Human Health Baseline Risk Assessment

Table 16.9 lists five remedial alternatives and their primary components. The nonaction alternative (Alternative 1) provides a baseline for comparison of other alternatives. Because no remedial activities will be implemented with the nonaction alternative, long-term human health and environmental risks for the site essentially will be the same as those identified in the baseline risk assessment. All other action alternatives with action have four common components ... 

A baseline risk assessment is conducted to assess the potential human health and environmental impacts associated with soil contamination. The primary exposure pathways evaluated for explosives contaminated surface soils are dust inhalation, soil ingestion, and dermal absorption. Reasonable Maximum Exposure (RME) concentrations are based on the 95% upper confidence interval (UCI) on the arithmetic mean of soil sampling data. The land use scenarios quantitatively evaluated may include industrial and residential use, utilizing EPA standard default exposure parameters. 

Human health risk assessment estimates the likelihood of health problems occurring if no cleanup action were ttikcn at the site. To cstiimite the baseline risk at a site, the following four-step process should be taken to detennine Uie possible human risk which will then detennine what sort of corrective action should be employed ... 

The purpose of an exposure and risk assessment is to characterize the magnitude and extent of human or environmental exposure to selected pollutants and to quantify the potential adverse effects of those exposures. The assessment can be used both to provide a baseline estimate of existing health risks attributable to an environmental pollutant and to determine the potential reduction in exposure and risk for various control options. Exposure and risk assessments are playing an increasingly central role in... 

Risk assessment typically begins with a characterization of the risks associated with baseline or current releases. The baseline assessment gives an indication of the potential for human health or ecological risk problems. The predicted changes in emissions and sources are then estimated and the expected risk from the option scenarios is evaluated. The risk evaluation is based on both risk reduction to the most highly exposed individuals and to the exposed population as a whole. Cumulative benefits of risk reduction are estimated by adding the benefits for each risk reduction option. 

Gomparison of the baseline human health risk assessment and the risk evaluation of alternatives. Baseline Human Health Risk Assessment (quantitative) ... 

This section presents three case examples of site-based lead exposure characterizations for subsequent risk assessment purposes. The case studies are based on research where environmental media-specific levels of Pb were determined as part of the epidemiological and statistical designs. For purposes of this section, such two-part case studies are desirable for, first, quantifying baseline exposure characterizations and eventual baseline human health risk characterizations and, second, for identification of which... 

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