Photodegradation and volatility of pesticides

BACKGROUND AND OBJECTIVES: Among the factors affecting the environmental fate of surface-applied pesticides several biological as well as abiotic factors, such as volatilization and photochemical transformations are of particular interest. Whereas reliable measurement methods and models for estimating direct photodegradation are already available for the compartments of water and atmosphere and individual subprocesses have already been described in detail, there is still a need for further elucidation concerning the key processes of heterogeneous photodegradation of environmental chemicals on surfaces. METHODS: In order to systematically examine the direct and indirect photodegradation of 14C-labeled pesticides on various surfaces and their volatilization behavior, a new laboratory device ('photovolatility chamber') was designed according to US EPA Guideline 161-3. Model experiments under controlled conditions were conducted investigating the impact of different surfaces, i.e. glass, soil dust and radish plants, and environmental factors, i.e. irradiation and atmospheric ozone (O3), on the photodegradation and volatilization of surface-deposited [phenyl-UL-14C]parathion-methyl (PM). RESULTS AND DISCUSSION: Depending on the experimental conditions, parathion-methyl was converted to paraoxon-methyl, 4-nitrophenol, unknown polar products and 14CO2. With respect to the direct photodegradation of PM (experiments without O3), the major products were polar compounds and 14CO2, due to the rapid photochemical mineralization of 4-nitrophenol to 14CO2. Paraoxon-methyl and 4-nitrophenol formation was mainly mediated by the combination of light, O3, and *OH radicals. In radish experiments PM photodegradation was presumably located in the cuticle compartment, which exhibited a sensitized photodegradation, as more unknown products were yielded compared to the glass and soil dust experiments. This could be explained by intensifying the inherent PM degradation in the dark with the same product spectrum. Due to photochemical product formation, which is an antagonistic process to the volatilization of parent compound, the volatilization of unaltered parathion-methyl from each surface generally decreased in the presence of light, particularly in combination with increasing O3 concentrations and *OH radical production rates. CONCLUSION: First results demonstrated that the photovolatility chamber provides a special tool for the systematic evaluation of (a) photodegradation of surface-located pesticide residues, i.e. measuring qualitative aspects of direct and indirect photodegradation together with relative photodegradation rates, and (b) volatilization of pesticides on surfaces by including and optionally varying relevant parameters such as light, atmospheric O3 concentration, surface temperature, air temperature, air flow rate. OUTLOOK: The experimental facility represents an important complement to lysimeter and field studies, in particular for experiments on the volatilization of pesticides using the wind tunnel system. With the photovolatility chamber special experiments on photodegradation, volatilization and plant uptake can be conducted to study key processes in more detail and this will lead to a better understanding of the effects of certain environmental processes on the fate of released agrochemicals contributing to an improved risk assessment.     

Experimental studies in the electrostatic precipitation of high-resistivity particulate

A pulsed charging system is described that eliminates reverse ionization inelectrostatic precipitation. The motivating concept is a purely electrical approach. The fundamental characteristic of this method is the relaxation time of the precipitated particulate. Laboratory studies indicate that this powering concept could increase precipitator performance on high-resistivity particulate by more than two orders of magnitude. Pilot results are also presented.     

Organizational level as a moderator of the relationship between justice perceptions and work‐related reactions

In this study, we examined the role of organizational level as a moderator of the relationships of procedural and distributive justice with seven employee attitudes and behaviors. Based on social identity and resource allocation theories, we suggested an allocational model of authority in organizations. We posited that lower rank encourages a more process‐oriented perspective that emphasizes procedural concerns while higher rank imbues a more result‐oriented perspective that emphasizes distributive outcomes. We considered the cultural context that characterized work relationships in our sample of respondents from a Chinese state‐owned enterprise. Significant sets of interactions supported the predicted relationships of procedural justice with three outcomes at lower levels and distributive justice with four outcomes at higher levels. Implications and extensions of these findings are considered. Copyright © 2006 John Wiley & Sons, Ltd.     

Ignition of dust-air atmospheres by ultrasonic waves

This paper shows the results of our investigations on the ignition source ultrasound in dust-air atmospheres. Ultrasound is, on the one hand, considered to be an ignition source according to international safety standards (EN 1127–1 (2011)). On the other hand, though, ultrasound is used for various applications in gases and air, such as level and flow measurement, or in the process industry, but no explosion accidents have yet been reported. Our research now shows that it is indeed possible to ignite dust-air mixtures in ultrasound fields under certain conditions. We conducted our experiments in an ultrasound standing wave field and used maize starch, calcium stearate and sulfur dust. For ignitions, an absorbing target was needed to convert the acoustic energy into heat. From theoretical estimations and experiments critical conditions that provoke ultrasonically triggered explosions are identified.     

