Lead in the Environment

Lead pollution

Lead in the Environment

A. Lead is an example of:

a heavy metal -- that is, a metallic element that in pure form is heavy. Examples: lead, mercury, cadmium, tin, chromium, zinc and copper. Most heavy metals are extremely toxic because, as ions or in certain compounds, they may be taken into the body, where they tend to combine with and inhibit the functioning of particular enzymes. Minute amounts can have severe physiological or neurological effects.

violation of principle of precautionary action which states that "(1) burden of proof of safety should be borne by the proponent of a new technology, not by the public; (2) where there are threats of serious or irreversible damage, lack of scientific certainty should not be used as an excuse for postponing measures to prevent environmental degradation." (Rachel's Environment & Health Weekly #540, April 3, 1997, "History of Precaution -- Part 2")

B. Why is lead an important environmental issue?

1. Lead (Pb) is an element -- hence it cannot be degraded or transformed into some other material, and it is extremely difficult to clean up after dispersal in our environment.

2. Lead already widely contaminates our environment.

3. Lead is harmful in very small amounts (as are most heavy metals); once absorbed into the body lead combines with and inhibits the functioning of certain enzymes -- often with severe physiological or neurological consequences.

C. Harmfulness of Lead (Effects)

Lead is a potent poison. Short-term exposure to high doses of lead can make you seriously ill. Long-term overexposure can cause numerous health problems, including:

anemia and other blood disorders

damage to your nervous system and brain

kidney disease

reproductive impairments in men (impotence and sterility) and women (decreased fertility, abnormal menstrual cycles, and miscarriages)

People who have held jobs with high levels of lead exposure have a 3.4 times greater likelihood of developing Alzheimer disease. ^REF

Lead overexposure can also cause birth defects, mental retardation, behavioral disorders, and death in fetuses and young children. You can expose your family to lead if you bring it home with you (e.g., on your skin, hair, or clothes).

Lead kills wildlife (such as birds ingesting lead shot)

Lead is "the greatest environmental threat to the nation's children" (U.S. Public Health Service)

3 million U.S. children (10-15% of preschoolers) have lead levels high enough to impair their neurologic development (->reading disorders, attention deficits, etc.). Chronic exposure to low levels of lead is tied to low birth weight, impaired mental development, hearing loss.

Under 1991 Public Health Service (PHS) standard, 2 out of 3 children in some communities are lead-poisoned (e.g., Oakland, CA; Chicago, IL). In Los Angeles, 32% of children are lead-poisoned.

EPA estimates that in 1992, Wisconsin had 22,170 lead-poisoned children.

Today no level of lead is considered to be actually safe.

Nonetheless -- U.S. Public Health Service has set guidelines for "acceptable" blood-lead level (in micrograms per deciliter-- don't need to memorize units, but look a magnitude of change over time):

until 1969, 60 thought to be safe; subsequently lowered--

1970 - 40

1975 - 30

1985 - 25

1991 - 10

"Maximum allowable level" of lead in drinking water = 0.05 mg/liter

20-50% of total lead in children is attributable to drinking water, depending on circumstances (1990)

Lead at 500 ppm in soil or solid waste qualifies the substance as "hazardous waste".

D. Proximate Causes of Lead Contamination

Lead pollution in U.S. environment is largely a result of earlier uses. According to lead pollution expert Howard Mielke, "Lead in paint and gasoline together accounts for most of the lead now in the human environment. In terms of raw tonnage, the amount of lead in gasoline over only the 57 years of its use from 1929 to 1986 roughly equals all of the lead in paints in 94 years of lead-paint production, from 1884 to 1978."^REF Lead poisoning may occur from:

leaded gasoline -- tetraethyl lead, TEL Lead from gasoline accounts for 80-90% of all existing environmental lead contamination.

leaded paint

dust and soil containing the above

drinking water (from lead pipes and solder)

incinerated products (e.g., printing inks & paper)

batteries (consume 83% of lead used in U.S. in 1990s)

hair dyes (optional more)

vinyl plastic children's products, including toys

imported mini-blinds (optional more)

lead weights used to balance motor vehicle wheels (optional more)

craft materials

smelter and industrial emissions

Under current technologic conditions, the only two major essential uses of lead are lead-acid batteries and radiation shielding.

The U.S. continues to introduce into commerce more than one million tons of lead yearly. The power storage battery industry is the largest end-user of lead, accounting for 83 percent of the estimated 1.357 Mmt (million metric tons) domestically consumed in 1993.

The U.S. is the world's largest recycler of lead scrap and is able to meet about 72 percent of its total refined lead production needs from scrap recycling."

Between 1987 and 1996 lead emissions in the U.S. dropped 50 percent, while ambient [air] concentration levels declined 75 percent. ^REF

E. Corporate capitalism is a basic cause of the lead problem, earlier and continuing: private profits at environmental and public expense. Technology may also be considered as a basic cause, but the development of TEL and promotion of its adoption are largely functions of corporate capitalism.

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Thomas Detwyler maintains this page (tdetwyle@uwsp.edu)
Last updated 25 October 2000