Effects of composing on sorption capacity of bagasse-based chars

A fresh bagasse sample (0-month) and two composted bagasse and pig manure mixed samples (1-month and 6-month) were used to produce carbon chars. Sample pyrolysis showed greater carbon char yields were obtained from the compost samples than from the bagasse sample. Fourier transform infrared spectra suggested that the chemical structures of the bagasse sample and the two compost samples were quite different, but that the three carbon chars obtained from those precursors were similar. Among the three pyrolyzed chars, the 0-month bagasse char displayed the largest sorption capacity of 3333 mg kg^?1 for the hydrophilic pollutant phenol, presumably resulting from its greater carbon content and O/C ratio. However, the sorption capacities for the hydrophobic pollutant naphthalene of the tow compost chars (3-month, 2001 mg kg^?1; 6-month, 1667 mg kg^?1) were greater than that of the 0-month bagasse char (1428 mg kg^?1). The results indicate that the compost chars had a greater preferential affinity for naphthalene than that in the bagasse char, suggesting that the compost chars possessed greater hydrophobicity.     

Influences of macroalga-derived dissolved organic carbon on the aquatic toxicity of copper and cadmium

In this study, the effect of dissolved organic carbon (DOC) derived from macroalga (Sargassum) on the acute toxicity of copper (Cu) and cadmium (Cd) to a freshwater cladoceran (Daphnia magna) was investigated. Potassium-loaded macroalga was incubated with ultrapure water to extract macroalgal DOC, which was then spiked with the constituents of the Elendt M7 hard water media. The 48 h median lethal concentration of Cu increased linearly with DOC levels but that of Cd was relatively independent of DOC levels (0-44 mg l(-1)). The independence of Cd toxicity on DOC level might be due to the competitive effect of high calcium concentrations in the media with Cd for the binding sites of DOC. The decreased Cu toxicity was a result of reduced Cu uptake as evidenced in a separate accumulation test. Also, the capability of the macroalgal DOC on reducing Cu toxicity was found to be comparable to DOC tested in other studies. Therefore, the present study suggested that the biosorption treatment process using macroalgae should consider the effect of DOC release from the biomass as a step of modifying the metal toxicity as well as influencing metal biosorption capacity.     

Influence of glyphosate and its formulation (Roundup) on the toxicity and bioavailability of metals to Ceriodaphnia dubia

This study examined the toxicological interaction between glyphosate (or its formulation, Roundup) and several heavy metals to a freshwater cladoceran, Ceriodaphnia dubia. We demonstrated that all binary combinations of Roundup and metals (Cd, Cu, Cr, Ni, Pb, Se and Zn) exhibited "less than additive" mixture toxicity, with 48-h LC50 toxic unit > 1. Addition of glyphosate alone could significantly reduce the acute toxicity of Ag, Cd, Cr, Cu, Ni, Pb and Zn (but not Hg and Se). The ratio between glyphosate and metal ions was important in determining the mitigation of metal toxicity by glyphosate. A bioaccumulation study showed that in the presence of glyphosate the uptake of some metals (e.g. Ag) was halted but that of others (e.g. Hg) was increased significantly. Therefore, our study strongly suggests that glyphosate and its commercial formulations can control the toxicity as well as the bioavailability of heavy metals in aquatic ecosystems where both groups of chemicals can co-occur.     

Employee responses to employment‐relationship practices: The role of psychological empowerment and traditionality

In studying the effect of employment‐relationship practices on employees, research has largely ignored individual differences, both cross‐culturally and within cultures. In this study, the authors examine the moderating effect of middle managers' traditionality, a within‐culture value orientation regarding submission to authority and endorsement of hierarchical role relationships, on their responses to an organization's employee–organization relationship practices. Based on social learning and social exchange theories, the authors expect the more traditional middle managers to respond less positively in terms of their performance and commitment to high levels of expected contributions and the associated psychological empowerment but respond more positively to high levels of offered inducements. Using a sample of 535 middle managers from 40 companies in China, the authors find support for all hypotheses except the moderating effect of traditionality on the relationship between offered inducements and performance. Additional analysis reveals that less‐traditional managers responded to economic rewards (but not developmental rewards) with higher job performance. The paper concludes with a discussion of implications for research and the practice of employment relationships. Copyright © 2014 John Wiley & Sons, Ltd.     

Establishment and applied research on environmental sustainability assessment indicators in Taiwan

The study utilizes the method of Material Flow, Ecological Footprint Model and other related indicators to establish the Indicator System of Sustainable Development. Principal Component Analysis is used to abstract the representative factors in order to estimate the indicators of ecological sustainable development during 1998~2005 in Taiwan, as well as to make policy recommendations. The research indicates following results: (1) The Direct Material Input (DMI) of Taiwan shows constant instability and depends on heavy import activity. The annual increase of considerable greenhouse gas emission leads to a comparative growth of the Domestic Process Output (DOP). The both material consumption and inventory formation of the economy are unsteady. In addition, the Physical Trade Balance (PTB) indicates that supply exceeds demand, as well as the occasional shortage of building materials. (2) The 2005 per capita Ecological Demand footprint in Taiwan is 6.5392 hm(2), making the Ecological Deficit per capita 4.8569 hm(2). The figures reflect that productivity and life intensity of residents have exceeded the carrying capacity of Taiwan's ecological economic system. (3) The overall Synthetic Trend Indicators of Sustainable Development in Taiwan are decreasing. Therefore, if proper measures are not adopted in time, the current weak sustainability will lead into the vicious circle which departs from sustainable development.     

