Agenda - Council - 08/28/1984 - Laserfiche WebLink

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I m I I I I I I I I I I I I August g, ]984 Pollution Control Agency Mr. and Mrs. Michael Lambrecht 6950 - 149th Lane. Ramsey, Minnesota 55303 D~r Mr. and Mrs. Lambrech~: Enclosed are the results from the June 13, 1984 sampling of your well. by repre- sentatives of the Minnesota Pollution Control Agency (MPCA) and Waste Management of Minnesota, Inc. Samples collected by MPCA personnel were analyzed by the Minnesota Department of Health (MDH); samples collected by Waste Management were analyzed by Environmental Testing and Certification (ETC), an independent private laboratory in Raritan, New Jersey. Results from both MDH and ETC indicate that no organic compounds are present at detectable concentrations in your water supply. Both MDH and ETC did report trace concentrations of methylene chloride in the sample from your well. This detection of methylene chloride, however, is not attributable to the presence of methylene chloride in your well water. Rather, the evidence indicates that this compound was inadvertently introduced in the laboratory .during sample bottle preparation. Methylene chloride is an organic solvent which is used in nearly every laboratory which carries out the kind of analyses done on your water sample. The most common usage is in extracting compounds from various types of samples. As a. result, low levels of methylene chloride are often present as background oontamination in laboratories. This is such a un{versally common problem that it is standard procedure to prepare and carry a "field blank" during sampling worK, which was dore as part of this sampling effort. This field blank is a sample Dottle which is cleaned and prepared in exactly the same way as the other sample bottles. It is then filled with organic-free water in the laboratory, and carried during the smmpling. If there is a problem ~ith background contamination by methylene chloride, or any other compound, it will be indicated by the presence of that compound in the fiel~blank. The enclosed data sheet for the field blank shows that methylene chloride was present in trace concentrations, which indicates that the methylene chloride noted in the private well samples was introduced into the sample as a result of .background laboratory contamination, and is not present in the well water. This type of probl~ was not unique to the sample taken from your well; the same thing hap- pened with all of the other seven residential well samples which were collected Phone: 612/296-7266 1935 Wes! County Road B2, Roseville, Minnesota 55113-2785 Regional Offices *Duluth. Brainerd'Detroi! Lakes'MarshalL-Rochester Equal Opportun4y Employer