The Changing Uses of Lead
Scientific research demonstrating how accumulated ingested lead is toxic to human health and how
accumulations of lead in the soil, air, and water are toxic to ecosystems is changing both how lead is
used and how it is disposed of after use.
What is Lead?
Lead is a corrosion-resistant dense metal that is easily molded and shaped. The chemical symbol
for lead, Pb, is an abbreviation of the Latin word plumbum, meaning soft metal. Archeological research
indicates that lead has been used by humans for a variety of purposes for more than 5,000 years.
Lead is rarely found in native form in nature but it combines with other elements to form a variety
of interesting and beautiful minerals. Galena, which is the dominant lead ore mineral, is blue-white in
color when first uncovered but tarnishes to dull gray when exposed to air.
Ancient Uses of Lead
Water pipes that date back to the Roman Empire, glazes on prehistoric ceramics, and the cosmetic kohl,
used by ancient Egyptians to darken their eyelids, are a few examples of ancient uses of lead. Today,
lead, which has been mined on all continents except Antarctica, is one of the most important metals to
Modern Uses of Lead
Prior to the early 1900s, lead was used in the
United States primarily in ammunition, burial vault
liners, ceramic glazes, leaded glass and crystal, paints
or other protective coatings, pewter, and water lines
and pipes. Following World War I, the demand for
lead increased because of growth in the production
of motorized vehicles, many of which use lead-acid
batteries to start their engines. The use of lead as
radiation shielding in medical analysis and video
display equipment and as an additive in gasoline also
contributed to an increase in the demand for lead.
By the mid-1980s, a significant shift in the uses of lead had taken place in the United States as a
result of compliance with environmental regulations and the substitution of other materials for lead in
nonbattery products, such as gasoline, paints, solders, and water systems. By the early 2000s, 88 percent
of apparent U.S. lead consumption was in lead-acid batteries, which was a substantial increase from
1960 when only 30 percent of global lead consumption was in lead-acid batteries. Today, the other
significant uses of lead are in ammunition, oxides in glass and ceramics, casting metals, and sheet lead.
Lead in the Environment
According to the U.S. Agency for Toxic
Substances and Disease Registry, environmental levels
of lead have increased more than 1,000-fold over the
past three centuries as a result of human activity. The
greatest increase took place between 1950 and 2000
and reflected the increased use of leaded gasoline
worldwide. During this period, the U.S. Government established Federal regulations and made
recommendations to limit lead emissions to protect public health in the United States.
Types of Lead Deposits
Research to better understand the geologic processes that form mineral deposits, including those
containing lead, is an important component of the USGS Mineral Resources Program. Lead commonly
occurs in mineral deposits along with other base metals, such as copper and zinc. Lead deposits are broadly
classified on the basis of how they are formed. Lead is produced mainly from three types of deposits:
sedimentary exhalative (Sedex), Mississippi Valley type (MVT), and volcanogenic massive sulfide (VMS).
Sedimentary Exhalative Deposits
Sedex deposits account for more than 50 percent of the world's lead resources. They are formed
when metal-rich hot liquids are released into a water-filled basin (usually an ocean) or in basin
sediments, which results in the precipitation of ore-bearing material within basin-floor sediments.
Mississippi Valley Deposits
MVT deposits are found throughout the world and get their name from deposits that occur in
the Mississippi Valley region of the United States. The deposits are characterized by ore mineral
replacement of the carbonate host rock; they are often confined to a single stratigraphic layer and
extend over hundreds of square kilometers. MVT deposits were a major source of lead in the United
States from the 19th century through the mid-20th century.
Volcanogenic Massive Sulfide Deposits
In contrast to Sedex and
MVT deposits, VMS deposits
have a clear association
with submarine volcanic
processes. They also can
contain significant amounts
of copper, gold, and silver,
in addition to lead and zinc.
The "black smoker" sea
vents discovered during
deep ocean expeditions are
examples of VMS deposits
being formed on the sea
Worldwide Supply of and Demand for Lead
Currently, approximately 240 mines in more than 40 countries
produce lead. World mine production was estimated to be
4.1 million metric tons in 2010, and the leading producers were
China, Australia, the United States, and Peru, in descending order
of output. In recent years, lead was mined domestically in Alaska,
Idaho, Missouri, Montana, and Washington. In addition, secondary
(recycled) lead is a significant portion of the global lead supply.
World consumption of refined lead was 9.35 million metric
tons in 2010. The leading refined lead consuming countries were
China, the United States, and Germany. Demand for lead worldwide
is expected to grow largely because of increased consumption
in China, which is being driven by growth in the automobile and
electric bicycle markets.
Ensuring Future Supplies of Lead
To help predict where future lead supplies might be located, USGS scientists
study how and where identified lead resources are concentrated in the Earth's crust
and use that knowledge to assess the likelihood that undiscovered lead resources
exist. Techniques to assess mineral resource potentials have been developed and
refined by the USGS to support the stewardship of Federal lands and to better
evaluate mineral resource availability in a global context.
United States Lead Resources
In the 1990s, the USGS conducted an assessment of U.S. lead resources
and concluded that about as much lead remained to be found as had already been
discovered. Specifically, the USGS found that 92 million metric tons of lead had
been discovered and estimated that about 85 million metric tons of lead remained
undiscovered in the United States.
Lead Production and Reserves
|Data is in thousand metric tons. Data from USGS Mineral Commodity Summary, January 2011.
Mineral resource assessments are dynamic. Because they provide a snapshot
that reflects our best understanding of how and where resources are located, the
assessments must be updated from time to time as better data become available
and new concepts are developed. Current research by the USGS involves updating
mineral deposit models and mineral environmental models for lead and other
important nonfuel commodities and improving the techniques used to assess for
concealed mineral resource potential. The results of this research will provide new information and decrease the amount of uncertainty in
future mineral resource assessments.
-- On production and consumption of lead:
-- On the assessment of undiscovered deposits of gold, silver,
copper, lead, and zinc in the United States:
-- On Mississippi Valley-type lead-zinc deposit model:
-- On sedimentary exhalative zinc-lead-gold deposit model:
-- On volcanogenic massive sulfide deposit model:
Did You Know? In 2009, with a 96 percent recycling rate, the standard lead-acid car battery was the most
recycled product in the United States.
|Typical lead-acid ignition batteries in automobiles contain about 10 kilograms of lead and need to be
replaced every 4 to 5 years. Lead-acid batteries also supply standby power for computer networks
and telecommunications systems and energy storage for wind and solar energy systems and hybrid-electric vehicles.
Image © iStockphoto and Hywit Dimyadi.
Did You Know? The English words plumbing, plumber, plumb, and plumb-bob derive from the Latin word for lead.
|Galena, a lead sulfide mineral (PbS), is the primary ore of lead. It is mined at many locations worldwide.
Did You Know? Lead levels in ambient air are currently 92 percent lower than they were in 1980 owing to
changes resulting from the Clean Air Act of 1970.
|The Viburnum Trend in southeastern Missouri contains the largest concentration of lead in North America. The Buick mine is one of six underground mines that currently produce lead in the Viburnum Trend ore district. Image by USGS.
|Lead pipes, such as these discovered in Bath, England, were used for plumbing by ancient Romans. Image by USGS.
Find it on Geology.com
More from Geology.com
|Sunstone: A feldspar with aventurescence caused by light reflecting from platy inclusions.|
|Rocks: Photos of igneous, sedimentary and metamorphic rocks.||
|Minerals: Information about ore minerals, gem materials and rock-forming minerals.|
|Satellite Images of cities, states and countries acquired by the Landsat satellite.|