Laserfiche WebLink
3.1 Water Quality Goal <br /> In general, water quality goals focus on protecting the existing water quality whenever that <br /> water quality is better than that required to protect all present and potential beneficial uses <br /> (Resolution 68-16) Numeric water quality standards based on Resolution 68-16 are associ- <br /> ated with the background levels, which in turn are subject to the reasonable limit of detection <br /> for the residual constituent of concern As indicated in Section 2 2 1, the constituents of <br /> concern are TPPH-g and BTEX compounds Parameters mentioned in the Basin Plan that are <br /> not relevant to the development of water quality protection standards for the site are pH, <br /> electric conductivity, total dissolved solids, chloride, total petroleum hydrocarbons as kero- <br /> sene, total oil and grease, and metal contanunants Volatile organic compounds are included <br /> because of the presence of BTEX compounds at the site These parameters are either <br /> (1) not found beneath the site (i e , total oil and grease), (2) not associated with impact <br /> identified beneath the site (i e , pH, total dissolved solids), or (3) naturally occurring (i e , <br /> metals) Reasonable limits of detection for the residual target compounds found beneath the <br /> site are shown below <br /> Concentration <br /> Compound arts per billion) <br /> Benzene 0 5 <br /> • Toluene 0 5 <br /> Eth lbenzene 0 5 <br /> Xylenes 0 5 <br /> TPPH-g and TPH-d 50 <br /> 3.2 Concentration Limits <br /> If the water quality goals cannot not reasonably be obtained, Resolution 92-49 Section HG <br /> and Chapter 15 allow the establishment of alternate concentration limits that may be greater <br /> than background levels At this time, these MCLS shall not exceed water quality criteria <br /> prescribed in Water Quality Control Plans and Policies adopted by the State and Regional <br /> Boards The applicable water quality criteria is provided by Resolution 88-63 that specifies <br /> that all groundwater is suitable for municipal and domestic supply, unless conditions preclude <br /> its use Since groundwater conditions beneath the site do not preclude its possible use as a <br /> municipal and domestic supply, numeric water quality goals associated with restoring this use <br /> pertain to the residual plume Municipal and domestic supply is the relevant beneficial use <br /> with the most stringent set of water quality goals The concentration limits are noted on the <br /> following page <br /> I <br /> 3201337B/CAP ANID DOC 10 November 30, 1995 <br />