Showing papers in "Environmental Science & Technology in 1982"

Effects of ambient temperature on aspects of airborne polycyclic aromatic hydrocarbons

Abstract: Three- to six-ring polycyclic aromatic hydrocarbons in the vapor phase (PAHs/sub vap/) and in the particulate phase (PAHs/sub pat) and total suspended particulate (TSP) in ambient air were sampled and determined year-round. At ambient temperature levels, substantial amounts of three-to five-ring PAHs were found in the vapor phase depending upon temperature (T, K) and the six-ring PAHs were all found in the particulate phase. For three- to five-ring PAHs, the Langmuir adsorption concept was introduced for PAHs/sub vap/ and PAHs/sub pat/ on the particulates. log ((PAHs/sub vap/) /)(PAHs/sub pat/) / (TSP))) was related to 1/T, and a high correlation (r = 0.834 to -0.942) was obtained between the two quantities. Thus, aspects of the three- to five-ring PAHs in ambient air were considered to be explained by using the Langmuir adsorption concept.

Binding of DDT to dissolved humic materials.

Abstract: Quantitative measurements have been made by using equilibrium dialysis techniques on the extent of binding between DDT and dissolved humic materials. A significant fraction of the dissolved DDT found in natural waters may be bound to dissolved humic materials. The extent of binding depends on the source of the humic material, the pH, the calcium concentration, the ionic strength, and the concentration of humic materials.

Microbial removal of hazardous organic compounds

Abstract: An in-depth evaluation of the potential for microorganisms to remove anthropogenic organic compounds, mainly priority pollutants and related compounds, is presented. The evaluation indicates that use of properly selected populations of microbes, and the maintenance of environmental conditions most conducive to their metabolism, can be an important means of improving biological treatment of organic wastes. One major theme is that microorganisms not normally associated with biological waste treatment have potential advantages when the removal of anthropogenic compounds is the goal. An extensive summary of examples of anthropogenic compounds and microorganisms that can attack them is presented in tabular form. A second table lists the selective uses of microorganisms for removal of different anthropogenic compounds. (KRM)

Partitioning of organic compounds in octanol-water systems

Abstract: National Academy of Sciences “Petroleum in the Marine Environment”; Washington, DC, 1975. Blumer, M.; Sass, J. Mar. Pollut. Bull. 1972, 3, 92-4. Clark, R. C.; Macled, W. In “Effects of Petroleum in Arctic and Sub-Arctic Environments”; Malins, Ed.; Academic Press, London, 1977; Vol. I, pp 91-199. Van Vleet, E.; Quinn, J. Enuiron. Sci. Technol. 1977,11, 1086-92. Van Vleet, E.; Quinn, J. J. Fish. Res. Board Can. 1978,35, 5, 536-43. Williams, P. J. LeB NERC final report GR3/1812,1976. Baker, J. M. In “Proceedings Joint Conference on Prevention and Control of Oil Spills”; API: Washington, DC,

Development and evaluation of sunlight actinometers.

Abstract: rn We have developed and used two binary chemical actinometers for sunlight measurements from 300 to 370 nm that have the great advantage of possessing adjustable quantum yields to provide half-lives ranging from a few minutes to several weeks in sunlight. One actinometer is the known p-nitroanisole (PNA)/pyridine (pyr) system in water, the half-life of which in sunlight can be varied from a few minutes to 12 h by changing the concentration of the pyridine. The other actinometer is p-nitroacetophenone (PNAP)/pyr, which has a half-life in sunlight ranging from several hours to 2 months and also can be adjusted by varying the concentration of pyr. Both systems are well behaved kinetically and have quantum yields invariant with wavelength from 313 to 366 nm. Neither PNA nor PNAP is volatile from water or readily sorbed, and each is easily analyzed by UV or HPLC. For PNA/pyr, 4 = 0.44[pyr] + 0.00028 and for PNAP/pyr, 4 = O.O169[pyr].

Formaldehyde and other carbonyls in Los Angeles ambient air.

