Description

Arsenic is a naturally occurring element, considered a heavy metal. The pure form of arsenic is not commonly found in the environment. However, arsenic is found in naturally formed and man-made compounds.

Treated wood (or pressure-treated wood) contains chromated copper arsenate (CCA), containing 22% arsenic.

Manufacturers of pressure treated wood agreed in early 2002 to phase-out the use of CCA as a wood preservative by December 31, 2003, and the EPA currently approves it for industrial pressure treatment only. Nevertheless, any outdoor wood, and soil around it, should be considered suspect over the coming years.

Arsenic, in pesticides is banned, but it is used in glass production, semiconductors, to make metal alloys (used in lead-acid car batteries, for example), and some medications (mostly veterinary). All of the arsenic used in the U.S. is imported; it is no longer produced in the U.S.

Various industries release arsenic into the air and groundwater, as well. These industries include mines and smelters, cotton gins, glass manufacturing operations, coal burning facilities, municipal incinerators and others. In addition, arsenic may leach from landfills that contain arsenic-laden ash produced by coal-burning power plants, treated wood, and other arsenic-containing products.

Inorganic arsenic is banned in pesticides and fertilizers, but organic arsenic is used in pesticides mostly in cotton fields and orchards.

Arsenic is also naturally present in very small quantities in food.

In some areas, where natural formations of arsenic exist, such as the western and southwestern United States and Alaska, drinking water may have relatively high arsenic concentrations.

In general, naturally occurring arsenic is usually found in the pentavalent form, which is less toxic than the trivalent form which humans add to the environment. (Arsenate is the form most prevalent in nature.)

Health Effects

Immediate Health Effects

If SWALLOWED, arsenic is Very Highly Toxic
If ABSORBED THROUGH SKIN, arsenic is Very Highly Toxic
If INHALED (SNIFFED OR BREATHED IN), arsenic is Highly Toxic

Longterm or Delayed Health Effects

Suspected Endocrine Disruptor = May interfere with, mimic or block hormones
Linked to diabetes, hypertension and cardiovascular disease.

Other

Breathing inorganic arsenic can give you a sore throat or irritated lungs. Higher levels of arsenic can cause nausea, vomiting, diarrhea, decreased production of red and white blood cells, abnormal heart rhythm, blood vessel damage, and a "pins and needles" sensation in hands and feet. Skin contact may cause redness and swelling but does not appear to result in any immediate internal effects.
Chronic arsenic intoxication is characterized by fatigue and malaise. Disturbances of the gastrointestinal tract, anemia and other blood abnormalities, skin abnormalities including the appearance of dark and light spots on the skin, pale bands on the fingernails and toes, small "corns" on the palms, soles, and trunk (hyperkeratosis), and "pins and needles" sensation in hands and feet may ultimately occur. Elevated levels of arsenic in hair, nails, and urine may be present long after exposure has stopped.
Several studies suggest a link between arsenic exposure and type II diabetes. Arsenic may also have immunological and cardiovascular effects, including hypertension, coronary artery disease, peripheral vascular disease, and atherosclerosis.
Birth defects have been observed in animals exposed to inorganic arsenic. It is not known whether this can occur in humans. Children may be more susceptible to arsenic than adults since they are less efficient at converting inorganic arsenic to the less harmful organic forms.
Inorganic arsenic may increase the risk of lung, bladder, prostate, liver, kidney, and skin cancers (both melanoma and non-melanoma). Skin cancer may occur in combination with other cancers, such as liver angiosarcoma, intestinal, and urinary bladder cancers and meningioma, in some cases. The World Health Organization, the U.S. Department of Health and Human Services, the U.S. Environmental Protection Agency, and the National Toxicology Program consider inorganic arsenic a human carcinogen.
The symptoms of acute inorganic arsenic poisoning occurring as a consequence of accidental or intentional ingestion are burning and dryness of the throat and breathing passages, disturbance of the gastrointestinal tract, and muscle spasms; dizziness, delirium, and coma may occur. Swelling of the face and about the eyelids may also occur. Very high levels of ingestion can result in death.

