Methodology Development and Evaluation
A final critical step is the quantitative evaluation of the ratio of chrysene to its methylated analogs (i.e., methyl aromatic ratio analysis), which can provide definitive differentiation of PAH compounds sourcing from high temperature pyrolytic processes from those that are associated with low temperature petrogenic or even natural PAH compounds. Since 1997, Dr. Smith has used his four (4) step approach, including MARA, to successfully eliminate PAH compounds and certain extractable petroleum hydrocarbon (EPH) fractions from consideration under the MCP at more than a dozen disposal waste sites.
Certified Clean Canisters for Indoor Air Analyses. Dr. Smith routinely recommends the use of certified clean canisters in the sampling of indoor air. Dr. Smith has helped several companies develop appropriate Standard Operating Procedures (SOPs) for submittal to analytical laboratories for the purpose of improving the quality and reproducibility of indoor air sample analyses. One of the most useful improvements in indoor air sampling and analysis is to require laboratory certified clean canisters. The SOP specifies the steps required in the laboratories “certification” of canisters supplied for use in sampling. These steps include the sampling of “clean” air, laboratory analysis of that air, and reporting of the result in a complete data package that includes a report and chromatograms for target analytes of interest.
Development of Appropriate Duplicate Indoor Air Analyses. Dr. Smith is spearheading a drive to develop a methodology for producing reproducible contaminate analyses from duplicate indoor air samples. Currently, duplicate indoor air air samples are collected using two Summa canisters, each with its own flow regulator, attached to a common sampling port or simply placed in close proximity to each other, each with its own sampling port. This method of collecting duplicate samples can result in significant variation in contaminate concentrations between the duplicate samples. Rather than a measure of laboratory reproducibility, such sample differences may simply reflect differential flow of indoor air into the Summa canister. Dr. Smith recommends using a simple dual canister sampling manifold (DCSM) connecting two canisters together through a single flow regulator and sample port as a useful means of evaluating laboratory precision and reproducibility.
Develop Methodology for Determining an Alternative Remedial Goal for Chromium. Dr. Smith developed a site-specific approach for deriving an alternative remedial goal for chromium in soil. The approach determines the relative solubility of chromium species in site soils using newly developed techniques differentiating between relatively non-toxic chromium species (CrIII) and more toxic ones (CrVI). Speciation techniques and a modifiedin vitro bioavailability test assessing chromium solubility in the gastrointestinal track can provide information useful in the derivation of an alternative risk-based cleanup levels for chromium in soil. The approach promises to offer substantial remedial cost savings over generically applied cleanup criteria.
Evaluation of Estrogenic Compounds in Sediment. A confidential client was under regulatory scrutiny as a potentially responsible party responsible for remediation of sediments containing persistent chlorinated organic compounds with estrogenic activity. Regulatory authorities focused on eliminating contaminated sediments with a potential to cause reproductive effects in wildlife through dredging of sediments in New York harbor. New Jersey determined that estrogenic compounds, historically associated with the client’s site, were primarily responsible for sediment reproductive toxicity. Dr. Smith critically reviewed the available assays of estrogenic activity, characterizing assays by their ability to differentiate between anti-estrogenic and estrogenic contaminants, sensitivity, selectivity, and cost. Dr. Smith developed an integrated approach for the phased analysis of the sediment estrogenic activity using a uniquein vitro bioassay. Client responsibility for sediment estrogenic activity is still being assessed.
Evaluation of Mercury Vapor Analyzer. Dr. Smith was retained by a homeowner concerned about the hazard posed by mercury vapor in his families home. Mercury vapor was detected in the home after a Michigan power company technician accidentally released elemental mercury during routine replacement of the gas regulator. Health authorities immediately moved the family out of the house to protect their health. Dr. Smith worked with legal counsel and the power companies consultant to determine appropriate remediation and post-remediation testing of the home. Post-remediation testing of airborne mercury vapor in the home was performed using the Lumex RA-915+ Mercury Analyzer, which although accepted by U.S. EPA Region V, had not been appropriately validated for this use. Under Dr. Smith’s direction, the home was appropriately cleaned and, using the Lumex Mercury Analyzer and an appropriate Quality Assurance/Quality Control (QA/QC) Program, determined to be safe for the homeowner’s family to return.