Abstract: From selective sampling and liquid chromatography analysis, ambient levels of carbonyl compounds as 2,4-dinitrophenylhydrazones have been measured in the Los Angeles area during severe photochemical pollution episodes. Gas-phase concentrations and diurnal profiles are presented for six carbonyls: formaldehyde (up to 48 ppb), acetaldehyde (less than or equal to 35 ppb), propanal (less than or equal to 14 ppb), butanal (less than or equal to 7 ppb), 2-butanone (less than or equal to 14 ppb), and benzaldehyde (less than or equal to 1 ppb). Also presented are particulate-phase concentrations and particle/gas distribution ratios for five carbonyls. Ambient carbonyl levels are discussed with respect to anthropogenic emissions and to photochemical production and removal in polluted air. Advantages and current limitations of the method employed are briefly discussed.

Reversible and resistant components of PCB adsorption-desorption: isotherms.

Abstract: Results from laboratory equilibration studies indicate that sediment-adsorbed 2,4,5,2',4',5'-hexachlorobiphenyl (HCBP) fractions may be comprised of both reversibly and strongly bound or resistant components. This evidence suggests that for many environmental modeling efforts it may be inappropriate to treat this and other PCB isomer adsorption reactions as either completely reversible or completely irreversible. The initial refinement of such models requires a means of estimating the relative magnitudes of the respective sorbed PCB fractions. To this end, a computational method has been derived to allow prediction of the magnitude of the reversible and more strongly adsorbed HCBP fractions from conventional isotherm data. The derivation, which is based upon experimentally observed linear HCBP isotherms, has also been applied to other organic molecules of similar isotherm character. This methodology provides an initial quantitative approximation of the strongly bound, resistant, sediment fractions while utilizing relatively simple experimental adsorption-desorption data. Results suggest that for montmorillonite clay, kaolinite clay, and natural lake sediment (Saginaw Bay, MI) linear isotherms effectively describe the relationships between both adsorbed HCBP fractions and the aqueous HCBP concentration. The implications of these and other model predictions for the cycling of PCB's in natural waters are discussed.

Acid precipitation in historical perspective

Abstract: The history of acid precipitation is traced from the first awareness of the problem in the mid-17th century to the present. An outline of the National Acid Precipitation Assessment program is also given, and the author makes recommendations for future research. (JMT)

Observations of nitrous acid in the Los Angeles atmosphere and implications for predictions of ozone-precursor relationships.

Abstract: Direct measurements of nitrous acid (HONO) were made in downtown Los Angeles and Riverside, CA, during night and early morning hours of July/August 1980 using a long-path differential optical absorption spectrometer. Up to 8 ppb of HONO were observed in Los Angeles, approximately twice the maximum levels previously measured in Riverside during the summer of 1979. Possible sources of the observed HONO are discussed. If the observed HONO levels are included in initial NO, concentration, EKMA isopleth calculations predict that more rigorous control of NO, emissions (especially a t low HC/NO, levels) or of hydrocarbons emissions is necessary to reduce ozone maxima by a given amount compared with predictions based on calculations neglecting initial HONO. Moreover, including HONO in the starting NO, leads to predictions of accelerated rates of oxidant production which results in much larger predicted O3 doses at elevated O3 levels. For example, the predicted O3 dosage at levels above 0.3 ppm ozone in the case of NMHC = 1 ppm and [NO,], = 0.12 ppm is increased by over 250% when 10 ppb of HONO is taken to be initially present.

Identification of atmospheric particulate sources in Washington, D.C. using chemical element balances

Abstract: During the summer of 1976, 130 air-filter samples were collected at 10 sites in the Washington, D.C., area and analyzed for 39 elements, with 37 samples also being analyzed for SO/sub 4//sup 2 -/, NO/sub 3//sup -/, and NH/sub 4//sup +/. Concentration patterns were interpreted by using chemical element balances for seven sources: coal, oil and refuse combustion, soil dust, motor-vehicle emissions, limestone, and marine aerosols. For 35 nonvolatile elements, predicted concentrations were, on the average, within a factor of 1.93 of observed values. Predicted concentrations of primary particulate matter plus SO/sub 4//sup 2 -/, NO/sub 3//sup -/, and NH/sub 4//sup +/ account for 65% of measured total suspended particulate (TSP) matter, the remainder presumably being condensed water, organic material, and sources not included. The largest fraction of primary TSP matter is soil, dust, much of which is entrained by urban activities. The limestone component may originate from agricultural liming, construction projects, or abrasion of concrete. Most elements are reasonably well fitted, major exceptions being Cr, Cu, Ni, and a small-particle component of Mn.

