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1 TPHg decreased from 1,800 gg/l (February 8, 2000) to 180 µg/1 (May 17, 2000) The same decreasing trend was observed for TPHg concentrations in MW3-2 and MW3-3 The benzene, toluene and ethylbenzene concentrations in MW3-2 and MW3-3 have increased or stayed relatively the same as compared with the previous quarter's results This could be attributed to the change in ' groundwater direction Xylene concentrations in all wells have continued to decline in all four quarters of sampling The concentrations of ethylbenzene, and xylene in all 3 wells are below the Maximum Contamination Levels (MCLS) for California drinking water Per SJCEHD's concurrence, MTBE ' compounds were not analyzed this quarter from the wells MTBE has not been detected in any soil or groundwater samples collected at this site ' CONCLUSIONS/RECOAUKENDATIONS ' Based on a review of the analytical results of the groundwater samples of MW3-1 through MW3-3 for BTEX and TPHg,the following conclusions are presented ' . Free phase petroleum product has not been detected in any of the wells on the site • The TPHg, ethylbenzene, and xylene concentrations for all groundwater samples of the May 17, 2000 monitoring event, decreased in comparison to the concentrations found during the February ' 8, 2000 monitoring event This suggests that natural attenuation, which may include intrinsic bioremediation, is continuing in the subsurface • The concentrations of benzene in all 3 wells are above the MCL (1 0 µg/1) for California drinlang water, though the level in MW3-1 is only slightly higher at 1 2 µg/1 • For MW3-1, benzene concentrations in groundwater remained the same as last quarter at 1 2 µg/l ' . The concentrations of toluene in MW3-2 and MW3-3 are above the MCL (150 µg/1) for California drinking water, however the concentration in MW3-1 is significantly below the MCL ' • The concentrations of ethylbenzene and xylene in all 3 wells are below the MCLS for California drinking water, 700µg/1 and 1750µg/1, respectively • A survey of domestic, municipal, agricultural, industrial and other supply wells within a 2,000- foot radius of the site has been conducted No municipal or drinking water supply wells were identified within the 2000-foot radius The following recommendations are presented for this site ' • The Port has conducted four quarters of ground water monitoring for this site The data collected to date suggests a downward trend in the concentration of the majority of the contaminants of concern ' • In light of the above, the Port believes that the four quarters of data obtained to date should be used to conduct an industry standard risk assessment in order to establish the low and acceptable level of risk posed by this site to human health and the environment 1 usi S2W gtr4 da 6 1