Water-based condensation particle counters for environmental monitoring of ultrafine particles

TSI Inc. (Shoreview, MN) has introduced three new water-based condensation particle counters (WCPCS) that were designed to detect airborne particles larger than 2.5 nm (model 3786), 5 nm (model 3785), and either 10 or 20 nm (model 3782). These WCPCs are well suited for real-time, environmental monitoring of number concentration of airborne ultrafine particles. Their unique design incorporates the use of water as the working fluid instead of alcohol. Water is odor free, readily available, and eliminates the problem of water condensation and absorption into alcohol working fluids during operation in humid environments. In this study, the performance of three TSI WCPCs was characterized for several aerosol compositions, including sucrose, salt (NaCl), dioctyl sebacate (DOS), dioctyl phthalate (DOP), emery oil (poly-alpha-olefin), silver, impurity residue particles, and ambient aerosol particles. All particles were size selected using a nano differential mobility analyzer (nano-DMA; model 3085, TSI Inc.) to create monodisperse challenge aerosols. The challenge aerosol was mixed uniformly with clean makeup flow and split into a WCPC and a reference instrument to determine the counting efficiency of the WCPC. For the model 3785 WCPC, the D50 (i.e., the particle diameter with 50% counting efficiency) was determined to be 3.1 nm for salt particles, 4.7 nm for sucrose and ambient particles, 5.6 nm for silver particles, and >50 nm for ultrapure oil particles. The sensitivity to oil droplets increased dramatically (D50 < 10 nm) when the oil was slightly contaminated. The D50 of model 3786 ultrafine water-based CPC (UWCPC) was 2.4 nm for impurity residue particles. The D50 of the model 3782 WCPC was 10.8 (with a nominal setting of 10 nm) or 19.8 nm (with a nominal setting of 20 nm) for sucrose particles. All three WCPCs have response times of less than 2 or 3 sec and are therefore able to detect fast-changing events.     

Curtin industrial safety trial: Managerial behavior and program effectiveness

Behavior-based safety has been found universally efficacious when evaluated under controlled conditions. The Curtin Trial aimed to test the general acceptability of behavior-based safety in Australian industry. A 50% failure rate was observed. This paper presents the results of a qualitative analysis of observed managerial behavior in relation to program effectiveness. Field notes taken in the course of 325 hours of participant observation during implementation of behavior-based safety in 9 work areas were analyzed qualitatively and categorized. These data were compared with statistical results of the safety program's effectiveness on improving safe practices and good housekeeping. Nine dimensions to managerial behavior were identified which were associated with program effectiveness. A relatively small number of studies investigating organizational characteristics and safety have found generally similar social environmental features to those observed in this study. Behavior-based safety appears to be effective only in organizations with recognizable managerial styles.     

Airway Reactivity to Sulfate and Sulfuric Acid Aerosols in Normal and Asthmatic Subjects

Recent epidemiologic studies have emphasized a relationship between alteration in lung function, respiratory symptoms in asthmatics, and elevated levels of sulfate air pollutants. In asthmatics, it has been reported that 1) the more acidic sulfate aerosols, sulfuric acid (H₂SO₄) and ammonium bisulfate (NH₄HSO₄), provoked the greatest changes in lung function and 2) a definite exposure-response relationship exists for H₂SO₄ inhalation. To determine if sulfate aerosol exposure caused increased reactivity to a known bronchoconstrictor, normal and asthmatic subjects inhaled subthreshold doses of carbachol after the following sulfates: H₂SO₄, NH4HSO4, and sodium bisulfate. A NaCI aerosol served as a control. Exposure times averaged 16 minutes with sulfate concentrations ranging from 100 μ/m³ to 1000 jtg/m₃. In normal subjects, prior inhalation of either 1000 yug/m₃ H₂SO₄ or NH4HSO4 significantly potentiated (P < 0.05) the bronchoconstrictor action of carbachol on airway conductance compared to NaCI and carbachol or carbachol alone by t-tests. For the asthmatic group, prior inhalation of either 1000/tg/m₃ H₂SO₄ or NH₄HSO₄ (P < 0.05), or 450 μ/m³ H₂SO₄ (P < 0.05) similarly enhanced the carbachol bronchoconstrictor effect compared to NaCI and carbachol. At the low 100 μ/m³, no sulfates altered the effects of carbachol on pulmonary function. Although mean changes between the sulfate groups did not attain significance by an analysis of variance, it was found that the bronchoconstrictor action of carbachol was potentiated by the sulfate aerosols more or less in relation to their acidity.     

Enantiomer fractions of chiral organochlorine pesticides and polychlorinated biphenyls in standard and certified reference materials

Enantiomeric ratios (ERs) and enantiomeric fractions (EFs) of a number of chiral organochlorine pesticides and PCB atropisomers were measured by chiral gas chromatography/mass spectrometry (GC/MS) in five standard (SRM) and certified (CRM) reference materials: SRM 1588a (organics in cod liver oil), SRM 1945 (organics in whale blubber), Marine Mammal Quality Assurance Exercise Control Material IV (NIST IV, organics in whale blubber), CRM trout, and CRM EC-5 (sediment). Target analytes were cis- and trans-chlordane, heptachlor exo-epoxide, oxychlordane, U82, MC5, MC6, MC7, o,p^′-DDT, and PCB congeners 91, 95, 136, 149, 174, 176, and 183. Measured ERs and EFs are in close agreement with the few literature values reported for some of these analytes in SRMs and CRMs. Chiral PCB ERs and EFs measured by one-dimensional chiral GC/MS were similar to values measured using multidimensional chiral GC/MS. Non-racemic chiral compositions are in agreement with known uptake and biotransformation in the respective environmental matrices. These values should aid in the quality assurance/quality control methodologies for chiral environmental chemistry using standardized reference materials.     