Kinetics of ozone decomposition: a dynamic approach

Abstract: rn Decomposition kinetics of ozone in aqueous solution were studied at 20 \"C and in the pH range 2-10, under both quiescent and dynamic conditions. The data obtained in a batch reactor under quiescent conditions were analyzed by integral, initial-rate, and differential methods. The results indicated that ozone decomposes by a second-order reaction with respect to ozone concentration. The second-order decomposition kinetics determined in the batch reactor was confirmed by using a mathematical model developed for ozone decompgsition in an ozone contact column and the experimental observations under such dynamic conditions. The rate of decomposition was found to be relatively insensitive to pH below 4 and relatively slow under such acidic conditions (kd = 0.27 L/(mol 8)). Above pH 4, the rate is pH dependent with kd = ko[OH-]o*55, where ko is specific to the chemical composition of the aqueous system.

Effects of complexation by chloride, sulfate, and thiosulfate on adsorption behavior of cadmium on oxide surfaces

Abstract: Adsorption of metal ions on oxide surfaces mediates the transport of these ions in natural aquatic systems as well as in many waste treatment operations. Often the metals exist in the bulk aqueous phase as complexes with inorganic or organic ligands. The effects of complexation by Cl,SO/sub 4/, and S/sub 2/O/sub 3/ on adsorption of Cd onto four different oxide solids have been studied. Increasing concentration of the ligand increases Cd adsorption in some cases and decreases it in others. All of the results are consistent with a model in which chloro and sulfato complexes are assumed to adsorb with the metal closer to the surface than the ligand, and thiosulfato complexes adsorb with the ligand closer than the metal.

Persistent organic chemicals in sewage effluents. 2. Quantitative determinations of nonylphenols and nonylphenol ethoxylates by glass capillary gas chromatography

Abstract: Nonylphenols and nonylphenol ethoxylates with one and two oxyethylene groups have been quantitatively determined in the effluents of six mechanical-biological sewage treatment plants. In three plants total concentrations of nonylphenolic compounds in the effluents ranged from 36 to 202 pg/L, representing from 0.5% to 2.3% of the total residual dissolved organic carbon. In three plants operated at low loading conditions nonylphenolic compounds were not detectable (

Fulvic acid: modifier of metal-ion chemistry.

Abstract: Fulvic acid, which is derived from the decay of plants and animals, is being studied for its role in the transport and toxicity of metal ions in soil and water. It is discussed in relation to the origin of humic substances and its interactions with metal ions. Techniques for investigating complexes of fulvic acid and metal ions are presented. They are separation and nonseparation analyses which are applied to speciation problems. The applicability, advantages, and disadvantages of both methods are presented. Separation of free and complexed metal ions can be done by chromatography, or with membranes that exclude the metal-ion complexes. Chromatographic techniques include liquid chromatography by size exclusion. Nonseparation techniques include voltametry and potentiometry, as well as fluorescence. A comparison of methods for calculation of the conditional stability constant K for complexes containing fulvic acid and copper (II) or cadmium (II) is presented.

Organic contaminants in groundwater near an underground coal gasification site in northeastern Wyoming

Abstract: Three groundwater samples collected near two underground coal gasification (UCG) sites 15 months after the end of gasification were analysed for dissolved organic contaminants. The contaminants consisted of phenols, aromatic carboxylic acids, aromatic hydrocarbons, ketones, aldehydes, pyridines, quinolines, isoquinolines, and aromatic amines. Concentrations ranged up to about 50 ppm with large variations both in the relative concentrations of acidic, neutral, and basic constituents and in the concentrations of individual compounds. Naphthalene o-xylene, 2-methylpyridine, and o-cresol were consistently present in high concentrations and were identified as UCG contaminant-indicator compounds that appear to be particularly useful for monitoring purposes. A simplified method of analysis for these compounds was developed.

