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.     

A Quality Assurance Management Plan

California Air Resources Board (CARB) staff developed a phased integrated approach to implement the Standing Air Monitoring Work Group’s (SAMWG) quality assurance requirements. This approach separates quality assurance requirements into a single project with a management plan and manager, and assigns each requirement to one of three key task areas—standardized methods and procedures measurement standards and tests, and audits. Tasks are assigned priorities and a detailed management plan is developed with SAMWG dates as milestones.

Benefits of the phased integrated approach are a streamlined, flexible quality assurance program; maximum utilization of personnel and resources; timely implementation of SAMWG requirements; a uniform quality assurance program applied to state, local, and private industry monitoring programs; and data with documented precision and accuracy. Additionally, peculiarities of procedures and analyzers that lead to data inaccuracies are quickly identified and corrected.     

Odor Threshold Measurement by Dynamic Olfactometry: Significant Operational Variables

Abstract

Combustion flue gases of three different industrial boilers firing miscellaneous fuels were monitored for a twoweek period. Nitric oxide (NO), sulfur dioxide (SO₂), carbon monoxide (CO), carbon dioxide (CO₂), and total hydrocarbons (CxHy) were continuously measured using single-component gas analyzers in parallel with a lowresolution Fourier Transform Infrared (FTIR) gas analyzer. Hydrogen chloride (HCl) was measured continuously using the FTIR analyzer and semi-continuously using a traditional liquid-absorption technique. Nitrous oxide (N₂O), nitrogen dioxide (NO₂), and water vapor (H₂O) were continuously measured using the FTIR analyzer only. Laboratory tests were conducted prior to the field measurements to assess the detection limits of the different measurement methods for each gas component. No significant differences were found between the results of the low-resolution FTIR analyzer and the single-component analyzers or the liquid absorption method.     

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.     

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.     

Effects of nano-TiO(2) in combination with ambient UV-irradiation on a leaf shredding amphipod

Production and use of engineered nanoparticles, such as titanium dioxide nanoparticles (nTiO₂), is increasing worldwide, enhancing their probability to enter aquatic environments. However, direct effects of nTiO₂ as well as ecotoxicological consequences due to the interactions of nTiO₂ with environmental factors like ultraviolet (UV) irradiation on representatives of detrital food webs have not been assessed so far. Hence, the present study displayed for the first time adverse sublethal effects of nTiO₂ at concentrations as low as 0.2 mg L⁻¹ on the leaf shredding amphipod Gammarus fossarum both in presence and absence of ambient UV-irradiation following a 7-d exposure. In absence of UV-irradiation, however, the effects seemed to be driven by accumulation of nTiO₂ at the bottom of the test vessels to which the gammarids were potentially exposed. The adverse sublethal and lethal effects on gammarids caused by the combined application of nTiO₂ and ambient UV-irradiation are suggested to be driven by the formation of reactive oxygen species. In conclusion, both the accumulation of nTiO₂ at the bottom of the test vessel and the UV induced formation of reactive oxygen species clearly affected its ecotoxicity, which is recommended for consideration in the environmental risk assessment of nanoparticles.     

Formation of a ternary neptunyl(V) biscarbonato inner-sphere sorption complex inhibits calcite growth rate

Neptunyl, Np(V)O(2)(+), along with the other actinyl ions U(VI)O(2)(2+) and Pu(V,VI)O(2)((+,2+)), is considered to be highly mobile in the geosphere, while interaction with mineral surfaces (inner- or outer-sphere adsorption, ion-exchange, and coprecipitation/structural incorporation) may retard its migration. Detailed information about the exact interaction mechanisms including the structure and stoichiometry of the adsorption complexes is crucial to predict the retention behavior in diverse geochemical environments. Here, we investigated the structure of the neptunyl adsorption complex at the calcite-water interface at pH 8.3 in equilibrium with air by means of low-temperature (15K) EXAFS spectroscopy at the Np-L(III) edge. The coordination environment of neptunyl consists of two axial oxygen atoms at 1.87(±0.01)?, and an equatorial oxygen shell of six atoms at 2.51(±0.01)?. Two oxygen backscatterers at 3.50(±0.04)? along with calcium backscatterers at 3.95(±0.03)? suggest that neptunyl is linked to the calcite surface through two monodentate bonds towards carbonate groups of the calcite surface. Two additional carbon backscatterers at 2.94(±0.02)? are attributed to two carbonate ions in bidentate coordination. This structural environment is conclusively interpreted as a ternary surface complex, where a neptunyl biscarbonato complex sorbs through two monodentate carbonate bonds to steps at the calcite (104) face, while the two bidentately coordinated carbonate groups point away from the surface. This structural information is further supported by Mixed Flow Reactor (MFR) experiments. They show a significant decrease of the calcite growth rate in the presence of neptunyl(V), in line with blockage of the most active crystal growth sites, step and kink sites, by adsorption of neptunyl. Formation of this sorption complex constitutes an important retention mechanism for neptunyl in calcite-rich environments.     

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 CaCl(2) 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.     

Protected area planning to conserve biodiversity in an uncertain future

Protected areas are a key instrument for conservation. Despite this, they are vulnerable to risks associated with weak governance, land-use intensification, and climate change. We used a novel hierarchical optimization approach to identify priority areas for expanding the global protected area system that explicitly accounted for such risks while maximizing protection of all known terrestrial vertebrate species. To incorporate risk categories, we built on the minimum set problem, where the objective is to reach species distribution protection targets while accounting for 1 constraint, such as land cost or area. We expanded this approach to include multiple objectives accounting for risk in the problem formulation by treating each risk layer as a separate objective in the problem formulation. Reducing exposure to these risks required expanding the area of the global protected area system by 1.6% while still meeting conservation targets. Incorporating risks from weak governance drove the greatest changes in spatial priorities for protection, and incorporating risks from climate change required the largest increase (2.52%) in global protected area. Conserving wide-ranging species required countries with relatively strong governance to protect more land when they bordered nations with comparatively weak governance. Our results underscore the need for cross-jurisdictional coordination and demonstrate how risk can be efficiently incorporated into conservation planning. Planeación de las áreas protegidas para conservar la biodiversidad en un futuro incierto