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Soil and ash surface samples (n= 44) were collected from three historical metal recovery facilities where copper scrap was a dominant feed stream, three sites of open burning where evidence of copper recovery was visible, and from a railroad car incineration facility. Concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are in the low parts per billion range with PCDF concentrations significantly lower in samples from the railroad car facility. In fly ash from a copper wire and aluminum scrap recovery facility, PCDD and PCDF concentrations are high, 50 and 460 ppm. Consistent with that cited for other combustion sources, ratios of PCDF to PCDD are mostly greater than 1. However, a lower ratio (0.4), is observed in samples from the railroad car incineration facility. OCDF and OCDD are significantly correlated with 2,3,7,8-TCDD toxicity equivalents (TEQ). These congeners may be inexpensively analyzed and may be useful as indicator chemicals at similar sites and facilities. Further investigations of metal recovery facilities and open burn sites worldwide are necessary.

We will briefly discuss vehicle emissions and the vehicle emissions inventory before reviewing remote-sensing technology for exhaust emissions and remote-sensing applications that help characterize and minimize exhaust emissions in the real world. Remote sensing is the only method available that can measure the HC and CO exhaust emission rates of large numbers of individual in-use vehicles. These measurements have helped focus attention on the problem of in-use emissions from malfunctioning and illegally altered vehicles. The method has a bright future as an aid in understanding in-use emissions, a monitor of progress in reducing fleet emission rates, and as an IM and enforcement tool. 11 refs., 2 figs.

Concentrations in air and on surfaces of malathion and impurities [malaoxon, isomalathion, O,O,S-trimethyl phosphorodithioate, O,O,O-trimethyl phosphorothioate, O,O,S-trimethyl phosphorothioate, and diethyl fumarate (DEF)] were determined at three sites during and for 9 days after a 1990 aerial spraying in California. Malathion spray was transformed via oxidation to malaoxon, hydrolysis to DEF, and selective volatilization. Malathion half-lives were 1.6 to >9 days, and depositions at three sites ranged from 1100 to 2413 μg/ft 2 , while malaoxon ranged from 2.9 to 6.0 μg/ft 2 .

Under the sponsorship of the World Health Organization (WHO), an interlaboratory calibration on the analysis of PCDD/PCDFs in human milk and blood was carried out which included 19 laboratories from 14 countries. The study design involved the analysis of three samples of each matrix in triplicate. Selected samples were spiked with native standards of certain 2,3,7,8-substituted congeners at concentrations known only to WHO staff. The study design resulted in approximately 4,000 individual pieces of PCDD/PCDF data generated by a variety of analytical methods, at various concentrations, and by laboratories of widely different experience. This was, by considerable margin, the largest study which allowed for the direct comparison of laboratory and method performance. The results of statistical analysis of this data base addresses the effect on data quality of clean up methods, instrumental methods, analyte concentration, laboratory QA programs, and laboratory experience. The study has shown that the laboratory is the single most important determinant of data precision and accuracy. The method of analyte enrichment (sample clean up), analyte measurement [gas chromatography/mass spectrometry (GC/MS) protocol], and analyte concentration have weaker correlations with data quality. 14 refs., 18 figs.

Eight chlorinated phenoxy acid and three ester herbicides are determined in soil and water by liquid chromatography with UV adsorption of quantitation and particle beam mass spectrometry for confirmation. Chromatography with UV detection (230 nm) gives quantitation limits of 12-80 ng in 10-μl injected volume (corresponding to 4.8-32 ppb in 125 mL of water and 20-133 ppb in 30 g of soil and 500 μL of final extract volume)

Anion-exchange liquid chromatography with detection via both particle beam mass spectrometry (electron impact and negative chemical ionization) and UV absorption spectrophotometry is used to characterize target and nontarget compounds in lyophilizates from three Stringfellow hazardous waste leachates - upstream, downstream, and a charcoal-treated mixture. Lyophilization retains essentially all the organic carbon, which is 513, 46.8, and 453 ppm, respectively. Charcoal treatment removes priority pollutants but not most the total organic carbon (TOC), which is primarily highly polar, nonextractable, and nonpurgeable material. Besides 4-chlorobenzenesufonic acid (from 53 to 69% of the TOC), seven additional major aromatic sulfonic acids are tentatively identified. All are sulfonated and chlorinated aromatic byproducts probably from DDT manufacture. Relative ratios of the aromatic sulfonic acids are not significantly altered by the charcoal treatment. The potential impact upon human health of these highly polar halogenated organic compounds is unknown.

Daminozide [Alar, succinic acid mono(2,2-dimethylhydrazide)] is measured directly as the parent compound in 11 commercially obtained apple juice samples at levels ranging from 0 to 280 ppb. Sample preparation involves only evaporation and treatment with methanol and acetone to precipitate sugars and inorganic salts. Analysis is via anion-exchange chromatography particle beam mass spectrometry, with positive chemical ionization using isobutane as a reagent gas. A method detection limit of 25 ppb is achieved in part by a signal enhancement resulting from the constant addition of malic acid to the mobile phase

Utilisation de divers hydrocarbures et d'halogenohydrocarbures. Relation entre les constantes de vitesse mesurees et le nombre d'hydrogenes primaires, secondaires et tertiaires presents dans l'alcane. Il existe egalement une relation avec le nombre et le type de substituants dans les halogenohydrocarbures

Absolute rate constants for the reaction OH + NH/sub 3/ ..-->.. NH/sub 2/ + H/sub 2/O were measured as a function of temperature from 297 to 364 K via the discharge flow technique with resonance fluorescence detection of OH. The rate constant was measured at five temperatures and fit to an Arrhenius expression to yield (4.55 +/- 1.1) x 10/sup -12/ exp((-973 +/- 78)/T) cm/sup 3/ molecule/sup -1/ s/sup -1/. A computer model of the experimental data was used to estimate rate constants for the exothermic reactions NH/sub 2/ + NO ..-->.. N/sub 2/ + H + OH and NH/sub 2/ + 2OH. The rate constant for quenching of OH(A/sup 2/..sigma../sup +/) at 297 K by ammonia was determined to be (9.6 +/- 0.8) x 10/sup -10/ cm/sup 3/ molecule/sup -1/ s/sup -1/. 35 references, 6 figures, 3 tables.