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Sent Bye BASELINE; 510 420 1707; Nov-12-99 9:02; Page 416 CONCLUSIONS HUMAN HEALTH Past and/or Current Q rac6ces ofhandling hazardous waste and substances at the site,and immediately off-site,appear to have resulted to a release of hazardous materials at the Weber Block property. The release does not pose an immediate potential hazard to public health or the environment, requiring the implementation of an expedited response action. The site is currently capped and:-the area is fenced, preventing entry to the site: The cumulative excess lifetime cancer risk, assuming future residential use of the property, was calculated as 3.3 x 10-5,which exceeds the DTSC threshold of 1 x 1 o'6.The cumulative hazard index was calculated as 0.67, which is less than the DTSC threshold of 1.4 for no n-carcinogens- ard Calculated risks and hazards using off--site groundwater data were higher. These risk and llw Cs in soil and ound �umin them maximum concentr anon o£COP � calculations were made ass g x routes (i ingestion underlying the site, conservative default assumptions, and conservative exposure ingestion and dermal contact with shallow groundwater underlying the site). Actual exposures and 7 risks/hazards under proposed redevelopment of the property as a water square/public meeting place are expected to be less than those calculated above. It is also important to note that other regulatory agencies consider risk estimates from I x 10 to L x 10 as posing a significant threat to public health. The calculated cumulative excess lifetime cancer risk for the Weber Block property is within this range of risk estimates. Under the proposed redevelopment of the site, capping of the site,raised landscape planter boxes, landscaping with clean soil to support landscape growth, and/or planned soil excavation activities would act to prevent potential exposure to contaminants in soil by ingestion and dermal contact. from the City of Stockton from outside of the immediate arca, Drinking water would be supplied under the ro osed redeveloprncnt project;risks and hazards from ingestion and dermal contact with p P These measures would drinking water would therefore not be experienced by future site users reduce or eliminate potential exposures to future on-site users and resulting risks and hazards. Calculated blood lead levels for adults and children were less than the DTSC threshold of 10 µg t lead/dI blood for the 99th percentile exposed individual. ECOLOGICAL HEALTH The aquatic habitat and the Center Street Bridge for nesting swallows are the orily known potentially E significant ecological habitats. However,the Stockton Channel provides limited aquatic habitat for ensitive fish species(tones & Stokes, 999) as the Channel fish species and is unlikely to support s is limited in terms of vegetation, tends to flush slowly, and has steep banks and fine bottom substrates,which limits habitat for aquatic species, Any construction-or project-related impacts to ent would . ecological receptors(i.e.,fish and swallows)associatedwith the Weber Block redevelopm be mitigated to reduce these to less than significant impacts. 97J693tk.pen.wpd-1 119r�4 33