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IMr Richard Bolades - 2 - 6 November 2000 IMr Nick Dingsa 1,2-DCA, tertbutyl alcohol, ethanol and methanol were detected at lesser concentrations The MTBE ' groundwater contamination is posing a potential threat to several neighboring domestic wells ' The remediation contractor will implement a groundwater pump-and-treat system at the site utilizing 8 I groundwater extraction wells Groundwater from the eight wells will be extracted at a cumulative rate of approximately 25 'a Ions per minute or a total of 36,000 gallons per day The extracted water will be ' passed through a series of activated carbon and treated media filters to remove the petroleum constituents The treatment system will meet the effluent limitations listed in Section C of Order No 5-00419 (enclosed) Treated water will be discharged via a buried 2-inch PVC pipe into the private ' agncultural tail water return Coldani Ditch which is located roughly 450 feet south of the site and treatment system NITRATES ' Elevated nitrate levels are common within the shallow groundwater in the general site vicinity An initial groundwater sample collected from beneath the site was screened for a variety of contaminants in addition petroleum contamination Nitrate was reported at 46 mg/1 as NO3,which just exceeds the ' state's drinking water maximum contaminant level (MCL) of 45 mg/1 nitrate as NO3 The project environmental contractor mchcates that the granular activated carbon will most likely not remove the nitrate from the effluent There are no promulgated acute or chronic freshwater aquatic life criteria for nitrate ' Coldani Ditch is a private agricultural ditch, winch flows to Upland Canal Upland canal is an additional agricultural supply and drainage ditch with significant dilution compared to that of Caldani Ditch There are presently no municipal or private drinking water intakes located on either water body Significant ' nitrate dilution would also be attained at White Slough and additionally, there are no domestic rises of White Slough in the immediate vicinity of the confluence of Upland Canal's with White slough ' The Discharger is being asked to additionally monitor for nitrates in the effluent and receiving water on a monthly basis If nitrate concentrations are observed to appreciably increase or a detrimental impact to receiving waters is observed (i a increased bio-stimulation), this Order will be revoked and the ' Discharger will be required to pursue an individual National Pollution Discharge Elunination System (NPDES) permit for the project that may include a requirement for nitrate treatment ' PUBLIC NOTIFICATION ' Pursuant to Section D of Attachment A of the General Order 5-00-119, the consultant for the Discharger published and sent a public notification letter to all recorded landowners within a 500-foot radius of the site and proposed discharge location The letter was dated 9 October 2000 and requested written or ' verbal response within 14 days of the date of the letter To date, neither Board staff nor the Discharger's consultant has received a response Certified mail receipts were received for 8 of the 9 owners who were contacted Board staff has made several unsuccessful attempts at contacting the remaining landowner I