New RSLs Have Arrived!

Biannually, typically in May and November, the United States Environmental Protection Agency (US EPA) updates their Regional Screening Level (RSL) tables. The RSLs provide comparison values for residential and commercial/industrial exposures to soil, air, and tap water (drinking water) with valuable information for risk assessments and site investigation screening applications. Although noted that the RSLs are not cleanup standards and should not be used as cleanup standards, our experience has shown more time than not the regulatory oversight agencies rely heavily upon RSL values to determine whether contamination at a Site has been sufficiently addressed. For this, and other reasons, it’s important that, as consultants, we are using the most up-to-date toxicity values, exposure parameters, and chemical-specific parameters when assisting our clients.

This year, the residential soil screening level for lead and lead compounds reduced from 400 mg/kg to 200 mg/kg; however, was reduced to 100 mg/kg in soil when other sources of lead are present.

Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) were recognized as hazardous substances under CERCLA in April 2024 (see our PFAS blog). Not surprisingly, the residential and commercial/industrial soil and tap water RSLs were significantly reduced for these chemicals. Additionally, Maximum Contaminant Levels (MCLs) were also established at 0.004 ug/L.

At Waterstone, we offer our clients help by utilizing the most up-to=date resources that are available for investigations, risk assessment and remediation projects by keeping abreast of the ever changing world of regulatory guidelines and standards.

Call us today and let us help you navigate the requirements to make your project a successful one.

Waterstone Environmental, Inc. 714-414-1122

What else changed since last time? Check here

Download the most recent RSLs with this hyperlink.