Exposure of trucking company workers to particulate matter during the winter

This study analyzed the workplace area concentrations and the personal exposure concentrations to fine particulate (PM_2.5), elemental carbon (EC), and organic carbon (OC) measured during the winter period in trucking companies. The averaged personal exposure concentrations at breathing zones of workers are much greater than those of the microenvironment concentrations. The highest difference between the area (microenvironment) and personal exposure concentrations was in the PM_2.5 concentrations followed by the OC concentrations. The area concentrations of PM_2.5, EC, and OC at a large terminal were higher than those at a small one. The highest area concentrations of PM_2.5, EC, and OC were observed in the shop areas followed by pick-up and delivery (P&D) areas. The area concentrations and personal exposure to PM_2.5, EC, and OC in the shop and P&D areas which are highly affected by diesel engine exhaust emissions were much higher than those in the docks which are significantly affected by liquefied petroleum gas (LPG) engine exhaust emissions. The highest EC fraction to the total carbon (EC + OC) concentrations was observed in the shops, while the lowest one was identified in the offices. The personal exposure of the smoking workers to PM_2.5 and OC was much higher than that of the non-smoking workers. However, the smoking might not significantly contribute to the personal exposure to EC. There were significant correlations between the PM_2.5 and OC concentrations in both the area and personal exposure concentrations. However, significant correlations between the PM_2.5 and EC concentrations and between the OC and EC concentrations were not identified.     

Sorption of cobalt and nickel on anaerobic granular sludges: isotherms and sequential extraction

The objective of this study was to investigate the sorption capacity and the fractionation of sorbed nickel and cobalt onto anaerobic granular sludges. Two different anaerobic granular sludges (non-fed, pH=7) were loaded with nickel and cobalt in adsorption experiments (monometal and competitive conditions). The combination of sequential extraction with the sorption isotherm analysis allowed the assessment of the sorption capacity of individual fractions present in the anaerobic granular sludges. The operational fractionation of the sorbed heavy metals was determined using a modified Tessier sequential extraction procedure. The sorption characteristics of each extracted fraction (exchangeable, carbonates, organic matter/sulfides and residual fractions) fitted well to the Langmuir model. The organic matter/sulfides fraction showed the highest affinity for cobalt and nickel in both sludges investigated compared to the other operationally defined fractions. The presence of iron negatively affected cobalt and nickel accumulation in this organic matter/sulfides fraction. The trace metals-iron sulfide interactions are likely to be the key process in controlling the distribution of cobalt and nickel during sorption onto non-fed methanogenic granules due to the high affinity of iron sulfides towards the metals studied.     

Mercury baseline levels in Flemish soils (Belgium)

It is important to establish contaminant levels that are normally present in soils to provide baseline data for pollution studies. Mercury is a toxic element of concern. This study was aimed at assessing baseline mercury levels in soils in Flanders. In a previous study, mercury contents in soils in Oost-Vlaanderen were found to be significantly above levels reported elsewhere. For the current study, observations were extended over two more provinces, West-Vlaanderen and Antwerpen. Ranges of soil Hg contents were distinctly higher in the province Oost-Vlaanderen (interquartile range from 0.09 to 0.43 mg/kg) than in the other provinces (interquartile ranges from 0.7 to 0.13 and 0.7 to 0.15 mg/kg for West-Vlaanderen and Antwerpen, respectively). The standard threshold method was applied to separate soils containing baseline levels of Hg from the data. Baseline concentrations for Hg were characterised by a median of 0.10mg Hg/kg dry soil, an interquartile range from 0.07 to 0.14 mg/kg and a 90% percentile value of 0.30 mg/kg. The influence of soil properties such as clay and organic carbon contents, and pH on baseline Hg concentrations was not important. Maps of the spatial distribution of Hg levels showed that the province Oost-Vlaanderen exhibited zones with systematically higher Hg soil contents. This may be related to the former presence of many small-scale industries employing mercury in that region.     