Effects of 4-methylbenzylidene camphor (4-MBC) on neuronal and muscular development in zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) embryos

The negative effects of overexposure to ultraviolet (UV) radiation in humans, including sunburn and light-induced cellular injury, are of increasing public concern. 4-Methylbenzylidene camphor (4-MBC), an organic chemical UV filter, is an active ingredient in sunscreen products. To date, little information is available about its neurotoxicity during early vertebrate development. Zebrafish embryos were exposed to various concentrations of 4-MBC in embryo medium for 3 days. In this study, a high concentration of 4-MBC, which is not being expected at the current environmental concentrations in the environment, was used for the purpose of phenotypic screening. Embryos exposed to 15 μM of 4-MBC displayed abnormal axial curvature and exhibited impaired motility. Exposure effects were found to be greatest during the segmentation period, when somite formation and innervation occur. Immunostaining of the muscle and axon markers F59, znp1, and zn5 revealed that 4-MBC exposure leads to a disorganized pattern of slow muscle fibers and axon pathfinding errors during the innervation of both primary and secondary motor neurons. Our results also showed reduction in AChE activity upon 4-MBC exposure both in vivo in the embryos (15 μM) and in vitro in mammalian Neuro-2A cells (0.1 μM), providing a possible mechanism for 4-MBC-induced muscular and neuronal defects. Taken together, our results have shown that 4-MBC is a teratogen and influences muscular and neuronal development, which may result in developmental defects.     

Environmental fate and non-target impact of glyphosate-based herbicide (Roundup) in a subtropical wetland

Mai Po Nature Reserve (Hong Kong) is an internationally important wetland for waterbirds. Roundup, a formulation based on glyphosate, has been used to control the widespread weeds within the reserve for many years but the fate and non-target impact of the herbicide is unknown. To fill this knowledge gap, we applied Roundup by hand-held sprayer to an estuarine and a freshwater pond in the dry season of year 2002. The surface water and sediment were sampled routinely for glyphosate concentrations following one month of application. In situ bioassays using local edible fish species were performed along with the herbicide application. Up to 52% of glyphosate in the surface water was transported to the unapplied regions by wind-driven current in the estuarine pond at 1 DPT (day post treatment). For both ponds, glyphosate concentrations in the water decreased rapidly after 1-3 DPT, but then decreased gradually over time. Both physical adsorption to the bottom sediments and microbial degradation are thought to contribute to these decreases. Interestingly, the persistence of glyphosate in the freshwater pond was longer than in the estuarine system, which is likely due to the considerably higher concentrations of chelating metals (i.e. Cu and Fe) present in the sediment (4.5 and 11-fold higher, respectively) which potentially reduced the bioavailability of glyphosate to the microbial decomposers. Lastly, fishes used in the in situ bioassays (both in applied and unapplied areas) showed similar survival rates, indicating that the use of Roundup at the provided application rate posed no serious hazard.     

Parathion degradation and its intermediate formation by Fenton process in neutral environment

The purpose of this study is to investigate parathion degradation by Fenton process in neutral environment. The initial parathion concentration for all the degradation experiments was 20 ppm. For hydrogen ion effect on Fenton degradation, the pH varied from 2 to 8 at the [H₂O₂] to [Fe²⁺] ratio of 2-2 mM, and the result showed pH 3 as the most effective environment for parathion degradation by Fenton process. Apparent degradation was also observed at pH 7. The subsequent analysis for parathion degradation was conducted at pH 7 because most environmental parathion exists in the neutral environment. Comparing the parathion degradation results at various Fenton dosages revealed that at Fe²⁺ concentrations of 0.5, 1.0 and 1.5 mM, the Fenton reagent ratio ([H₂O₂]/[Fe²⁺]) for best-removing performance were found as 4, 3, and 2, resulting in the removal efficiencies of 19%, 48% and 36%, respectively. Further increase in Fe²⁺ concentration did not cause any increase of the optimum Fenton reagent ratio for the best parathion removal. The result from LC-MS also indicated that hydroxyl radicals might attack the PS double bond, the single bonds connecting nitro-group, nitrophenol, or the single bond within ethyl groups of parathion molecules forming paraoxons, nitrophenols, nitrate/nitrite, thiophosphates, and other smaller molecules. Lastly, the parathion degradation by Fenton process at the presence of humic acids was investigated, and the results showed that the presence of 10 mg L⁻¹ of humic acids in the aqueous solution enhanced the parathion removal by Fenton process twice as much as that without the presence of humic acids.