Stakeholder Involvement in Coastal Decision-making Processes

This article discusses the current framework of coastal decision making which tends to exclude participation by individuals and those without a strong institutional representation. A distinction is drawn between institutional and local stakeholders to illustrate weaknesses in the existing decision framework. It is argued that particularly in the coastal environment, the relationship between changes in physical form and changes in social welfare is critical to understanding how decision making may engage more fully with local stakeholders and ultimately improve decision outcomes. A reordering of stakeholder engagement in decision systems at the coast is proposed and a framework is outlined which enhances the capacity of local stakeholders to influence decision making.     

FOREST COVER,IMPERVIOUS‐SURFACE AREA,AND THE MITIGATION OF STORMWATER IMPACTS1

ABSTRACT: For 20 years, King County, Washington, has implemented progressively more demanding structural and nonstructural strategies in an attempt to protect aquatic resources and declining salmon populations from the cumulative effects of urbanization. This history holds lessons for planners, engineers, and resource managers throughout other urbanizing regions. Detention ponds, even with increasingly restrictive designs, have still proven inadequate to prevent channel erosion. Costly structural retrofits of urbanized watersheds can mitigate certain problems, such as flooding or erosion, but cannot restore the predevelopment flow regime or habitat conditions. Widespread conversion of forest to pasture or grass in rural areas, generally unregulated by most jurisdictions, degrades aquatic systems even when watershed imperviousness remains low. Preservation of aquatic resources in developing areas will require integrated mitigation, which must including impervious‐surface limits, forest‐retention policies, stormwater detention, riparian‐buffer maintenance, and protection of wetlands and unstable slopes. New management goals are needed for those watersheds whose existing development precludes significant ecosystem recovery; the same goals cannot be achieved in both developed and undeveloped watersheds.     

Vulnerability of exporting nations to the development of a carbon label in the United Kingdom

Carbon labels inform consumers about the amount of greenhouse gases (GHGs) released during the production and consumption of goods, including food. In the future consumer and legislative responses to carbon labels may favour goods with lower emissions, and thereby change established supply chains. This may have unintended consequences.We present the carbon footprint of three horticultural goods of different origins supplied to the United Kingdom market: lettuce, broccoli and green beans. Analysis of these footprints enables the characterisation of three different classes of vulnerability which are related to: transport, national economy and supply chain specifics.There is no simple relationship between the characteristics of an exporting country and its vulnerability to the introduction of a carbon label. Geographically distant developing countries with a high level of substitutable exports to the UK are most vulnerable. However, many developing countries have low vulnerability as their main exports are tropical crops which would be hard to substitute with local produce.In the short term it is unlikely that consumers will respond to carbon labels in such a way that will have major impacts in the horticultural sector. Labels which require contractual reductions in GHG emissions may have greater impacts in the short term.     

土壤中总石油烃污染（TPH）的微生物降解与修复研究进展

微生物降解和修复是处理土壤中总石油烃(TPH)污染最简单、有效的方法之一.论文阐述了土壤TPH污染的产生、危害以及物理、化学、生物等修复方法的各自特点,其中重点介绍了微生物修复方法,论述了土壤中TPH在微生物表面的吸附、转运,在微生物体内的降解以及相关降解酶及基因;详细介绍了电子受体、温度、pH、营养元素等外界因素对微生物修复TPH污染的影响,在此基础上对土壤TPH污染的微生物修复现状和发展趋势进行了讨论.     

The Role of Mineral Weathering Rate Determinations in Generating Uncertainties in the Calculation of Critical Loads of Acidity and their Exceedance

Current legislation within Europe aimed at limitingecosystem damage resulting from inputs of atmosphericpollution is based on the critical load concept. Mineralweathering rates are central to the calculation ofcritical loads (acceptable levels) of acid deposition.The authors have undertaken a number of studies whichillustrate the complications and limitations inherent inpredicting mineral weathering rates and the implicationswhich these have for critical loads calculations andmapping. Calculated weathering rates and critical loadsfor two acid-sensitive parent materials (greywackes andgranites) are presented and are used to illustrate theimpact that uncertainty can have on critical loadexceedances. The results have obvious implications forportraying the uncertainties of critical loads to policy makers.     

Complete reproductive skew within white-browed sparrow weaver groups despite outbreeding opportunities for subordinates of both sexes

The distribution of reproductive success within societies is a key determinant of the outcomes of social evolution. Attempts to explain social diversity, therefore, require that we quantify reproductive skews and identify the mechanisms that generate them. Here, we address this priority using life history and genotypic data from >600 individuals in 40 wild groups of the cooperatively breeding white-browed sparrow weaver, Plocepasser mahali. We show that groups comprise up to six males and seven females, but within-group reproduction is completely monopolised by a single dominant male and female, while extra-group males sire 12–18 % of offspring. Strong within-group kin structure could frequently explain these monopolies, as subordinates had typically delayed dispersal from their natal groups and so frequently (1) lacked within-group outbreeding partners, and/or (2) stood to gain little from contesting dominant reproduction, being almost as related to the dominant’s young as they would have been to their own. Kin structure alone cannot account entirely for these monopolies, however, as they remained complete following the immigration of unrelated males and females. That subordinate females remain reproductively quiescent despite also showing comparable body condition to dominants, overlapping them substantially in age, and showing no evidence of elevated stress hormone levels raises the possibility that they exercise reproductive restraint due instead to a threat of action by dominants and/or deficits in offspring fitness that might arise if subordinates bred. Our findings highlight the complexity of the mechanisms that generate reproductive disparities in animal societies and the challenge of identifying them when skews are complete.