Chromium Analysis at a Ferrochrome Smelter,a Chemical Plant and a Refractory Brick Plant

Techniques were developed to sample and analyze the Cr content of participate samples with emphasis on determining the concentration of the carcinogen Cr⁺⁶. Cr⁺⁶ is extracted to alkaline solution and analyzed colorimetrically. Residual particles are extracted with acid solution to remove soluble Cr⁺³, which is determined by atomic absorption spectrometry. This methodology was tested on samples from three diverse types of sources: a ferrochrome smelter, a chemical plant, and a refractory brick plant. Identical quadruplicate samples were collected to determine accuracy and precision of the collection and analysis procedures, and extraction of Cr⁺⁶ and Cr⁺³. A statistical analysis revealed that the precision of Cr⁺⁶ analysis is comparable to that of the particulate mass determination. The stability of Cr⁺⁶ In particulate form and in solution was determined. Size resolved particulate samples were collected to determine the particle size versus the Cr⁺⁶ content. At the ferrochrome smelter and the chemical plant the majority of the Cr⁺⁶ was contained in the respirable particles. The accuracy and completeness of the chemical methods employed were verified by neutron activation analysis, x-ray photoelectron spectroscopy, and scanning electron microscopyenergy dispersive x-ray analysis.     

Determination of organochlorine and organophosphorus pesticide residues in low moisture,nonfatty products using a solid phase extraction cleanup and gas chromatography

Abstract

A multiresidue solid‐phase extraction (SPE) method for the isolation and subsequent gas Chromatographie determination of organochlorine and organophosphorus pesticide residues in low‐moisture, nonfatty products is described. Residues are extracted from samples with an acetonitrile/water mixture. Cleanup of the extract is performed using graphitized carbon black and anion exchange SPE columns, and analysis is performed by gas chromatography with Hall electrolytic conductivity and flame photometric detection. Recovery data was obtained by fortifying corn, oats and wheat with pesticides. The average recoveries were 79–123% for eight organochlorine and 51–122% for 28 organophosphorus pesticide residues. The limit of quantitation for chlorpyriphos was 0.05 ppm using the Hall electrolytic conductivity detector and <0.005 ppm using the flame photometric detector.     

Distribution of Light Hydrocarbons in Ambient Air

The diversity of hydrocarbons which are present in ambient polluted air provide a potentially rich source of information concerning the nature of this type of pollution. Measurements of the relative amounts of various hydrocarbons can be correlated with the various possible sources. Since hydrocarbon reactivities vary widely it is also possible to estimate the extent to which various individual hydrocarbons have reacted. Except for samples taken deliberately near sources of hydrocarbon pollution these air samples invariably resemble auto exhaust with an addition of natural gas and of C₃–C₅ paraffins which resemble gasoline vapor. Samples taken in industrial areas and near the smoke plume from a brush fire showed distinctive differences in composition. During the smog season in the fall of 1968 good data were obtained of “typical” or “representative” samples of light, medium and heavy smog. These show the expected depletion of more reactive hydrocarbons in a much more convincing way than before. By comparing these distributions with composition in unreacted samples and by making use of data from bottle irradiations, it was possible to estimate the contribution of the various hydrocarbons in terms of “amount reacted.” The amounts of higher hydrocarbons present and reacted were also estimated from gasoline composition.     

Air Pollution Controls at Braintree Incinerator

A new incineration plant has replaced the sanitary landfill in Braintree, Mass. Designed in 1966 and completed in 1971 it includes sophisticated air pollution controls although existing laws or codes did not require them. The results of dust loading tests conducted by an independent organization are presented.     

Particle Size Distributions of Kraft Paper Mill Aerosols Obtained by Airborne Sampling

Size distributions of particles at several downwind points in a Kraft paper mill plume have been determined by means of airborne sampling. Size distributions from samples close to the stack were found to have a log normal frequency distribution, but significant deviations from the log normal were found farther downwind. Several possible physical mechanisms are postulated as causes for this behavior. Plume dilution with background particles appears to be the most likely mechanism. The airborne sampling system is described, and electron micrographs of sampled particles are presented.     

Simultaneous analysis of free and sulfo-conjugated steroid estrogens in artificial urine solution and agricultural soils by high-performance liquid chromatography

A simple and robust analytical method was developed to simultaneously detect and quantify 17β-estradiol (E2), estrone (E1), 17β-estradiol-3-sulphate (E2-3S), and estrone-3-sulphate (E1-3S) in aqueous solutions (calcium chloride and artificial urine solutions) and agricultural soils using high performance liquid chromatography and UV detection. The standards for all four compounds were linear in the range of 0.01 to 1.0 μg mL^?1 (n = 6) and 1.0 to 20 μg mL^?1 (n = 6), respectively, with correlation coefficients > 0.999. The on-column limits of detection at an injection volume of 50 μL and S/N (signal: noise) ratio of 3 were: 9.0 ng mL^?1, 10 ng mL^?1, 5.0 ng mL^?1, and 7.0 ng mL^?1 for E2-3S, E1-3S, E2 and E1, respectively. The limit of detection and quantification in artificial urine solution and CaCl₂ solution was 1.0 ng mL^?1 for all four compounds. Method detection limits for the compounds in the 3 soils ranged from 2 to 2.4 ng g^?1 (E2-3S and E1-3S), and 1.0 to 2.9 ng g^?1 (E2 and E1), respectively.     

Continuous Measurement of Diesel Particulate Emissions

Evaluation of emerging diesel particulate emissions control technology will require analytical procedures capable of continuous or “real-time” measurement of transient organic and elemental carbon emissions. Procedures based on the flame ionlzation properties of organic carbon and the opacity or light extinction properties of elemental carbon are described, and applied for measurement of particulate emissions from diesel engines. The Instrumentation provided adequate sensitivity and time resolution for observation of the transient emissions associated with typical automobile urban driving conditions. Analytical accuracy is evaluated by comparing Integrated average results to measurements using classical gravimetric filtration and solvent extraction procedures. Mass specifc extinction coefficients are evaluated using the Beer-Lambert law. A simplified linear model relating elemental carbon concentration to opacity is also evaluated.     

Formaldehyde,Melhanol and Hydrocarbon Emissions from Methanol-fueled Cars

Exhaust and evaporative emissions tests were conducted on several methanol- and gasoline-fueled vehicles. Separate samples for chromatographlc analysis of formaldehyde, methanol, and Individual hydrocarbons were collected in each of the three phases of the driving cycle and in each of the two portions of the evaporative emissions test. One vehicle, equipped with an experimental variable-fuel engine, was tested using methanol/gasoline fuel mixtures of 100, 85, 50,15, and 0 percent methanol. Combustion-generated hydrocarbons were lowest using methanol fuel, and increased several-fold as the gasoline fraction was increased. Gasoline components In the exhaust Increased from zero as the gasoline fraction of the fuel was Increased. On the other hand, formaldehyde emissions were several times higher using methanol fuel than they were using gasoline. A dedicated methanol car and the variable-fuel car gave similar emissions patterns when they both were tested using methanol fuel. The organic-carbon composition of the exhaust was 85-90 percent methanol, 5-7 percent formaldehyde, and 3-9 percent hydrocarbons. Several cars that were tested using gasoline emitted similar distributions of hydrocarbons, even through the vehicles represented a broad range of current and developmental engine families and emissions control systems. These vehicles continue the trend of the past twenty years toward less photochemically reactive exhaust, with higher percentages of methane and total alkanes, and correspondingly lower percentages of oleflns and aromatlcs.