Christopher R. Fortune

Movement and Deposition of Two Organophosphorus Pesticides within a Residence after Interior and Exterior Applications

ABSTRACT Post-application temporal and spatial distributions of two organophosphorus pesticides, diazinon (O,O-diethyl O-[6-methyl-2-(1-methylethyl)-4-pyrimidinyl] phosphorothioate, CAS No. 333-41-5) and chlorpyrifos [O,O-diethyl-O-(2-isopropyl-6-methyl-4-pyrimidinyl) phosphorothioate, CAS No. 2921-88-2], were monitored after homeowner applications for indoor and outdoor insect control. Samples of indoor air, vacuumable carpet dust, carpet dislodgeable residues, deposits on bare floors, table tops and dinnerware, surrogate food, and residues on childrens hands and toys were taken before and up to 12 days after treatments in the family room, kitchen, and childs bedroom. Results from the study demonstrate the nature and magnitude of translocation of pesticides from the areas of application to surfaces accessible for human contact and permit comparisons of potential exposures via respiration and dermal contact/oral ingestion. Potential indoor inhalation exposures were estimated to be as high as 0.5 ^g/kg/day for diazinon applied indoors and 0.05 |ag/kg/day for chlorpyrifos applied to the outside perimeter of the house. While ingestion of carpet dust at the rate of 100 ^g/day would have added a maximum of only ~0.01 ^g/kg/day to the daily dose, residues found on the childrens hands suggest that repeated mouthing could have contributed as much as 1-1.5 ^g/kg/day. These estimates are below the U.S. Environmental Protection Agency (EPA) reference dose for chlorpyrifos, but exceed those for diazinon.

Superfund contract laboratory program method evaluation : ambient air volatile organic compounds from canisters

A GC/MS system that is modified for the addition of internal standards has been used to run the Superfund method for volatile organic compounds in ambient air as described in the Statement of Work for the Superfund Contract Laboratory Program/Statement of Work (CLPSOW). The analysis method applies to air samples retrieved from GL (SUMMA-polished) stainless steel canisters. Generic performance criteria were tested by using full-scan mass spectrometry. The method quantitalion limit was determined to be less than the contract-required quantitation limit (CRQL) for 37 of the 41 target compounds; replicate analyses of field samples achieved CLP/SOW-specified values of precision (±25% difference relative to the average value for two analyses) for all target gas concentrations above the CRQLs; and audit accuracy values at a nominal 5-ppb v concentration averaged 9.6% unsigned average relative percentage difference. Field tests at the French Limited Superfund site near Crosby, Texas, support the choice of the scanning mode of mass spectrometer operation in that many nontargeted compounds occur at high concentrations. However, method quantitation limits for targeted compounds are increased by factors ranging from five to ten from those obtainable in the selected ion monitoring mode of mass spectrometer operation in that many nontargeted compounds occur at high concentrations. However, method quantitation limits for targeted compounds are increased by factors ranging from five to an from those obtainable in the selected ion monitoring mode

Improvements in the methodology for measuring hydrochloric acid in combustion source emissions

Abstract In sampling gaseous hydrochloric acid in combustion source emissions by the standard method (collection of particles in a probe plug followed by absorption of gaseous HCl in an impinger solution), there is a potential for error due to interaction of HCl with the filtering medium and/or with particles on the filter. A laboratory study was conducted to examine the interaction of gaseous HCl with glass and quartz media and with particles from coal‐fired and incinerator boilers. Also, some source sampling results obtained by different methods at cement production plants, oil‐fired boilers, and a coal‐fired boiler were examined. On the basis of both studies, it is recommended that sampling for gaseous HCl in combustion source emissions employ a quartz filter medium, high‐velocity sample flow, minimum filter temperature, and minimum sample volume. This approach is expected to yield the most accurate HCl mass emission rates for source categories having significant chlorine in fuels or processes.

The use of isopropanol to distinguish H2SO4 from particulate sulfate on filters

Abstract Potential interferences in the anhydrous isopropanol (a‐IPA) extraction method for separating sulfuric acid from particulate sulfate on filters were investigated. The method involves separation and recovery of the acid with a‐IPA, followed by aqueous extraction of the particulate sulfate. Analysis for sulfate in the two separate fractions was performed by ion chromatography. The solubility of ammonium sulfate in a‐IPA was measured and the effects of temperature and moisture content of the solvent on ammonium sulfate solubility were determined. The solvent recovery procedure was used to analyze samples collected at an oil‐fired utility boiler. Before analysis, each filter was cut in half and one half of each filter was exposed to an ammonia atmosphere to neutralize any free sulfuric acid. All filter halves were then extracted with a‐IPA followed by a separate aqueous extraction by ultrasonication. Neither a small uptake of moisture by the a‐IPA nor elevated temperatures up to 30° C had a significa...