Effect of Dust Size Distribution on the Collection Efficiency of Pulse-Jet Fabric Filters

Recent advances in vehicle emission control technology have reduced the effectiveness of the conventional tailpipe test used In inspection and maintenance programs. A different approach Is being followed in Harris County, Texas (Houston area), based on identification and correction of misfuellng and tampering. Misfueling Is being identified by using a lead-sensitive test paper to detect lead deposits in the tailpipe that result from using leaded gasoline. Field tests of this procedure demonstrated that it Is reliable and accurate for the Intended purpose. The data also indicated the need to observe certain precautions to avoid contamination and other potential sources of error. This procedure and other emission-related checks have been added to the annual safety inspections. These tests are conducted on vehicles of 1980 model year and later, by approximately 1150 Inspection stations throughout the county that conduct annual safety Inspections. Experience with the first few months of this program has been excellent.     

Identification of a potential source of chloroform in urban air: Preliminary Communication

A new potential source of elevated chloroform (CHCl₃) concentrations in urban air is reported. The exhaust gases from gasoline internal combustion engines operated on conventional “leaded” fuel and not equipped with catalytic converters contain parts-per-billion concentrations of chloroform which can, in congested urban areas, contribute significantly to the ambient concentration of chloroform. Exhaust gases from engines burning conventional “leaded” gasoline contain much higher levels of chloroform than do exhaust gases from engines equipped with catalytic converters and operating on “nonleaded” gasoline.     

Potential for childhood lead poisoning in the inner cities of Australia due to exposure to lead in soil dust

This article presents evidence demonstrating that the historical use of leaded gasoline and lead (Pb) in exterior paints in Australia has contaminated urban soils in the older inner suburbs of large cities such as Sydney and Melbourne. While significant attention has been focused on Pb poisoning in mining and smelting towns in Australia, relatively little research has focused on exposure to Pb originating from inner-city soil dust and its potential for childhood Pb exposures. Due to a lack of systematic blood lead (PbB) screening and geochemical soil Pb mapping in the inner cities of Australia, the risks from environmental Pb exposure remain unconstrained within urban population centres.     

Applications of Anthropogenic Lead ArchaeoStratigraphy (ALAS Model) to Hydrocarbon Remediation

A model, which employs the use of high precision stable lead isotopic analyses, has been developed to estimate the age of hydrocarbon releases. The ALAS Model (Anthropogenic Lead ArchaeoStratigraphy) is based on calibrated, systematic increases in lead isotope ratios of gasolines caused by shifts in sources of lead ores used by the U.S. lead industry, including manufacturers of alkylleads, to more radiogenic Mississippi Valley Type (MVT) deposits. Acquisition of high quality samples (free product, gasoline-impacted soil and groundwater) of known age and subsequent analyses of the hydrocarbon component by high precision lead isotopic analyses by thermal ionization mass spectrometry (TIMS) have produced the ALAS Model calibration curve. Age uncertainties range from - 1 to 2 years for gasoline releases which occurred between 1965 and 1990, the major era of leaded gasoline usage. Analytical methods required to measure lead isotope ratios on ~5 nanograms of lead with precisions and accuracy of < - 0.1% (2 SEM ) are discussed in detail. Published lead isotopic measurements of gasoline-derived anthropogenic lead of samples throughout the United States are used to demonstrate the wide geographic range over which the ALAS Model may be applied. Two representative case studies involving an early 1970s free product release in California and the discrimination of a 1970s from modern unleaded gasoline release in Florida demonstrate the use of the model on single and multiple hydrocarbon releases, respectively, in different geographic regions of the United States. A third investigation focuses on the use of lead isotopes to correlate dissolved phase hydrocarbons with their source, in this case, unleaded (aka low lead) gasoline releases in New Jersey. Dissolved phase hydrocarbons (BTEX/MTBE) are shown to carry the lead isotopic signature of the unleaded gasoline into groundwater, allowing the specific source of the release to be identified. Investigations of lead isotopes as tracers of MTBE in groundwater are ongoing. However, both laboratory and field data indicate MTBE carries the lead isotopic signature of its unleaded gasoline source into groundwater, demonstrating the potential of the lead isotopic system as a discriminant of MTBE sources. Although developed to estimate the age of leaded gasoline releases, the ALAS Model has been successfully applied in studies requiring age dating of jet-A, diesel, kerosene, motor oil, and heating oil. These petroleum distillates are suspected of accidentally acquiring small, yet significant quantities of alkylleads during refining, allowing accurate ALAS Model ages to be determined. When lead levels in these petroleum distillates are within their normal range, typically tens to hundreds of ppb lead, it is possible to use lead isotopic ratios to correlate environmental releases of these products to their source or other releases.     

