Photocatalytic degradation of lignin using Pt/TiO2 as the catalyst

Photocatalytic degradation of lignin was studied with the use of catalysts TiO(2) and Pt/TiO(2). The influence of several experimental parameters, i.e. pH, catalyst dosage and illumination on lignin degradation was investigated. The results showed that application of UV irradiation alone has almost no effect on the reduction of dissolved organic carbon (DOC) and American Dye Manufacture Institute value (ADMI). However, the addition of TiO(2) and Pt/TiO(2) reduced the original DOC (251 mg l(-1)) by more than 40% within 30 min of treatment and the reaction can be simulated with pseudo-first order kinetics. Rapid degradation of lignin was observed in acidic solution using either TiO(2) or Pt/TiO(2) as the catalyst compared to high pH cases. The content of Pt in the Pt/TiO(2) catalyst is 1%. In addition, too much catalyst addition has not increased the DOC and ADMI reduction proportionally. The investigation also indicated that the photocatalytic degradation rates could be enhanced 1-6 times faster after doping TiO(2) with Pt in different pH cases. A modified Nernst type model was adopted to simulate the decoloring process using TiO(2) and Pt/TiO(2) based on the profiles of oxidation reduction potential during the photocatalytic reaction. The developed equation can be used to predict the color removal efficiency of lignin wastewater by the photocatalytic process.     

Safety in fishing — learning from experience

This article critically examines the level of safety in some sections of the UK fishing industry not only by looking at the available statistics but also by examining actual recent case histories.In 1989 the UK Department of Transport established the Marine Accident Investigation Branch (MAIB). Case histories published by MAIB have been taken as the basis for the article in order to illustrate and draw lessons from incidents that occur in fishing.Fishing will always be a high risk profession but there are ways in which risks can be diminished. Many of the problems are due to vessels being built below the 12 m threshold at which the 1975 Safety Rules currently apply. Some of the vessels lack adequate reserve stability to withstand capsize in the dynamic situation and there are deficiences in design and safety equipment. The training programmes introduced by Seafish for Survival, Fire Fighting and First Aid are now mandatory for all new entrants and these have almost certainly resulted in the saving of lives. However, there needs to be a much greater awareness of accident prevention and the article makes a plea for this to be given more attention.Each case study is probably unique or there are some specific circumstances as to why the accident happened. Nevertheless, there are always underlying lessons to be learnt from every incident of this type, even if there is no loss of life or serious injury.     

Treatment of remediation wastes in RCRA corrective action management units

This article explains new EPA regulations that provide for use of corrective action management units (CAMUs) and temporary units (TUs) as cost-effective techniques for remediating hazardous wastes at facilities undergoing RCRA corrective action and at CERCLA remediation sites. The author outlines EPA criteria for approving the use of CAMUs, discusses the benefits and limitations of using them, and recommends possible ways to improve on the CAMU concept.     

RESERVOIR TROPHIC STATE EVALUATION USING LANISAT TM IMAGES1

ABSTRACT: Reservoir water quality is traditionally monitored and evaluated based on field data. Collecting and analyzing field water quality data are costly and time consuming tasks, and whether a limited number of field data truly characterize the spatial variation of the trophic state within a vast water body is often disputed. In this study we utilize Landsat TM data to estimate the water quality and trophic state of the Te‐Chi reservoir in Central Taiwan. A modified multi‐parameter model of Carlson's trophic state index (TSI) was developed for the Te‐chi reservoir. Water quality parameters (concentration of chlorophyll‐a, total phosphorous measurement, and secchi disk depth) required by the model are found to have high correlations with combinations of TM bands. Therefore, TM data are used to map the trophic state of the reservoir. TM‐derived TSI maps of the reservoir reveal that, in summer, the trophic state in the reservoir generally improves from upstream to downstream and that zones of distinct trophic state exist. A trophic state index based on secchi disk depth may give erroneous values in the upstream section of the reservoir pool due to high sediment concentration in the reservoir inflow. We conclude that the Te‐Chi reservoir is eutrophic or worse in summer and meso‐eutrophic in winter. Implementation of best management practices to reduce nonpoint source pollution in the upstream watershed is highly recommended. This study demonstrates the capability of mapping the trophic state in impounded water bodies using the Landsat TM data.     

Mitigating exotic impacts: restoring deer mouse populations elevated by an exotic food subsidy.

