Variations in speciated emissions from spark-ignition and compression-ignition motor vehicles in California's south coast air basin

The U.S. Department of Energy Gasoline/Diesel PM Split Study examined the sources of uncertainties in using an organic compound-based chemical mass balance receptor model to quantify the contributions of spark-ignition (SI) and compression-ignition (CI) engine exhaust to ambient fine particulate matter (PM2.5). This paper presents the chemical composition profiles of SI and CI engine exhaust from the vehicle-testing portion of the study. Chemical analysis of source samples consisted of gravimetric mass, elements, ions, organic carbon (OC), and elemental carbon (EC) by the Interagency Monitoring of Protected Visual Environments (IMPROVE) and Speciation Trends Network (STN) thermal/optical methods, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, alkanes, and polar organic compounds. More than half of the mass of carbonaceous particles emitted by heavy-duty diesel trucks was EC (IMPROVE) and emissions from SI vehicles contained predominantly OC. Although total carbon (TC) by the IMPROVE and STN protocols agreed well for all of the samples, the STN/IMPROVE ratios for EC from SI exhaust decreased with decreasing sample loading. SI vehicles, whether low or high emitters, emitted greater amounts of high-molecular-weight particulate PAHs (benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, and coronene) than did CI vehicles. Diesel emissions contained higher abundances of two- to four-ring semivolatile PAHs. Diacids were emitted by CI vehicles but are also prevalent in secondary organic aerosols, so they cannot be considered unique tracers. Hopanes and steranes were present in lubricating oil with similar composition for both gasoline and diesel vehicles and were negligible in gasoline or diesel fuels. CI vehicles emitted greater total amounts of hopanes and steranes on a mass per mile basis, but abundances were comparable to SI exhaust normalized to TC emissions within measurement uncertainty. The combustion-produced high-molecular-weight PAHs were found in used gasoline motor oil but not in fresh oil and are negligible in used diesel engine oil. The contributions of lubrication oils to abundances of these PAHs in the exhaust were large in some cases and were variable with the age and consumption rate of the oil. These factors contributed to the observed variations in their abundances to total carbon or PM2.5 among the SI composition profiles.     

Efficiency of ASTM Method D4994-89 for Recovery of Enteric Viruses from Biosolids

The ASTM Method D4994-89 has been used in the United States for almost two decades to assess the virological quality of biosolids. However, the efficiency of this method for recovery of different enteric viruses has never been determined. The method was found to recover several different enteroviruses and adenovirus 2 with an efficiency ranging from 18.1 ± 5.5 to 24.6 ± 7.8%.     

Manipulation of dietary protein and nonstarch polysaccharide to control swine manure emissions

Odor and greenhouse gas (GHG) emissions from stored pig (Sus scrofa) manure were monitored for response to changes in the crude protein level (168 or 139 g kg(-1), as-fed basis) and nonstarch polysaccharide (NSP) content [i.e., control, or modified with beet pulp (Beta vulgaris L.), cornstarch, or xylanase] of diets fed to pigs in a production setting. Each diet was fed to one of eight pens of pigs according to a 2 x 4, full-factorial design, replicated over three time blocks with different groups of animals and random assignment of diets. Manure from each treatment was characterized and stored in a separate, ventilated, 200-L vessel. Repeated measurements of odor, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions from the vessels were taken every two weeks for eight weeks. Manure from high-protein diets had higher sulfur concentration and pH (P < or = 0.05). High-NSP (beet pulp) diets resulted in lower manure nitrogen and ammonia concentrations and pH (P < or = 0.05). Odor level and hedonic tone of exhaust air from the storage vessel headspaces were unaffected by the dietary treatments. Mean CO2 and CH4 emissions (1400 and 42 g d(-1) m(-3) manure, respectively) increased with lower dietary protein (P < or = 0.05). The addition of xylanase to high-protein diets caused a decrease in manure CO2 emissions, but an increase when added to low-protein diets (P < or = 0.05). Nitrous oxide emissions were negligible. Contrary to other studies, these results do not support the use of dietary protein reduction to reduce emissions from stored swine manure.     

Regional electricity transmission planning and SEA: The case of the electricity company ScottishPower

Since 21 July 2004, formal strategic environmental assessment (SEA) requirements are in place for certain plans and programmes in European Union member states. Many public plans and programmes have been identified to fall under these requirements, and there has been a range of research activities particularly in land use and transport planning. However, the way in which SEA is to be applied in the private sector has remained largely unclear. Furthermore, to date there has been comparatively little reported private sector experience and the concrete benefits that SEA may deliver to private companies have not yet been discussed to any large extent. In order to address this shortcoming, the paper looks at SEA application in electricity transmission planning, taking the specific case of the privatized company ScottishPower as an example. Based on the evidence obtained, it is suggested that a structured SEA process can strengthen the environmental component and improve private sector decision-making processes. Corporate governance can be improved, if SEA is applied in a tiered system, addressing different issues and tasks at distinct stages in a clearly defined decision making hierarchy.     

Application of Biobarriers for Groundwater Containment at Fractured Bedrock Sites

Biological barriers are a beneficial application of biofilms that aim at reducing the hydraulic conductivity (K) in geological formations. Several studies have shown the potential benefits of creating such barriers either by stimulating the indigenous microbial community (biostimulation) or injecting bacteria (bioaugmentation). For example, laboratory experiments show that groundwater microorganisms attached to a ceramic surface and generated a biofilm as thick as 1,100 μm. In a limestone fracture, this bacterial community clogged a single fracture up to 99.2 percent within 22 days. At the field scale, applications in porous aquifers led to a five‐fold decrease in K after 2.5 days of biostimulation, and a bioaugmentation with a starved, adapted bacterial culture decreased K by 99.4 percent. One promising development of the biobarrier concept is a field application at a fractured bedrock site. Using a multidisciplinary approach and focusing on a well‐characterized fracture system, a field trial was undertaken in Southern Ontario to measure the extent of bioclogging and the stability over time. This article focuses on the literature pertinent to the preparation of this field trial and presents the innovative approach selected to monitor the bioclogging in such a challenging environment.     

Conspecifics as cues: A mechanism for habitat selection in the Panamanian grass anole (Anolis auratus)

Summary In an experimental choice situation, individuals of both sexes of the lizard Anolis auratus choose to associate with a conspecific individual regardless of its sex. Further, individuals of both sexes associate with an individual of A. tropidogaster, a related species. Given the choice between the two species, they choose their own. Given the choice between a conspecific and a small patch of natural habitat, they do not choose one or the other consistently. These experiments indicate that conspecific association does not function just as a mate selection mechanism as has been previously proposed. The initial association may, in addition, serve a habitat selection function. Conspecifics can thus be seen as cues indicating the presence of suitable habitat as well as being important biological factors in themselves.     

Zur chemie der marsoberfläche

Analyses of 13 samples of Martian surface materials with the Viking X-ray fluorescence spectrometers show SiO₂ similar to that of terrestrial mafic rocks, whereas Fe₂O₃, Cl, and S are higher and Al₂O₃, K₂O, Rb, Sr, Y, and Zr are lower. Low totals suggest presence of CO₂, H₂O, and Na₂O. Duricrust fragments are higher in S than fines, but samples from both landing sites are surprisingly similar. We suggest that Martian surface materials are aeolian deposits of complex mixtures of weathering products of maficultramafic rocks, possibly consisting of iron-rich clays, sulfates, iron oxides, carbonates, and chlorides.