The Collection and Analysis of Inorganic Dust Downwind of Source Effluents

Two directionally oriented high-volume samplers are used to pinpoint the collection of specific inorganic dusts from an industrial emission. One of the samplers is placed upwind of the source, and the other downwind. Both samplers are activated by winds blowing from the direction of the source to the downwind sampler. Both are de-activated when the wind shifts from the 30° sampling arc. Thus, the upwind sampler “sees” background dust, and the downwind sampler “sees” material originating from the source. Microsorban filters are used to collect the dust materials. The filter is then dissolved in benzene and the residue washed with benzene to remove the filter material and organic substances collected. The residue consists of dry, inorganic dust, which is then subjected to X-ray diffraction and optical microscopy, for analysis. This technique was successfully used to collect and analyze cement dust and mica dust from two separate industrial sources. The technique has promise for the analysis of a wide variety of inorganic materials which can be identified by X-ray diffraction, optical microscopy or other techniques.     

Public Reaction to SIP Revisions for Ozone Reduction

ABSTRACT

This study utilized a biotrickling filter with blast-furnace slag packings (sizes = 20-40 mm; specific surface area = 120 m²/m³) to treat toluene in an air stream. Also studied were the effects of volumetric loading (L), nutrient addition, and superficial gas velocity (U_g) or gas retention time on toluene elimination capacity. Experimental results indicate that, for a test period of 121 days, with no excess biomass removal, toluene removal efficiencies of over 90% were obtained with U_g < 80 m/hr and L < 30 g/m³.hr. For a test period of 49 days, with U_g < 80 m/hr and L increased from 1.2 to 81 g/m³.hr, the absence of nutrient supplementation did not limit the toluene elimination capacity. Nutrients stored in the biofilm could adequately support the microbial activity for the toluene elimination. According to data regression, a simplified mass-transfer model is proposed, which correlates the contaminant concentration with the packing height or gas empty bed retention time. As verified, the model proposed herein can be applied to cases involving low influent contaminant concentrations or loadings to the extent that none or only a trace amount of the contaminant can be found in the recirculation liquid. Although small media with larger specific surface areas can achieve a better mass transfer, the problems of frequent backwashing and relatively greater gas resistance in using this type of media probably outweigh the advantages, particularly for full-scale systems that would not be watched as closely as laboratory test systems.     

From Bathymetry to Bioshields: A Review of Post-Tsunami Ecological Research in India and its Implications for Policy

More than half a decade has passed since the December 26th 2004 tsunami hit the Indian coast leaving a trail of ecological, economic and human destruction in its wake. We reviewed the coastal ecological research carried out in India in the light of the tsunami. In addition, we also briefly reviewed the ecological research in other tsunami affected countries in Asia namely Sri Lanka, Indonesia, Thailand and Maldives in order to provide a broader perspective of ecological research after tsunami. A basic search in ISI Web of Knowledge using keywords “tsunami” and “India” resulted in 127 peer reviewed journal articles, of which 39 articles were pertaining to ecological sciences. In comparison, Sri Lanka, Indonesia, Thailand and Maldives had, respectively, eight, four, 21 and two articles pertaining to ecology. In India, bioshields received the major share of scientific interest (14 out of 39) while only one study (each) was dedicated to corals, seagrasses, seaweeds and meiofauna, pointing to the paucity of research attention dedicated to these critical ecosystems. We noted that very few interdisciplinary studies looked at linkages between pure/applied sciences and the social sciences in India. In addition, there appears to be little correlation between the limited research that was done and its influence on policy in India. This review points to gap areas in ecological research in India and highlights the lessons learnt from research in other tsunami-affected countries. It also provides guidance on the links between science and policy that are required for effective coastal zone management.     

