Removal of Prussian blue from contaminated soil in the rhizosphere of cyanogenic plants

The fate of radiolabeled cyanide in soil was investigated during exposure to cyanogenic plant species, sorghum (Sorghum bicolor var. P721) and flax (Linum usitassimum var. Omega-Gold), in fully-contained growth chambers. Labeled cyanide was subject to microbial transformation, assimilation by plant roots, incorporation and biodegradation in plant tissue. For this study, (14)C-labeled cyanide was added to soil, and distribution of (14)C activity was assessed before plant establishment and after harvest. After 3 months of plant growth, 7% of the (14)C-labeled cyanide was converted to (14)CO(2) with sorghum and 6% with flax, compared with only 2% conversion in unplanted soil. A small amount of unaltered cyanide was shown to be accumulated by the plants (approximately 140 mg cyanide/kg plant or <0.1% of the total). Results from this experiment demonstrate the potential of cyanogenic plants for use in phytoremediation of cyanide-contaminated soil.     

Collembola and macroarthropod community responses to carbamate, organophosphate and synthetic pyrethroid insecticides: direct and indirect effects

Non-target effects on terrestrial arthropod communities of the broad-spectrum insecticides chlorpyrifos and cypermethrin and the selective insecticide pirimicarb were investigated in winter wheat fields in summer. Effects of chlorpyrifos on arthropod abundance and taxonomic richness were consistently negative whereas effects of cypermethrin were negative for predatory arthropods but positive for soil surface Collembola. Pirimicarb effects were marginal, primarily on aphids and their antagonists, with no effect on the Collembola community. Collembola-predator ratios were significantly higher following cypermethrin treatment, suggesting that cypermethrin-induced increases in collembolan abundance represent a classical resurgence. Observations in other studies suggest Collembola resurgences may be typical after synthetic pyrethroid applications. Collembola responses to insecticides differed among species, both in terms of effect magnitude and persistence, suggesting that coarse taxonomic monitoring would not adequately detect pesticide risks. These findings have implications for pesticide risk assessments and for the selection of indicator species.     

Flood proneness and coping strategies: the experiences of two villages in Bangladesh

This paper explores peoples' indigenous survival strategies and assesses variations in people's ability to cope with floods in two flood‐prone villages in Bangladesh. It reveals that people continuously battle against flood vulnerability in accordance with their level of exposure and abilities, with varied strategies employed at different geophysical locations. The paper reports that people in an area with low flooding and with better socioeconomic circumstances are more likely to cope with impacts compared to people in areas with high and sudden flooding. Similarly, households' ability to cope varies depending on people's socioeconomic conditions, such as education, income and occupation. Although floods in Bangladesh generate socioeconomic misery and cause damage to the environment, health and infrastructure, people's indigenous coping strategies have helped them to reduce significantly their vulnerability. Such flood‐mitigating strategies should be well recognised and emphasised further via proper dissemination of information through an early‐warning system and subsequently external assistance.     

Effectiveness of dust dispersion in the 20-L Siwek chamber

The Siwek 20-L chamber is widely used throughout the world to evaluate the explosibility of dusts. This research evaluated the quality of dust dispersion in the Siwek 20-L chamber using Pittsburgh coal, Gilsonite, and purple K dusts. A Pittsburgh Research Laboratory (PRL) optical dust probe was used to measure optical transmittance through the dust cloud at various locations within the chamber. A total of 540 tests were performed, with triplicate tests at five nominal dust concentrations and six locations. The two standard dispersion nozzles (rebound and perforated annular nozzle) were compared. The transmissions corresponding to the normal ignition delay period were used to: (a) determine variations in spatial uniformity of dispersion obtained with both nozzles; (b) make comparisons between the experimental transmission data and those calculated from theory for the three dusts; and (c) make comparisons with transmission data measured in the PRL 20-L and Fike 1-m³ dust explosion chambers.The uniformity of dispersion for the three dusts was similar with both nozzles, despite the differences in nozzle geometry and mode of operation. Transmission data of the three dusts were all significantly lower than those calculated from theory. This was discovered to be, in part, due to significant reduction in particle size that occurred during dispersion. By measuring particle sizes before and after dispersion, values of 60%, 50%, and 20% reduction in particle size (based on the surface-weighted mean diameter) were obtained for Pittsburgh coal, Gilsonite, and purple K, respectively. Transmission data from the PRL 20-L, Fike 1-m³ and the Siwek 20-L chambers indicated comparable results in terms of uniformity of dispersion. However, transmission data from the Siwek 20-L chamber were significantly lower than those of the PRL and Fike chambers. Again, this was attributed, in part, to the significant reduction in particle size that occurred during dispersion in the Siwek chamber. The design of the outlet (dispersion) valve of the Siwek 20-L apparatus charge vessel was largely responsible for the particle break-up. The contribution to particle break-up by the dispersion nozzles and the high level of turbulence in the chamber were found to be minimal. This is a significant finding in that the dust particle size tested for explosibility in the Siwek chamber is considerably smaller than the original dust sample.     

