US EPA lowered the guidance levels for lead in residential soil at CERCLA sites and RCRA Corrective Action facilities from 400 parts per million (ppm) to 200 ppm, or 100 ppm in areas with multiple sources of lead exposure.
On January 17, 2024, the US Environmental Protection Agency (US EPA) lowered the regional screening level (RSL) and regional removal management level (RML) for lead-contaminated soil in residential areas from 400 ppm to 200 ppm. Furthermore, US EPA proposed an RSL of 100 ppm in residential areas with additional sources of lead exposure, including lead water service lines, lead-based paint, and non-attainment areas where air lead concentrations exceed National Ambient Air Quality Standards (NAAQS). This updated guidance applies to Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites (more commonly known as “Superfund” sites) and Resource Conservation and Recovery Act (RCRA) Corrective Action facilities.
The previous RSL of 400 ppm in residential areas, which was in effect for more than three decades, was based on a target blood lead level (BLL) of 10 μg/dL in children. To derive the revised lead soil guidance levels of 200 and 100 ppm, US EPA used a target BLL of 5 μg/dL and 3.5 μg/dL in children, respectively. A BLL of 5 μg/dL was the Centers for Disease Control and Prevention (CDC) blood lead reference value (BLRV) until 2021, at which time the BLRV was updated to 3.5 μg/dL. The current BLRV of 3.5 μg/dL means that the CDC estimates that 97.5% of US children aged 1 to 5 years have BLLs at or below 3.5 μg/dL. The CDC has stated that the BLRV is neither a health-based toxicity value nor a regulatory standard.
The updated soil lead guidance applies to all residential sites subject to CERCLA response and RCRA Corrective Action authorities, including sites previously addressed and/or deleted from the National Priorities List. Because a substantial number of properties are expected to undergo evaluation due to this updated guidance, US EPA does not expect all regions to be able to address all properties immediately. US EPA regions will continue to use the existing prioritization process to determine what sites will be evaluated and remediated.
US EPA noted that screening levels are not cleanup standards, and the impact of lower screening levels will depend on how this guidance is applied in specific states. Indeed, US EPA states in its guidance, “While this update will help EPA site teams make site-specific cleanup decisions to protect nearby communities, EPA makes cleanup decisions specific to each site, using site-specific factors, including risk factors and community input that can vary from site to site.” US EPA cautioned, however, that cleanup levels for lead-contaminated sites should not be set at values below natural background levels of lead in soil. According to US EPA, urban background soil lead concentrations can be as high as 2,500 ppm but vary greatly across cities.
For more information, refer to US EPA’s website and/or contact Gradient.
Steven R. Boomhower, Ph.D.
Senior Toxicologist
Kyle J. Colonna, Ph.D., M.P.H.
Epidemiologist
Rosemary L. Mattuck, M.S.
Senior Environmental Engineer
Gradient Receives Risk Assessment Specialty Section Award at the 2024 Society of Toxicology Annual Meeting
Gradient poster received the Risk Assessment Specialty Section Award at the Society of Toxicology 63rd Annual Meeting and ToxExpo
The Society of Toxicology (SOT) Risk Assessment Specialty Section has given an award to a poster authored by Gradient as part of the SOT 2024 Annual Meeting. The winning poster, “Evaluating the Potential for Reproductive Effects from Intermittent Lead Exposures Using Blood Lead Modeling Under Proposition 65,” was authored by Gradient scientists Steven Boomhower, Jiayang Chien, Rosemary Mattuck, and Barbara Beck. The poster was presented at SOT’s 63rd Annual Meeting and ToxExpo in Salt Lake City, Utah, earlier this week.
SOT has 29 Specialty Sections that “may propose sessions for the Annual Meeting, exchange information via newsletters, present awards, and participate in other scientific activities.” In particular, the Risk Assessment Specialty Section “provides opportunities for enhancing knowledge and recognition of current issues, challenges and tools for risk assessment, as well as facilitating discussions to advance the science of risk assessment.”
See a list of Gradient’s SOT posters and presentations here.
Gradient is an environmental and risk sciences consulting firm renowned for scientific excellence. We utilize scientific principles and a systematic study of the data, along with an independent perspective, to help our clients understand their issues. Since 1985, we have delivered work products that are responsive and protective, with the highest professional standards.
