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� <br /> FACT SHEET ORDER NO. 5-00i-031 -$- <br /> ATTACHMENT C <br /> CITY OF LODI <br /> WHITE SLOUGH WATER POLLUTION CONTROL PLANT <br /> SAN JOAQUIN COUNTY <br /> 1 Drinking Water Standard. <br /> 2 Criteria Continuous Concentration,an estimate of the highest concentration of a material in surface water to <br /> which an aquatic community can be exposed indefinitely without resulting in an unacceptable effect. <br /> 3 Criteria Maximum Concentration,an estimate of the highest concentration of material in surface water to <br /> which an aquatic community can be exposed briefly without resulting in an unacceptable effect. <br /> 4 Assuming hardness of 113 mg/l. <br /> 5 Expressed as dissolved metal. <br /> 6 Expressed as total recoverable metal. <br /> Cyanide: Cyanide is found in industrial effluents associated with steel, petroleum, plastics, <br /> synthetic fibers, metal plating, mining and chemical industries. The Basin Plan water quality <br /> objective for cyanide is a maximum concentration of 10 µg/1. EPA's ambient water quality criteria <br /> for protection of aquatic life are a continuous concentration of 5.2 µg/1 (30-day average, chronic <br /> criteria), and a maximum concentration of 22 gg/l (expressed as a 1-hour average, acute criteria). <br /> Effluent sampling results show cyanide concentrations have exceeded the EPA acute and chronic <br /> criteria, as well as the Basin Plan objective. The detection level for the analyses exceeded the <br /> criteria during 1997. Effluent limitations for cyanide have been included in this Order based on the <br /> Basin Plan objective and the chronic criteria, with no mixing zone designated. The Discharger is <br /> not currently capable of meeting this limit. Full compliance with the cyanide limitation is not <br /> required by this Order until 1 May 2004. <br /> Lead: EPA's ambient water quality criteria for protection of aquatic life are a continuous <br /> concentration of 3.7 gg/l (30-day average, chronic criteria), and a maximum concentration of <br /> 72 µg/1 (expressed as a 1-hour average, acute criteria), based on a water hardness of 113 mg/l. <br /> These criteria were originally developed using metals concentrations expressed as total recoverable <br /> metals. Whereas the dissolved fraction of metals more closely approximates the biologically <br /> available fraction, conversion factors were used to predict how different the criteria would be if they <br /> had been based on measurement of the dissolved concentrations in all of the toxicity tests. These <br /> Conversion Factors (CF) from total recoverable to dissolved, have the effect of reducing the water <br /> quality criteria concentrations. For lead, the conversion factor for both the acute and chronic <br /> criteria is hardness dependent, and is expressed as: CF=1.46203-[ln(hardness)(0.145712)]. For a <br /> hardness of 113 mg/l, the CF=0.773. <br /> 40CFR 122.45(c) requires that permit limits be expressed as total recoverable metal. A reasonable <br /> assumption is that the metal concentration in the receiving water is biologically available to the <br /> same extent as during the toxicity testing which established the criteria. Therefore, the water <br /> quality criteria, expressed as dissolved metal, has been divided by the conversion factor for <br /> purposes of comparing with analytical results (for total recoverable metals) and for establishing an <br /> effluent limitation. <br /> Effluent monitoring for lead has shown the median concentration to be 1.5 gg/1, and the highest <br /> measured to be 10 gg/l. Sampling results have shown that the total recoverable concentration of <br /> lead in the effluent has exceeded the converted chronic criteria for protection of aquatic life in 3 of <br />