SITE INFORMATION AND CORRESPONDENCE_1998-2000

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JUN,01-2004 15:41 97•_ 362 8100 - • • 916 362 8100 P.05 CLF:AN(JP AND ABATEMENT OKOER,NO. 5-00-707 FORMER UNOCAL AND MONTGOMERY WARDS 3 5606 AND 5400 PACIFIC AVENUE, STOCKTON SAN JOAQUfN COUNTY previous sampling results show high concentrations of TPHg and benzene in June 1999 and December 1999, 6. Unocal and Wards have both indicated in their monitoring reports that the natural groundwater flow direction beneath their sites is easterly (away from RTW); however, from late Spring to Fall when the RIW is operating,the flow direction is southwesterly towards the m la 7. In May 1997, following County directive, Unocal sampled the RTW, and reported TPHg and benzene concentrations at 110 pg/l and 28 µg/1, respectively, The R1W has been sampled an additional seven times, and petroleum hydrocarbons have been identified in five of the eight samples collected. The June 2000 groundwater sample contained TPHg at 138 lig/1, and benzene at 8.4µg/1. 8. The Taste and Odor Threshold for gasoline is 5 µg11, and the California Department of Health Services Primary Maximum Contaminant Level for benzene is 1.0 µg/1. 9. On 22 August 2000, at the direction of Board staff to Delta,RIW was taken out of service and will not be put back in use without prior Board approval. Delta is currently using city-supplied water to irrigate the campus. 10. The unauthorized releases at the Unocal and Wards sites, as individual or commingled plumes are likely to be the source of petroleum contamination found in the RIW. At this time, Unocal and Wards are both considered jointly responsible for all activities necessary to investigate and analyze the effects of the contamination identified in the RIW, and all other actions as necessary to abate the effects of the contamination, and replace the irrigation watei'source for Delta. 11. Section 13304(a) of the California Water Code provides that: "Any person who has discharged or dfeeharges wane into the waters of rhis stare In violation ofary waste die•charge requirement or other order or prohibition issued by a regional board or the stare board,ar whe has causrd o•permuted, causes or peemlrs, or threadens to cause arptrmlt any waste 10 be drscharged or deposited where it 4, or probobty*U be. d(seharged Into the waters afrhe aware and-creates, or threetens to create,a condition ofpvl(ulton or nuisance,shot,upon order ojthe regional board cleanup such waste or abate the effects of the waste,ar• in the care of threatanad pollution a• nuisance, talro other necesaney remedial action, Including• but not limned to,overseeing cleanup and abatement efforts. (!parr falture ofany person to comply with the cleanup and abatement ander, the Attornrty Generol, at the request ofihe board shall petirion the superior court jot that county for the issuance of on iryunetion requiring the person to comply with the ardor. In any such salt the rout!shat!Nave jurisdiction to grant a prohibitory or mandatory injunedon, tbher prellndnery nr pe•mnnnnr, av the fact may warrant." 12. The Water Quality Control Plan for the Regional Water Quality Control Board, Central Valley Region, (4th Edition) (Basin Plan) establishes beneficial uses and water quality objectives to protect the beneficial uses. Water quality objectives for groundwater as specified in the Basin Plan include primary and secondary-maxinluiR contaminant levels. Waste has been discharged to waters of the state at concentrations,that exceed water quality objectives. Exceedance of water quality objectives constitutes pollution. There Fore, waste has been discharged or deposited where it has created and continues to threaten to create a condition of pollution or nuisance.