Applications of Anthropogenic Lead ArchaeoStratigraphy (ALAS Model) to Hydrocarbon Remediation

A model, which employs the use of high precision stable lead isotopic analyses, has been developed to estimate the age of hydrocarbon releases. The ALAS Model (Anthropogenic Lead ArchaeoStratigraphy) is based on calibrated, systematic increases in lead isotope ratios of gasolines caused by shifts in sources of lead ores used by the U.S. lead industry, including manufacturers of alkylleads, to more radiogenic Mississippi Valley Type (MVT) deposits. Acquisition of high quality samples (free product, gasoline-impacted soil and groundwater) of known age and subsequent analyses of the hydrocarbon component by high precision lead isotopic analyses by thermal ionization mass spectrometry (TIMS) have produced the ALAS Model calibration curve. Age uncertainties range from  ± 1 to 2 years for gasoline releases which occurred between 1965 and 1990, the major era of leaded gasoline usage. Analytical methods required to measure lead isotope ratios on ∼5 nanograms of lead with precisions and accuracy of < ± 0.1% (2_SEM) are discussed in detail. Published lead isotopic measurements of gasoline-derived anthropogenic lead of samples throughout the United States are used to demonstrate the wide geographic range over which the ALAS Model may be applied. Two representative case studies involving an early 1970s free product release in California and the discrimination of a 1970s from modern unleaded gasoline release in Florida demonstrate the use of the model on single and multiple hydrocarbon releases, respectively, in different geographic regions of the United States. A third investigation focuses on the use of lead isotopes to correlate dissolved phase hydrocarbons with their source, in this case, unleaded (aka low lead) gasoline releases in New Jersey. Dissolved phase hydrocarbons (BTEX/MTBE) are shown to carry the lead isotopic signature of the unleaded gasoline into groundwater, allowing the specific source of the release to be identified. Investigations of lead isotopes as tracers of MTBE in groundwater are ongoing. However, both laboratory and field data indicate MTBE carries the lead isotopic signature of its unleaded gasoline source into groundwater, demonstrating the potential of the lead isotopic system as a discriminant of MTBE sources. Although developed to estimate the age of leaded gasoline releases, the ALAS Model has been successfully applied in studies requiring age dating of jet-A, diesel, kerosene, motor oil, and heating oil. These petroleum distillates are suspected of accidentally acquiring small, yet significant quantities of alkylleads during refining, allowing accurate ALAS Model ages to be determined. When lead levels in these petroleum distillates are within their normal range, typically tens to hundreds of ppb lead, it is possible to use lead isotopic ratios to correlate environmental releases of these products to their source or other releases.     

Atmospheric lead deposition to Okefenokee Swamp, Georgia, USA

Contamination of the environment from atmospheric deposition during the twentieth century is pervasive even in areas ostensibly considered pristine or remote from point sources. In this study, Pb concentrations in a 210Pb-dated peat core collected from the Okefenokee Swamp, GA were used to assess historical contaminant input via atmospheric deposition. Lead isotope ratios were determined by dynamic reaction cell ICP-MS (DRC-ICP-MS). Increases in Pb concentration occurred in the late nineteenth century and a marked rise in Pb concentrations pre-dated the widespread use of leaded gasoline within the US. The 206Pb/207Pb ratios of 1.19 during this period were consistent with coal combustion emissions. A later increase in Pb concentration, concurrent with a trend toward more radiogenic 206Pb/207Pb ratios in gasoline is consistent with an increased input of Pb from leaded gasoline emissions. However, it appears that coal combustion emissions remain a major source of Pb to the Okefenokee.     

