Four billion dollars are spent annually in the treatment of wood for power lines, docks, guard rails and playground equipment. They are treated with chromated copper arsenate (CCA) and can keep the wood preserved for 25 years. This is great around salt water and oceans.
DANGERS are that this arsenic slowly leaks into the soil and then the groundwater. Hazardous wastes have special landfills, but treated wood does not.
THE PROBLEM is how to dispose of this treated wood. It is now burned in unlined landfills or simply tossed out. 77 tons of arsenic is in Florida landfills and should increase seven times to 35 million cubic feet in the next 15 years as treated wood ages. The sandy soil is Florida does not hold metals well. Their landfills do not distinguish between illegal mulch and old wood treated or not treated all look alike.
Other states (CT, MINNESOTA, WISCONSIN AND IOWA) are now scrutinizing their wood disposal practices. California has a sealant every 2 years but this does not hold the arsenic from being released. Disney now is using organic treated wood because of the scare. Overseas wood having CCA is banned in Switzerland, Japan and Vietnam. Alternative chemicals however may have some environmental problems.
HOW MUCH ARSENIC IS DANGEROUS?
This is an insidious problem. Arsenic is a natural element and a poison. It was used medically to treat leukemia. It also was in embalming fluid 100 years ago. It is a by product of copper mining and gold and silver refining.
Recently it is used in batteries. Currently it is used as an herbicide on golf courses. We import 30,000 tons annually from China and Chile.
A major concern is that there are high levels of arsenic in bladder, lung and skin cancer. The EPA has recently lowered the safe level from 50 parts/billion to 10 parts /billion. A standard of 0.8/billion is considered safe. In the US, about 5parts/billions are considered normal. It often takes about 20 years for cancer to be evident.