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Jul-29-98 11:O1A ACZ ~ ora111111'II'11''1''11 970 ~ -2216 P.O2 <br />~"'~~ Laboratories, Inc. <br />July 29, 1998 <br />Ms. Stephanie Carter <br />Cyprus Yampa Valley Coal Cotp. <br />29588 Roun County Road 27 <br />Oak Creek , CO 80467 <br />Re: Data Reporting of Colt(orm Results <br />Dear Ms. Carter. <br />ACZ reported a value of "too numerous to count" (TMC) on CYCC sample 300E, ACZ lab Number <br />L 17946-1 G, taken on April 1. 1998. The analysis wa performed using the method 9222 D, from the <br />Standard Methods for The Examination of Water and Wastewater, l8th edition, 1992. <br />The method basically calls for multiple aliquots of a sample to be filtered through a 0.45 um grided (filter. <br />the filter is then placed in a microbiological petn dish containing the applicable nutrient medium. After <br />a 24 hour incubation period at 44.5 degrees C, the Cecal coliform colonies are counted. The methods for <br />calculating and reporting coliform bacteria growth are outlined in section 6 of the method, which I have <br />attached. The method states that anew sample should be obtained and more appropriate dilution made. <br />Because ACZ never really knows the source of these waters, we perform a series of 3 dilutions; using 2, <br />5 and l5 m1s of sample. ]n most cases these dilutions yield an acceptable number of colonies on the <br />plate that allow (or accurate extrapolation to 100 mis. In this case all dilutions were masked with <br />coliform growth not allowing for any counts to fie made and hence, reporting "fNTC. Since this <br />particular site is normally Clean, we had no reason to change the normal dilution factors. <br />A possible solution to future problems of this kind would be for ACZ to extend the range of dilunons <br />performed. This should help in some cases but may not always work. Because of the 24 hour holding <br />trine restriction, the best course of action would be to receive a second sample for analysis. However, <br />this does not answer the problem of how to deal with the reporting of coltform data for compliance <br />purposes? <br />1(you have any questions or problems please give me a call at 879-6590. <br />Sincerely. <br />Scott Habermehl <br />Project Manager <br />2773 Downhill Dnve Phone (B00) 334.5493 <br />S1e8mboal Springs, CO 80487 FAX No. (970) 879-2216 <br />