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pathways may include ingestion of, and dermal contact with, contaminated tap <br /> water and inhalation of volatile chemicals in shower stall air. <br /> • These pathways should be considered. <br /> d. The text does not explain how the lead soil PRG concentration of 130 mg/kg <br /> was calculated. <br /> • Please explain how this PRG concentration was calculated and also <br /> provide the corresponding blood lead level. <br /> C. Toxicity equivalence factors used to determine the PRGs for PAHs have not <br /> been used appropriately (Table 6-1). PRGs for PAHs, other than <br /> benzo(a)pyrene, have not been adjusted as stated in footnote h. For example, <br /> the PRG for benzo(a)anthracene should be 0.71 mg/kg not 0.071 mg/kg. <br /> • Table 6-1 should be reviewed and updated. <br /> f. The Phase 11 Data Needs section (6.4) should discuss data requirements for the <br /> baseline risk assessment. It is not possible to determine if there will be <br /> sufficient data to prepare a baseline risk assessment, given the information <br /> provided for each potential contaminant site. In sections where chemicals were <br /> detected, the frequency of detection (i.e., number of detects over the total <br /> number of samples) needs to be provided. In general, if a chemical is detected <br /> in more than 5% of the samples, it should be included in the list of chemicals <br /> of potential concern, with the possible exception of Class A carcinogens. <br /> Additionally, paragraph 6.4.2.6.1 (second sentence) should define "significant <br /> fraction." <br /> • Please discuss data requirements for the baseline risk assessment and <br /> define "significant fraction." <br /> 25. Paragraph 6.3.2.1.1, "On-Depot Receptors", Page 6-8 <br /> Although the day care center does not appear within the 66 previously identified sites, <br /> Paragraph 6.3.2.1.1 identifies the day care children as a sensitive subpopulation. UST <br /> 2 site is adjacent to this facility and high total lead is reported in the ground water. <br /> Additionally, the day care center is in the vicinity of other UST's and SWW's. If <br /> there is a possibility that previously unidentified contamination could be present at the <br /> day care center, then the soil at this facility should be analyzed. <br /> • Consider augmenting the limited surface soil database at the day care facility <br /> during Phase 11 efforts. <br /> EPA 14FEB94 9/10 <br />