Mineral matter and trace-element vaporization in a laboratory-pulverized coal combustion system

Abstract: The composition and size distribution of fly ash produced by burning a Montana lignite at two temperatures, 2050 and 2450, were determined. The ash showed a bimodal size distribution with a submicron fraction that was significantly enriched in the volatile trace species. The amount of submicron aerosol increased markedly with combustion temperature, from 4% of the ASTM ash value of the coal at 2050 K to 20% at 2450 K, supporting the hypothesis that the enrichment in more volatile species of the smaller ash particles is due to a process of vaporisation and recondensation of mineral constituents.

Visibility and aerosol composition in Houston, Texas

Abstract: eelationships between light extinction coefficients, visual range, and aerosol mass and composition were studied in Houston, TX. Light extinction coefficients, measured with a telephotometer and black-box targets, agreed accurately with sums of light scattering and absorption coefficients. The light-scatteing coefficient due to particles in heated air was highly correlated (R = 0.987) with the mass concentration of fine particles (<2.5 ..mu..m), and the ratio of averages was 3.5 m/sup 2/g/sup -1/. Major species in the fine fraction were 18% carbon and 54% sulfate and related cations; the average sulfate was predominantly ammonium sulfate mixed with 19% sulfuric acid during the day and 7% sulfuric acid at night. The coarse fraction (2.5-15 ..mu..m) was alkaline and consisted of 69% crustal matter, 12% carbon, and 7% nitrate. The average daytime light extinction coefficient was apportioned 32% to sulfate and related cations, 17-24% to carbon, 16% to water on particles, 6% to Rayleigh scattering, 5% to nitrogen dioxide, and 13 +/- 7% to unmeasured matter.

Nitrated polycyclic aromatic hydrocarbons in urban air particles.

Abstract: The organic extract of urban air particles from St. Louis, MO, was fractionated by high-performance liquid chromatography. The moderately polar fraction was characterized by gas chromatography-electron impact and methane negative ion chemical ionization mass spectrometry. The compounds identified in the sample included nitronaphthalene, 9-nitroanthracene, 3-nitrofluoranthene, 1-nitropyrene, arenecarbonitriles, and several polycyclic ketones, quinones, and anhydrides. These studies represent the first mass spectrometric evidence of nitroaromatics in urban air particles.

Destruction of pollutants in water with ozone in combination with ultraviolet radiation. 1. General principles and oxidation of tetrachloroethylene

Abstract: Oxidation of organic micropollutants in water is significantly faster with ozone in combination with ultraviolet radiation than one would predict on the basis of the individual processes involved. A formalism for the analysis of O/sub 3//UV kinetics is presented in which substrate decay is represented as a linear combination of terms representing purging, ozonation, photolysis, and photolytic ozonation (O/sub 3//UV). For the substrate tetrachloroethylene (TCE) the process is overall first order in TCE. With a continuously sparged stirred tank reactor, times for the elimination of 63% of the substrate (T/sub 1/) have values of 100, 26, 20, and 7 min for purging, ozonation only, photolysis only, and photolytic ozonation, respectively. Significant retardation of O/sub 3//UV kinetics is observed in a lake-water matrix as opposed to purified water, possible due to a radical intermediate involved in the O/sub 3//UV process.

Gas-chromatographic speciation of methylstannanes in the Chesapeake Bay using purge and trap sampling with a tin-selective detector

Abstract: : A method was developed permitting detection and speciation of both volatile and non-volatile organotin compounds in aqueous media. The method employed a commercial gas chromatograph (GC) with a flame photometric detector (FPD) optimized for tin-selective detection. Solvated organotins were volatilized with sodium borohydride during the purge cycle of a commercial automatic purge and trap sampler (P/T). Purged volatiles and species volatilized by hydridization were concentrated on a Tenax-GC filled trap at ambient temperature. Tetramethyltin (Me4SN) present in the sample is unaffected by the reduction process. The P/T-GC-FPD method was used to analyze water samples collected from the Chesapeake Bay and Baltimore Harbor. Varying amounts of methyltin compounds, including tetramethyltin and methyltin hydrides, were detected in polluted sites in Baltimore Harbor. In vitro studies using GC-MS confirmed earlier reports of microbial methylation of inorganic Sn(IV) by a strain of Pseudomonas species isolated from the Chesapeake Bay. Consequently, biogenic origins are suspected for the methylstannanes (Me(n)SnH(4-n) n = 2,3) found in the Chesapeake Bay. (Author)