Why biota still accumulate high levels of PCB after removal of PCB contaminated sediments in a Norwegian fjord

Accumulation of polychlorinated biphenyls (PCBs) in blue mussels (Mytilus edulis) and semipermeable membrane devices (SPMDs) was still high after the removal of PCB contaminated sediments from a Norwegian fjord by dredging. The accumulation of low chlorinated PCB congeners with a low octanol water-partitioning coefficient (K_ow) in blue mussels and SPMDs was higher than for the highly chlorinated congeners with a high K_ow. The accumulation of low chlorinated congeners was also higher in a lightly contaminated area compared to a highly contaminated area. That dredging the contaminated sediments was unsuccessful in lowering PCB levels in the biota may be for the following reasons: (1) Due to the low solubility of PCBs in the water it is possible that a decrease in the sediment concentration of PCB would leave the water concentrations of PCB unchanged. (2) Removal of the fine organic sediments may also play an important role, since a seabed with coarse inorganic material has a lesser ability to bind PCB. (3) The dredging may whirl up fine contaminated particles that eventually settles on the seabed producing a thin contaminated sediment layer that determine the water concentration. (4) Bioaccumulation in blue mussels and in the SPMDs occurs mostly from PCB dissolved in the water column. Since the water concentration of PCB is unchanged by the dredging, the accumulation in SPMDs and mussels is the same as before dredging. Further monitoring need to be carried out to report the long-term effect of the dredging.     

Rapid liquid–liquid extraction for the reliable GC/MS analysis of volatile priority pollutants

Mass spectrometry is a powerful tool for the analysis of organic pollutants in the environment. Nevertheless, sample preparation for GC/MS analysis is often criticized for being too laborious and requiring expensive equipment. Thus, purge-and-trap or headspace devices are the most popular nowadays to investigate volatile organic pollutants. At the same time, modern commercial high-resolution mass spectrometers allow for the significant simplification of the sample preparation procedures due to better acquisition rate, accurate mass measurements, and improved sensitivity. Here, we used a time-of-flight high-resolution mass spectrometer Pegasus GC-HRT (LECO, USA) to identify and quantify 47 volatile priority organic pollutants in water. The developed accelerated water sample preparation approach requires just 1 mL of water and 1 mL of dichloromethane. The detection limits of the analytes are about 1 μg L^?1, while the quantification limits are approximately 5 μg L^?1. These limits correspond to those required by Method 8260C of the United States Environmental Protection Agency. Here, we demonstrate that sample preparation for the reliable and sensitive GC/MS analysis of volatile organic priority pollutants may be achieved in 5 min in 5-mL vials in the field or just prior to GC/MS analysis in the laboratory without the use of any expensive equipment.     

Frequency of abnormal heavy metal blood levels in Wegener's granulomatosis

Previous studies suggested environmental exposures, including mercury (Hg) and lead (Pb), may be related to Wegener's granulomatosis. In this study, investigations were extended to include the measurement of heavy metals in blood samples from patients diagnosed with Wegener's. Diagnosis was confirmed by using the 1990 Classification Criteria for Wegener's granulomatosis established by the American College of Rheumatology (ACR). Using commercial lab testing, whole blood heavy metal screenings were obtained from patients, and results were then compared with validated subject self-report questionnaire estimates of exposure. Thirty-eight Wegener's patients were enrolled; 10 of the 38 exhibited abnormal lab values. In those 10 subjects 3 had elevated nickel (Ni), 7 with increased cobalt (Co), 3 with higher manganese, 1 with elevated copper, and 1 with increased Hg. Overall, the questionnaire results did not correlate with the blood heavy metal analysis. Approximately 26% of Wegener's subjects in this study displayed abnormal heavy metal levels. These findings are likely underestimates since blood levels are an insensitive means for assessing total body burden of heavy metals. From these preliminary studies it appears that elevated Co is a common finding in Wegener's patients but Ni and Hg were also found to be increased. The proportion of patients with abnormal heavy metal levels is more than expected by chance alone. In order to yield more definitive results, further analysis is needed with a larger data set, more controls and more sensitive measurements (hair, urine, or nail samples).     

An empirical survey of the benefits of implementing pay for safety scheme (PFSS) in the Hong Kong construction industry

Introduction

The Government of the Hong Kong Special Administrative Region (SAR) has implemented different safety initiatives to improve the safety performance of the construction industry over the past decades. The Pay for Safety Scheme (PFSS), which is one of the effective safety measures launched by the government in 1996, has been widely adopted in the public works contracts. Both the accident rate and fatality rate of public sector projects have decreased noticeably over this period.

Method

This paper aims to review the current state of application of PFSS in Hong Kong, and attempts to identify and analyze the perceived benefits of PFSS in construction via an industry-wide empirical questionnaire survey. A total of 145 project participants who have gained abundant handson experience with the PFSS construction projects were requested to complete a survey questionnaire to indicate the relative importance of those benefits identified in relation to PFSS. The perceived benefits were measured and ranked from the perspectives of the client and contractor for crosscomparison.

