Laserfiche WebLink
GAVIN NEWSOM <br /> GOVERlN+OR <br /> YANA <br /> CSLIFORXIa CIA <br /> SEC ETARYN FOR <br /> Water Boards ENVIRONMENTAL PROTECTION <br /> Central Valley Regional Water Quality Control Board <br /> 11 June 2024 <br /> Rachel Roskelley <br /> J.R. Simplot Company <br /> 16777 South Howland Road <br /> Lathrop, CA 95330 <br /> LUST CASE- SITE INVESTIGATION STATUS <br /> J.R. SIMPLOT COMPANY(T0607700166) <br /> 16777 SOUTH HOWLAND ROAD, LATHROP, SAN JOAQUIN COUNTY <br /> This letter is intended (1) to capture the status of your investigation actions made in <br /> response to the leaking underground storage tank (LUST) case opened in 1988 at your <br /> property and (2) to identify the next steps of case investigation. Since 2009, various <br /> environmental consultants have submitted annual groundwater monitoring reports for <br /> the J.R. Simplot Company LUST cleanup case located at 16777 South Howland Road <br /> in Lathrop (Site). Central Valley Regional Water Quality Control Board (Water Board) <br /> staff reviewed the Problem Assessment Report (PAR) submitted by Weston dated <br /> 27 July 1989 and the 2023 Annual Underground Storage Tank Groundwater Well <br /> Sampling (2023 Annual Monitoring Report) report submitted by WSP USA Environment <br /> and Infrastructure Inc. (WSP) dated 4 April 2024. Additionally, Water Board staff has <br /> reviewed the historical data available on GeoTracker and completed an evaluation of <br /> Site investigation and remediation status which is summarized below. <br /> Prior to 1982, you stored gasoline in two 5,000-gallon connected USTs and diesel in <br /> one 10,000-gallon UST. In 1982, two 5,000-gallon gasoline USTs were removed and <br /> replaced by a single 10,000-gallon gasoline UST. In 1988, two 10,000-gallon USTs (one <br /> gasoline, one diesel) were removed from the Site. Reportedly, the diesel UST was <br /> observed leaking along the tank seam during removal. Excavation confirmation soil <br /> sampling in 1988 and 1989 confirmed the presence of total petroleum hydrocarbons <br /> (TPH), benzene, toluene, ethylbenzene, and xylenes (BTEX). Soil impacts beneath the <br /> gasoline UST indicated that the previous gasoline UST (removed in 1982) had a <br /> release. In 1989, groundwater samples confirmed the presence of TPH and BTEX in <br /> groundwater near the former UST excavation. In 1989, Weston installed and sampled <br /> three groundwater monitoring wells (MW-1, MW-2, MW-3). Groundwater sampling was <br /> not recorded again until 2009 when annual sampling resumed from 2009 through 2023. <br /> In 2009, Well MW-1 could not be located and has not been located since. BTEX <br /> concentrations in groundwater significantly increased in 2017 and 2018 but have <br /> consistently decreased since 2018. In the 2023 Annual Monitoring Report, WSP <br /> recommends discontinuing annual groundwater monitoring at MW-2 and MW-3. <br /> MARK BRADFORD, CHAIR I PATRICK PULUPA, Es4., EXECUTIVE OFFICER <br /> 11020 Sun Center Drive#200, Rancho Cordova,CA 95670 1 www.waterboards.ca.govIcentralvalley <br />