Lead isotope ratios in the urban air of eastern and central Russia

In order to characterize airborne lead in eastern and central Russian cities in terms of lead isotope ratios, aerosol samples were collected at six selected cities and Moscow, and their lead concentrations and isotope ratios were studied by comparing them to the data of ore lead used in Russia. All eastern Russian cities (Vladivostok, Khabarovsk and Yakutsk) were found to have isotope ratios similar to those of ore leads in Kazakhstan, the major lead producer for Russia. Samples collected in Moscow also showed isotope ratios similar to those of eastern Russian cities. The contribution from coal combustion to airborne lead was considered to be small even in winter, in these cities. This observation suggested that the origin of lead in these Russian atmosphere regions is closely related to the lead products (e.g. leaded gasoline). The lead isotope ratios in three eastern Russian cities were very close to the value for Russian air mass reported previously in Japan, which were also in good agreement with the same observation in Sweden. However, considerably different lead isotope ratios were observed in central Russian cities, Kemerovo and Nizhnevartovsk, indicating that specific lead emissions, such as industrial activities using Precambrian-age ores or unique leaded gasoline, might contribute to the atmospheric lead.     

Lead (Pb) isotopic fingerprinting and its applications in lead pollution studies in China: A review

As the most widely scattered toxic metal in the world, the sources of lead (Pb) observed in contamination investigation are often difficult to identify. This review presents an overview of the principles, analysis, and applications of Pb isotopic fingerprinting in tracing the origins and transport pathways of Pb in the environment. It also summarizes the history and current status of lead pollution in China, and illustrates the power of Pb isotopic fingerprinting with examples of its recent applications in investigating the effectiveness of leaded gasoline phase-out on atmospheric lead pollution, and the sources of Pb found in various environmental media (plants, sediments, and aquatic organisms) in China. The limitations of Pb isotopic fingerprinting technique are discussed and a perspective on its development is also presented. Further methodological developments and more widespread instrument availability are expected to make isotopic fingerprinting one of the key tools in lead pollution investigation.     

Unleaded Gasoline Shortages and Fuel Switching

The use of leaded gasoline in automobiles equipped with catalytic converters causes deactivation of the converters and leads to significant increases in emissions of reactive hydrocarbons, a precursor of ozone. Such fuel switching may be a contributing factor to the increase in photochemical smog levels recently observed in the South Coast Air Basin (SOCAB).     

Occurrence of PCDD/Fs in urban air before and after the ban of leaded gasoline

The source of PCDDs and PCDFs in automotive exhaust is not yet fully explained. The chlorinated hydrocarbons used in the formulation of lead-alkyl additives were suspected as a possible major source. Based on this, the decreasing use of leaded gasoline followed by its final ban (occurred on 1/1/2002, in Italy) should have resulted in a decreasing presence of PCDD/Fs in urban air and possibly some differences in their profile. To investigate these aspects, we monitored PCDD/Fs for one year starting in September 2001, at a medium-traffic road site in Rome, with weekly frequency. Results were then compared with those obtained in a previous study performed before the ban (from February 2000 to January 2001) at the same site. As compared with the previous study, the yearly-averaged overall PCDD/F concentration, as toxic equivalent of 2,3,7,8-TCDD, decreased from 60 to 50 fg m(-3) I-TEQ; it remained unchanged, however, if one sample with a particularly high PCDD/F content was excluded from each data set. The monthly trend confirmed the one found in the former study. On an annual basis, the two mean congener profiles were almost identical. The concentration levels and the constancy of profiles, as calculated for the two periods, do not support the hypothesis of a major role of leaded gasoline, substantially different from unleaded one, in contributing to PCDD/F air pollution.     

Improving the environmental and performance characteristics of vehicles by introducing the surfactant additive into gasoline

The operation of modern vehicles requires the introduction of package of fuel additives to ensure the required level of operating characteristics, some of which cannot be achieved by current oil refining methods. The use of additives allows flexibility of impact on the properties of the fuel at minimal cost, increasing the efficiency and environmental safety of vehicles. Among the wide assortment of additives available on the world market, many are surfactants. It has been shown that the introduction of some surfactants into gasoline concurrently reduces losses from gasoline evaporation, improves the mixture formation during injection of gasoline into the engine and improves detergent and anticorrosive properties. The surfactant gasoline additive that provides significant improvement in the quality of gasoline used and environmental and operating characteristics of vehicles has been developed and thoroughly investigated. The results of studies confirming the efficiency of the gasoline additive application are herein presented.     

