Evaluation of vacuum filter sock surface sample collection method for Bacillus spores from porous and non-porous surfaces

Vacuum filter socks were evaluated for recovery efficiency of powdered Bacillus atrophaeus spores from two non-porous surfaces, stainless steel and painted wallboard and two porous surfaces, carpet and bare concrete. Two surface coupons were positioned side-by-side and seeded with aerosolized Bacillus atrophaeus spores. One of the surfaces, a stainless steel reference coupon, was sized to fit into a sample vial for direct spore removal, while the other surface, a sample surface coupon, was sized for a vacuum collection application. Deposited spore material was directly removed from the reference coupon surface and cultured for enumeration of colony forming units (CFU), while deposited spore material was collected from the sample coupon using the vacuum filter sock method, extracted by sonication and cultured for enumeration. Recovery efficiency, which is a measure of overall transfer effectiveness from the surface to culture, was calculated as the number of CFU enumerated from the filter sock sample per unit area relative to the number of CFU enumerated from the co-located reference coupon per unit area. The observed mean filter sock recovery efficiency from stainless steel was 0.29 (SD = 0.14, n = 36), from painted wallboard was 0.25 (SD = 0.15, n = 36), from carpet was 0.28 (SD = 0.13, n = 40) and from bare concrete was 0.19 (SD = 0.14, n = 44). Vacuum filter sock recovery quantitative limits of detection were estimated at 105 CFU m(-2) from stainless steel and carpet, 120 CFU m(-2) from painted wallboard and 160 CFU m(-2) from bare concrete. The method recovery efficiency and limits of detection established in this work provide useful guidance for the planning of incident response environmental sampling for biological agents such as Bacillus anthracis.     

Volatile emissions from the flea beetle Altica litigata (Coleoptera: Chrysomelidae) associated with invasive Ludwigia hexapetala

The flea beetle Altica litigata (Chrysomelidae) is an insect herbivore to plants within the families Lythraceae and Onagraceae, including ornamentals such as crape myrtle, Lagerstroemia spp. This insect is important both as a pest species and as a naturally occurring biological control agent due to its aggregate feeding behavior, which typically results in severe defoliation of the host plant. Despite the negative economic impact to ornamentals and contrary benefits as a biological control agent, there are few reports on the semiochemical communication of this family of insects. Uruguayan primrose-willow (Ludwigia hexapetala) is an invasive aquatic weed in California and serves as a host to A. litigata. To better characterize this association, the volatile emissions of A. litigata were collected while the flea beetles were: in containers by themselves, in containers with L. hexapetala leaves, in situ on L. hexapetala leaves in a growth chamber, and in situ on L. hexapetala leaves in the field. For comparison, the volatile emissions of A. litigata associated with two subspecies of creeping water primrose (L. peploides) were also evaluated. Two himachalene-type sesquiterpenes, showing the same carbon skeleton as compounds previously reported from Aphthona flava and Epitrix fuscula, were detected as volatiles from A. litigata.     

Modelling of occupational respirable crystalline silica exposure for quantitative exposure assessment in community-based case-control studies

We describe an empirical model for exposure to respirable crystalline silica (RCS) to create a quantitative job-exposure matrix (JEM) for community-based studies. Personal measurements of exposure to RCS from Europe and Canada were obtained for exposure modelling. A mixed-effects model was elaborated, with region/country and job titles as random effect terms. The fixed effect terms included year of measurement, measurement strategy (representative or worst-case), sampling duration (minutes) and a priori exposure intensity rating for each job from an independently developed JEM (none, low, high). 23,640 personal RCS exposure measurements, covering a time period from 1976 to 2009, were available for modelling. The model indicated an overall downward time trend in RCS exposure levels of -6% per year. Exposure levels were higher in the UK and Canada, and lower in Northern Europe and Germany. Worst-case sampling was associated with higher reported exposure levels and an increase in sampling duration was associated with lower reported exposure levels. Highest predicted RCS exposure levels in the reference year (1998) were for chimney bricklayers (geometric mean 0.11 mg m(-3)), monument carvers and other stone cutters and carvers (0.10 mg m(-3)). The resulting model enables us to predict time-, job-, and region/country-specific exposure levels of RCS. These predictions will be used in the SYNERGY study, an ongoing pooled multinational community-based case-control study on lung cancer.     

Scale and self-governance in agri-environment schemes: experiences with two alternative approaches in the Netherlands

Agri-environment schemes in the Netherlands have been criticized for their lack of effectiveness. Explanations were sought in the limited size of the individual farm and in the shallowness of the measures. We distinguish three scale problems: in the spatial dimension (from farm element to landscape), in the management dimension (from add-on measure to farming system) and in the governance dimension (from little to much space for self-governance by farmers). These scale concepts are used to translate insights from ecology and agro-economy to governance approaches. We analyse case studies of two new approaches: an area approach with group contracts and spatial coordination of agri-environmental measures, and a farming system with substantial adaptations of the farming concept. Both approaches have elements of increased self-governance and could offer inspiration for schemes elsewhere. We propose that appropriate space for self-governance is necessary when choosing another scale approach for making agri-environment schemes more effective.     

