Gradient Principal Scientist Dr. Caroline Tuit will host a forum session at the 2023 Society for Chemical Hazard Communication Annual Meeting, October 3-5, 2023 in Arlington, VA.

Gradient is presenting at PSX 2023, taking place October 17-19, 2023, in Boston, Massachusetts.  See presentation details below.

Gradient’s PSX 2023 Presentations:

“D2:  Challenges in Ingredient Disclosure Alignment and Supplier Communication”
Kim Reid, Ari Lewis (Moderator)
Express Session
Room:  Burroughs (Westin Boston Seaport)
10/17/23 @ 3:30 pm-4:00 pm

“I1:  Current Regulatory and Scientific Developments in Microplastics”
Andrew Yeh, Lisa Bailey, Adam Grossman (Praedicat, Inc.), Matthew Tymchak (Moderator)
Education Session
Room:  Burroughs (Westin Boston Seaport)
10/18/23 @ 11:00 am-12:00 pm

“J3:  Strategies for Evaluating Endocrine Disruption Potential Across Large Chemical Portfolios”
Ari Lewis, Tim Verslycke (Moderator)
Express Session
Room:  Harbor Ballroom (Westin Boston Seaport)
10/18/23 @ 1:30 am-2:30 pm


On September 27, 2023, Gradient Principal Dr. Joel Cohen will be giving a presentation on “Case Studies Addressing Identification and Assessment of Potentially Carcinogenic Substances, Cohort of Concern Constituents, and Common Degradation Products” at Biocompatibility Insights 2023.

Limulus Bio, now a part of Veranex, will be hosting Biocompatibility Insights 2023, a two-day conference and training day created to inspire, educate, and network. This event will take place September 26-28, 2023, in Annapolis, MD, and you can register to attend here: Dr. Cohen joins a program of thought leaders and safety professionals with expertise in analytical chemistry, toxicology, and new approach methods for evaluating the biocompatibility of biomedical products.

To learn more about Biocompatibility Insights 2023, please visit:

In this issue of Trends, we provide several articles on the topic of environmental justice (EJ).

Articles include:

Gradient Principal Dr. Tom Lewandowski will be participating in a round table discussion at the 2023 Prop. 65 Annual Conference in San Francisco, CA on September 18th, 2023.

Barbara D. Beck and Robyn L. Prueitt authored the chapter “Use of Toxicology in the Regulatory Process” for the seventh edition of Hayes’ Principles and Methods of Toxicology, a benchmark reference in the toxicology field.

Gradient Principal Dr. Barbara D. Beck and Principal Scientist Dr. Robyn L. Prueitt, both with extensive expertise in toxicology and human health risk assessment, along with Dr. Edward J. Calabrese of the University of Massachusetts, authored a chapter for the seventh and latest edition of Hayes’ Principles and Methods of Toxicology, a well-respected and popular textbook and resource used by graduate students, educators, and professionals. Hayes’ Principles and Methods of Toxicology offers detailed coverage of the manifold aspects of fundamental and applied toxicology since its first edition was published in 1982.

The chapter, “Use of Toxicology in the Regulatory Process,” provides a comprehensive look at the concepts, methodologies, and advancements in the use of toxicology to regulate exposure to potentially harmful substances for the protection of public health. This chapter focuses primarily on regulatory toxicology approaches at the federal level in the United States, with an additional discussion on regulatory frameworks at the state and international level. These approaches include programs to regulate chemicals in the environment and laws related to exposures to toxic substances. Concepts described in the chapter include:

Join us in thanking Drs. Beck and Prueitt for their contribution to the field of toxicology. For more information about Hayes’ Principles and Methods of Toxicology and the chapter authored by Drs. Beck and Prueitt, click here.


Barbara D. Beck, Ph.D., DABT, ATS, AAAS Fellow

Robyn L. Prueitt, Ph.D., DABT
Principal Scientist

Dr. Julie Goodman featured in Adverse Reactions podcast series, presented by the Society of Toxicology (SOT) and hosted by SOT members Anne Chappelle and David Faulkner.

Bringing Cohorts in Cahoots with Lab Science” explains how the fields of epidemiology and toxicology “can complement each other to evaluate public health risks. Dr. Goodman also dives into the finer points of systemic reviews and meta-analyses.”

Listen for free here:

Gradient is presenting at ACS Fall 2023 – Harnessing the Power of Data on August 13-17, 2023, in San Francisco, CA & Hybrid.

The California Department of Toxic Substances Control proposes to add microplastics to the Candidate Chemicals List. The proposal would enable the agency to evaluate products containing microplastics as potential Priority Products under California’s Safer Consumer Products Regulations.

In a recent proposal, the California Department of Toxic Substances Control (DTSC) is seeking to add microplastics to the Candidate Chemicals List.  Candidate Chemicals exhibit a “hazard trait and/or environmental or toxicological endpoint” that may contribute to adverse effects in humans, animals, or ecological communities.  The two hazard traits that are the basis of DTSC’s proposed listing of microplastics are environmental persistence and mobility.  DTSC uses the Candidate Chemicals List to identify potential Chemicals of Concern in Priority Products, as part of California’s Safer Consumer Products (SCP) Regulations.  If the proposal is adopted, DTSC would be able to evaluate and propose products as Priority Products based on whether they contain microplastics or will potentially release microplastics into the environment.  If the Priority Products are then adopted, after undergoing a formal comment and rulemaking process, manufacturers of those products would be required to assess safer alternative chemicals or product designs, as part of DTSC’s detailed Alternative Analysis process.

In its proposal, DTSC lists a range of products that may contain microplastics, including:


DTSC defines microplastics as “solid polymeric materials to which chemical additives or other substances may have been added, which are particles having at least three dimensions that are less than 5,000 micrometers (μm).” Notably, the DTSC proposed definition of microplastics does not set a lower size limit of 1 nanometer (nm), which is in contrast to the European Chemicals Agency (ECHA) and the Interstate Technology and Regulatory Council (ITRC), as well as the California State Water Resources Control Board, which identifies microplastics as “particles which have at least three dimensions that are greater than 1 nm and less than 5,000 micrometers (µm).” In addition, the DTSC definition does not differentiate between primary microplastics, those substances that are added deliberately during the manufacturing process, and secondary microplastics, which are derived from the degradation of larger plastic products. Thus, unless the proposed language is modified prior to adoption, both primary and secondary microplastics would be considered Candidate Chemicals under the DTSC proposal.

Though the addition of microplastics to the Candidate Chemicals List would not in itself result in new regulatory requirements, new obligations would emerge if DTSC proposes and adopts a new Priority Product, which could have a significant impact on manufacturers and businesses who sell their products in California. If you have any questions about how the DTSC proposal may impact your business, please contact:

Tom A. Lewandowski, Ph.D., DABT, ERT, ATS

Matthew P. Tymchak, M.S. 
Senior Hydrologist

Tim Verslycke, Ph.D.

Andrew Yeh, Ph.D., DABT
Senior Toxicologist

Gradient will present on a panel discussion hosted by Boston Analytical on Navigating Unknown Compounds in Medical and Combination Device E&L Studies, from a Chemistry, Toxicology and Regulatory Standpoint! The panel will include individuals from Boston Analytical, Gradient and Kymanox – See below:

Will Parker, Director of E&L and Nitrosamines Laboratories at Boston Analytical
@Stefanie Johns, PhD, Director, Regulatory Affairs at Kymanox
Isaac Mohar, Ph.D., DABT, Principal Scientist/Toxicologist at Gradient

Click below to register today!
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