SGM-SF_2017with 12/20 Revisions

ANSI/AARST SGM-SF 2017 (with 1220 revisions) Soil Gas Mitigation Standards for Existing Homes 60 Appendix A INFORMATIVE — CHEMICAL VAPOR INTRUSION A-1 Understanding Chemical Exposure Concerns A-1.1 Health Risks The risk of adverse health effects fromexposure to a toxic chemical or substance depends on the nature, frequency and duration of exposure to the chemical(s). Variables associated with the nature of the exposure include: a) the concentrations of chemicals present; b) the environmental medium in which the chemicals are present (e.g., indoor air, liquids or solid, including soil and/or groundwater); and c) the route of exposure: − Inhalation of vapor-phase contaminants or particulate matter containing sorbed contaminants (or hazardous building material particulates) that result in absorption of contaminants or adverse effects in the respiratory system. Note that some chemicals are more toxic via inhalation compared to other routes of exposure because chemicals that are absorbed from the respiratory system are not passed through the liver first where some degree of detoxification can otherwise occur. − Dermal contact resulting in absorption of contaminants through the skin − Ingestion resulting from hand-to-mouth actions following dermal contact − Ingestion of particulate matter as a result of inhalation and then swallowing of particulates A-1.2 Site classifications Formal site classifications or listings are based upon state requirements and/or information obtained by firms that have provided assessment of a site. A-1.3 Informational description of site classifications Class 3: Continuous or Chronic Risk Concerns of harmful effects from average low-level exposure (e.g., ≥ 26 years) or repeated exposure events to somewhat higher concentrations that can result in a similar degree of hazardous average exposure. Class 2: Subchronic Risk Concerns of harmful effects with average exposure across 10% of a life span or repeated exposure events to higher concentrations that can result in a similar degree of hazardous average exposure. Class 1: Acute Risk Concerns of harmful effects from immediate or short-term exposure (e.g., < 30 days). Rapid Response Situations with immediate concern when estimated exposure concentrations exceed health- protective concentrations for short-term or acute exposure. A-1.4 Partial list of chemicals commonly associated with contaminated soil Advisory Note 1 Lists provided herein are intended to shed light on some of the more common contaminants found at contaminated residential sites. Arsenic naturally occurring; industrial discharges Cadmium Hexavalent chromium Mercury Lead naturally occurring; industrial discharges; older paint residues Polynuclear aromatic hydrocarbons (PAHs) products of combustion (such as creosote, soot); petroleum constituents (diesel fuel, fuel oils)