Evolution of the magnitude and spatial extent of the weekend ozone effect in California's South Coast Air Basin, 1981-2000

Since the mid-1970s, ozone (O3) levels in portions of California's South Coast Air Basin (SoCAB) on weekends have been as high as or higher than levels on weekdays, even though emissions of O3 precursors are lower on weekends. Analysis of the ambient data indicates that the intensity and spatial extent of the weekend O3 effect are correlated with-day-of-week variations in the extent of O3 inhibition caused by titration with nitric oxide (NO), reaction of hydroxyl radical (OH) with nitrogen dioxide (NO2), and rates of O3 accumulation. Lower NO mixing ratios and higher NO2/oxides of nitrogen (NOx) ratios on weekend mornings allow O3 to begin accumulating approximately an hour earlier on weekends. The weekday/weekend differences in the duration of O3 accumulation remained relatively constant from 1981 to 2000. In contrast, the rate of O3 accumulation decreased by one-third to one-half over the same period; the largest reductions occurred in the central basin on weekdays. Trends in mixing ratios of O3 precursors show a transition to lower volatile organic compound (VOC)/NOx ratios caused by greater reductions in VOC emissions. Reductions in VOC/NOx ratios were greater on weekdays, resulting in higher VOC/NOx ratios on weekends relative to weekdays. Trends in VOC/NOx ratios parallel the downward trend in peak O3 levels, a shift in the location of peak O3 from the central to the eastern portion of the basin, and an increase in the magnitude and spatial extent of the weekend O3 effect.     

Pollution incidence and political jurisdiction: evidence from the TRI

Few issues are more contentious for local communities than industrial pollution. When local industries pollute, lawmakers and regulators must balance two primary concerns: economic prosperity and the environment. The role of political pressure is well documented in environmental policy. What is less clear is the role jurisdictional or boundary considerations play in determining the implementation of environmental laws. Anecdotal evidence suggests that local regulators are more lenient in their treatment of polluters when the incidence of pollution falls partially on those outside the state. One explanation for such behavior is that regulators take actions to maximize political support. This paper tests this jurisdictional model using toxics release inventory (TRI) data from 1987 to 1996. We find that facilities’ emissions into the air and water are systematically higher in counties that border other states. These results are consistent with the hypothesis that jurisdictional considerations are an important determinant of pollution incidence.     

Gender analysis and international financial institutions

The following article is an attempt to reconcile the opinions of various activist-oriented non-governmental organizations (NGOs) on the use of gender analysis as a policy tool in the field of international development and macroeconomic policy. Of special concern to the author is the evolving relationship between international financial institutions (IFIs) and grassroots environmental NGOs seeking reform in macroeconomic policy initiation, implementation and evaluation. The ideas presented below are those of the author alone, and are solely intended to facilitate dialogue between the aforementioned parties as an alternative to the characteristic set of untenable demands and concomitant uncompromising resistance. Thus stated, the reader is challenged to remove his/her professional hat to accept or reject the validity of the propositions with an equal proportion of reason and intuition.     

POTENTIAL FOR REDUCING NITROGEN POLLUTION THROUGH IMPROVED AGRONOMIC PRACTICES1

ABSTRACT: According to the 1990 National Water Quality Inventory nutrient runoff from agriculture is one of the largest contributors to watershed contamination. Nutrient balance studies suggest that many farmers use more fertilizer than necessary because of insufficient crediting for nutrients coming from manure and legumes. Using data from the USDA's 1990 Farm Costs and Returns Survey, we found that farmers raising only conventional crops spend between $470 to $624 million more per year on fertilizer than necessary. This accounts for a range of 24 percent to 32 percent of total annual nitrogen (N) purchases. The excess N amounts to between 2.5 to 3.3 billion pounds N and has considerable water pollution potential. Farmers and the fertilizer industry have responded positively to highly focused research and education programs which support improved crediting of these nutrients.