CORRESPONDENCE_1982-1983 - Laserfiche WebLink

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HONORABLE BOARD OF SUPERVISORS May 5, 1982 Page Ten for the farming community and the general public. In 1978 The Environmental Protection Agency published a report on cadmium additions to agricultural lands via commercial phosphate fertilizers. The level of cadmium applied directly to soils in superphosphate fertilizers is reported in that study at 40 to 175 ppm. Although cadmium wastes have never been received at the Forward Inc. site, the levels of cadmium used in fertilizers in the fields adjacent to the site are 35 times more concentrated than waste materials permitted in the site. Williams and David examined agricultural soils that had received cumulative additions of superphosphate fertilizers of up to 3500 lbs per acre over 20 or more years. They indicated that more than 80% of fertilizer cadmium was contained in the first 6 inches of topsoil. The use of phosphate fertilizers on vegetable crops presents one of the greatest potential hazards of cadmium addition of the foot chain according to the EPA reports. In discussing concentrations of chemicals we often use the term "part per million" to describe how much of a pot- entially harmful substance is present in a waste material. A part per million is simply one pound contained in a million pounds of something else, for example one part per million of copper in soil is equivalent to the amount of copper in one penny mixed with a pickup truck load of dirt. One part per billion is the equivalent amount of copper in one penny distributed throughout 50 railroad boxcars. . Much of the controversy over the Forward Inc. site concerns toxic sub- stances. What is a toxic substance? The statement made by Emil Mrak, a member of the Commission of Pesticides, is that "There are no harmless substances; there are only harmless ways of using substances" and this correctly notes that a chemical is harmful only within prescribed conditions of usage. The zinc chloride stored at the Forward, Inc. site is the same chemical used in eye drops as an astringent. Mixed with water at 0. 5% concentration it is beneficial to man, and mixed with dirt at 20% concentration it is a waste material disposed of in a State approved containment site. So the issue is not what chemicals in our daily environment can be harmful if misused, but really how safe are chemicals that have been stored in an approved site to prevent them from being harmful to the environment. Nicotine, one of society' s social poisons is also used as a pesticide in such