Use of California Human Health Screening Levels (CHHSLs) in ...

The CHHSLs presented in this document are NOT adequate to evaluate ALLenvironmental conditions at ALL contaminated sites. Other environmentalconcerns posed by the presence of contamination at a site may include:• Leaching of contaminants from soil to groundwater and subsequentimpacts to groundwater quality;• Intrusion of subsurface vapors into basements or buildings withsubstandard ventilation systems and subsequent impacts to indoor air;• Uptake of contaminants in edible fruit and vegetables and subsequentintake by humans;• Exposure of children and teachers at school sites;• Toxicity to terrestrial flora and fauna;• Gross contamination, including nuisance (odors, etc.) and aestheticconcerns.A summary of potential environmental concerns that may also be relevant at a sitefor a particular chemical is also provided in Table 1.The CHHSLs specifically do not address contamination in groundwater, surfacewater or sediment or the erosion of contaminated soils and subsequent runoff intoa nearby wetland, stream or other aquatic habitat. Contamination identified inthese media or that may threaten these media must be considered separately.References for evaluation of contaminants in these media are provided in Chapter4.The soil gas CHHSLs for the intrusion of vapors into buildings may not beadequately conservative for estimating impacts to indoor air in poorly ventilatedbasements or buildings with substandard ventilation systems in general.Additional guidance on this subject is provided in Section 2.5.2.The CHHSLs for direct-exposure to soils concerns are calculated assuming thatspecific exposure pathways are complete for the human receptor: incidental soilingestion, dermal absorption of chemicals in soil, and inhalation of vapors orparticulate matter in ambient (outdoor) air. For volatile chemicals, the soil gasCHHSLs are calculated assuming that the exposure pathway of inhalation ofJanuary 20051-4CHHSLS