8/18/1982 - Laserfiche WebLink

Home Browse Search

E1,1 , 6. I BQDK 51 PACE 30, chronic toxicity is not a major problem because of the rapid breakdown of the compound in the environment. However, studies have shown that this rapid breakdown only occurs under certain soil conditions, i.e., when the soil is aerobic (oxygenated) and the pH is alkaline. Under these conditions the reported half life (time for the existing concentration to be reduced in half) of Temik varies from 6 weeks to 3 years. In acid soils and/or anaerobic (oxygen free) conditions such as those commonly found in surficial soils and aquifers of Florida, the compound is likely to be extremely persistent. Known ground water contamination cases due to Temik have been reported in Long Island, New York, Wisconsin and Virginia. The ground water contam- ination in Long Island was apparently severe enough to move State officials to ban the use of Temik in the State and institute a drinking water stan- dard of 7 parts per billion for the compound. Very little information exists with respect to ground water contamination by Temik in Florida even though approximately 300,000 acres of citrus groves are regularly sprayed with the compound. Union Carbides' own experimental data from a study conducted in Hillsborough County showed Temik concentrations in the soil at 7 feet below land surface to be 80 parts per billion and at 8 feet to be 70 parts per billion. No ground water samples were analyzed in connection with this study, however, given the physical characteristics of the compound it is likely to be present in ground water well in excess of the New York standard. To answer your questions: Should we be concerned about Temik? - Yes. Actions that might be taken are 1) initiate ground water sampling and analysis in selected areas of the State where the insecticide is used 2) restrict the over application of the pesticide. Dr. Herb Nigg of the University of Florida Agricultural Research Center, Lake Alfred, Florida, maintains that the compound is over applied in the State and that a much more restricted application rate could be utilized without deleterious effects on the control of nematode populations. I trust that your concerns have been addressed in this letter, but should you have any further questions, do not hesitate to call. Sincerely, L Geoffrey Watts Groundwater Section Slides were also shown by Mr. Combs as he gave his presentation. He reported that because of the CBS News and other media reports on Temik concerning citrus, the University of Florida, Department of Citrus, conducted various tests and found no problem with the chemical. Mr. Combs noted that as far as the County was concerned, it would cost the citrus growers approximately $125 an acre to use this product, which was very expensive. He added that the chemical is applied into the ground by chiseling it in 1" or 2" below the surface; most of this work must be done by custom applicators. 30