Laserfiche WebLink
Aquatic life criteria were based on the most stringent of the fresh and salt water criteria, <br /> to be fully protective of all receiving waters. <br /> f. Receiving Water Hardness. Ambient hardness values are used to calculate freshwater <br /> WQOs that are hardness dependent. In determining the WQOs for this Order, Regional <br /> Water Board staff used a hardness value of 100 mg/L as CaCO3,which is a conservative <br /> value and generally protective of aquatic life in all circumstances contemplated by the <br /> General Permit. <br /> g. Site-Speci�c Translators (SSTs).NPDES regulations at 40 CFR 122.45(c)require that <br /> effluent limitations for metals be expressed as total recoverable metal. Since applicable <br /> WQOs for metals are typically expressed as dissolved metal, translators must be used to <br /> convert metals concentrations from dissolved to total recoverable and vice versa. The <br /> CTR includes default translators; however, site-specific conditions, such as water <br /> temperature,pH, suspended solids, and organic carbon greatly affect the form of inetal <br /> (dissolved,non-filterable, or otherwise)present in the water and therefore available to <br /> cause toxicity. In general, the dissolved form of the metal is more available and more <br /> toxic to aquatic life than non-filterable forms. Site-specific translators can be developed <br /> to account for site-specific conditions, thereby preventing exceedingly stringent or under <br /> protective WQOs. <br /> Receiving waters for discharges from the facilities covered under the General Permit are <br /> varied, and, therefore, site specific conditions are varied. In dete�nining the need for and <br /> calculating WQBELs for all metals except for copper and nickel, the Regional Water <br /> Board has used default translators established by the USEPA in the CTR at 40 CFR <br /> 131.38 (b) (2), Table 2 to be protective in all circumstances. Most discharges are <br /> anticipated to eventually enter San Francisco Bay, and, therefore, the site specific <br /> translators were applied in determining criteria for copper and nickel. For copper,the <br /> Regional Water Board applied the SSTs adopted by Regional Water Board Resolution <br /> No. R2-2007-0042 for North and Central San Francisco Bay, and the SST contained in <br /> the Basin Plan Table 7.2.1-1 for South San Francisco Bay. For nickel,the Regional <br /> Water Board applied the translators for North and Central San Francisco Bay based on <br /> the recommendation of the Clean Estuary Partnership's North ofDumbarton Bridge <br /> Copper and Nickel Development and Selection of Final Translators (2005), and applied <br /> the translators contained in Table 7.2.1-1 of the Basin Plan for South San Francisco Bay. <br /> These translators for copper and nickel are summarized below. <br /> Table F-4. SSTs for Co er and Nickel for San Francisco Ba <br /> Copper Nickel <br /> San Francisco Bay Segment AMEL MDEL AMEL MDEL <br /> Translator Translator Translator Translator <br /> North 0.38 0.66 0.27 0.57 <br /> Central 0.73 0.87 0.65 0.85 <br /> South 0.53 0.53 0.44 0.44 <br /> Attachment F—Fact Sheet F-18 <br /> For VOC and Fuel General NPDES Pernut No.CAG912002 <br />