chemical profiles of the heavy metals: mercury, arsenic, and lead
Mercury, Arsenic, and Lead
A Centuries' Old Story
Mercury found in hair samples from 10 of 10 Washingtonians; and
Arsenic found in urine samples from 4 of 10 Washingtonians; and
Lead found in blood sample from 1 of 10 Washingtonians in the Pollution in People study
Mercury, arsenic, and lead are found naturally in the earth, but just because they’re natural chemical elements doesn’t mean they’re harmless. They are heavy metals with a long history of industrial and personal use—and just as long a history of harming human health.
- Mercury is in our air from the combustion of diesel, jet fuel, and heating oil. It deposits on land and water, then concentrates in the food chain.
- Mercury is also emitted by the coal-burning power plant in Centralia, and by manufacturers, oil refineries, medical waste disposal facilities, dental offices, and cremation facilities.
- When mercury gets into water, bacteria convert it to toxic methylmercury, which builds up in fish. When we eat fish that contain mercury, it tags along and settles in our bodies.
- Mercury is in many consumer products, including: fluorescent light bulbs, electrical fixtures, auto switches, thermostats, medical equipment, and dental amalgam fillings. Mercury is also used in thermometers, although this use in Washington is being phased out in favor of non-mercury digital thermometers.
Until 2002, arsenic compounds were used to treat wood to prevent rot. The arsenic leaches out into soil and rubs off the wood on to people or animals.
Arsenic is also in the soil from smelters and some pesticides.
Arsenic compounds are still used to make special glass, semi-conductors (gallium arsenide), some paints, dyes, metals, soaps, and drugs.
Seafood can contain arsenic (although in a less-toxic form), as does drinking water in some locations.
- Lead is in frighteningly large array of consumer products, from art supplies and automobile components to speciality paints, some hair dyes, and even candy.
- PVC products often contain lead.
Gasoline and paint are now lead-free in the U.S. and many other countries. But despite a 1978 ban, lead paint on the walls of older homes and buildings continues to be a primary source of lead exposure for children. In certain areas and homes, lead from paint contaminates soil and house dust too.
Drinking water can contain lead that leaches out of pipes.
Some soils in Washington are contaminated with lead from two now-shuttered smelters (facilities that process metals) or past use of the pesticide lead arsenate in orchards.
Workers exposed to lead on the job can bring it home on clothing and shoes, exposing their family members.
Lead and mercury exact their most devastating toll on the developing brain.
Children exposed to lead at a young age are more likely to suffer from shorter attention spans and are less able to read and learn than their peers.
Children with above-average mercury exposures have learning difficulties.
Recent studies also suggest that arsenic can harm the developing brain.
Many other health effects of these metals are well-known.
Common Health Effects
(some occur only at high exposure levels)
high blood pressure, anemia
memory and learning difficulties
miscarriage, decreased sperm production
|Mercury||blindness and deafness brain damage
lack of coordination
death if exposed to high levels
known human carcinogen: lung and skin cancer
nausea, diarrhea, vomiting
peripheral nervous system problems
Only relatively recently have people begun to take action to curtail the use of mercury, arsenic, and lead. Local advocacy and legislation have made a difference in reducing continued pollution with these metals.
- Lead - Decades of evidence on lead’s health effects were amassed before the metal was banned in paint and gasoline, and lead is still allowed in many consumer products.
- Arsenic - Arsenic-treated wood was extremely widely used before manufacturers agreed to phase it out.
- Mercury - Recently, a number of states, including Washington and Oregon, have passed legislation to address mercury use in products such as thermometers and thermostats, but major sources like coal burning continue.
- Mercury - King County has had tremendous success in reducing mercury pollution from dental offices by cracking down on dentists to keep mercury out of their wastewater. Mercury in dental offices comes from amalgam fillings, which are about half mercury by weight. State law requires dentists to use devices called separators, which remove mercury from wastewater, but compliance in the past has been poor. By conducting inspections and threatening fines, King County was able to achieve 97% compliance and a 50% reduction in mercury in wastewater between 2000 and 2003 (King County 2005).
The following actions would reduce ongoing exposure to these toxic heavy metals:
Lead, mercury, and arsenic should be phased out of products.
Coal burning should be replaced with conservation and cleaner sources of fuel for energy production. In the meantime, existing coal-fired power plants should be required to install the best technology to limit mercury emissions.