The SOT Weekly Update published an essay written by Barbara Beck titled, “My Circuitous Scientific Path through Academic, Industry, and Consulting” as part of a “series designed to celebrate SOT member diversity and showcase the diverse pathways and experiences of its members.”
The essay starts with, “I have a confession regarding my scientific and career journey to toxicology.” Read the essay.
Gradient is presenting at the 2024 Annual Meeting of the Society of Toxicology, taking place March 10-14, 2024, in Salt Lake City, Utah. See presentation details below, and click the links to view poster abstracts.
Gradient’s 2024 SOT Meeting Presentations:
“Considerations for Identification Confidence in Chemical Characterization and Risk Assessments”
Isaac Mohar, Joshua Young (US FDA), Eric Sussman (MCRA)
Exhibitor-Hosted Session
Room 155 C
3/13/24 @ 3:00 pm-4:00 pm
“P484: Application of a 3D QSAR Approach for the Re-evaluation of Organophosphorus Compounds for Cohort of Concern Identification“
Alex Gauthier, Thomas Dugan, Hayley Gadol
Session: Medical Devices
3/11/24 @ 9:15 am-11:15 am
“P324: Deriving an Allowable Exposure Limit for Isobornyl Acrylate for Skin Sensitization in Skin-Contacting Consumer Products“
Seth Larch, Rebecca Ticknor, Isaac Mohar, Tom Lewandowski
Session: Skin Sensitization
3/11/24 @ 9:15 am-11:15 am
“P489: Modifications to Toxtree’s Revised Cramer Module in the Context of Cramer Classification Predictions for Medical Device Extractables“
Pranav Mashankar, Brigitte Cronin, Rachel Chang, Joel Cohen
Session: Medical Devices
3/11/24 @ 9:15 am-11:15 am
“P482: What Is a More Conservative Approach for Risk Assessment? Comparing Materials Characterization Data with an Extractables Profile for a Permanent Orthopedic Implant“
Cassandra Meakin, Catalina Restrepo, Stephanie Kearing, Lindsey Borton
Session: Medical Devices
3/11/24 @ 9:15 am-11:15 am
“P483: Derivation of Fit-for-Purpose Non-Cancer Duration-Based TTC Values for Medical Device Constituents“
Taylor Builee (Taylor Builee LLC), Sherry Parker (SParker Toxicology and Consulting), Bindu Prabhakar (WuXi AppTec), Frances Hsia (Boston Scientific), Alessia Stornetta (Boston Scientific), Stephen Bond, Michael Peterson, Valériane Levelut (NAMSA)
Session: Medical Devices
3/11/24 @ 9:15 am-11:15 am
“P172: Considerations for Deriving a Safe Intake of Propylene Glycol“
Charlotte Marsh, Steven Boomhower, Ari Lewis
Session: Safety Assessment: Non-pharmaceutical
3/11/24 @ 11:45 am-1:45 pm
“P156: Evaluating the Potential for Reproductive Effects from Intermittent Lead Exposures Using Blood Lead Modeling Under Proposition 65“
Steven Boomhower, Jiayang Chien, Rosemary Mattuck, Barbara Beck
Session: Risk Assessment I
3/11/24 @ 2:15 pm-4:15 pm *Risk Assessment Specialty Section Award Winner*
“P375: Critical Analysis of Sperm Parameter Data Used as the Basis for a Tolerable Daily Intake for Bisphenol A“
Mary Hixon, Robyn Prueitt, Julie Goodman
Session: Reproductive Toxicology I
3/12/24 @ 11:45 am-1:45 pm
“P117: Protecting Against Adverse Reproductive and Gestational Outcomes from Workplace Exposures: Screening Assessments for Developmental and Reproductive Toxicity“
Nicole Olgun, Mary Hixon, David Dodge, Tom Lewandowski
Session: Risk Assessment II
3/12/24 @ 11:45 am-1:45 pm
“P156: Critical Evaluation of Immunotoxicity Data Used as the Basis for a Tolerable Daily Intake for Bisphenol A“
Robyn Prueitt, Mary Hixon, Julie Goodman
Session: Risk Assessment III
3/12/24 @ 2:15 pm-4:15 pm
“#1212: Looking into the Future: How to Evaluate Safety of New and Unique Consumer Electronics”
Tom Lewandowski
Informational Session: From My Cosmetics to Smart Watch, Toxicology Touches It All!
