AWWA WQTC69297

This powerpoint presentation begins by presenting research objectives that include the following: evaluate the impact of not strictly following U.S. Environmental Protection Agency (USEPA) guidelines for preservation and storage of synthetic organics; evaluate the impact of extended storage at room temperature on analyte stability, e.g. simulate long transit times; evaluate impact of eliminating "dangerous goods" from preservation, e.g. facilitate international transport; and, eliminate dual stage preservation, e.g. de-chlorination followed by acidification. Reasons for evaluating alternatives include the following: there are inconsistencies between various 500 series methods for the same analyte; two-stage preservation for disinfected samples is a source of field errors; for international projects, sending acids is sometimes prohibited, Keep It Simple; and, the World Health Organization (WHO) regulates some analytes that are not covered in USEPA regulations and there is no literature data on preservation. Observations on pesticide/SOC analysis and degradation with 525 scheme include the following: under refrigeration, almost all target analytes are stable for 28 days when acidified; however, without acidification but with refrigeration, almost all target analytes are stable for at least 7 days; without refrigeration there are significant differences by compound class with acidification vs neutral pH, and is also somewhat matrix dependent; and, for some compounds acidification enhances degradation whereas de-chlorination does not. Significant observations from Part One studies indicate: cyanazine unstable if acidified, but dechlorination is acceptable (contrary to 525); heptachlor is relatively stable without acidification (more stable than with acid); diazinon is relatively stable without acidification; and, a few USEPA regulated analytes show significant degradation when preserved per method requirements. Studies in process and recommendations include the following: 527 Preservation in Matrices (as was done with 525 options in part 1); evaluation of Room Temperature Storage with 527; develop Triage Scheme for Data Interpretation Based on Findings; it appears clear that USEPA can move away from two-stage preservation; and, USEPA can also clarify existing options. Includes table, figures.