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PUBLIC P�_.__ij'ALTH SERVICES Q�,N <br /> SAN JOAQUIN COUNTY z: <br /> ENVIRONMENTAL HEALTH DIVISION <br /> Karen Furst, M.D., M.P.H., Health Officer <br /> 304 East Weber Avenue, Third Floor • Stockton, CA 95202 ` FOR <br /> 209/468-3420 <br /> DALE BOYETT APR 0 2 2001 <br /> BOYETT PETROLEUM <br /> P 0 BOX 576277 <br /> MODESTO CA 95357-6277 <br /> Re: BOYETT'PETROLEUM Site Code: 1433 <br /> 419 S.MAIN ST. <br /> MAN`1ECACA 95336 <br /> San Joaquin County Public Health Services, Environmental Health Division (PHS/EHD) <br /> has received the graphic interpretation of the two Cone Penetrometer Testing (CPT) <br /> exploratory borings at the above referenced site on February 2, 2001. Numerical logs of the <br /> two CPT borings were not included. A two-page written letter and a map dated February 7, <br /> 2001 from WHF, Inc. (WHF) were mailed along with the results. The letter briefly <br /> summarized the CPT drilling and concluded: "there are signowi t aquadudes[sic]on Lbe site, <br /> which are below the grwndmter table and would p&W&the zertical migration cf ax Vwtes." There is <br /> no signature of a Registered Geologist,Professional Engineer, or Certified Hydrogeologist <br /> associated with the interpretation of the CPT work or the conclusion presented in this letter. <br /> The letter stated that a final Report of Findings along with the CPT logs would be submitted <br /> after completion of the deep monitoring well. <br /> PHS/EHD has the following comments: <br /> • An aquiclude is defined as a saturated geologic unit that is incapable of transmitting <br /> significant quantities of water under ordinary hydraulic gradients. This term was <br /> originally used to describe materials that seem to be impervious to water. It is widely <br /> understood among geologists that such materials do not exist in nature. At some point, <br /> all geologic materials transmit water to some degree. Therefore,this term is not <br /> appropriate and has not been used by professional geologists for decades. A more <br /> appropriate term for low permeability material is "aquitard." <br /> • There is no evidence that there are significant aquitards on the site that will prevent the <br /> vertical migration of oxygenates. The stratigraphy of the area consists of interbedded <br /> sand,silts and clays, and the areal extent of the silt and clay layers encountered at the site <br /> is unknown. Therefore,it cannot be assumed that clay layers encountered in CPT-1 and <br /> CPT-2 at approximately 50 feet below ground surface (bgs) are continuous and will <br /> prevent the vertical migration of oxygenates. Moreover,the statement in the second <br /> paragraph that the deep well will be placed below the groundwater table is meaningless. <br /> Groundwater has been documented at the site at a depth of approximately 15 to 20 feet <br /> A Division of San Joaquin County Health Care Services <br />