Consumer Factsheet on: MERCURY
List of
Contaminants
As part of the Drinking Water and Health pages, this fact
sheet is part of a larger publication: National Primary Drinking Water
Regulations
This is a factsheet about a chemical that may be found in some public or
private drinking water supplies. It may cause health problems if found in
amounts greater than the health standard set by the United States Environmental
Protection Agency (EPA).
What is Mercury and how is it used?
Mercury is a liquid metal found in natural deposits as ores containing other
elements. Electrical products such as dry-cell batteries, fluorescent light
bulbs, switches, and other control equipment account for 50% of mercury
used.
Why is Mercury being regulated?
In 1974, Congress passed the Safe Drinking Water Act. This law requires EPA
to determine safe levels of chemicals in drinking water which do or may cause
health problems. These non-enforceable levels, based solely on possible health
risks and exposure, are called Maximum Contaminant Level Goals.
The MCLG for mercury has been set at 2 parts per billion (ppb) because EPA
believes this level of protection would not cause any of the potential health
problems described below.
Based on this MCLG, EPA has set an enforceable standard called a Maximum
Contaminant Level (MCL). MCLs are set as close to the MCLGs as possible,
considering the ability of public water systems to detect and remove
contaminants using suitable treatment technologies.
The MCL has also been set at 2 ppb because EPA believes, given present
technology and resources, this is the lowest level to which water systems can
reasonably be required to remove this contaminant should it occur in drinking
water.
These drinking water standards and the regulations for ensuring these
standards are met, are called National Primary Drinking Water Regulations. All
public water supplies must abide by these regulations.
What are the health effects?
Short- or Long-term: EPA has found mercury to potentially cause the
following health effects when people are exposed to it at levels above the MCL
for relatively short periods of time: kidney damage.
How much Mercury is produced and released to the environment?
Large amounts of mercury are released naturally from the earths crust.
Combustion of fossil fuels, metal smelters, cement manufacture, municipal
landfills, sewage, metal refining operations, r most notably, from chloralkali
plants are important sources of mercury release. Nearly 8 million lbs. of
mercury were produced in the U.S. in 1986.
From 1987 to 1993, according to EPAs Toxic Chemical Release Inventory,
mercury releases to land and water totaled nearly 68,000 lbs. These releases
were primarily from chemical and allied industries. The largest releases
occurred in Tennessee and Louisiana. The largest direct releases to water
occurred in West Virginia and Alabama.
What happens to Mercury when it is released to the environment?
Mercury is unique among metals in that it can evaporate when released to
water or soil. Also, microbes can convert inorganic forms of mercury to organic
forms which can be accumulated by aquatic life.
How will Mercury be detected in and removed from my drinking water?
The regulation for mercury became effective in 1992. Between 1993 and 1995,
EPA required your water supplier to collect water samples once and analyze them
to find out if mercury is present above 2 ppb. If it is present above this
level, the system must continue to monitor this contaminant every 3 months.
If contaminant levels are found to be consistently above the MCL, your water
supplier must take steps to reduce the amount of mercury so that it is
consistently below that level. The following treatment methods have been
approved by EPA for removing mercury: Coagulation/Filtration; Granular
Activated Carbon; Lime softening; Reverse osmosis.
How will I know if Mercury is in my drinking water?
If the levels of mercury exceed the MCL, the system must notify the public
via newspapers, radio, TV and other means. Additional actions, such as
providing alternative drinking water supplies, may be required to prevent
serious risks to public health.
This is a factsheet about a chemical that may be found in some public or
private drinking water supplies. It may cause health problems if found in
amounts greater than the health standard set by the United States Environmental
Protection Agency (EPA).
Drinking Water Standards:
MCLG: 2 ppb
MCL: 2 ppb
Mercury Releases to Water and Land, 1987 to 1993 (in pounds):
|
Water |
Land |
TOTALS |
6,971 |
60,877 |
|
Top Six States
| |
TN |
164 |
29,161
|
LA |
431 |
21,829
|
DE |
117 |
3,860
|
OH |
29 |
2,760
|
AL |
1,462 |
4,001
|
WV |
1,657 |
454
|
|
Major Industries*
| |
Chemical, allied products |
12,269 |
74,720
|
Electric lamps |
0 |
2,750
|
Paper mills |
2,500 |
0
|
Learn more about your drinking water!
EPA strongly encourages people to learn more about their drinking water, and
to support local efforts to protect and upgrade the supply of safe drinking
water. Your water bill or telephone books government listings are a good
starting point.
Your local water supplier can give you a list of the chemicals they test for
in your water, as well as how your water is treated.
Your state Department of Health/Environment is also a valuable source of
information.
For help in locating these agencies or for information on drinking water in
general, call: EPAs Safe Drinking Water Hotline: (800) 426-4791.
For additional information on the uses and releases of chemicals in your
state, contact the: Community Right-to-Know Hotline: (800) 424-9346.
|