A test of value congruence effects

This study investigated value congruence effects on organizational commitment and job satisfaction. We used the competing values framework to measure values, and response‐surface methodology employing polynomial regression equations to investigate congruence effects. Our sample, 1,358 hospital employees, made judgments about their personal preferences for the four competing value sets—internal process, open systems, rational goal, and human relations. They also rated how much the same values were operating in the organization. We predicted that organizational commitment and job satisfaction would be maximized when a ‘match’ or ‘congruence’ occurred between the two component value measures. We evaluated congruence effects using the following criteria: (1) the proportion of variance explained by the overall equation was significant; (2) the quadratic and interaction terms were significant individually and as a set, and their signs were in the right direction; (3) the implied constraints were valid; and (4) no higher‐order terms beyond those indicated by the model were significant. The results indicated that although quadratic and interaction components were present in all eight models, they were weak in their support for congruence. The study's findings suggested that congruence effects were relatively unimportant compared to main effects in explaining variance in organizational commitment and job satisfaction, at least in the large organization we investigated in this study. Copyright © 1999 John Wiley & Sons, Ltd.     

Long work hours: a social identity perspective on meta‐analysis data

The current study utilizes social identity theory to investigate employees' work hours. Specifically, we use meta‐analysis to examine the relationships between hours worked and indicators of organizational identity (e.g., organizational support and tenure), occupational identity (e.g., human capital investments and work centrality), and family identity (e.g., family responsibilities and family satisfaction). The meta‐analysis also allowed us to explore other important correlates of hours worked (e.g., situational demands, job performance, mental health, and physical health), moderating variables (e.g., age, gender, and job complexity), and curvilinear relationships of work hours to social identity indicators. Overall, we found that occupational factors and situational demands had the strongest relationships with hours worked, hours worked were negatively associated with measures of employee well‐being, gender had several significant moderating effects, and there were curvilinear relationships between hours worked and well‐being and work–family conflict variables. The article concludes with directions for future theoretical and empirical research. Copyright © 2008 John Wiley & Sons, Ltd.     

General health status and functional disability following injury in traffic crashes

OBJECTIVE: With increasing rates of survival associated with traffic crashes, a shift to understand the consequences of injury has risen to prominence. This prospective cohort study set out to examine general health status and functional disability at 2 months and 6-8 months post-crash. METHODS: Participants were otherwise healthy adults aged 18-59 years admitted to hospitals, excluding those with moderate-severe head injury and spinal cord injury. Sixty-two adults completed interviews prior to discharge and at 2 months and 8 months post-discharge. RESULTS: By 8 months post-crash, 89 percent had resumed employment and or study, two thirds rated the resolution of their medical problems to be excellent (14.5 percent) or good (53 percent), and 82 percent were considered to be fully self-sufficient with respect to activities of daily living. Despite this, results from the SF-36 indicated significant reductions in health status at 2 and 8 months post-crash relative to pre-crash health, with domain scores up to 26 percent lower than pre-crash scores, while assessment of activities of daily living indicated residual functional disability at both follow-up times. Self-reported pain was higher for both males and females at both follow-up times compared with pre-crash self-reported pain. CONCLUSION: This study demonstrated significant, ongoing loss of health-related quality of life and impairment associated with injuries sustained in road crashes, highlighting the need for continuing care post-discharge to facilitate a rapid return to optimal health.     

Low back pain among residential carpenters: ergonomic evaluation using OWAS and 2D compression estimation.

Occupational low back pain (LBP) remains a leading safety and health challenge. This cross-sectional investigation measured the prevalence of LBP in residential carpenters and investigated ergonomic risk factors. Ninety-four carpenters were investigated for LBP presence and associated risk factors. Ten representative job-tasks were evaluated using the Ovako Working Posture Analysis System (OWAS) and ErgoMaster 2D software to measure elements of posture, stress, and risk. Job-tasks were found to differ significantly for total lumbar compression and shear at peak loading (p < .001), ranging from 2 956 to 8 606 N and 802 to 1 974 N respectively. OWAS indicated that slight risk for injury was found in 10 job-tasks while distinct risk was found in 7 of the 10 job-tasks. Seven of the 10 job-tasks exceeded the National Institute for Occupational Safety and Health (NIOSH) action limit of 3 400 N for low back loading. The point prevalence for LBP was 14% while the annual prevalence was 38%.