Results

The survey findings suggested the most significant benefits derived from adopting PFSS were: (a) Increased safety training; (b) Enhanced safety awareness; (c) Encouragement of developing safety management system; and (d) Improved safety commitment. A wider application of PFSS should be advocated so as to achieve better safety performance within the construction industry.

Impact on Industry

It is recommended that a similar scheme to the PFSS currently adopted in Hong Kong may be developed for implementation in other regions or countries for international comparisons.     

Evolution of vehicle exhaust particles in the atmosphere

Aerosol mass spectrometer (AMS) measurements are used to characterize the evolution of exhaust particulate matter (PM) properties near and downwind of vehicle sources. The AMS provides time-resolved chemically speciated mass loadings and mass-weighted size distributions of nonrefractory PM smaller than 1 microm (NRPM1). Source measurements of aircraft PM show that black carbon particles inhibit nucleation by serving as condensation sinks for the volatile and semi-volatile exhaust gases. Real-world source measurements of ground vehicle PM are obtained by deploying an AMS aboard a mobile laboratory. Characteristic features of the exhaust PM chemical composition and size distribution are discussed. PM mass and number concentrations are used with above-background gas-phase carbon dioxide (CO2) concentrations to calculate on-road emission factors for individual vehicles. Highly variable ratios between particle number and mass concentrations are observed for individual vehicles. NRPM1 mass emission factors measured for on-road diesel vehicles are approximately 50% lower than those from dynamometer studies. Factor analysis of AMS data (FA-AMS) is applied for the first time to map variations in exhaust PM mass downwind of a highway. In this study, above-background vehicle PM concentrations are highest close to the highway and decrease by a factor of 2 by 200 m away from the highway. Comparison with the gas-phase CO2 concentrations indicates that these vehicle PM mass gradients are largely driven by dilution. Secondary aerosol species do not show a similar gradient in absolute mass concentrations; thus, their relative contribution to total ambient PM mass concentrations increases as a function of distance from the highway. FA-AMS of single particle and ensemble data at an urban receptor site shows that condensation of these secondary aerosol species onto vehicle exhaust particles results in spatial and temporal evolution of the size and composition of vehicle exhaust PM on urban and regional scales.     

Sustainable Use of Biotechnology for Bioenergy Feedstocks

Done correctly, cellulosic bioenergy should be both environmentally and economically beneficial. Carbon sequestration and decreased fossil fuel use are both worthy goals in developing next-generation biofuels. We believe that biotechnology will be needed to significantly improve yield and digestibility of dedicated perennial herbaceous biomass feedstocks, such as switchgrass and Miscanthus, which are native to the US and China, respectively. This Forum discusses the sustainability of herbaceous feedstocks relative to the regulation of biotechnology with regards to likely genetically engineered traits. The Forum focuses on two prominent countries wishing to develop their bioeconomies: the US and China. These two countries also share a political desire and regulatory frameworks to enable the commercialization and wide release of transgenic feedstocks with appropriate and safe new genetics. In recent years, regulators in both countries perform regular inspections of transgenic field releases and seriously consider compliance issues, even though the US framework is considered to be more mature and stringent. Transgene flow continues to be a pertinent environmental and regulatory issue with regards to transgenic plants. This concern is largely driven by consumer issues and ecological uncertainties. Regulators are concerned about large-scale releases of transgenic crops that have sexually compatible crops or wild relatives that can stably harbor transgenes via hybridization and introgression. Therefore, prior to the commercialization or extensive field testing of transgenic bioenergy feedstocks, we recommend that mechanisms that ensure biocontainment of transgenes be instituted, especially for perennial grasses. A cautionary case study will be presented in which a plant’s biology and ecology conspired against regulatory constraints in a non-biomass crop perennial grass (creeping bentgrass, Agrostis stolonifera), in which biocontainment was not attained. Appropriate technologies that could be applied to perennial grass feedstocks for biocontainment are discussed.     

Non-timber forest products farming and empowerment of rural women in Ghana

United Nations estimates indicate that up to 70% of the world’s poor are female, and women in developing countries constitute the majority of the labour force, playing a key role in managing community resources and helping to improve food security and protect the environment. Increased attention in recent years has been focused on the potential role of non-timber forest products (NTFPs) in improving the incomes and health of women in developing countries. NTFPs farming and marketing are very critical for the economic empowerment of rural poor, particularly women. Despite this potential, the contribution of NTFPs farming to the empowerment of women remains largely undervalued and understudied. This paper examines the potential contribution of NTFPs farming in poverty reduction and livelihood improvement of women in Ghana using the Sefwi Wiawso District (SWD) and Bibiani-Bekwai District (BBD) in the Western Region of Ghana as a case study. The paper explores the contribution of NTFPs farming to the total annual income, acquisition of assets, health, and food security of women through participatory research methods. ANOVA and Pearson Correlation (p < 0.05) show that a significant association exists between total annual income of women, acquisition of assets, health, food security, and the income earned from NTFPs in the SWD and BBD. The study revealed that NTFPs can contribute significantly to the economic empowerment of women. The paper asserts that commercialisation of NTFPs will have a greater impact on women’s livelihoods and therefore any opportunity for increasing their involvement is very essential for the empowerment and sustainable development of rural communities in Ghana.     

