SITE INFORMATION AND CORRESPONDENCE

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PAUL VERMA 2 19 December 1990 CITY OF TRACY My comments regarding Division 2 (Special Requirements) of the Specifications are as follows: 1 . Project Description: The City of Tracy (the City) proposes to treat excavated contaminated soils removed from City owned property, formerly owned by Beck Development Company, to complete the Schulte Road Expansion Project. The 12,000 cubic yards of contaminated soils, containing oil & grease up to 11 , 100 parts per million (ppm) , will be taken to the proposed land treatment facility, which is a nine acre site at the Tracy Municipal Airport. The City proposes to put the contaminated soils in 18 treatment cells with a total capacity of 15,000 cubic yards. Each 22,500 cubic-foot cell will be underlined and covered with 6 mil plastic liner and surrounded by a two foot soil berm. The land treatment facility will only receive excavated soils from the Schulte Road project. 2. In Section 13, the fourth paragraph states that the plastic cover may be a loose cover which does not have to be tightly secured. I recommend that the specification be amended to state that the cover should be tightly secured to prevent damage from wind and other storm events. Although not required, a 10 mil or thicker plastic liner would be preferable since the bottom liner will have to support the weight of the equipment placing the soil in the treatment cells. Also, the fifth paragraph should be worded to state that the Contractor should repair or replace the cover within a specific time period (preferably 48 hours) after damage has been discovered. 3. A provision should be placed in the specifications that requires and allocates time for review and approval of the Bioremediation Plan by Regional Board staff. The QA/QC Plan for the treatment and sampling program should also be submitted to the Regional Board for review and approval . 4. In Section 15, the City requires monthly sampling at the treatment facility. No rationale was given in the specifications justifying the necessity of monthly sampling. The specifications state that the Contractor shall arrange and pay for the analysis of random statistical samples on a monthly basis. It does not state whether the Contractor is to take grab or composite samples. It does not state that the Contractor must take representative samples from each cell or how the Contractor will demonstrate statistically or analytically that the samples are representative. I recommend that the City include a provision in the specifications that requires a Sampling Plan which should be submitted to our office for review and approval . The Sampling Plan should state how the initial or background, monitoring, or verification (QA/QC)