Author Archives: ToxStrategies

On July 2, 2015, the Center for Environmental Health (CEH) submitted a petition to the Office of Health Hazard Assessment (OEHHA) for an administrative rulemaking to repeal or amend the Maximum Allowable Dose Level (MADL) for lead under Proposition 65.  The basis for the petition was three-fold: (1) the original MADL for lead, established in 1989, did not meet the standards set forth for determining a MADL under Proposition 65, (2) OEHHA did not re-evaluated the MADL for lead in 2013 when it changed the basis for listing lead as a reproductive toxicant under Proposition 65, and (3) an appeals court ruling (Envt’l Law Found. V. Beech-Nut Nutrition Corp. [2015] 235 Cal.App.4th 307) had the effect of increasing the MADL from 0.5 ug/day to 7 ug/day.  In response to this petition, OEHHA will initiate a rule making to update the existing MADL for lead.  Given that lead has been the subject of numerous lawsuits and/or 60-day notices under Proposition 65, a change in the MADL for lead could have significant implications for companies doing business in California.

ToxStrategies scientists have substantial experience assisting our clients with Proposition 65 compliance, including derivation of safe harbor levels and estimating exposure to listed chemicals.  We will follow OEHHA’s rulemaking process closely and provide future updates as warranted.

Documents pertaining to CEH’s petition and OEHHA’s response can be found here.

ToxStrategies is pleased to announce a new publication titled Duodenal crypt health following exposure to Cr(VI): Micronucleus scoring, γ-H2AX immunostaining, and synchrotron X-ray fluorescence microscopy.  ToxStrategies’ own Dr. Chad Thompson is the lead author on this publication, while several other ToxStrategies’ scientists also served as co-authors.

This research provides a comprehensive assessment of micronuclei in the crypts of Swiss roll duodenal sections from B6C3F1 mice following Cr(VI) exposure.  The study results found:

• Oral gavage of 50 mg/kg cyclophosphamide significantly increased micronuclei.
• Cr(VI) in drinking water (up to 180 ppm) for 7 days did not increase micronuclei.
• Chromium was localized to duodenal villi by X-ray fluorescence microscopy.
• γ-H2AX immunostaining did not differ between vehicle-and Cr(VI)-treated mice.

This paper was published in Mutation Research and is available in the August 2015 issue. A free copy of the complete paper can be downloaded here.

The EPA just released a draft database of 1,173 hydraulic fracturing-related chemicals that were listed in the external review draft Assessment of the Potential Impacts of Hydraulic Fracturing for Oil and Gas on Drinking Water Resources (released June 4, 2015). The database provides physicochemical and toxicological information from a host of different sources, including: EPI Suite, LeadScope, QikiProp, Reaxys, IRIS, PPRTV, ATSDR, among others. The database also contains background information about how the list of chemicals was compiled.

The full draft database can be downloaded here.

On June 11, 2015, EPA released two technical guidance documents for evaluating vapor intrusion:

• OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air (VI Guidance)
• Technical Guide for Addressing Petroleum Vapor Intrusion at Leaking Underground Storage Tank Sites (Petroleum UST VI Guidance)

The VI Guidance provides a five-step process for evaluating whether the VI exposure pathway is complete and recommendations for completing a human health risk assessment, as well as mitigation measures, if necessary. The Petroleum UST VI Guidance considers the degradation of petroleum in the vadose zone and relies on separation distances to establish whether VI is a potentially complete exposure pathway.

ToxStrategies scientists and engineers have substantial experience addressing the vapor intrusion pathway. Example projects include modeling potential migration of vapors from the subsurface into building interiors, developing indoor air sampling plans, conducting indoor air sampling, developing applicable health-based screening levels, and assisting clients with community outreach.

Both documents can be found here.

The EPA has been conducting a 5-year, state-of-the-science assessment to determine the potential impacts of hydraulic fracturing activities on drinking water resources in the United States. On June 4^th, the EPA released an External Review Draft report, titled Assessment of the Potential Impacts of Hydraulic Fracturing for Oil and Gas on Drinking Water Resources.

The assessment found that “hydraulic fracturing activities have not led to widespread, systematic impacts to drinking water resources” but also “identifies important vulnerabilities to drinking water resources.”

ToxStrategies staff have been actively involved in assessing the potential human health impacts of natural gas exploration and production activities. Example projects include those involving conducting safety assessments for hydraulic fracturing fluids, assessing potential human health risks associated with impacts on ambient air, and assessing human health risks associated with accidental releases during drilling activities.

The full EPA report can be viewed here.

One of ToxStrategies’ Principal Scientists, Deb Proctor, attended, presented, and chaired at the 2015 ENV-Vision (Environmental Vision) Conference this week in Washington, DC.

The presentation, titled Cumulative Risk Assessment of Urban Air Toxics:  A Pilot Study in San Antonio, Texas, was held on Wednesday, May 13 at 1:00 pm in Crystal Ballroom Salon B during Session 4a:  Air Toxics Health & Risk Assessment.  We hope you were able to stop by and check out her talk.

ENV-Vision is an Electric Power Research Institute (EPRI) event hosted by the Air & Waste Management Association (AWMA).  This conference aims to exchange research results on current and emerging issues in the electricity sector, and to develop a shared vision to address the most critical environmental and sustainability challenges through engagement of electric industry leaders, regulators, NGOs, academics, and other stakeholders.

For more information on the conference, click here.

Alea Goodmanson and Camarie Perry will be at the annual TCEQ Environmental Trade Fair & Conference this week in Austin, TX.  They’re looking forward to seeing some familiar faces and meeting new people.  Stop by and visit them at booth #517!

We are pleased to announce that Dr. Andrea Weir has joined ToxStrategies, Inc. as a Senior Consultant and will be based in the Washington, DC area. Dr. Weir is a board certified toxicologist with 28 years of experience in toxicology, primarily in drug development. She has worked in both the contract research industry and at the U.S. Food and Drug Administration (USFDA).

Prior to joining ToxStrategies, Dr. Weir was a regulatory toxicologist at the USFDA for approximately 12 years, working primarily in the Center for Drug Evaluation and Research (CDER). During this time, Dr. Weir served as a pharmacology/toxicology reviewer and was responsible for critically reviewing the nonclinical sections of regulatory submissions such as INDs, NDAs, and BLAs. Dr. Weir actively participated in meetings (e.g., pre-IND meetings) advising pharmaceutical and biopharmaceutical companies regarding their nonclinical development plans, particularly the study design and data interpretation, as well as addressing toxicities and other challenges encountered in nonclinical studies. She was also actively involved in several internal FDA/CDER subcommittees. Following the USFDA, Dr. Weir was a Senior Scientific Advisor at Charles River Laboratories. She actively participated on numerous scientific advisory committees within the pharmaceutical and biopharmaceutical industry, which were held to obtain expert advice on various aspects of the nonclinical drug development process.

Dr. Weir has extensive experience with biopharmaceuticals such as monoclonal antibodies and fusion proteins, and with chemically-synthesized molecules. Her experience extends to a variety of clinical indications including rheumatoid arthritis, oncology and rare diseases, as well as multiple routes of administration including oral, intravenous, dermal, and ocular. Dr. Weir also has extensive experience in the design and interpretation of nonclinical toxicology studies (GLP and non-GLP) and in applying data from such studies to the overall drug development process. Dr. Weir has co-authored numerous journal articles and book chapters relating to drug development, and served as co-editor of a text titled Assessing Ocular Toxicology in Laboratory Animals.

To read more about Dr. Andrea Weir and get her contact information, please visit her company web page.