How Exposures Occur

Absorption Through Skin

More rarely, arsenic may be penetrate the skin after a child has touched pressure treated wood. Generally, skin contact does not result in internal effects.

Drinking Water

Children can ingest arsenic from contaminated drinking water, especially where arsenic is naturally found, such as the southwestern U.S, or near landfills and polluting facilities, such as mines and smelters, cotton gins, glass manufacturing operations or refineries.

Food

Children may consume residues of arsenic compounds through contamination of foods by pollution, pesticides or fertilizers, livestock residues (from medications and pesticide treatments), or high levels of naturally occurring arsenic. The highest levels of arsenic are detected in seafood, poultry, meats (e.g., pork), mushrooms, salt, and grains. Chicken may contain significant arsenic contamination because chicken feed is often supplemented with arsenic-based drugs to control intestinal parasites. One study found arsenic levels three to four times higher in chicken than in other meat and poultry. Generally seafood contains the organic form of arsenic, which is less toxic.

In the Womb

Arsenic can cross the placenta to the developing embryo/fetus. Arsenic is found at low levels in breast milk. However, the benefits for babies from breast feeding outweigh the risks of arsenic exposure. Breastfed babies are healthier than those who are bottle-fed; they experience fewer allergies, respiratory illnesses, and skin problems. In its 2005 policy statement, Breastfeeding and the Use of Human Milk, the American Academy of Pediatrics highly recommends breast feeding for all infants for one year.

Ingestion of Treated Wood or Contaminated Soil

Arsenic leaches from treated wood into soil. Children can be exposed by touching CCA surfaces or ingesting soil that surrounds the wood. Children may be more susceptible to arsenic than adults since they are less efficient at converting inorganic arsenic to the less harmful organic forms. They can also be exposed by touching the soil and later putting their hands in their mouths.
Some area of the U.S. contain naturally high levels of arsenic. Children may be exposed to arsenic by hand-to-mouth activity, or from eating dirt.

Inhalation

It is possible for children to breathe in arsenic from air, particular near facilities that release arsenic, or when arsenic-treated lumber is burned, or from sawdust when arsenic-treated lumber is cut.

Significant Statistics

Approximately 90% of the wood sold in the United States for outdoor use is pressure treated and injected with toxins that act as preservatives and pesticides.

News Note: Arsenic Wood Preservative Phased Out in U.S. Pesticide Action Network. 2008.

http://www.panna.org/node/1220.

Arsenic has been found in at least 1,149 of the 1.684 current or former sites on the National Priorities List (NPL), the most serious hazardous waste sites in the nation identified by the U.S. Environmental Protection Agency.

Toxicological Profile for Arsenic. Agency for Toxic Substances and Disease Registry, . August 2007.

http://www.atsdr.cdc.gov/toxprofiles/tp2.html

There is a report that exposure to arsenic may contribute to gestational diabetes which poses risks for both mother and baby long term.

Barrett JR 2009. Mother Load: Arsenic May Contribute to Gestational Diabetes. Environ Health Perspect 117:A310-A310. doi:10.1289/ehp.117-a310b. 1 July 2009.

http://ehsehplp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info:doi/10.1289/ehp.117-a310b.

Arsenic is a metalloid, meaning it has properties of both metals and non-metals. Elemental arsenic is a solid steel grey material, but it is rarely found in its elemental form.

Public Health Statement for Arsenic. Department of Health and Human Services. August 2007.

http://www.atsdr.cdc.gov/toxprofiles/phs2.html.

Solutions

How to detect arsenic

Wood in decks, patio furniture, children’s playground equipment, benches and picnic tables may contain CCA.

Manufacturers of wood treated with arsenic compounds have been asked to add warning labels to their products and to provide safety information through a toll-free consumer hotline, a web site and an improved consumer fact sheet. Wood that has been pressure treated with CCA has a greenish tint (but this can fade over time). CCA is no longer used for wood in residential projects or playgrounds, but older structures can contain wood preserved before CCA was phased out.

