registered for use today," Houlihan said.
"The companies that produce these chemicals have a responsibility to
know if their products end up in babies, and to share what they learn
with the public."

The American Chemistry Council, which represents the industry supports
the biomonitoring studies, and agrees with the CDC's cautionary
statement that the mere detection of a chemical does not necessarily
indicate a risk to health.

"The information in the report should not be cause for undue concern,"
said the Council, "but a springboard for better understanding of
exposure and - with more information - how the human body interacts
with the environment."

The Third National Report on Human Exposure to Environmental Chemicals
and an executive summary are available online at:
http://www.cdc.gov/exposurereport.

Quote of Note
"We abuse land because we regard it as a commodity belonging to us.
When we see land as a community to which we belong, we may begin to
use it with love and respect."
-- Aldo Leopold, American environmentalist and author

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