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Mr. Richard Mills - 2 - June 5, 1986 Site 84, Pond D's outfall, is the only discharge point covered by CDPS Permit 0027154. Effluent from this site periodically exceeds receiving stream standards for molybdenum, zinc and copper. Detection limits on cadmium and mercury are higher than the receiving stream standards, indicating that these metals may also be a problem. Silver levels exceeded receiving stream standards during the first three quarters of the year, but it is our understanding that the analytical procedure was in question during that time. Estimates of salt concentrations (EC and TDS) are in excess of levels which CMLRD considers acceptable to avoid material damage without natural adequate streamflow dilution. Data Quality Both field and laboratory data quality was examined to evaluate the reliability of the data. Field analyses of discharge and electrical conductivity were studied while mass balance and total dissolved salt concentrations were evaluated to ascertain gross analytical accuracy. Lastly, an examination of the efficiency of detection limits were performed. Discharge data along Foidel Creek indicated that there were no losing reaches. However, Fish Creek data showed a losing reach in 1985 between site 1001 and 1002. Has this been historically true? The Division strongly recommends that gaging equipment be checked at 1002 and requests to be informed of the results. Analytical laboratory data can be checked using three methods: mass balance analyses, a comparison of calculated and gravimetrically determined total dissolved solids (TDS) values or a comparison of electrical conductivity and total dissolved solids (TDS). A random survey of mass balance showed cations consistently being reported at levels ten percent higher than anions. Consequently, calculated TDS should have been 10 percent higher then the gravimetric determination. However calculated TDS and the gravimetric TDS had no consistent relationship with each other. We strongly recommend that you request the lab to achieve greater compatibility between these values. The comparison of EC and TDS is the least rigorous quality check, because the relationship is site specific. Natural waters low in sulfates generally should show the relationship: TDS = 0.6EC As sulfate concentrations rise (as in waters surrounding coal mines) this may become a 1:1 relationship. However, there is no documentation that we are aware of which ever shows EC lower than TDS and a random check showed low EC's 40 percent of the time. We recommend that standards be used frequently out in the field to calibrate the conductivity meter, and that laboratory analyses of EC be run on a random basis to verify field procedures.