If you have recently purchased treated wood without labeling indicating the type of preservatives used, contact and ask the manufacturer about what was used. Wood that has been pressure treated has a greenish tint (although this can fade over time).

Read all labels on pesticides and wood products. Ask manufacturers or applicators for Material Safety Data Sheets (MSDS) on the products used for safety information about ingredients. You can also find MSDS sheets at Vermont Safety Information Resources Inc.
The Safe Drinking Water Act requires that community water systems monitor arsenic levels, and make public when levels exceed the set Maximum Contamination Level (MCL) of 50 parts per billion (ppb). EPA has revised the standard, ordering that it fall to 10 ppb by 2006.

Community water systems are required to produce annual consumer confidence reports and mail them to every water customer.

If your water source is a well, your water is not monitored for contaminants as is required for public water supplies by the Safe Drinking Water Act. Private testing of the water is necessary.

Even if your water comes from a community water system, contaminant levels can vary from house to house. You can have your water tested by sending samples to a certified laboratory.

You can search for water quality reports from your water provider, obtain information on well water testing and find a list of state-certified drinking water laboratories at the U.S. EPA’s Office of Water’s website or call the EPA’s Safe Drinking Water Hotline, 800-426-4791.

Home Testing Kits:

Note: If home tests reveal high levels, follow up with a professional assessment. An industrial hygienist or environmental laboratory (listed in the yellow pages under “laboratory” or “environmental”)

Inexpensive arsenic testing kits are available online.

How to minimize exposure to arsenic

Seal treated wood with a waterproof sealant every six months. See also: How to Avoid Arsenic Exposure from CCA-Treated Wood.
Block access to areas below treated decks so that children and animals cannot enter.
Avoid sanding or finishing treated wood to avoid dispersing arsenic in soil and the air. If you do use arsenic-treated wood in home projects, you should wear dust masks, gloves, and protective clothing to decrease exposure to sawdust. Always work with this wood outdoors, and DO NOT ALLOW CHILDREN TO ENTER THE AREA!
Do not use acid washes or brighteners on treated wood, as doing so will accelerate the release of arsenic from the wood.
Do not allow food to contact treated wood.
Do not burn treated wood or compost sawdust, chips or small wood scraps derived from treated wood.
To dispose of treated wood properly, contact your local sanitation department for details.
If you live in an area with high levels of arsenic in water or soil, you should use cleaner sources of water and limit contact with soil (e.g., keep children away from soil, wash their hands frequently, plant groundcover, clean and dust your house frequently, install an air filter).

If your drinking water contains arsenic at levels higher than 10 parts per billion, you can improve it by installing a water filter. For more information, see Water Filters.
Eat a healthy diet. There is some evidence to suggest that people who do not eat enough protein and other nutrients may not convert the more harmful inorganic form of arsenic into the less toxic organic form as readily.

Alternatives

Try to minimize use of wood in locations where rot or insect infestation is likely. Look for non-wood solutions, such as recycled plastic lumber, metal and concrete.
When it’s not possible to avoid wood, look for naturally rot-resistant species, such as cedar, redwood, douglas fir, ponderosa pine, and the tropical wood purple heart. Black locust is a suitable replacement for some uses, according to Organic Gardening Magazine (July/August 1997). But try to obtain wood (Particularly redwood and cedar) that has been harvested from a certified, sustainably managed forest, or re-use it or use reclaimed wood. See Independently Certified Wood.
When you must use treated wood, look for wood products that have been treated with alternatives to CCA, such as ACQ Preserve, which is made of ammonium copper quaternary. Treatment with boron or borate preserves wood can be far less hazardous, but it is not as long-lasting or effective as other treatments. Borate preservatives may leach out of wood in wet conditions, although they are effective for treatment against termites when wood will not be exposed to weather.

The Healthy Building Network has a database of distributors that carry safer products.