Laserfiche WebLink
FACT SHEET, ATTACHMER C • <br /> WASTE DISCHARGE REQUIREMENTS ORDER NO. 5-00- 8 <br /> CITY OF LODI <br /> 10 WHITE SLOUGH WATER POLLUTION CONTROL PLANT <br /> SAN JOAQUIN COUNTY <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. <br /> Lead: EPA's ambient water quality criteria for protection of aquatic life are a continuous <br /> concentration of 2.8 µg/1 (30-day average, chronic criteria), and a maximum concentration of <br /> 72 µg/I (expressed as a 1-hour average, acute criteria), based on a water hardness of 110 mg/1. <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-[In(hardness)(0.145712)]. For a <br /> hardness of 110 mg/1, the CF=0.777. <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 µg/l, and the highest <br /> measured to be 10 µg/1. 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 /> 18 samples. Effluent limitations for lead have been included in this Order based on the converted <br /> chronic criteria. <br /> Mercury: Effluent monitoring for mercury has shown the median concentration to be non- <br /> detectable at<0.2 µg/1, and the highest measured to be 0.63 gg/l. The accuracy of the analyses is <br /> questionable without implementing "clean technique" (EPA Method 163 1) for sample collection, <br /> handling, and analyses. The current EPA Ambient Water Quality Criteria for continuous <br /> concentration of mercury (30-day average, chronic criteria) is 0.77 µg/1, and the proposed California <br /> Toxics Rule concentration is 0.050 µg/1. Mercury is listed under the California 303(d) list as a <br /> pollutant causing impairment in the Sacramento-San Joaquin Delta. This listing is based partly on <br /> elevated levels of mercury in fish tissue. Because the Sacramento-San Joaquin Delta has been listed <br /> as an impaired water body for mercury based on fish tissue impairment, the discharge must not <br /> cause or contribute to increased mercury levels in fish tissue. <br /> In view of the uncertainty of applicable water quality criteria, and the accuracy of existing sampling <br /> results, this permit does not contain a water quality-based effluent limitation for mercury. This <br /> Order requires monitoring for mercury for the purpose of establishing a performance-based effluent <br />