Fluoride Emissions and Forest Growth

Abstract

The October 1995 court decision allowing Ethyl Corporation to offer methylcyclopentadienyl manganese tricarbonyl (MMT) for sale to refiners for introduction into unleaded gasoline as an octane enhancer is likely to result in increased fine (PM_2.5) manganese (Mn) concentrations in ambient air. Concern exists regarding possible health effects. In this paper, recent fine Mn concentrations in three monitoring networks and one U.S. Environmental Protection Agency (EPA) study of personal exposure are analyzed. One network consists mainly of rural sites in national parks in the United States, a second consists mainly of urban sites in California, and the third consists mainly of urban sites in Canada where MMT has been used for a number of years. During the late 1980s and early 1990s, mean ambient concentrations ranged from 1 ng/m³ in the mostly rural network to 3 ng/m³ in the mostly urban California network to 12 ng/m³ in the MMT-impacted Canadian network. Several lines of evidence suggested that some of the fine Mn observed in the United States during the 1986-1992 period was contributed by automobiles using leaded gasoline, for which MMT was a registered fuel additive. However, the near-disappearance of leaded gasoline has resulted in a very small portion of fine Mn being attributed to automobiles in the years since 1992.A source apportionment analysis suggested that crustal contributions to ambient fine Mn are on the order of 1-2 ng/m³ in both the United States and Canada.     

Is adaptive management helping to solve fisheries problems?

Adaptive management has been widely recommended as a way to deal with extreme uncertainty in natural resource and environmental decision making. The core concept in adaptive management is that policy choices should be treated as deliberate, large-scale experiments; hence, policy choice should be treated at least partly as a problem of scientific experimental design. There have now been upwards of 100 case studies where attempts were made to apply adaptive management to issues ranging from restoration of endangered desert fish species to protection of the Great Barrier Reef. Most of these cases have been failures in the sense that no experimental management program was ever implemented, and there have been serious problems with monitoring programs in the handful of cases where an experimental plan was implemented. Most of the failures can be traced to three main institutional problems: i) lack of management resources for the expanded monitoring needed to carry out large-scale experiments; ii) unwillingness by decision makers to admit and embrace uncertainty in making policy choices; and iii) lack of leadership in the form of individuals willing to do all the hard work needed to plan and implement new and complex management programs.     

Gasoline prices and economic policy uncertainty: what causes what,and why does it matter? Evidence from 18 selected countries

In this paper, we examine asymmetric causal relationships between gasoline prices and economic policy uncertainty in a panel of 18 countries over the period 1998–2017, using the recently introduced panel causality approach of Hatemi et al (Appl Econ, 48:2301–2308, 2016) that accounts for asymmetric dynamics and is robust to both cross-sectional dependence and slope heterogeneity. Empirical findings reveal asymmetric causal relationships between gasoline prices and economic policy uncertainty in the sampled countries. Specifically, results show that economic policy uncertainty and gasoline prices have positive and negative asymmetric bidirectional causal relations in 13 countries. No feedback causality was detected between gasoline prices and economic policy uncertainty in 5 countries. Based on the results, we infer that positive and negative asymmetric causal relations exist between economic policy uncertainty and gasoline price, with attendant policy implications in sampled regions.

     

Institutional frameworks for sustainability? A comparative analysis of the forest sectors of Russia and the Baltic States

After the break-up of the Soviet system, the divergence in forest management among Soviet republics became obvious. While the forest sectors of the Baltic States have been fundamentally changed, Russia has not been able to develop an institutional framework that would fit the prerequisites for social-ecological resilience. It is argued that sustainable development requires institutional frameworks that have the capacity to adapt and learn, and thus to treat policies as experiments that are constantly assessed and readjusted. This, however, requires a participatory approach and in this respect the Baltic States are believed to be on a more promising track. Finally, it is concluded that only to the extent that suitable institutional frameworks will be developed will social-ecological resilience be a significant feature of the natural resources management in the former communist countries.     

Remanence of lead pollution in an urban river system: a multi-scale temporal and spatial study in the Seine River basin,France

Total lead (Pb) concentration and Pb isotopic ratio (²⁰⁶Pb/²⁰7Pb) were determined in 140 samples from the Seine River basin (France), covering a period of time from 1945 to 2011 and including bed sediments (bulk and size fractionated samples), suspended particulate matter (SPM), sediment cores, and combined sewer overflow (CSO) particulate matter to constrain the spatial and temporal variability of the lead sources at the scale of the contaminated Seine River basin. A focus on the Orge River subcatchment, which exhibits a contrasted land-use pattern, allows documenting the relation between hydrodynamics, urbanization, and contamination sources. The study reveals that the Pb contamination due to leaded gasoline that peaked in the 1980s has a very limited impact in the river nowadays. In the upstream Seine River, the isotopic ratio analysis suggests a pervasive contamination which origin (coal combustion and/or gasoline lead) should be clarified. The current SPM contamination trend follows the urbanization/industrialization spatial trend. Downstream of Paris, the lead from historical use originating from the Rio Tinto mine, Spain (²⁰⁶Pb/²⁰⁷Pb?=?1.1634?±?0.0001) is the major Pb source. The analysis of the bed sediments (bulk and grain size fractionated) highlights the diversity of the anthropogenic lead sources in relation with the diversity of the human activities that occurred in this basin over the years. The “urban” source, defined by waste waters including the CSO samples (²⁰⁶Pb/²⁰⁷Pb?=?1.157?±?0.003), results of a thorough mixing of leaded gasoline with “historical” lead over the years. Finally, a contamination mixing scheme related to hydrodynamics is proposed.     

