Wednesday, October 6, 2010

Environmental toxins: Risks, effects to kids

HISTORICALLY, in 1904 an epidemic of lead poisoning was reported among
children who ingested leaded house paints. These children were
described to have brain, nerves and vision problems besides being weak
and anemic. For those who have survived, problems of behavior were

Besides lead-based paints, other sources of lead toxins are motor
vehicle emissions, canned foods and contaminated water. After
eliminating lead solder used in canned foods, leaded gasoline and
lead-based paints the incidence of lead toxicity in children have
decreased significantly.

But the problem continues as other sources are numerous such as
industrial waste, battery casings burned as fuel, from the
contaminated dirt, dust, toys, foods, and water, also from the
improperly glazed ceramic cups, plates, cans soldering, maternals used
for make-up, eye brow pencil and hair dyes.

In metropolitan Manila, Cebu and other large cities, lead constitutes
a large portion of the air pollution coming from automobile exhaust

Compared to adults, children are more efficient in absorbing ingested
lead often enhanced by the presence of nutritional deficiency from
high fat diet and low iron intake.

Lead is a heavy metal poison which affects major organs and body
systems such as the blood, the kidneys, gasrtointestinal, reproductive
and particularly the central nervous system. Lead toxicity occurs
after inhalation, ingestion or through the skin.

Once absorbed 90 percent of lead is primarily deposited in the bones.
Chronic exposure is the most important factor in the production of
lead toxicity. Lead has a long half life (the time required for half
the amount of lead introduced into the body to be eliminated or
disintegrated by the natural process).

The most obvious and serious manifestations of lead toxicity in
children are loss of consciousness and convulsions which are often
prolonged. The onset usually begins with non specific episodes of
nausea, irritability and listlessness initially mistaken or attributed
to common infectious gastro-enteritis.

Most children with elevated blood lead levels are without symptoms. If
present, they are non-specific. However, a cluster of complaints
including poor appetite, vomiting, abdominal pain, constipation,
change in mental status such as irritability or sleepiness, decrease
in play activity, regression in developmental milestone maybe the
beginning signs of lead intoxication.

Lead poisoning is currently defined as blood levels in excess of 10
micrograms of lead per 100 ml of blood. About eight-36 percent of
preschool children are noted to have lead levels higher than 10

Evidences are increasing that lead associated intellectual deficit can
occur even at blood level below 10 micrograms per 100 ml of blood. An
increase of blood levels to 1 microgram was associated with a 7.4
point IQ deficit.

In the Philippines studies have shown that a microgram increase in
blood lead levels was associated with 3.32 point decline in cognitive
functioning in children age 6 months to 3 years, and 2.47 point
decline in ages 3 to 5 years of age. Findings also suggested that
folate and iron deficiency in children are noted to be more
susceptible to the negative cognitive effects of lead.

There is an increasing concern of chronic low level exposure that
produce subtle but substantial problems in brain functions such as
distractability, impulsitivity, day dreaming, lower class ranking,
increase absenteeism and the child more likely to drop out from

Lead exposure was found to be a risk factor for spontaneous abortion.
Pregnant women whose blood lead levels are between 10-14 micrograms
per 100 ml of blood were at fivefold increased risk for spontaneous

In lead intoxication there is an increased risks for long term
neuropsychomotor after effects if the lead exposure is more intense,
prolonged or if it occurs at an early age when the central nervous
system is still developing.

Recurrence of symptoms increases the likelihood of permanent damage.
In cases where exposure is low-dose and chronic, the subtle effects
are usually noted when the child enters school like impaired motor
development, growth retardation, delayed nerve conduction and early
tooth decay.

Prevention of lead intoxication are of two types: Primary prevention
include: removal of the many potential sources of lead including
cleaning wet mopping of household dust, promote personal cleanliness
and frequent washing of child hands, toys, etc. Secondary prevention
includes screening for elevated blood lead levels. This is done
between 12-24 months of age or earlier.


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