3/12/24 @ 4:45 pm – 6:05 pm, Grand Ballroom J
“P414: Applying EEDmax Approach from ISO 10993-17:2023 to Risk Assessment of DEHP“
Colleen Clarke, Perry Piatos, Seth Larch, Rachel Chang
Session: Regulation/Policy
3/13/24 @ 2:15 pm-4:15 pm
Gradient announces five employees promoted to Principal and Principal Scientist in 2024.
John Kondziolka, M.S. is promoted to Principal Scientist: Mr. Kondziolka’s practice focuses on competition for water resources, contaminant fate and transport, and assessing risk for sustainable chemical transitions.
Lindsey K. Borton, M.P.H. is promoted to Principal: Ms. Borton has a practice in biological evaluation and toxicological risk assessment of medical devices.
Robyn L. Prueitt, Ph.D., DABT is promoted to Principal: Dr. Prueitt has developed a practice in toxicology, carcinogenesis, and human health risk assessment.
Jeffrey T. Rominger, Ph.D. is promoted to Principal: Dr. Rominger is an environmental engineer and scientist at Gradient whose practice focuses on chemical fate and transport, environmental forensics, and environmental fluid mechanics.
Caroline B. Tuit, Ph.D. is promoted to Principal: Dr. Tuit is an environmental chemist with expertise in data quality and environmental forensics for evaluating the sources, fate, and transport of chemicals.
Here is wishing them the best in their new leadership roles.
Gradient has joined the Geosyntec family of companies. This partnership will advance the shared vision of Geosyntec and Gradient to bring robust and trusted scientific analyses to bear on diverse and challenging environmental, health, and safety issues.
Geosyntec is a consulting and engineering firm specializing in collaborating with both private and public sector clients to tackle new ventures and complex challenges related to our environment, natural resources, products, and civil infrastructure. With a collective staff exceeding 2,200 professionals, including engineers, scientists, and various technical and project support personnel, Geosyntec operates from over 100 offices across the United States, Australia, Canada, Finland, Ireland, Spain, Sweden, the United Arab Emirates, and the United Kingdom.
Manu Sharma, MS, PE, President of Gradient, said, “Since our inception, Gradient has held steadfast focus on our dual mission of providing trusted scientific analysis on complex environmental and health issues while supporting a collaborative, collegial, and multidisciplinary team. Geosyntec was built on similar values and has also grown and flourished by supporting its people and maintaining a commitment to the highest professional standards. Together, Gradient and Geosyntec will harmonize our strengths to address the most consequential environmental, health, and safety challenges facing our clients around the world.”
Peter Zeeb, PhD, PG, President, and CEO of Geosyntec, said, “Geosyntec and Gradient are both unwavering in our commitment to rigorous science and engineering delivered with exceptional client service. Gradient tackles complex environmental, health, and safety issues for their clients and brings a complementary, deep subject matter expertise and several new service offerings to our family of companies. This partnership enables us to provide a broader scope of services to our combined clients and accelerates our ability to service target markets focused on emerging and current societal-scale challenges.”
Learn more about Geosyntec at www.geosyntec.com
Morrissey Goodale (Morrissey Goodale | Advisory Services for the AEC Industry) served Gradient as an advisor on the transaction.
Gradient will present at Energy, Utility & Environment Conference (EUEC) 2024. February 13-15, 2024. Dallas, TX.
Gradient Presenting at EBC 5th Annual PFAS Seminar. February 6, 2024. Framingham, MA.
Ifeoluwa A. Bamgbose was awarded a Certificate in Regulatory Sciences from the University of Arkansas for Medical Sciences (UAMS) in August 2023.
Gradient Principal Scientist Dr. Isaac Mohar will be presenting at the Pharm Ed Resources, Inc. Extractables & Leachables West 2023 conference, November 2-3, 2023 in La Jolla, CA.