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

Home

m I I I I I I I I I I I I I I I Minnesota Pollution Control Agency August 10, 1984 Mr. and Mrs. Gary Olson 15021 Garnet Street Ramsey, Min6esota 55303 Dear Mr. and Mrs. Olson: Enclosed are the results from the June 13, 1.984 sampling 6f your ~ell by repre- · sentatives of the Minnesota Pollution Control Agency {MPCA) and Waste Management of Minnesota, Inc. Samples collected by MPC~ personnel were'analyzed by the Minnesota Department of Health (MDH); samples collected by Waste ~anagement 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. MDH did report trace concentra- tions of methylene chloride in the s&mple 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 s~nple bottle preparation. Methylene chloride is an organic solvent which is used in nearly every labora- .tory 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 con- tamination in laboratories. This is such a universally common proble~ that it is standard procedure to prepare and carry a "field blank" during s~npling work, which was done as part of this smnpling effort. This field blank is a s&mple bottle 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 sampling. If there is a proble~ with background cont~nination by methylene chloride, or any other compound, it will be indicated by the pre- sence of that compound in the field 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 problem was not unique to the sample taken from your well; the sa~ne thing happened with all of the other seven residential well s~mples which were collected during our s~pling work Phone:61~2/296-7266 1935 Wesl Courtly Road B2, Roseville, Mmnnesota 55113-2785 Regional Offices · Dululh Bra~nerd/Dehoi! Lakes'Marshall Rochester Equal Opp~tu~ty