SITE INFORMATION AND CORRESPONDENCE_1998-2000

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0 CLEANUP AND ABATEMENT ORDER NO. 5-00-707 3 FORMER UNOCAL AND MONTGOMERY WARDS 5606 AND 5400 PACIFIC AVENUE, STOCKTON SAN JOAQUIN 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 RIW); however, from late Spring to Fall when the RIW is operating, the flow direction is southwesterly towards the RIW. 7. In May 1997,following County directive,Unocal sampled the RIW, and reported TPHg and benzene concentrations at 110 µg/1 and 28 µg/l,respectively. The RIW 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 µg/1, an benzene at 8.4µg/1. 8. The Taste and Odor Threshold for gasoline is 5 µg/l, 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 servi e and will not be put back in use without prior Board approval. Delta is currently using city-s pplied 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 water source for Dell a. 11. Section 13304(a) of the California Water Code provides that: "Any person who has discharged or discharges waste into the waters of this state in violation ofany waste dis Marge requirement or other order or prohibition issued by a regional board or the state board, or who has caused or permitted, causes or permits, or threatens to cause or permit any waste to be discharged or deposited where it is, or prob bly will be, discharged into the waters ofthe state and creates, or threatens to create,a condition ofpollution or nuisance,)shall upon order of the regional board cleanup such waste or abate the effects of the waste, or, in the case of threatened gqolhuion or nuisance, take other necessary remedial action, including, but not limited to, overseeing cleanup and abatement efforts. Upon failure of any person to comply with the cleanup and abatement order, the Attorney General, at the request of the board, shall petition the superior courtfor that countyfor the issuance ofan injunction requiring the person to comply with the order. In any such suit, the court shall have jurisdiction to grant a prohibitory or mandatory injunction, either preliminary or permanent,as the fact may warrant." 12. The Water Quality Control Plan for the Regional Water Quality Control Board, Centra 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 maximum contaminant levels. Waste has been discharged to waters of the state at concentrations that exceed water quality objectives. Exceedance bf water quality objectives constitutes pollution. Therefore, waste has been discharged or deposited where it has created and continues to threaten to create a condition of pollution or nuisance.