How do you know which substances to
avoid? Toxic chemicals with particularly powerful effects include
heavy metals, organic solvents and pesticides. Endocrine-disrupting
chemicals such as dioxin, PCBs and phthalates -- substances that
leach out of plastic packaging and wraps -- may also be harmful to
High levels of
exposure linked to infertility in males and spontaneous abortion in
women. New evidence suggests that low exposures also may have
serious health effects. Since lead crosses into the fetal brain,
there may be long-term effects on behavior and intelligence, for
example.Major sources: old house paint; exterior paint on old steel
structures such as bridges and railways; lead-soldered faucets.
Toxic to the
developing brain, mercury is a known cause of birth defects and
severe neurological effects. The most dangerous form is organic
mercury: It is most easily absorbed and thus can cross the placenta
and make its way into the developing fetus. Contaminated fish,
particularly fish-eating fish like swordfish, tuna, shark and pike,
are major food sources for humans. Mercury can also be inhaled, as
it is a contaminant in coal and oil burning, chlorine manufacture
and waste incineration.
Manganese, abundant in nature, is an essential mineral at low doses.
But at high levels, it is toxic to the brain and lungs. It may also
interfere with human hormones and damage male fertility and
reproduction. At high levels, manganese also appears to disrupt
fetal development; high levels have been implicated in stillbirth
and club foot deformities.
regions, manganese is added to gasoline as an anti-knock agent.
Because they evaporate in the air at room temperature, organic
solvents can penetrate the skin and are easily inhaled. In fact,
studies have found that taking a 10-minute shower in contaminated
water exposes a person to more solvents than drinking two quarts of
the same water.
solvents also can cross the placenta, sometimes accumulating in high
concentrations in the fetus. Solvents have been shown to increase
the risk of spontaneous abortion as well as certain birth defects
and childhood cancers.
Organic solvents are found in many settings, including electronic
factories, dry cleaning and auto repair places, labs and paint
shops. Solvents come out of cars' tail pipes in the form of gasoline
exhaust and they remain on clothing in dry-cleaning bags.
by design, pesticides are intended to kill insects, weeds and
fungus. Unfortunately, that means most are toxic to human nervous
systems as well. Pesticides have been linked to cancer and
reproductive, developmental, neurological and immune-system damage,
depending on exposure levels.
The diets of infants and children are likely to contain pesticide
residues. A 1994 government study found pesticide residues on 2
percent of vegetables and 1.5 percent of grains as well as in dairy
products, eggs, fish and fruits.
Sources: Residues can be found in food, water, homes and on pets.
Pesticides are most often used for outdoor lawn and garden care, but
indoor air and dust also tend to have high concentrations.
Chemicals that interfere with the normal function of
hormones in men, women and developing infants, endocrine disruptors
include chemicals that act as estrogens, anti-estrogens, androgens
such as testosterone and anti-androgens. Endocrine systems generally
control body growth, organ development, metabolism and regular body
processes such as kidney function, body temperature and calcium
regulation; therefore endocrine disruptors also include chemicals
that interfere with hormones such as thyroid, cortisol, insulin or
growth regulators. Scientists are attempting to compile a list of
such chemicals -- and it keeps growing. These chemicals are being
tested for potential links to prostate, testicular and breast
cancers, as well as lowered sperm counts and behavioral and learning
The pesticide DDT, described in Rachel Carson’s 1962 book, "Silent
Spring," is now recognized by many scientists as a potent estrogenic
chemical. Other synthetic chemicals that act as endocrine disruptors
and to which humans are widely exposed include dioxin, a byproduct
of various industrial process, primarily waste incineration;
polychlorinated biphenyls (PCBs), now banned but still persistent in
the environment and in the food chain; and phthalates, perhaps the
most abundant man-made chemicals of all.
About one billion pounds of 25 different phthalate compounds are
produced each year, and they tend to accumulate in fat tissue and
are easily absorbed through the skin. Major sources: plastic wrap,
soft plastics, including soft plastic toys, plastic medical
equipment and some household products.
Source: Generations at Risk