Production supervisor impacts on subordinates' safety outcomes: an investigation of leader-member exchange and safety communication

PROBLEM: Supervisors are increasingly important to the functioning of manufacturing operations, in large part due to their role as leaders. While supervisors' relations and communication with their subordinates are known to be important in influencing subordinates' behavior, little is known about how these two factors will impact subordinates' safety. This study investigated how much each factor contributes to safety-related outcomes for blue-collar production employees. METHOD: Production employees at five Pennsylvania wood manufacturers completed a survey during their work shift. Five hundred and ninety eight employees provided data on leader-member exchange (LMX), safety communication, and safety-related events. Archival data on OSHA recordables were also obtained from the producers' human resources database. RESULTS: Analyses found that the influence of LMX was greater than that of safety communication in predicting safety-related events. Neither LMX nor safety communication was significantly related to OSHA recordables. Results also demonstrated that employee job satisfaction and demographic variables such as gender and age have safety implications. IMPACT ON INDUSTRY: Results from this study further emphasize the importance of production supervisors and illustrate the potential role of leader-member exchange in enhancing workplace safety. Specifically, organizations should foster positive social exchange between their employees and supervisors and enhance the leadership qualities of supervisors to help reduce workplace injuries.     

Occurrence and fate of pharmaceutical and personal care products in a sewage treatment works

The occurrence and fate of eight pharmaceutical and personal care products (PPCPs) during sewage treatment has been studied in a pilot-scale treatment plant, comprising a primary settler (2.85 m(3)), an aeration tank (1.845 m(3)) and a secondary clarifier (0.5 m(3)), placed on site at a wastewater treatment works in the north west of the UK. It was fed both with raw sewage and the return liquor produced after sludge centrifugation, thus representing the most common configuration for a municipal sewage treatment plant based on the activated sludge process. Samples were taken at six different locations, including the return liquor stream, and analysed for musk fragrances and pharmaceutically active compounds belonging to various therapeutic groups such as anti-inflammatory drugs, tranquillisers and antiepileptics. Mass balances were conducted for those PPCPs that were quantifiable. The fate of the PPCPs was found to differ according to their physical-chemical characteristics. Anti-inflammatories underwent a degradation process and were almost completely removed from sewage during the biological treatment step. Musk fragrances were only partially removed, through adsorption onto the primary suspended solids and the biomass in the aerobic process, due to their strong lipophilic characteristics. The results of this study provide increasing evidence that the partial removal of these substances through the sewage treatment process contribute to the environmental occurrence of PPCPs. Consequently, existing STPs should be upgraded in order to attenuate the release of these substances into the aquatic environment.     

Influence of environmental factors on burrow irrigation and oxygen consumption in the mudflat invertebrate Urechis caupo

We examined burrow irrigation activity by the mudflat worm Urechis caupo in response to suspended food, ambient hypoxia (down to 3.3 kPa PO₂), hydrogen sulfide exposure (up to 100 µmol l^-1), and short-term temperature change (range 10-22°C). In normoxic, nutrient-free water at 14°C, O₂ consumption ( [(M)\dot]O₂ ) \left( {\dot M{\rm O}_2 } \right) was 45 nmol min^-1 g^-1, water flow rate ( [(V)\dot]_W ) \left( {\dot V_{\rm W} } \right) was 27 ml min^-1 (0.66 ml min^-1 g^-1), frequency of peristaltic waves (F_P) was 2.6 contractions min^-1, stroke volume (SV) was 11 ml, and O₂ extraction coefficient (EO₂) was 0.27. Adding suspended food to the burrow water occasionally elicited stereotypical feeding behavior but had no effect on any measured variables during nonfeeding periods. Hypoxia greatly decreased [(M)\dot]O₂ \dot M{\rm O}_2 (75% reduction at 3.3 kPa PO₂) but did not affect [(V)\dot]_W \dot V_{\rm W} , F_P, SV, or EO₂. Sulfide at 50 µmol l^-1 or less had no effect on burrow irrigation activity, whereas 100 µmol l^-1 sulfide decreased [(V)\dot]_W \dot V_{\rm W} by 58% and F_P by 50% but had no effect on SV. Temperature strongly affected [(V)\dot]_W \dot V_{\rm W} (Q₁₀ of 1.9 from 10°C to 22°C). We propose that U. caupo's ability to live in the hypoxic, sulfidic mud of productive mudflat environments, combined with its very efficient mucous net, allows it to process much less water for feeding than other suspension-feeding invertebrates. This, in turn, necessitates an efficient O₂ extraction mechanism, which is provided by the water lung activity of U. caupo's unique hindgut.     

The geographic distribution of trace elements in the environment: the REGARDS study

Research on trace elements and the effects of their ingestion on human health is often seen in scientific literature. However, little research has been done on the distribution of trace elements in the environment and their impact on health. This paper examines what characteristics among participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study are associated with levels of environmental exposure to arsenic, magnesium, mercury, and selenium. Demographic information from REGARDS participants was combined with trace element concentration data from the US Geochemical Survey (USGS). Each trace element was characterized as either low (magnesium and selenium) or high (arsenic and mercury) exposure. Associations between demographic characteristics and trace element concentrations were analyzed with unadjusted and adjusted logistic regression models. Individuals who reside in the Stroke Belt have lower odds of high exposure (4th quartile) to arsenic (OR 0.33, CI 0.31, 0.35) and increased exposure to mercury (OR 0.65, CI 0.62, 0.70) than those living outside of these areas, while the odds of low exposure to trace element concentrations were increased for magnesium (OR 5.48, CI 5.05, 5.95) and selenium (OR 2.37, CI 2.22, 2.54). We found an association between levels of trace elements in the environment and geographic region of residence, among other factors. Future studies are needed to further examine this association and determine whether or not these differences may be related to geographic variation in disease.     

Demographic antecedents and performance consequences of structural holes in work teams

This paper addresses two important questions concerning social fragmentation in work teams. First, from where do disconnections between team members, measured in terms of the proportion of structural holes within the work team, derive? Second, what are the consequences for team performance of having more or less structural holes between team members? In answering the first question, the research investigated whether demographic diversity in teams played a role in predicting the proportion of structural holes in team friendship networks. For 19 teams at a wood products company, there were no effects of ethnic and gender diversity on structural hole proportions. However, age diversity significantly reduced the extent of structural ‘holeyness.’ In investigating the second question, two countervailing tendencies were considered. In the absence of structural holes, teams are likely to be at low risk for new ideas. But fragmented teams in which team members are separated by many structural holes are likely to have difficulty coordinating. The researchers demonstrated a curvilinear effect: a moderate level of structural diversity in teams was positively associated with team performance. Thus, the research suggested that it is structural diversity (measured in terms of the proportion of structural holes) rather than demographic diversity that matters in the prediction of team performance. Copyright © 2006 John Wiley & Sons, Ltd.