Excerpts from Recent Findings-2

EXCERPTS … - from "Chromated Copper Arsenate" in the Journal of Pesticide Reform, Vol. 11, No.1. Spring 1991. By Northwest Coalition for Alternatives to Pesticides, Box 1393, Eugene, OR 97440-1393. (541) 344-5044.

E-mail: info@pesticide.org;URL:http://www.efn.org/~ncap.

Following is a summary of some key quotes:

"Chromated copper arsenate (CCA) is a mixture of metallic salts used as a wood preservative. As the name suggests, these salts contain arsenic, copper, and chromium. They are used to protect wood from decay by microbes, fungi, and wood-feeding insects. Typical uses include treatment of fenceposts, decking, playground equipment, and structural lumber used where it will be in contact with concrete or the ground."

"Common brand names of CCA formulations are Osmose, Wolman, and Rentokil."

"A high incidence of herpes infections and respiratory infections has been found in cases of subacute arsenic poisoning, suggesting that arsenic may suppress the immune system."

"The lethal oral dose of arsenic for an adult human is between 1 and 2.5 milligrams per kilogram (mg/kg) of body weight…… Chronic effects include damage to mucous membranes; irritation of eyes; irritation, darkening and lesions of the skin; disturbances and degeneration of the peripheral nervous system; swelling and damage of the liver; abnormal heart function; and hearing loss."

"Exposure to arsenic has been associated with induction of cancer since the nineteenth century. Exposure to arsenic increased the risk of lung cancer in epidemiological studies of workers who manufactured or used arsenic-containing pesticides and workers in smelters who were exposed to high levels of arsenic."

"The U.S Environmental Protection Agency (EPA) classifies arsenic as a Group A carcinogen, having evidence of human carcinogenicity."

Mode of Action

Arsenic: Arsenic toxicity to living organisms results at a molecular level because if mimics phosphate ions. High-energy bonds between phosphate ions are an important part of the respiratory process (the process by which a cell obtains energy from sugar compounds) in all higher organisms. If arsenic takes the place of phosphate in these high energy compounds they rapidly break down instead of performing their usual function. Arsenic (III) is more toxic than arsenic (V) and there is some evidence that arsenic (V) is converted into arsenic (III) living organisms.

An indication of arsenic’s broad-spectrum toxicity is the use of arsenic-containing compounds as insecticides, rodenticides, herbicides, and plant growth regulators.

Chromium. Chromium (III) is thought not to produce toxic effects and is an essential nutrient in humans in

amounts of 50-200 micrograms (m g) per day. Chromium (VI) is almost totally derived from human activities and is toxic because it is a strong oxidizing agent to which biological membranes are easily permeable.

Copper. Copper inhibits some of the enzymes involved in respiration, photosynthesis, and nitrogen fixation. It also interferes with osmo-regulation, the process by which an organism maintains an appropriate water balance. Copper is most toxic to organisms which concentrate copper, have high surface to volume ratios, or have permeable gill surfaces that facilitate rapid uptake of the metal. For example, fungal spores up to one hundred times that found in their immediate environment and algae, in addition tor having a high surface to volume ratio, accumulate up to 83,000 times the ambient copper concentration.

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Page 2 of "Chromated Copper Arsenate"

"In Portugal, vineyard workers spraying copper sulfate 15 to 20 days per year developed lung lesions, some of which later became cancerous. In addition, liver damage, sometimes progressing to liver cancer, was noted."

IMPACTS ON NONTARGET ORGANISMS

"Arsenic acid has caused deer kills following its use as an herbicide on farmland."

"Chromium is acutely toxic to soybean plants raised hydroponically if present at 30-60 milligrams per liter (mg/l) of nutrient solution."

"Chronic effects of chromium exposure have also been documented. Hydroponic soybeans showed a reduction in leaf weight and leaf chlorophyll concentration following chromium exposure 1/3,000-/6,000 times that which caused mortality."

"Copper appears to be more toxic to embryonic and juvenile stages of aquatic vertebrates than to adult stages." "Chronic effects of copper exposure on algae and aquatic invertebrates have been studies in detail."

IMPACTS ON WATER QUALITY

"In acidic water (pH 3.5) 68 percent of the arsenic, 53 percent of the chromium, and all of the copper leached out during a forty-day period. If the water was neutral (pH 7.0) only 9 percent of the arsenic, 1 percent of the chromium, and less than 1 percent of the copper leached. .. These results suggest that CCA treated wood exposed to organic acids (in swampy ground or soil with high humus levels, for example) will leach readily."

 

CONCLUSION

"All of this CCA-treated wood is a concentrated source of metals that are acutely and chronically toxic to a wide range of organisms, from single celled algae to humans. In humans, the ability of CCA’s ingredients to cause disorders of the nervous system, damage to various organs, cancer, and birth defects is well documented. The sensitivity of other organisms varies from species, but the most susceptible species are damaged at concentrations of several parts per billion. Although chromium (VI) can be transformed to the less toxic chromium (III), the toxicity of arsenic and copper is a permanent legacy of treated wood."

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FROM -Robert S. Leathers . . . Architect PC

PRESSURE-TREATED LUMBER

"In the wipe tests we have had done on our projects, we have continually found only low levels of arsenic present. In most of the testing done we have found between 1 and 10 ug/100 cm2 (micrograms per hundred square centimeters) of arsenic in any given spot. One wipe test turned up 24.7 ug/100cm2, and on one occasion we came up with 45 ug/100 cm2 under a platform. To give you some idea of what these levels mean: the California Department of Health Services uses 25 ug/100 cm2 as policy guideline for what is considered a safe level."

Published February 1987. 2 pp.

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