Accurate Chemical Analysis of MTBE in Environmental Media

The new millennium ushers in changes for refiners of automobile gasoline in the United States, as well as for the state and federal regulators who establish guidelines for gasoline formulation and environmental regulation governing the fate of gasoline-related chemicals in the nation's air, soil and groundwater. One current issue in the gasoline formulation debate centers on the comparison of the proven benefits of the addition of chemical oxygenates—especially methyltert -butyl ether (MTBE)—to gasoline (to improve tailpipe emission quality) against the presumed environmental problems caused by the presence of oxygenates in ground- and surface waters due to fugitive releases of gasoline. Credible debate on this subject presumes that current and past environmental monitoring data for MTBE in environmental samples is accurate and precise. Experience suggests that this assumption is not correct, in part because certain analytical methodologies—particularly older methods supported by the U.S. Environmental Protection Agency—can fall short of reasonable data quality goals for measurement of MTBE. This Technical Note summarizes the standard EPA methods available to site investigators who need to measure MTBE in environmental media, the limitations and advantages of these measurement techniques, and recommendations for improving these standard EPA methods to yield the highest quality MTBE environmental residue data.     

Distribution patterns of lead accumulation in roadside soils: a case study from Erzurum, Turkey

Surface soils along roadsides or near to industrial areas may contain high concentrations of lead that adversely affect plant production. Lead contamination of roadside soils is generally attributed to the exhaust emissions of automobiles operating with leaded gasoline. The objectives of this study were to determine the relationships between lead accumulation in soils and the distance from the road edge, predominant wind direction and soil depth, and to define vertical and horizontal distribution patterns of lead accumulation within the study area. The lead content of soil decreased rapidly with the distance from the road, and the relationship was described by a power function. The contamination was more dependent on the predominant wind direction. Our results indicated that lead that had accumulated within the top few centimetres of soil had been mixed throughout the ploughing layer in cultivated lands. Soils within 40 m of the motorway had at least 2 to 6 times higher amounts of lead than the background level.     

Vapor pressure response to denaturant and water in E10 blends

On December 16, 1993, the U.S. Environmental Protection Agency (EPA) released the final rule on reformulated gasoline (RFG). This rule will affect the composition of as much as 45% of the gasoline used in the United States by the summer of 1995. The acceptance of any gasoline component lies in its ability to contribute to the RFG program's environmental goals. This study was conducted to determine the effect of water and ethanol denaturant on gasoline Reid vapor pressure (RVP) for which little quantitative data are available. This paper addresses two new areas where environmental goals may be achieved while maintaining the use of ethanol-blended gasolines within ozone nonattainment areas.     

Ecotoxicological research and related legislation in Serbia

Introduction

Several hot spots of severe freshwater pollution and sediment contamination (mostly heavy metals, polyaromatic hydrocarbons and polychlorinated biphenyls) have been identified in Serbia as the consequence of outdated environmental legislation, negligible amounts of properly treated waste waters and accidental spills.

Discussion

Since ecotoxicological methods have never been incorporated into risk assessment procedures, mandatory effluent discharge or ambient water monitoring programmes, ecotoxicological research, based on bioaccumulation studies, conventional ecotoxicological tests and, recently, biomarkers of exposure and effect have been restricted to independent small- to medium-scale studies, conducted, basically, to confirm, underline or oppose the results of chemical-based monitoring and to lament on inadequate environmental regulations/policy and management practice. Although hot and unresolved ecotoxicological problems still remain beyond the reach of ecotoxicological research currently conducted in Serbia, or are tackled only sporadically, it is to be expected that on-going research and institutional capacity building should, hopefully, increase the competence and competitiveness of scientific community and speed up the process of harmonisation of national environmental legislation and policy with European Union.