Mercury transport between sediments and the overlying water of the St. Lawrence River area of concern near Cornwall, Ontario

Contaminated sediments in the St. Lawrence River remain a difficult problem despite decreases in emissions. Here, sediment and pore water phases were analyzed for total mercury (THg) and methyl mercury (MeHg) and diffusion from the sediment to the overlying water was 17.5 ± 10.6 SE ng cm⁻² yr⁻¹ for THg and 3.8 ± 1.7 SE ng cm⁻² yr⁻¹ for MeHg. These fluxes were very small when compared to the particle-bound mercury flux accumulating in the sediment (183 ± 30 SE ng cm⁻² yr⁻¹). Studies have reported that fish from the westernmost site have higher Hg concentrations than fish collected from the other two sites of the Cornwall Area of Concern, which could not be explained by differences in the Hg flux or THg concentrations in sediments, but the highest concentrations of sediment MeHg, and the greatest proportions of MeHg to THg in both sediment and pore water were observed where fish had highest MeHg concentrations.     

Predicting the form and direction of work role performance from the Big 5 model of personality traits

This research examined the prediction of the form and direction of work role performance from the Big 5 model of personality traits. Nine dimensions of work role performance are created by cross‐classifying the form of work role behavior (proficient, adaptive, and proactive) with the level at which that behavior contributes to effectiveness (individual, team, and organizational). The authors collected self‐report measurements of personality from 1447 government employees and supervisor ratings of performance. Openness to experience and agreeableness had opposing effects on individual proactivity – openness was positively related, whereas agreeableness was negatively related to this dimension. Openness to experience also had opposing effects on the form of work role performance – it was positively related to individual and organizational proactivity but negatively related to team and organizational proficiency. Conscientiousness was a stronger predictor of individual task proficiency than the remaining eight dimensions, whereas the reverse was true for neuroticism. Extraversion was negatively related to individual proficiency. Using a broad taxonomy of performance that incorporates a theoretical framework for distinguishing between constructs shows promise for identifying which personality traits are important for which aspects of work role performance. Copyright © 2011 John Wiley & Sons, Ltd.     

Carbon stocks,emissions, and aboveground productivity in restored secondary tropical peat swamp forests

Mitigation and Adaptation Strategies for Global Change - Tropical wetlands such as peat swamp forests (PSFs) have been known globally as one of the carbon (C)-rich ecosystems. However, there is...     

Nitrous oxide gas removal by using compost-based biofilter medium

This paper is aimed at introducing our research result in the efficiency in removing nitrous oxide gas (N2O) by using compost as a medium filter,which is actually a kind of manure derived from cow faeces at Kukusan Kelurahan farm containg wood chips and some other microorganisms.Practically speaking,N2O is a major greenhouse gas,whose continuous presence in the atmosphere is expected to last over a 100 years and produce its radiative warming effect just next to CO2.In spite of its rather small concentration in the atmosphere,it is the Number Four largest greenhouse gas contributor to the overall global warming,behind carbon dioxide,methane and water vapour.The biofiltration experiments we have conducted to explore its removing rate of N2O from flue gas help us to find various operating factors in the biofilter system.So far as we know,N2O gas has been fed from the top of the column.It was flowing through the column when it is made to get circulated with a peristaltic pump for 6 hours.The data obtained in our paper prove to be in conformity with the Langmuir adsorption model.The highest N2O gas removing efficiency can be made to be as high as 70.22% at the highest biofilter length of 50 cm with the gas flowing rate of 200 mL/min.The results of this research have finally been modeled by the Langmuir adsorption isotherm formula with its K value obtained being 16.949 L/mol.     

Evaluation of extracted organic carbon and microbial biomass as stability parameters in ligno-cellulosic waste composts

Extracted organic C and microbial biomass were evaluated as stability parameters in 3 different ligno-cellulosic waste composts. Organic C was extracted by both water and alkali and further separated in humic-like carbon (HLC) and nonhumic carbon (NHC). Conventional humification parameters, such as humification index and degree of humification were calculated from NHC and HLC. Microbial biomass carbon (B(C)) was determined as an indicator of the degree of biochemical transformation, whereas ninhydrin reactive N (B(NIN)) was measured to obtain the stability parameter B(NIN)/N(TOT) (N(TOT), total N). The water-extracted organic C did not provide reliable information on the transformations underwent by the ligno-cellulosic wastes during composting, since its content remained almost unaltered during the whole process. In contrast, parameters based on the alkali-extracted organic C and microbial biomass clearly reflected organic matter (OM) changes during the process. There was an increase in the net amount of HLC in the alkali extracts throughout composting, especially in the first 7 to 12 wk of the process, as well as a relative enrichment of HLC with respect to NHC. Values of humification index and degree of humification in end products were consistent with an adequate level of compost stability. The stability parameter B(NIN)/N(TOT) showed to be a reliable indicator of stability in ligno-cellulosic wastes. Parameters based on the alkali-extracted C and microbial biomass clearly reflected the transformation of the OM during composting and can be used as stability parameters in ligno-cellulosic waste composts.