Contaminated sites should be cleaned up promptly and fully. Where a large geographic area is contaminated, state government should take measures to ensure facilities such as schools and day care centers are not sited on contaminated soil.
Solid-waste and medical-waste incinerators should be shut down and replaced with waste and toxicity reduction, reuse, recycling, and composting programs.
Health care facilities, including hospitals and dental offices, should phase out mercury-containing products in favor of safer alternatives.
- Government agencies should expand programs to remove, collect, and safely store mercury from thermostats, thermometers, and switches.
- School districts should take remedial action to eliminate lead exposure to children from school drinking water.
We come into contact with lead, mercury, and arsenic in many ways, but there are some steps we can take to reduce our exposure.
Remove treated wood. Remove wood treated with the preservatives CCA or ACZA, which contain arsenic. If removing arsenic-treated wood is not an option, you can paint or seal the wood to reduce leaching and contact exposure. Choose semi-transparent deck stains for deck surfaces and play structures, and latex paint for fences, tables, and other furniture. Reapply the coating when it shows signs of deterioration.
Avoid fish high in mercury. Avoid fish high in mercury, such as king mackerel, tilefish, swordfish, orange roughy, and marlin. Limit consumption of tuna, especially steaks and canned ‘white’ albacore. Lower-mercury choices include wild salmon, sardines, anchovies, Atlantic herring, Dungeness crab, Pacific cod, Alaskan black cod, farmed striped bass, tilapia, farmed catfish, clams, mussels, and Pacific oysters.
If you eat sport-caught fish, check for specific guidance on mercury levels in Washington water bodies or coastal waters. Fish and shellfish advisories are available from the Washington State Department of Health
Limiting mercury intake from fish is especially important for young children and women who are pregnant, nursing, or of child-bearing age.
You can find additional guidance on fish choices at the following websites:
Environmental Working Group: Mercury in Seafood (includes Tuna Calculator):
Fish are an excellent source of nutrients, including protein, omega-3 fatty acids, and vitamin D, and we encourage people to continue eating fish following these precautions.
Watch for lead paint. If you live in a home built before 1978, it is likely to contain lead-based paint. If the paint is chipping, peeling, or otherwise deteriorating, or if you want to remodel, hire a certified abatement worker to remove or contain contaminated paint. Use door mats, remove shoes at the door, and vacuum and clean regularly to reduce lead that accumulates in house dust.
Protect drinking water. Avoid exposure to lead that may be leaching from plumbing by flushing your cold water pipes (run water until it becomes as cold as it will get) before drinking, and only use cold water for drinking or cooking.
Avoid PVC. Choose alternatives to products made of PVC, which often contain lead, especially for items that are likely to come into direct contact with children’s hands and mouths, such as toys, teethers, and lunchboxes. Old toys and furniture made prior to 1978 may also contain lead-based paint. For consumer product safety information and recalls for lead products, visit the Consumer Product Safety Commission’s website.
Watch for lead in dishware. Do not use old, imported, or homemade ceramic dishware, unless you know that the glazes do not contain lead. Avoid leaded crystal, as well as imported food cans, which can contain lead solder.
Make sure medicines are free of toxic metals. Some home remedies, as well as drugs and cosmetics, can contain these metals. Look at ingredient lists, talk to your doctor, and avoid folk remedies and other medicines that contain lead, arsenic, or mercury.
Be cautious with mercury-containing products.When possible, choose products without mercury, such as digital thermostats and thermometers. Be careful not to break fluorescent light bulbs, mercury thermometers, or other household items containing liquid mercury. These products release harmful mercury vapors when broken. If they do break, use appropriate clean-up methods, see the EPA's web site.
Check paints and art supplies. Avoid paints containing mercury compounds, which are still found in some paints as pigments. Also avoid lead solder and artists’ paints and glazes that contain lead. Information on some products containing these ingredients is available from the Household Products Database. Otherwise, ask the manufacturer.
Skip herbicides with arsenic. Avoid arsenic-containing herbicides, which have ingredients listed as monosodium methanearsonate (MSMA), calcium acid methanearsonate, or cacodylic acid.
Consider composite fillings. Consider choosing composite dental fillings rather than mercury-containing amalgam fillings.
- See our section on safer food
- See our section on less-toxic product choices
- State of Washington's Mercury Chemical Action Plan