Chemical and toxicological evaluation along with unprecedented transformation products during photolysis and heterogeneous photocatalysis of chloramphenicol in different aqueous matrices

Environmental Science and Pollution Research - As the presence of antibiotics in environmental waters enhances antimicrobial resistance, photolysis and heterogeneous photocatalysis of...     

The value of chick feathers to assess spatial and interspecific variation in the mercury contamination of seabirds

In 1991 we compared eggs, down and body feathers of chicks of Common Terns, Herring Gulls and Black-headed Gulls in their utility to assess contamination with mercury. Like eggs feathers distinctly show interspecific and intersite differences in contamination. Highest levels were found in Common Terns, lowest in Black-headed Gulls. Chicks hatched at the Elbe had much higher mercury levels than those in other areas of the German North Sea coast. Conversion ratios between tissues have to be used with caution.     

Heavy-metal ion complexation by particulate matter in the leachate of solid waste: a multi-method approach

The metal ion binding characteristics of particulate matter obtained from column experiments on the anaerobic digestion of solid waste were studied using a titrimetric approach. The experimental set-up allowed us to study the dynamics of particle bound ligand concentrations during digestion processes typically found in landfills.We developed a continuous titration method by simultaneously using a Cd-sensitive and pH electrode and combining metal and acid/base titrations. This technique allows for a more precise determination of pK_a-log K_M pairs for each ligand than metal titrations alone. The results were compared with titration methods using differential pulse anodic stripping voltammetry (DPASV) and atomic absorption spectroscopy (AAS) with longer equilibration times in order to further characterize ligand properties such as reaction kinetics, the electrochemical lability of the respective complex during DPASV, the distinction between metal adsorption to particulate matter and metal complexation by soluble ligands adhered to particles, reversibility of the binding process by competition studies, and resistance against purging with nitrogen gas.The properties of seven major metal binding ligands were identified and assignments to the most likely functional groups were made. The most important ligand properties are for ligand A: pK_a ≈ 9.2, log K_cd ≈ 7.0 fast reaction kinetics (mercapto groups); ligand B: pK_a = 4.8, log K_Cd ≈ 6.0, slow reaction kinetics (chelates with 3 or 4 carboxylic groups); ligand C: pK_a ≈ 6.0, log K_Cd ≈ 13.0, irreversible metal binding at basic pH-values (uptake inside bacterial cells); ligand D: pK_a = 7.7, log K_Cd = 4.0, runs parallel to N content of particulate matter with digestion time (primary amines neighboring oxo groups); ligand E: pK_a ≈ 12.0, log K_Cd = 9.0, runs parallel to P content of particulate matter (phosphate); ligand F:pK_a > 9.0, log K_{Cdf = pKa + 0.4}, runs parallel to N content of particulate matter (primary amines neighboring SH groups); and ligand G: pK_a ≤ 4.8, log K_Pb ≈ 4.3, strong Pb²⁺ ligand, even at low pH-values.Metal ions were found to be irreversibly bound by ligand C at low heavy-metal concentratins, whereas at higher concentrations the binding is reversible and can be predicted using the mass of the digestion process (methanogenic phase). All other ligands have their concentration maximum in the transition phase between acetogenic and methanogenic phase.     

Neuroscience and organizational behavior: Avoiding both neuro‐euphoria and neuro‐phobia

Organizational neuroscience has great promise for advancing organizational research and practice. The field, however, is developing rapidly and has also become the subject of technological and methodological challenges that must be considered when conducting or interpreting neuroscience research as applied to organizational behavior. We explore four issues we deem to be important in understanding the role of neuroscience in organizational behavior research: (i) neuroscientific research and reductionism; (ii) the need to address methodological and technological challenges in conducting this type of research; (iii) how neuroscientific research is meaningful in organizations (the “So what?” issue); and (iv) neuroscience as just another management fad. In addressing these issues, we hope to set out a roadmap that will enable organizational scholars to avoid past mistakes and thus serve to advance multidisciplinary research in organizational behavior using neuroscientific approaches. Copyright © 2014 John Wiley & Sons, Ltd.     

Estimating the marginal cost of nature conservation: evidence from Israel

Contrary to many studies regarding the efficient use of resources that measure the marginal cost of nature conservation by looking at a specific objective and asks about efficient way to achieve it, this article tries to estimate the (marginal) cost of nature conservation in a more flexible way. Instead of looking at a specific objective and then not being able to compare different objectives, we take an approach that is based on experts’ valuation of increased satisfaction from nature conservation. We trace the marginal cost of conservation from their answers and use official cost statistics. Officials in the Israeli Nature and Parks Authority (NPA) were surveyed to determine the activities required to increase the level of nature conservation in two districts of the NPA as well as nationwide. We determined the costs of these proposed activities, and subsequently were able to calculate the total cost and marginal cost of conservation efforts. When operating on a limited budget, conservation authorities can use these schedules as an additional tool to help determine the efficiency of different proposed activities both on a regional scale and nationwide, and to ensure the sustainability of the resulting conservation. In addition, our results demonstrate the existence of economies of scale in nature conservation, and the benefit of both bottom-up and top-down decision processes in nature conservation.     

Resource implications of materials waste in engineering manufacture

A quantitative analysis is presented of not only the direct but also of the indirect effects resulting from the fact that waste in any one part of a nation's industrial structure also induces waste in other parts.     

Degradation of soil fumigants as affected by initial concentration and temperature

Soil fumigation using shank injection creates high fumigant concentration gradients in soil from the injection point to the soil surface. A temperature gradient also exists along the soil profile. We studied the degradation of methyl isothiocyanate (MITC) and 1,3-dichloropropene (1,3-D) in an Arlington sandy loam (coarse-loamy, mixed, thermic Haplic Durixeralf) at four temperatures and four initial concentrations. We then tested the applicability of first-order, half-order, and second-order kinetics, and the Michaelis-Menten model for describing fumigant degradation as affected by temperature and initial concentration. Overall, none of the models adequately described the degradation of MITC and 1,3-D isomers over the range of the initial concentrations. First-order and half-order kinetics adequately described the degradation of MITC and 1,3-D isomers at each initial concentration, with the correlation coefficients greater than 0.78 (r2> 0.78). However, the derived rate constant was dependent on the initial concentration. The first-order rate constants varied between 6 and 10x for MITC for the concentration range of 3 to 140 mg kg(-1), and between 1.5 and 4x for 1,3-D isomers for the concentration range of 0.6 to 60 mg kg(-1), depending on temperature. For the same initial concentration range, the variation in the half-order rate constants was between 1.4 and 1.7x for MITC and between 3.1 and 6.1x for 1,3-D isomers, depending on temperature. Second-order kinetics and the Michaelis-Menten model did not satisfactorily describe the degradation at all initial concentrations. The degradation of MITC and 1,3-D was primarily biodegradation, which was affected by temperature between 20 and 40 degrees C, following the Arrhenius equation (r2 > 0.74).