Arsenic has a bad reputation. It's an element that has been used as a poison since the Middle Ages. It has been used to kill commoners as well as dignitaries such as King Eric XIV of Sweden and Napoleon Bonaparte. Medical research has shown that it can cause cancer, especially of the bladder and lung. Children are exposed to it every time they play on playground equipment made from certain types of pressure-treated wood.
Since the 1970s, most wood used for playground equipment has been pressure-treated with a preservative called chromated copper arsenate (CCA). In the last few years, safety concerns about arsenic in drinking water and CCA-treated wood have come to the public's attention. Scientists found that children who play on equipment made from CCA -treated wood have an increased risk of developing lung or bladder cancer during their lifetimes.
Chromated copper arsenate protects wood against decay from dry rot, fungi, insects and marine borers. CCA is injected into wood under high pressure and turns the wood a greenish color. Then, the wood is often stained brown. It is sold in lumberyards under different trade names (such as Wolmanized® wood). It is also used for decks, outdoor furniture, fencing, utility poles, pilings and boat docks.
The arsenate in CCA is a form of arsenic. Children's hands pick up an arsenic residue from playground structures and then can transmit it to their mouths, exposing themselves to higher amounts of arsenic than usual. Younger children, especially age 6 and under, tend to put their hands in their mouths frequently and to eat without washing their hands first, increasing their risk of exposure.
Arsenic occurs naturally in the environment. It's in the air, water, soil, and in some foods, especially seafood. It isn't normal nor desirable for humans to have zero arsenic intake. Some experts at the Food and Drug Administration estimate that the average adult American consumes about 30 micrograms per day. Arsenic has beneficial uses: Before the discovery of penicillin, it was used as a treatment for syphilis. It is now being tried as a treatment for a type of leukemia.
Each time a child plays on CCA-treated playground equipment, he or she is exposed to about 3.5 micrograms of arsenic, says the Consumer Product Safety Commission. This is not a large amount, and for most children, it is probably within a safe range. However, children who are already exposed to higher-than-average amounts of arsenic in their water and food will be the ones most at risk of developing cancers later in life.
The makers of CCA-treated wood recommend safety precautions for anyone working with their products. Sawing and sanding should be done outdoors, wearing a dust mask, goggles and gloves. Scraps and sawdust should be disposed of in municipal solid waste; this wood should never be burned since toxic chemicals are released in smoke and ash. Sawdust should not be composted or used as mulch. After working with the wood, wash hands and all exposed body parts with soap and water before eating, drinking or smoking.
Now that the EPA and the public are focused on CCA, manufacturers of pressure-treated wood have voluntarily agreed to stop treating wood with CCA for most consumer uses by the end of 2003. Companies in the Northwest such as Conrad Forest Products in Rainier and North Bend, Ore., and Exterior Wood Inc. in Washougal, Wash., are already offering alternative, copper-based wood preservatives that don't contain arsenic, such as ACZA, ACQ and CBA.
How much should you worry about whether your kids are exposed to CCA-treated wood? You don't need to prohibit them from playing on playground equipment, but teach them to wash their hands thoroughly with soap and water after playing and before eating. Playgrounds should post notices for parents letting them know that the equipment is made from CCA-treated wood, and recommend hand washing after playing. New playground equipment and outdoor furniture should be made with arsenic-free wood.
Arsenic is not the most dangerous chemical kids are exposed to (secondhand smoke from cigarettes is certainly worse), but we should do whatever we can to minimize their exposure.
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