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Charge Question 3 Clarification

Additional Information/Clarification on the August 14/15 Scientific Advisory Panel Dietary Session’s Charge Question 3

Charge Question 3: Bayer Drinking Water Consumption Survey Data The CSFII data does not contain information on the time and amounts of direct drinking water consumption. Bayer CropScience sponsored a study, Drinking Water Consumption Survey (DWCS) that was designed to obtain a distribution of water intake for a 24-hour time period from a representative sample of the US population. Participants recorded their water consumption (time of day and amount consumed) over a one-week (7 consecutive day) period. The authors, Barraj et.al. (2004), suggested that it may be possible to “allocate the total daily water consumption amount reported in the CSFII into various drinking occasions” using information from the DWCS. In addition to offering a fixed option for allocating direct drinking water throughout the day, the Agency is planning to include in SHEDS-Multimedia v. 4 the option to allocate direct drinking water consumption throughout the day through empirical use of the Bayer DWCS data.

Please comment on the advantages and disadvantages of providing an option to use the Bayer DWCS data in SHEDS-Multimedia v. 4. Please include in your comments any statistical concerns or issues associated with the design and conduct of the DWCS study.


EPA considers the dietary session of this SAP meeting to be a consultation on a variety of disparate topics rather than a formal review. We have not provided the Panel with working dietary software, nor have asked the Panel for a formal review of the dietary code.  As such, we offer the following clarification to Charge Question 3: 

EPA Clarification of Charge Question 3:   EPA recognizes that it has provided each of the Panel members with only background information on the Bayer DWCS as part of the document “An Update on the Development of the SHEDS-Dietary Model”  and has not provided Panel members with the Bayer submission itself.  The intended purpose of the above charge question was less to receive specific comments on the conduct and analysis of the Bayer DWCS, but rather to introduce this as a possible source of data  and obtain the Panel’s thoughts and ideas on the conceptual utility of this kind of study, in principle. More specifically, we are looking for advice from the Panel on ways studies conducted in this way could be interpreted and potentially used and any suggestions the Panel might have on ways data collected in this manner should be examined and interpreted. EPA has, to date, only performed exploratory analysis of the data provided by Bayer and has not yet formally reviewed this submission or used it as part of a regulatory decision.  EPA will use the thoughts and ideas presented by the Panel in its discussion of this topic and, if warranted at a later date, may present the study and our analysis to the Panel, along with our proposed use of the study as an available option in the SHEDS model.  

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