Effects of black carbon on bioturbation-induced benthic fluxes of polychlorinated biphenyls

It is unknown whether carbonaceous geosorbents, such as black carbon (BC) affect bioturbation by benthic invertebrates, thereby possibly affecting sediment-water exchange of sediment-bound contaminants. Here, we assess the effects of oil soot on polychlorinated biphenyl (PCB) mass transfer from sediment to overlying water, for sediments with and without tubificid oligochaeta as bioturbators. PCB levels were so low that toxicity to the oligochaeta played no role, whereas soot levels and binding affinity of PCBs to soot were so low that pore water PCB concentrations were not significantly affected by binding of PCBs to soot. This setup left direct effects of BC on bioturbation activity as the only explanation for any observed effects on mass transfer. Mass transfer coefficients (K_L) for benthic boundary layer transport were measured by a novel flux method using Empore™ disks as a sink for PCBs in the overlying water. For the PCBs studied (logK_ow 5.2-8.2), K_L values ranged from 0.2 to 2 cm × d⁻¹ in systems without tubificids. Systems with tubificids showed K_L values that were a factor of 10-25 higher. However, in the presence of oil soot, tubificids did not cause an increase in mass transfer coefficients. This suggests that at BC levels as encountered under field conditions, the mechanism for reduction of sediment-water transfer of contaminants may be twofold: (a) reduced mass transfer due to strong binding of the contaminants to BC, and (b) reduced mass transfer of contaminants due to a decrease in bioturbation activity.     

Historical trends of polychlorinated dibenzo-p-dioxins and dibenzofurans in three dated sediment cores from Mexico

This paper describes the first report of dioxins and furans (PCDDs/Fs) in sediment cores from Mexico. Sedimentation rates and vertical fluxes were estimated using ²¹⁰Pb dating. Two cores correspond to marine sediments and one to an endorheic lake. Concentrations of PCDDs/Fs found in the three sites are typical of non-impacted areas with low concentrations when compared to reference values. However the PCDDs/Fs sediment profiles show an increasing concentration trend in the upper core sections. This behavior is different from that found at many sites around the globe where diminishing concentrations have been reported. A strong predominance of OCDD was observed, and a comparison to typical composition profiles of industrial and other sources did not result in clear origin assignments for these measured compounds. We suggest that local sources may be responsible for the increase in concentration and, because these undetermined sources have not been curtailed, their importance is still growing.     

Field evaluation of particulate matter measurements using tapered element oscillating microbalance in a layer house

The tapered element oscillating microbalance (TEOM) is one type of continuous ambient particulate matter (PM) monitor. Adsorption and desorption of moisture and semivolatile species may cause positive or negative artifacts in TEOM PM mass measurement. The objective of this field study was to investigate possible uncertainties associated with TEOM measurements in the poultry operation environment. For comparisons of TEOM with filter-based gravimetric method, four instruments (TEOM-PM10, low-volume PM10 sampler TEOM-PM2.5, and PM2.5 speciation sampler) were collocated and tested inside a poultry house for PM2.5 and PM10 (PM with aerodynamic equivalent diameter < or =2.5 and < or =10 microm, respectively) measurements. Fifteen sets of 24-hr PM10 concentrations and 13 sets of 24-hr PM2.5 measurements were obtained. Results indicate that compared with filter-based gravimetric method, TEOM gave significantly lower values of both PM10 and PM2.5 mass concentrations. For PM10, the average ratio of TEOM to the gravimetric method was 0.936. For PM2.5, the average ratio of TEOM to the gravimetric method was 0.738. Particulate matter in the poultry houses possibly contains semivolatile compounds and moisture due to high levels of relative humidity (RH) and gas pollutants. The internal heating mechanism of the TEOM may cause losses in mass through volatilization. To investigate the effects of TEOM settings on concentration measurements, the heaters of two identical TEOMs were set at 50 degrees C, 30 degrees C, or no heating at all. They were collocated and tested for total suspended particle (TSP), PM10, and PM25 measurements in layer house for 6 weeks. For all TSR PM10, and PM2.5 measurements, the internal TEOM temperature setting had a significant effect (P < 0.05). Significantly higher PM mass concentrations were measured at lower temperature settings. The effects of environmental (i.e., temperature, RH, NH3 and CO2 concentrations) and instrumental (i.e., filter loading and noise) parameters on PM measurements were also assessed using regression analysis.