Reducing ammonia emissions and volatile fatty acids in poultry litter with liquid aluminum chloride

This study was a pen trial in which the effects of adding different rates of liquid aluminum chloride (AlCl(3)) on litter pH, total volatile fatty acids (VFAs), and ammonia (NH(3)) fluxes was evaluated. Liquid AlCl(3) treatments used in this study were sprayed on the rice hull surface at rates of 100 g, 200 g, and 300 g liquid AlCl(3)/kg rice hulls; untreated rice hulls served as controls. Litter pH, total VFAs, and NH(3) fluxes were all lowered (P< 0.05) by all of the liquid AlCl(3) treatments compared with controls during certain times of the 5 week study. However, there were no significant differences among treatments on litter pH at the end of the study (from 3 to 5 weeks) or NH(3) fluxes at beginning of the study (0 to 3 weeks). Total VFAs were reduced 16 %, 29 %, and 53 % by 100 g liquid AlCl(3)/kg rice hulls, 200 g liquid AlCl(3)/kg rice hulls, and 300 g liquid AlCl(3)/kg rice hulls, respectively. Liquid AlCl(3)additions reduced NH(3) fluxes by 35 %, 57 % and 67 %, respectively, at the low, medium and high rates. In summary, these results indicate that adding liquid aluminum chloride to rice hulls would be a useful tool in reducing the negative environmental impact of poultry litter. It should be noted that the decreased VFA production and NH(3) volatilization was chiefly associated with reduction in litter pH.     

Removal of mercury(II) from aqueous solutions using the leaves of the Rambai tree (Baccaurea motleyana)

This study was undertaken to evaluate the biosorption potential of a natural, low-cost biosorbent, Rambai leaves (Baccaurea motleyana), to remove trace amounts of Hg(II) from aqueous solutions. It was found that the amount of Hg(II) biosorption by Rambai leaves increased with initial metal ion concentration, contact time, and solution pH but decreased as the amount of biosorbent increased. The maximum biosorption capacity was 121.95 mg/g for an initial concentration range of 5 to 120 ppb. Overall, kinetic studies showed that the Hg(II) biosorption process followed pseudo-second-order kinetics based on pseudo-first-order and intraparticle diffusion models. Isotherm data revealed that the biosorption process followed both Freundlich and Langmuir isotherms. The value of separation factor, R(L), from the Langmuir equation and rate of biosorption, n, from the Freundlich model also indicated favorable adsorption.     

A land use regression model for predicting ambient fine particulate matter across Los Angeles, CA

Land use regression (LUR) models have been used successfully for predicting local variation in traffic pollution, but few studies have explored this method for deriving fine particle exposure surfaces. The primary purpose of this method is to develop a LUR model for predicting fine particle or PM(2.5) mass over the five county metropolitan statistical area (MSA) of Los Angeles. PM(2.5) includes all particles with diameter less than or equal to 2.5 microns. In the Los Angeles MSA, 23 monitors of PM(2.5) were available in the year 2000. This study uses GIS to integrate data regarding land use, transportation and physical geography to derive a PM(2.5) dataset covering Los Angeles. Multiple linear regression was used to create the model for predicting the PM(2.5) surface. Our parsimonious model explained 69% of the variance in PM(2.5) with three predictors: (1) traffic density within 300 m, (2) industrial land area within 5000 m, and (3) government land area within 5000 m of the monitoring site. These results suggest the LUR method can refine exposure models for epidemiologic studies in a North American context.     

Timekeeping in the honey bee colony: integration of circadian rhythms and division of labor

The daily patterns of task performance in honey bee colonies during behavioral development were studied to determine the role of circadian rhythmicity in age-related division of labor. Although it is well known that foragers exhibit robust circadian patterns of activity in both field and laboratory settings, we report that many in-hive tasks are not allocated according to a daily rhythm but rather are performed 24 h per day. Around-the-clock activity at the colony level is accomplished through the performance of some tasks by individual workers randomly with respect to time of day. Bees are initially arrhythmic with respect to task performance but develop diel rhythmicity, by increasing the occurrence of inactivity at night, prior to becoming foragers. There are genotypic differences for age at onset of rhythmicity and our results suggest that these differences are correlated with genotypic variation in rate of behavioral development: genotypes of bees that progressed through the age polyethism schedule faster also acquired behavioral rhythmicity at an earlier age. The ontogeny of circadian rhythmicity in honey bee workers ensures that essential in-hive behaviors are performed around the clock but also allows the circadian clock to be engaged before the onset of foraging. Received: 6 October 1997 / Accepted after revision: 28 March 1998     

The evolution of empty nuptial gifts in a dance fly, Empis snoddyi (Diptera: Empididae): bigger isn't always better

