Evaluation of Contaminated Properties
Use of California Human Health Screening Levels in Evaluation of Contaminated Properties is a publication of California Environmental Protection Agency (CalEPA).
The
California Human Health Screening Levels (CHHSLs or "Chisels") are
concentrations of 54 hazardous chemicals in soil or soil gas that the
CalEPA considers to be below thresholds of concern for risks to human
health.
The
CHHSLs can be used to screen sites for potential human health concerns
where releases of hazardous chemicals to soils have occurred.
Under
most circumstances, the presence of a chemical in soil, soil gas or
indoor air at concentrations below the corresponding CHHSLs can be
assumed to not pose a significant health risk to people who may live
(residential CHHSLs) or work (commercial/industrial CHHSLs) at the
site.
The
presence of a chemical at concentrations in excess of a CHHSL does not
indicate that adverse impacts to human health are occurring or will
occur but suggests that further evaluation of potential human health
concerns is warranted.
The CHHSLs are NOT regulatory "cleanup standards". Use of the CHHSLs is voluntary on the part of those who choose to use them.
At
sites where cleanup of contaminated soils to levels at or below the
CHHSLs would be costly, the time and effort to develop more
site-specific cleanup may be desired.
At
sites where the extent of contaminated soil is limited or the timeframe
available to carry out cleanup actions is very short, use of the CHHSLs
as final soil cleanup standards may be cost-beneficial.
Regulatory agencies cannot be compelled to use the CHHSLs as final cleanup standards for a contaminated property.
The table below presents CHSSLs for indoor air and soil gas.
Example:
The indoor air CHSSL for Tetrachloroethylene (dry cleaning solvent,
also known as PCE or Perc) inside residential space is 0.412 micrograms
per cubic meter of air. For this chemical as vapor in the soil
under a residential space, the CHSSL is 180 micrograms per cubic meter
of air.
Go to http://www.calepa.ca.gov/Brownfields/documents/2005/CHHSLsGuide.pdf to download the complete publication. |
