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1.02. The Property is being remediated pursuant to an Oversight and Consultation
<br /> Agreement pursuant to Chapter 6.8 of Division 20 of the Health and Safety Code, under
<br /> the oversight of the Department. A Revised F reliminary Endangerment Assessment
<br /> Report, approved by the Department on March 13, 2000, requires that a deed restriction
<br /> be recorded as part of the site remediation, be ause lead, benzo (a) pyrene, benzene,
<br /> toluene, ethylbenzene, xylenes, methyl tert-butyl ether (MTBE), which are hazardous
<br /> substances, as defined in H&SC section 25316, and a hazardous material as defined in
<br /> H&SC section 25260, were detected in groundw ter, soil, and sediment samples, below
<br /> the surface of the Property. Pursuant to the California Environmental Quality Act, Public
<br /> Resources Code section 21000 et seq., thI Department has reviewed a Draft
<br /> Supplemental Environmental Impact Report/En7ironmental Assessment (Draft EIR/EA)
<br /> dated January 12, 2000. The Department commented on the Draft EIRIEA in a letter
<br /> dated February 23, 2000. Both the Draft EIR/E-,lh,. and the Department's comment letter
<br /> identified the need for a deed restriction for the Weber Block Project.
<br /> 1.03. As detailed in the Revised Preliminary Endangerment Assessment approved
<br /> by the Department on March 13, 2000, all or a po [on of the subsurface soil, and sediment
<br /> within the.Stockton Channel of the Property cont in hazardous substances, as defined in
<br /> H&SC section 25316, which include the following contaminants of concern at the following
<br /> maximum concentration: benzo (a) pyrene (1.2 milligram/kilogram (mg/kg)), lead (206
<br /> mg/kg), and arsenic (22.1 mg/kg). Groundwater in ear the former Shell site on the Property
<br /> ranged from 16 to 19 feet below ground surface uring the monitoring events conducted
<br /> in July 1998, October 9998, January 1999, and April 1999. Maximum contaminant
<br /> concentrations in groundwater monitoring of eleven wells include: benzene (2.6
<br /> milligrams/liter (mg/1)), toluene (8.3 mg/1), ethylbenzene (2.2 mg/1), xylenes (9.5 mg/1),
<br /> methyl tertiary-butyl ether (MTBE) (1.75 mgll), anc total petroleum hydrocarbons (47 mg/1).
<br /> Maximum contaminant concentration in an unfiltered groundwater sample collected from
<br /> the south side of the Stockton Channel contained lead at 75.3 ug/1. In a Report dated
<br /> October 6, 2000, by Baseline Environmental Consulting, the groundwater in the area from
<br /> the south side of the Stockton Channel was re-sampled. This sample was filtered prior to
<br /> analysis. The analysis of this groundwater sample for total lead was reported at a
<br /> concentration of less than 3.0 ug/l, the laboratory reporting limit.
<br /> Based on the Final Risk Assessment the calcula ed excess lifetime cancer risk from soil
<br /> ingestion and dermal contact for the Site was 2.3 x 10.5, which exceeds the 1 x 10-6 cancer
<br /> risk level. The largest contributor to the risk f om this exposure pathway was from
<br /> benzo(a)pyrene. The excess lifetime cancer risk from groundwater ingestion and
<br /> showering/bathing with volatile organic compoun s and non-volatile organic compounds,
<br /> as calculated using on-site groundwater data, was 1.1 x 10-5. The largest contributor to the
<br /> risk from this exposure pathway was benzene. The cumulative excess cancer risk from
<br /> soil ingestion and dermal contact, groundwater ingestion and showering/bathing with
<br /> shallow Rroundwater underlying the Site, ambien . air, and indoor air was calculated to be
<br /> 3.3 x 10- .
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