Adaptive female choice is thought to have led to the evolution of nutritionally valuable nuptial gifts in many insect species. However, in several dance fly species, males offer and females accept “empty gifts” with no nutritional value. In the species studied here, Empis snoddyi Steyskal, males produce empty balloons comprised of hundreds of silk bubbles and form mating swarms that females approach to investigate males. Males within the swarm engage in agonistic interactions. The empty balloon has been hypothesized to be an indicator of male condition such that males with larger balloons are predicted to have higher mating success and be more successful in male-male interactions than males with smaller balloons. We examined the role of male body size and balloon size in the context of intersexual and intrasexual selection. We found that neither male body size nor balloon size affected the outcome of pairwise male-male interactions. Using multiple-regression techniques, we found significant linear selection for increasing male body size and decreasing balloon size associated with mating success, a surprising result given a positive relationship between male body size and balloon size. A visualization of selection showed the highest peak of male mating success for larger males with intermediate-size balloons. These results can be explained by a trade-off between long-range attraction of females using large balloons and close-range attraction of females via improved flying efficiency associated with smaller balloons. Both male body size and balloon size are important components in determining male mating success; however, the empty balloon does not appear to play a typical role as a sexually selected ornament. Received: 29 December 1997 / Accepted after revision: 7 October 1998     

Controls on vegetation structure in Southwestern ponderosa pine forests, 1941 and 2004

Long-term studies can broaden our ecological understanding and are particularly important when examining contingent effects that involve changes to dominance by long-lived species. Such a change occurred during the last century in Southwestern (USA) ponderosa pine (Pinus ponderosa) forests. We used five livestock grazing exclosures established in 1912 to quantify vegetation structure in 1941 and 2004. Our objectives were to (1) assess the effects of historical livestock grazing on overstory structure and age distribution, (2) assess the effects of recent livestock grazing and overstory on understory vegetation, and (3) quantify and explain changes in understory vegetation between 1941 and 2004. In 1941, canopy cover of tree regeneration was significantly higher inside exclosures. In 2004, total tree canopy cover was twice as high, density was three times higher, trees were smaller, and total basal area was 40% higher inside exclosures. Understory species density, herbaceous plant density, and herbaceous cover were negatively correlated with overstory vegetation in both years. Most understory variables did not differ between grazing treatments in 1941 but were lower inside exclosures in 2004. Differences between grazing treatments disappeared once overstory effects were accounted for, indicating that they were due to the differential overstory response to historical livestock grazing practices. Between 1941 and 2004, species density declined by 34%, herbaceous plant density by 37%, shrub cover by 69%, total herbaceous cover by 59%, graminoid cover by 39%, and forb cover by 82%. However, these variables did not differ between grazing treatments or years once overstory effects were accounted for, indicating that the declines were driven by the increased dominance of the overstory during this period. Our results demonstrate that historical livestock grazing practices are an aspect of land-use history that can affect ecosystem development. Grazing history must be considered when extrapolating results from one site to another. In addition, the understory vegetation was more strongly controlled by the ponderosa pine overstory than by recent livestock grazing or by temporal dynamics, indicating that overstory effects must be accounted for when examining understory responses in this ecosystem.     

Aerosol Particle Processing and Removal by Fogs: Observations in Chemically Heterogeneous Central California Radiation Fogs

Fog composition and deposition fluxes of fog waterand fog solutes were measured in six radiation fogevents in San Joaquin Valley, California duringwinter 1998/1999. Measurements made at 2 hrintervals with 0.30 m² and 0.06 m² Teflondeposition plates yielded excellent reproducibility(relative standard deviations of 3.8–6.0%) forwater, nitrate, sulfate and ammonium. Water fluxesmeasured at 5 min intervals with a recordingbalance agreed well with the deposition platemeasurements before 8:00 AM. After 8:00 AMevaporation proved problematic. The averagedeposition velocity from the study for fog nitrate(3.8 cm s^-1) was less than those for fogsulfate (5.1 cm s^-1) and ammonium (6.7 cms^-1). All three species generally exhibitedsmaller deposition velocities than fog water. Thespecies dependent trend in deposition velocitieswas consistent with preferential enrichment ofthese species in small fog drops (nitrate > sulfate> ammonium).