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Background:
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Lead is an odorless, tasteless, soft,
gray metal. On exposure to air, lead is rapidly covered with
a film of oxide, hydroxide, and carbonate. Similarly, when
lead is exposed to water with dissolved oxygen, lead
hydroxide, sulfate and carbonate are formed. A small amount
of the salts then pass into solution. Lead salts are found
in air, food, household dust and soil. If ingested or
inhaled over a period of time, lead and its salts may cause
serious internal damage such as impaired kidneys, nervous
system and red blood cells. Particularly susceptible to the
toxic metal or salts are small children.
According to tests compiled for the
Environmental Protection Agency (EPA), our tri-state region
is free from high level of lead in the drinking water.
However, Philadelphia is the exception. Of the 162 homes
tested by the city's Water Department, 15% exceeded the
federal guidelines which specify that no more than 10% of
the homes should exceed a lead level of 15 parts per
billion.
Lead gets into the drinking water
through the use of lead-containing pipes, solder, brass and
chrome-plated faucets. The homes most likely to have a lead
problem are older houses with lead pipes and homes with lead
service lines.
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Material:
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Lead Check™ swabs, lead and
copper pipe, leaded and lead-free solder, lead sinkers,
ceramic pieces, glassware (including crystal), old toys and
food cans.
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Procedure:
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Part 2
1. Give the class additional swabs to
take home.
2. Have students test the follow areas
or items at home as listed in the data table below.
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Area or Item
in the Home
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Lead Present
(Pink)
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Lead Not
Present
(No color change)
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Comments
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Any exposed pipe
near the washing
machine
Any solder on
pipe joint
3. Interpret and discuss the data with
your family.
4. In order to reduce your family's
exposure to lead, read and share the following guidelines as
listed below:
- The lead levels can be
substantially reduced by running the water for 15 to 30
seconds until it is cold.
- Do not drink or cook with hot tap
water. Lead salts are more soluble in hot water than in
cold. Also, boiling hot tap water increases the danger by
increasing the lead concentration by evaporation.
- Do not add hot water to baby
formula.
5. Students will prepare a brief oral
presentation of the data as a basis for their
results.
6. Finally, pupils will discuss what
precautions they will take now and in the future to reduce
their family's exposure to high levels of lead as a basis
for their conclusions.
*Note: This
hands-on-science experiment can be used in cooperative
learning groups.
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