Comment letters to the National Commission on Commission on Fraudulent Financial Reporting, 1987 (Treadway Commission) Vol. 2

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Key structure-activity relationships in the vanadium phosphorus oxide catalyst system

The crystal structure of vanadyl pyrophosphate has been redetermined using single crystals obtained from a near solidified melt of a microcrystalline catalyst sample. Crystals that index as vanadyl pyrophosphate obtained from this melt are variable in color. Crystallographic refinement of the single crystal x-ray diffraction data indicates that structural differences among these materials can be described in terms of crystal defects associated with linear disorder of the vanadium atoms. The importance of the disorder is outlined in the context of its effect on the proposed surface topology parallel to (1,0,0). Models of the surface topology simply and intuitively account for the non-stoichometric surface atomic P/V ratio exhibited by selective catalysts of this phase. These models also point to the possible role of the excess phosphorus in providing site isolation of reactive centers at the surface. 33 refs., 7 figs

Using the ELISA Method to Track Atrazine Occurrence in a National Monitoring Program

During the past two decades, numerous monitoring programs have been conducted to characterize the occurrence and use of atrazine, the most commonly applied herbicide in the United States. In 2003, AWWA and the Water Industry Technical Action Fund jointly sponsored the Atrazine Monitoring Program to expand on previous studies and assess atrazine occurrence patterns in US drinking water systems. A commercially available enzyme‐linked immunosorbent assay (ELISA) test method was used to determine atrazine occurrence in 38 water sources from 33 utilities surveyed. The ELISA method used, although relatively precise, was found to be inaccurate for many of the waters tested in this study; the testing kit has since been modified to address interferences caused by oxidants. However, the data presented here, collected using the original ELISA method, reflect observed “trends” in atrazine occurrence rather than accurate atrazine concentrations