Lead Toxicity: Low-Level Environmental Exposure
"Introduction Lead poisoning is as ancient as Roman history, and
indeed lead has been used extensively by the Romans and
described by the Romans. The purpose of the manuscript is not to
discuss classic lead toxicity and lead poisoning effects, but to
address the concept of low-level environmental lead toxicity and
poisoning.
Low-Level Environmental Exposure In developed countries lead
poisoning is not prevalent; however, in developing countries
lead poisoning is extremely common, to such an extent that
world-wide lead toxicity and lead poisoning remain the most
common of occupational poisoning. The most common occupational
and environmental exposures to lead are encountered in the
manufacturing of lead batteries, paints and colors; lead
compounds; rubber products and glass; grinding, dicing and
cutting by power tools, products containing lead; sanding down
from the application of lead paints and glazes; inhalation of
lead oxide fumes in the demolition of old industrial buildings
and cutting lead pipes with gas powered burning torches; firearm
instructors; and law enforcement agents in the process of
firearm instruction. The most common environmental nonindustrial
exposure to lead is via the drinking water and in communities
residing around incinerators, toxic dumps, and manufacturing
industries utilizing lead and releasing lead into the
environment. Organic lead compounds have been added to petrol as
anti knock agents for over half a century, and exposure may
result from handling of these compounds in refineries or during
cleaning out of tanks which contained leaded petrol.
In the last 10 years, studies by the Environmental Protection
Agency, as well as other international regulatory agencies, have
shown that chronic low-level exposure to lead is associated with
societal problems, such as brain dysfunction in children exposed
to lead in drinking water, neurobehavioral changes in adults,
hypertension and chronic kidney disease. As a result, the
Environmental Protection Agency has moved to reduce the lead
concentration in drinking water to very low levels. This notion
of low level toxicological exposure to lead is changing the
presenting picture of lead toxicity. While in the past the
classic presentation would be the patient who has been exposed
to high levels of lead and developed abdominal pain, anemia and
neurological changes, the picture now becomes more subtle, as a
result of prolonged low-level exposure which affects mainly the
central nervous system and causes neurobehavioral changes. Also,
the issue of prolonged lead exposure and hypertension has
recently been recognized as a societal problem and a cause for
hypertension and kidney disease.
"