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leachate at this site would be equal to(0.05 x n)milli- nated Level for arsenic in the solid waste is(0.05 x n) grams arsenic per liter of leachate. milligrams of soluble arsenic per kilogram of waste. The goal in calculating Designated Levels for a solid Soluble concentrations of constituents in solid wastes waste is to determine concentrations of soluble con- are determined by performing the Waste Extraction stituents in the waste above which leachate may be Test(WET)from§66700 of Title 22 CCR,or a variation able to carry them to ground or surface waters in of this test. The test involves a ten-fold dilution of amounts that could cause water quality goals to be solid waste into an extract solution,agitation for 48 exceeded. Therefore,the next step in the methodology hours,followed by filtration and analysis of the liquid is to convert the Designated Level for leachate into one phase. Results are expressed in milligrams of ex- which may be applied to concentrations of constituents tractable constituent per liter of extract solution. The in a solid waste prior to disposal. Evidence presented Soluble Designated Level for a constituent of a solid by DHS in the Statement of Reasons for the Hazardous waste,expressed in the same units,is equal to the Waste Identification Regulations(Title 22 CCR,Divi- water quality goal times the environmental attenuation sion 4,Chapter 30)indicates that the concentrations of factor divided by the ten-fold dilution of the WET. For constituents in leachate could either be numerically the Figure 6 example,the Soluble Designated Level for higher or lower than the soluble constituent concentra- arsenic is equal to(0.05 x n-m-10)milligrams of arsenic tions in the solid waste prior to leaching. In the per liter of extract. calculation of Designated Levels,an assumption is made that these concentrations are numerically equal. Concentrations of constituents in landfill leachate Therefore,the Soluble Designated Level for a constitu- should not be confused with concentrations of constitu- ent in a solid waste is numerically the same as the ents in extract from the Waste Extraction Test. They Designated Level for the same constituent in leachate are not the same. Concentrations of constituents in which forms at the base of the landfill—the water leachate are the result of the accumulation of constitu- quality goal times the environmental attenuation ents from the waste as moisture migrates through a factor. In the example of Figure 6,the Soluble Desig- landfill or waste pile. Concentrations of constituents in the extract from the WET are the result of a specific laboratory procedure where waste constituents are SOLUBLE DESIGNATED LEVEL FOR A extracted from a solid waste by an extract solution CONSTITUENT OF CONTAMINATED SOIL under a predetermined set of circumstances. The extract from the WET is,therefore,not a simulation of DOMESTIC leachate,but a measure of the amounts of waste WATER constituents that may be leached from the waste in a WELL CONTAMINATED SITE landfill. _ As If k0 006 CONTAMINATED SITE CLE.%NUI oosxn�- '-Mfront Ntaofoxww o w.,., rte w�Ee DHS has prepared a document entitled The California Site Mitigation Decision Tree Manual which presents m Arsenic (OAS:n) ° a detailed procedures for determining cleanup/mitiga- "` * > ;,,..: .�'`� ;" s<'V'>•`k` tion levels for sites contaminated with toxic subs ie.cirM . The object of theseP rocedures i P s to revert toxicologic impacts on humans and other potential "biological receptors of concern". While sufficient to cover DHS`s concerns regarding site cleanups,Ps the proceduresin this s document are of designed to protect all present an d probable future beneficial uses of waters of the State that may be adversely impacted by the contaminants, . rye wee®, as required by the Porter-Colog 1e Water Quality . . . . . . . . . . . - . . . . . . . . . . • . . Control Act. Therefore,another methodology must be . . . . . • • • • • • • • • used by the State and Regional Water Boards to fill this • • -0.05 mg Arsenic!liter of water• . . . . GROUND need. . . . .(DrbftV Wow ) . . . . <;3 WATER F1OW Comparison of Figures 6 and 7 shows that the threat posed to water quality by contaminated soils is similar Figure 7 to that posed by wastes in an unlined landfill. There- Designated Level Methodology Summary Page 6