The weekend matters: Relationships between stress recovery and affective experiences

Non-work experiences during the weekend provide opportunities to recover from work demands and to replenish lost resources. This longitudinal study examined how specific recovery experiences during the weekend (relaxation, mastery, control, and detachment), as well as non-work hassles, were associated with specific positive and negative affective states during the following workweek. Participants (N = 229) completed surveys before the weekend, during the weekend, and during the following workweek. Hierarchical regression analyses revealed that after controlling for affective states the previous week, recovery experiences during the weekend significantly explained variance in affective states at the end of the weekend and during the following workweek. Suggestions for future research include a closer examination of the role of individual differences, self-regulation, and specific work demands in employee stress recovery. Copyright © 2010 John Wiley & Sons, Ltd.     

Lethal and sublethal effects of the pyrethroid,bifenthrin, on grass shrimp (Palaemonetes pugio) and sheepshead minnow (Cyprinodon variegatus)

This study investigated the lethal and sublethal effects of the pyrethroid insecticide bifenthrin on adult and larval grass shrimp, Palaemonetes pugio, and adult sheepshead minnows, Cyprinodon variegatus. The effects were determined by conducting 96-h aqueous static renewal tests and 24-h static tests with sediment. Oxidative stress biomarkers, lipid peroxidation, glutathione, and catalase were also assessed. The 96-h aqueous LC₅₀ value for adult shrimp was 0.020 μ g/L (95% CI: 0.015–0.025 μ g/L) and for larval shrimp was 0.013 μ g/L (95% CI: 0.011–0.016 μ g/L). The 96-h aqueous LC₅₀ for adult sheepshead minnow was 19.806 μ g/L (95% CI: 11.886–47.250 μ g/L). The 24-h sediment LC₅₀ for adult shrimp was 0.339 μ g/L (95% CI: 0.291–0.381 μ g/L) and for larval shrimp was 0.210 μ g/L (95% CI: 0.096–0.393 μ g/L). The oxidative stress assays showed some increasing trends toward physiological stress with increased bifenthrin concentrations but they were largely inconclusive. Given the sensitivity of grass shrimp to this compound in laboratory bioassays, additional work will be needed to determine if these exposure levels are environmentally relevant.     

Tagging Diesel and Residential Oil Furnace Emissions in Roanoke,Virginia, with Enriched Isotopes of Samarium

Stable isotopic tracers were used in Roanoke, Virginia, to tag particulate emissions from diesel trucks and residential oil furnaces, two sources of soot and PAHs which cannot be differentiated on the basis of known constituents. Approximately 1.6 g of enriched ¹⁴⁹Sm were used to tag 264 m³ of diesel fuel burned by the city bus and truck fleets; 0.39 g of ¹⁵⁰Sm were used to tag 106 m³ of residential heating oil. Picogram amounts of the tracers were determined simultaneously by thermal-ionization mass spectrometry in fine particles collected within the city at signal-to-noise ratios as large as 6000. These results demonstrate the feasibility of tracing particles from multiple combustion sources with stable, separated isotopes.     

An Analysis of the Yearly Changes in Sulfur Concentrations at Various National Parks in the United States, 1980-1996

ABSTRACT

An apparent increasing trend in the summer concentrations of particulate sulfur at Shenandoah (for the time period 1982-1995) and at Great Smoky Mountains (for the time period 1984-1995) has been pointed out by some researchers. Others have suggested that these increasing trends may be an analytical artifact resulting from the switch from the Stacked Filter Units (SFU) measurement system to the IMPROVE (Interagency Monitoring of Protected Visual Environments) measurement system that occurred during the winter of 1987. To obtain a better understanding of the effect of the protocol change, we investigate the changes in the seasonal averages of sulfur concentrations for successive pairs of years for the period 1980-1996 for about 20 national park sites in the United States. For the period 1980-1987, we use sulfur data from the old (SFU) database and for the period 1988-1996, we use the IMPROVE database. Changes from one year to the next similar to that between 1987 and 1988 occurred during other years and seasons suggesting that chance causes alone could perhaps explain it, the degree to which chance could have caused the changes was measured using the permutation test for matched. At the very least, additional information such as side by side readings using SFU and IMPROVE measurement methods, may be needed to better understand any systematic effect in the sulfur measurements that may be ascribable to the protocol change.     

Long‐term mercury accumulation in the presence of cadmium and lead in oseochromis aureus (Steindachner)

Abstract

The effects of cadmium and lead on chronic mercury accumulation were investigated in O. aureus. After 140 days’ exposure the accumulation of mercury in the liver, brain, gill filaments, intestine, caudal muscle, spleen, trunk kidney and eye was analysed. The exposure concentrations were 0.05, 0.10 and 0.20 mg/L for mercury alone. O. aureus was also exposed to mixtures of 0.05 mg/L mercury with lead (0.05 mg/L and 0.50 mg/L or cadmium (0.05 mg/L) and 0.10 mg/L mercury with 0.10 mg/L cadmium. In food fish, a knowledge of toxic metal accumulation patterns is of great importance because of their contribution to the human diet and, as fishmeal, to the diet of agricultural animals. The trunk kidney consistently accumulated higher concentrations of mercury than any of the other tissues investigated.     

Control of Environmental Noise

The article reviews the current state of knowledge of noise and how people respond to noise. Sources of community noise are discussed and existing federal legislation pertaining to noise is mentioned. Methods of reducing the noise impact on communities from aircraft, surface transportation, and industrial sites are presented. Interior noise in industry, OSHA noise standards and means of controlling the noise to minimize hearing impairment are emphasized.