The Cardno ChemRisk View
Cardno ChemRisk presented an abstract at the 2017 Society of Toxicology Annual Meeting in Baltimore, Maryland titled, “Risk Assessment for the Consumption of Ochratoxin A (OTA) in Breakfast Cereals in the US”.
Ochratoxin A (OTA) is a naturally occurring mycotoxin and is a stable contaminant found in the production and storage of cereals and grains. OTA is of interest, as it has been shown to cause kidney tumors in mice and rats, and is classified as a Group 2B carcinogen by the International Agency for Research on Cancer (IARC). Additionally, Health Canada has derived a negligible cancer risk intake (NCRI) of 4 ng/kg bw/day, corresponding to a 1 in 100,000 risk level, based on a TD05 of 19.6 μg/kg bw/day and a safety factor of 5000. In the U.S., there is currently no health based guidance value for OTA.
In our analysis, we assessed the potential cancer risks associated with consumption of OTA in different grain-based cereals in the U.S. OTA intake was estimated using the mean and maximum estimates of U.S. cereal consumption (various age groups, as reported in the EPA 2011 Exposure Factor Handbook) and mean OTA levels in grain-based U.S. cereals (as calculated from published literature).
Our results illustrated that OTA doses associated with mean cereal consumption rates are below the NCRI “negligible cancer risk” dose. The OTA doses associated with maximum consumption rates approach the NCRI value for several cereal types and exceed the NCRI for conventional oat cereal. Therefore, we concluded that the risk of cancer in the U.S. from OTA exposure is not likely to be of concern based on mean estimates of U.S. cereal consumption and mean OTA levels in grain-based cereals. However, under conditions of high consumption of oat cereal the OTA intake exceeds the NCRI.
If you would like to learn more about Cardno ChemRisk's experience with coal ash, please contact Paul Scott
In particular, we are pleased to announce that Bethany Winans, Ph.D., received the Best Paper of the Year. Her paper, titled "Linking the aryl hydrocarbon receptor with altered DNA methylation patterns and developmentally induced aberrant antiviral CD8+ T cell responses," was nominated by a researcher at Michigan State University and was selected from among four other nominated papers. The SOT cited its outstanding contribution to understanding the impact that early life exposure to pollutants has on the developing immune system.
Our staff fully enjoyed the conference, as well as the great ambiance of the city. We extend our congratulations to all of the presenters at the conference. We would like to thank the SOT organizers for hosting us. We would also like to thank everyone who took time to visit our posters and presentations. If you have any further questions, please see our presenter Q&A series, Parts I, II, III, IV and V, or reach out to the authors directly. Their contact information can be found in the professionals section of our website.
1. What's the title of your presentation and when is the presentation/poster session?
QSAR Modeling Toxicity Predictions of the Constituents of Crude 4-Methylcyclohexanemethanol (MCHM) and Structurally Related Chemical. Bethany will present on Monday, March 14th in the afternoon session
2. What was the scope of your research?
Approximately two years ago, a mixture containing crude MCHM was accidentally released into the Elk River in West Virginia, affecting the drinking water supply of ~300,000 people. We used quantitative structure-activity-relationship ((Q)SAR) modeling and structural alerts to predict the toxicity of the constituents of crude MCHM and other structurally related chemicals. For those constituents for which toxicity data exist, we compared the (Q)SAR predictions to the toxicity data to assess the applicability of the models for these compounds.
3. What did you find?
Overall, the constituents of crude MCHM and structurally related compounds were predicted to have low to moderate acute toxicity, low potential for skin and eye irritation, and low mutagenic potential; these findings are consistent with available toxicity data. Some of the chemicals were predicted to have the potential to be skin sensitizers or associated with developmental toxicity, but these predictions were not supported by the animal data, suggesting that the models may not be valid for predicting these endpoints for these chemicals. Predictions from (Q)SAR modeling and experimental data for the constituents of crude MHCM and structurally related compounds suggest that these chemicals pose little risk to human health at concentrations likely experienced following the Elk River spill.
4. What the next steps/what other research is needed?
Following the Elk River spill, the National Toxicology Program (NTP) performed a number of toxicity tests on crude MCHM and its constituents. The NTP recently completed these studies, and noted that "[th]e collected findings from the studies supported the adequacy of the drinking water screening levels established at the time of the spill [1 ppm in water], and found very little reason for concern about long-term health effects" (West Virginia Chemical Spill: NTP Research Response and Findings, February 2016, p. 1).
This type of predictive toxicological evaluation can be used in other situations as well. (Q)SAR modeling can be used to predict the toxicity of a number of compounds, and provides a rapid screening-level assessment to identify potential toxicological endpoints for chemicals of concern.
Continue checking our site to read more from our scientists!
As in previous years, a group of researchers from Cardno ChemRisk will attend the 2016 Society of Toxicology's Annual Meeting in New Orleans from March 13-17. At SOT, we will present recent research during posters and presentations.
Between today and the start of the conference, the Cardno ChemRisk View will feature a series of presentations, as described by staff (you can read the 2015 entries here and here). First up is Lindsey Garnick from our San Francisco office: