(CASAC) Peer Review of EPA's Integrated Science Assessment

Dr. Richard SchlesingerComments on SOx ISA – 2 nd DraftOverall, the 2 nd draft improves on the 1 st in integrating the various disciplines. However,there is still room for improvement in some of the sections as noted below. In manycases, the various disciplines are not really integrated but rather separate discussions ofeach are just placed in the same section. A true integration would interweave the epi withmechanistic support from the controlled studies.The inclusion of a section on mixtures, i.e., 3.1.5, is an improvement, but it is not clearwhy that section was placed where it was. I think that a section on mixtures and thepotential for interaction related to all health outcomes from SO2 for all exposurescenarios should be developed and placed at the end of the chapter prior to theConclusions.Table 5-3 is excellent and provides a very nice summary overview of the conclusions ofthe ISA and comparison to the previous Criteria Document.Specific Issues1. Section 3.1.3 is titled, Respiratory Effects Associated with Peak Exposure. Inreality, this is a discussion of studies that involve exposures for 1 hr or less tosingle levels of SO2 without any baseline in animal and human clinicalevaluations. Thus, the use of the term peak may be misleading since this mayimply some higher level relative to some lower baseline. This section should alsobe renumbered as follows:3.1.3.1 Clinical Studies3.1.3.2 Animal Studies2. Section 3.1.4 discusses Epi studies and this should be reflected in the sectionheading. Furthermore, lines 7-21 on page 3-17 should be moved to section 3.1.2.3. Section 3.1.4.3 is an attempt to integrate animal, human clinical and epi studies.4. Page 3-48, lines 15-17. The inconsistency may be due to the fact that the specificnature of the interaction may depend upon the specific co-pollutant.5. Section 3.1.6 seems to be out of place here. Perhaps the material could beintegrated into other sections.40