What are regional screening levels?

The Regional Screening Levels (RSL) can be described as risk-based concentrations derived from standardized equations combining exposure information assumptions with EPA toxicity data (United States Environmental Protection Agency, 2020).

What is an RSL EPA?

The RSL website is now the source of screening levels for all the EPA regions. The RSL tables provide comparison values for residential and commercial/industrial exposures to soil, air, and tapwater (drinking water). The unified use of the RSLs, to screen chemicals at Superfund sites, promotes national consistency.

How is hazard quotient calculated?

The step-by-step procedure is described below. 1. The hazard quotient is calculated for the median exposure to each phthalate ester by dividing the median exposure in mg kg−1-day−1 (Table 3 or 4) by the RfD in mg kg−1-day−1 for the respective phthalate ester (Table 2).

How do you calculate RfD?

RfD = LOAEL/(UF x MF) = 25/8000 = 0.003 (mg/kg/day). Suppose the estimated exposure dose (EED) for humans exposed to the chemical under the proposed use pattern were 0.01 mg/kg/day (i.e., the EED is greater than the RfD).

How long does arsenic last in soil?

9000 years
(3) One estimate of the residence time for arsenic in soil is 9000 years. (2) Since arsenic is expected to remain in soil for centuries or longer, contaminated soil left at the site must be considered a potential source of exposure throughout this time frame.

What are the 3 main causes of soil pollution?

The root cause of soil pollution is often one of the following:

  • Agriculture (excessive/improper use of pesticides)
  • Excessive industrial activity.
  • Poor management or inefficient disposal of waste.

How often does EPA review and update regional screening levels?

EPA regularly reviews and updates Regional Screening Levels and Regional Removal Management Levels twice a year. As the science on PFAS evolves, EPA may update these values and add other PFAS chemicals. Regional Screening Levels are used to identify contaminated media (i.e., air, tap water, and soil) at a site that may need further investigation.

What are the regional screening levels?

The residential and industrial air regional screening values can be used to screen chemicals that are detected in the air (e.g., indoor and outdoor) from a variety of sources. For assistance/questions please use the Regional Screening Levels (RSLs) contact us page.

What screening levels are available in the default tables?

Screening levels are presented in the default tables for residential soil, outdoor worker soil, residential indoor air, worker indoor air and tap water. In addition, the calculator provides a fish ingestion equation.

Where can I find updates on screening TPHS in risk assessments?

See the FAQ page for updates on screening TPHs in risk assessments. The new construction worker landuse equations were modified to more clearly define averaging time and time of exposure for exposures less than one year. For scenarios lasting less than one year, please contact your regional risk assessor for guidance.