Laserfiche WebLink
14 August 2006 <br /> Former Tesoro Terminal; + - 2 - g <br /> 1700 South River Road p t <br /> Yolo County <br /> borings were analyzed for total petroleum-hydrocarbon as gasoline (TPH-g), benzene, <br /> toluene, xylene; ethylbenzene (BTEX), chloride,.total dissolved solids (TDS) and electrical <br /> conductivity (EC). One soil sample from B3 was analyzed for TPH-g and BTEX. No other <br /> soil samples were analyzed. Analytical results indicated groundwater in the three borings. <br /> had been impacted by chloride and TDS. Only groundwater from boring B3 was impacted <br /> by TP.H-g and BTEX"..Based on these results, San Joaquin County�Environmental Healthy <br /> Department requested additional site investigation at the site. The additional.site <br /> investigation consisted of drilling four soil borings to a depth of 20 feet, then converting the <br /> borings to monitoring wells. For the purposes of comparison, a sample of the water from the <br /> shipping channel was taken and analyzed for chloride and TDS. N 1 ' <br /> R ,5,w .. - # ..� - .t 3 j h �y a ? A'► •.. <br /> -- - :A-quarterly monitoring;program, directed;by San Joaquin County.EHD, began in the first <br /> quarter of 2006. Sampling analysis consists of TPH-g, Methyl-t-Butyl Ether (MtBE), BTEX, ' <br /> chloride and TDS. Quarterly-results indicate groundwater flow direction is to the,north- <br /> :northwest, away from the shipping channel. <br /> The attached table presents the sampling results for chloride, TDS and EC at the site. <br /> The groundwater samples collected from soil boring B-2, located adjacent to the brine pit, <br /> and MW-1 located down gradient from the brine pit, exhibit the highest concentrations of <br /> chloride and TDS. MW-2, located up gradient a`nd adjacent to the ship channel initially <br /> contained concentrations of chloride and TDS greater than the'ship channel and-:above the <br /> "background" groundwater sample obtained from B-1. ; <br /> Regional Water=Board staff has the following comments regarding the contents of the <br /> reports and the quarterly sampling results: '' " <br /> 1. The question arises as to whether the groundwater samples'taken from:B-1 represent <br /> background conditions for the area.' The intent to use B-1 to provide background levels <br /> for-chloride and TDS may be compromised because it is`located down gradient from Y' <br /> the brine pit. VWT needs toiJber as.ses_s,background, lev_els-for,,the.:s.ite,by coalectin.g; <br /> groundwater samples up gradient at a distance that will not have been impacted by the <br /> brine pit. For ezample,-MW-2, located approximately 150 feet up gradient from the <br /> brine pit may have been impacted by brine (based on the analytical results). <br /> 2. The brine pit still 'has several inches of salt at the bottom of it. The salt needs to be <br /> rem 'e <br /> od and'the pit backfilled so it will not continue to be a conduit for surface water <br /> infiltration. Mr. Stephen°Lankford, of Geo-Phase Environmental, Inc. has indicated ' <br /> that source removal of`soiHn the tank pit area may be conducted to remove <br /> hydrocarbon contamination. During this action, soil exhibiting elevated levels of salt <br /> should be"removed. <br /> f <br />