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l <br /> WASTE DISCHARGE REQUIREMENTS GENERAL ORDER NO. R5-2008-0149 4 <br /> i IN-SITU GROUNDWATER REMEDIATION AT SITES IMPACTED BY VOLATILE ORGANIC <br /> COMPOUNDS, NITROGEN COMPOUNDS, PERCHLORATE, PESTICIDES, <br /> SEMI-VOLATILE COMPOUNDS, HEXAVALENT CHROMIUM AND/OR PETROLEUM HYDROCARBONS <br /> duration ; (4) best practicable treatment and control , including adequate monitoring and <br /> hydraulic control to assure protection of water quality, are required ; and (5) the discharge <br /> will not cause WQOs to be exceeded beyond the treatment zone and it is expected that <br /> increases in concentrations above WQOs caused by the treatment will be reduced over <br /> time. A slight residual increase in salts may occur at some sites subject to this Order but <br /> will be limited to a maximum 10 percent increase over background and less than the WQO <br /> listed below in Finding No. 15. See Groundwater Limitation E .3 . <br /> 15 . This Order addresses water quality as it relates to the chemicals being injected , as well as <br /> the byproducts and breakdown products produced by the reactions of the injectants , <br /> chemicals being treated and geological materials . Cleanup criteria for groundwater are <br /> established in an appropriate enforcement document — Record of Decision , Cleanup and <br /> Abatement Order, or Remedial Action Plan and are not discussed further as a part of this <br /> Order. As discussed above, chemicals are injected to stimulate reduction in <br /> concentrations of the target waste constituent and the target waste constituent may <br /> undergo a series of transformations to other constituents as it degrades . The injected <br /> chemical itself may leave residuals of its components, as well as cause changes in <br /> groundwater chemistry that liberate metals found in the formation materials . <br /> Background/baseline concentrations of metals and total dissolved solids will be established <br /> pursuant to the attached Monitoring and Reporting Program . The applicable WQOs are the <br /> narrative toxicity objective, Primary and Secondary Maximum Contaminant Levels , and the <br /> narrative taste and odor objective as found in the Basin Plan. Numerical limits in this Order <br /> implement those WQOs. The following Table presents the numerical WQOs for potential <br /> waste constituents of concern at the site: <br /> Constituent WQO Reference <br /> trichloroethene 0.8 /L California Public Health Goal <br /> tetrachlorethene 0.06 /L California Public Health Goal <br /> vinyl chloride 0.05 /L California Public Health Goal <br /> cis 1 ,2-dichlorethene 6 /L Primary Maximum Contaminant Level <br /> 1 ,2-dichlorethene 10 /L Primary Maximum Contaminant Level <br /> 1 ,2-dichloroethane 0.4 /L California Public Health Goal <br /> 1 , 1 -dichloroethene 6 /L Primary Maximum Contaminant Level <br /> 1 , 1 -dichloroethane 3 /L California Public Health Gaal <br /> 1 ,2, 3-trichloro ro ane 0.0007 /L Draft California Public Health Goal <br /> 1 ,2-dichloro ro ane 0.5 /L California Public Health Goal <br /> 1 -chloro ro ane 280 /L IRIS <br /> propene 28 /L Taste and Odor <br /> iron 300 /L Secondary Maximum Contaminant Level <br /> manganese 50 /L Secondary Maximum Contaminant Level <br /> hexavalent chromium 2 /L Draft PHG <br /> total chromium 50 /L Primary Maximum Contaminant Level <br /> total dissolved solids 450 m /L Food and Agricultural Organization <br /> sulfate 250,000 /L Secondary Maximum Contaminant Level <br /> sodium 20,000 /L USEPA Health Advisory <br /> bromate 10 /L Priamry Maximum Contaminant Level <br /> chloride 106,000 Ng/L Agricultural Water Quality Goal — Food and <br /> A <br />