Leader‐member exchange,differentiation, and task interdependence: implications for individual and group performance

We investigated the effects of leader‐member exchange (LMX) differentiation on individual and group performance with a sample of 120 work groups consisting of 834 employees who represented six different organizations. LMX differentiation was defined as the degree of variability in the quality of LMX relationships formed within work groups. Hierarchical Linear Modeling (HLM) results did not indicate support for a main effect of LMX differentiation on individual performance. Rather, the results demonstrated that LMX moderated the relation between LMX differentiation and individual performance, such that increases in LMX differentiation were accompanied by increases in individual performance for low LMX members, but no change in individual performance for high LMX members. At the group level, there was not a main effect for LMX differentiation on group performance. However, the hierarchical regression results revealed that the relation between LMX differentiation and group performance was moderated by task interdependence, such that for groups high in task interdependence, the greater the differentiation among group members, the higher the performance of the group. Conversely, for groups with relatively lower levels of task interdependence, differentiation among subordinates was not related to group performance. Finally, LMX differentiation was positively related to group performance in groups with a low LMX median, but was not related to performance in groups with a high LMX median. Copyright © 2006 John Wiley & Sons, Ltd.     

Flexibility in daily travel routines causes regional variation in bird migration speed

We used novel Global Positioning System-based satellite telemetry to reconstruct daily time budgets on travelling days of a long-distance migrant, the Osprey Pandion haliaetus, to reveal how landscape affects migratory performance. We compared daily travel routines between the Ospreys’ passage of Europe and the Sahara. In Europe, where feeding habitat is abundant, Ospreys fed both before–after flights and during interruptions, thus, combining migration with foraging. This resulted in a 2.7-h shorter daily flight period in Europe than in the Sahara. A calculated energy budget indicated that a ‘fly-and-forage migration strategy’ is favourable in Europe because associated benefits (energy intake) more than outweigh costs (reduced flight time). The much shorter flight time in Europe was the main explanation why Ospreys covered on average 78 km less distance on a travelling day in Europe than in the Sahara. In addition, there were regional differences in hourly flight speeds that are most probably the result of variation in thermal soaring conditions. We conclude that landscape properties have a profound effect on migration through regional variation in daily routines.     

Concentrations of Particulate Matter Emitted from Large Cattle Feedlots in Kansas

Effective August 1, 1978 the Government of Canada ordered that all future federal regulations of significant economic import, covering the subjects of health, safety and fairness be preceded by the publication of a formal socioeconomic impact analysis (SEIA). Environmental protection regulations are included. I encountered my first public reaction to this announcement at a conference in Ottawa on the subject of “Jobs and the Environment”. A union official duly observed that the SEIA was obviously industry’s answer to having to carry out Environmental Impact Assessments. Not much later, I was told by a senior environmental official of an overseas country that what SEIA really did was to place the burden of proof on governments as to the need for control, rather than leaving industry to show that their activities were not damaging to the environment.     

ESTIMATING EROSION RISKS ASSOCIATED WITH LOGGING AND FOREST ROADS IN NORTHWESTERN CALIFORNIA1

ABSTRACT: Erosion resulting from logging and road building has long been a concern to forest managers and the general public. An objective methodology was developed to estimate erosion risk on forest roads and in harvest areas on private land in northwestern California. It was based on 260 plots sampled from the area harvested under 415 Timber Harvest Plans completed between November 1978 and October 1979. Results confirmed previous findings that most erosion related to forest management occurs on a small fraction of the managed area. Erosion features larger than the minimum size inventories in this study (> 13 yd³) occupied only 0.2 percent of the area investigated. Linear discriminant analysis was used to develop two equations for identifying critical sites (sites with erosion >100 yd³ac^?1). The equations were based on slope, horizontal curvature (an expression of local topography), and soil color (on road sites) or the strength of the underlying rocks (on harvest sites). The equations can be used in planning to estimate the erosion risk of proposed activities. They can also be used to estimate acceptable risk thresholds based on the value of competing resources.     

Enhanced oil recovery: Environmental issues and state regulatory programs

During 1977–1978, Oak Ridge National Laboratory (ORNL) prepared environmental impact assessments for nine U.S. Department of Energy-sponsored enhanced oil recovery (EOR) field demonstration projects located in six states and reviewed the oil regulations for all oil-producing states. These evaluations revealed some potentially important environmental impacts associated with EOR including (1) pollution of land and surface waters from spills or leaks of oil and brine or other chemicals, (2) loss of biota, (3) excessive erosion and sedimentation (mostly in hilly terrain) and subsequent deterioration of surface-water quality, (4) contamination of groundwater, and (5) excessive air emissions from thermal operations. Potential groundwater impacts include (1) production of toxic and carcinogenic substances from synergistic interactions among chemicals used primarily in the micellar-polymer flooding technique, (2) formation of acid waters with small amounts of oil and metal residues and oxides from in situ combustion, and (3) corrosion of well casings and potential leaks of hydrogen sulfide primarily from injection of miscible carbon dioxide. For use of EOR techniques to expand in an environmentally acceptable manner, environmental planning (including monitoring, protection measures, and reclamation strategies) must be an integral part of the initial project development. Acceptable monitoring, prevention, mitigation, and reclamation procedures are available for most of the identified environmental problems, but the best techniques may not be known by operators or required by law. Most states have stringent controls for plugging abandoned wells and disposal of waste material, but these may not be enforced because of limited staff and funds. However, other environmental considerations, e.g., reclamation plans, water quality and other monitoring programs, and abandonment plans, are often lacking. The need for additional environmental planning and monitoring requirements specific to the oil-production industry is emphasized. States are encouraged to continue strengthening and upgrading their oil-regulatory programs to safeguard the environment. More studies are needed on (1) toxicity and carcinogenicity of chemicals used in injection processes, (2) evaluation of groundwater monitoring methods, and (3) reclamation procedures for soils contaminated by oil and brine.