SU0007861 - Laserfiche WebLink

Home Browse Search

Draft Supplemental Environmental Impact Report Page IV.E-4 Forward Inc. Landfill 2014 Expansion Project • Northern California Re-Entry Facility and renovation of adjacent Dewitt-Nelson Youth _ Correctional Facility • NorCal (formerly Opus)Logistics Center All existing and future receptors are considered in the health risk assessment since a grid base is used for the model that includes all sites, whether they are occupied or not. Health Risk Assessment SCS Engineers prepared a Health Risk Assessment(HRA) for the applicant that evaluates hazardous air pollutant(HAP) air emission levels for the Forward Landfill. The objective of the HRA is to evaluate potential health risks that may occur as a result of the proposed landfill expansion due to air emissions. The original HRA has been peer-reviewed by Miller Environmental Consultants/KB Environmental Sciences,prior to incorporation into this 2013 EIR. The HRA information was further updated based on comments on the 2013 EIR and also changes to the Project Description for the Supplemental EIR. The HRA focuses on quantifying potential health risks (cancer and non-carcinogenic) associated with off-site residents and off-site workers resulting from pollutant emissions from the proposed landfill modifications. Under CEQA, the net difference (or change)in conditions (comparing the existing to future year conditions) are evaluated to the significance thresholds. As such, the HRA is considered an incremental HRA;the cancer risks for the proposed project minus the baseline cancer risk. Cancer risk is defined as the lifetime probability of developing cancer from exposure to carcinogenic substances. Cancer risks are expressed as the chances in one million of contracting cancer,for example one cancer case among one million people exposed. Incremental cancer — risks are determined by summing the individual risk for each air toxics. The incremental risk from exposure to a given air toxic is calculated by multiplying the concentration(or dosage level) of the given air toxic by its specific unit risk factor or potency slope. The unit risk factor or potency slope of an air toxic is derived from epidemiological studies, and the published values are based on the assumption that a person would be exposed to the given air toxic at that dosage constantly for 70 years or for the life of the project. The cancer risk from current landfill operations is calculated to be 1.2 x 10-5. �- Health risks (acute'and chronics impacts) for each non—carcinogenic air toxics are determined using a Hazard Index (HI), which is the ratio of the predicted exposure concentration to a threshold level that could cause adverse health effects other than cancer, as established by the OEHHA. The Hazard Quotient(HQ)of each non—carcinogenic substance is added to the calculated HQ of the other non—carcinogens to produce an overall HI. Existing health risks from the current landfill operations are calculated to be 0.0004 for the acute HI, 0.00005 for the chronic HI. Impacts 'A health effect(non-cancer) produced within a short period of time(few minutes to several days) following an exposure to air toxics 'A health effect(non-cancer) produced from a continuous exposure occurring over an extended period of time (weeks, months,years)