The threat posed by exotic organisms to native systems has led to extensive research on exotic invaders, yet management of invasives has progressed relatively slowly. This is partly due to poor understanding of how exotic species management influences native organisms. To address this shortfall, we experimentally evaluated the efficacy of an invasives management tool for restoring native deer mouse (Peromyscus maniculatus) populations elevated by exotic species. The exotic insects, Urophora spp., were introduced in North America for biological control of the Eurasian invader, spotted knapweed (Centaurea maculosa), but instead of controlling C. maculosa, Urophora have become an important food resource that doubles P. maniculatus populations, with substantial indirect effects on other organisms. We hypothesized that herbicide suppression of Urophora's host plant would reduce the Urophora food resource and restore P. maniculatus populations to natural levels. Prior to treatment, mouse populations did not differ between controls and treatments, but following treatment, P. maniculatus were half as abundant where treatment reduced Urophora. Peromyscus maniculatus is insensitive to direct herbicide effects, and herbicide-induced habitat changes could not explain the P. maniculatus response. Treatment-induced reductions of the Urophora food resource offered the most parsimonious explanation for the mouse response: Multistate mark-recapture models indicated that P. maniculatus survival declined where Urophora were removed, and survival rates were more correlated with variation in population size than movement rates. Other demographic and reproductive parameters (sex ratios, reproductive status, pregnancy rates, and juvenile recruitment) were unaffected by treatment. These results suggest the Urophora biocontrol elevated P. maniculatus survival, and the herbicide treatment restored mouse populations by removing the exotic food and reducing survival. This work illustrates the importance of mechanistic understandings of community and population ecology for improving invasive species management.     

Analysis of two-state multivariate phenotypic change in ecological studies

Analyses of two-state phenotypic change are common in ecological research. Some examples include phenotypic changes due to phenotypic plasticity between two environments, changes due to predator/non-predator character shifts, character displacement via competitive interactions, and patterns of sexual dimorphism. However, methods for analyzing phenotypic change for multivariate data have not been rigorously developed. Here we outline a method for testing vectors of phenotypic change in terms of two important attributes: the magnitude of change (vector length) and the direction of change described by trait covariation (angular difference between vectors). We describe a permutation procedure for testing these attributes, which allows non-targeted sources of variation to be held constant. We provide examples that illustrate the importance of considering vector attributes of phenotypic change in biological studies, and we demonstrate how greater inference can be made than by evaluating variance components with MANOVA alone. Finally, we consider how our method may be extended to more complex data.     

Predicting richness effects on ecosystem function in natural communities: insights from high-elevation streams

. Despite the increased complexity of experimental and theoretical studies on the biodiversity-ecosystem functioning (B-EF) relationship, a major challenge is to demonstrate whether the observed importance of biodiversity in controlled experimental systems also persists in nature. Due to their structural simplicity and their low levels of human impacts, extreme species-poor ecosystems may provide new insights into B-EF relationships in natural systems. We address this issue using shredder invertebrate communities and organic matter decomposition rates in 24 high-altitude (3200-3900 m) Neotropical streams as a study model. We first assessed the effects of stream characteristics and shredder diversity and abundance on organic matter decomposition rates in coarse- and fine-mesh bags. We found the interaction term shredder richness x shredder abundance had the most significant impact on decomposition rates in the field, although water discharge may also play a role locally. We also examined the relative contribution of the three most abundant shredders on decomposition rates by manipulating shredder richness and community composition in a field experiment. Transgressive overyielding was detected among the three shredder species, indicating complementary resource use and/or facilitation. By integrating survey and experimental data in surface response analyses we found that observed B-EF patterns fit those predicted by a linear model that described litter decomposition rates as a function of increasing shredder richness and the relative abundance of the most efficient shredders. Finally, the validity of our approach was tested in a broader context by using two independent but comparable data sets from 49 French and Swedish streams showing more complex shredder community structure. Results revealed that richness and identity effects on decomposition rates were lost with increasing shredder community complexity. Our approach of combining experimental and empirical data with modeling in species-poor ecosystems may serve as an impetus for new B-EF studies. If theory can explain B-EF in low-diversity ecosystems, it may also have credibility in more complex ones.     

An evaluation of indoor and outdoor biological particulate matter

The incidences of allergies, allergic diseases and asthma are increasing world wide. Global climate change is likely to impact plants and animals, as well as microorganisms. The World Health Organization, U.S. Environmental Protection Agency, U.S. Department of Agriculture, U.S. Department of Health and Human Services, and the Intergovernmental Panel on Climate Change cite increased allergic reactions due to climate change as a growing concern. Monitoring of indoor and ambient particulate matter (PM) and the characterization of the content for biological aerosol concentrations has not been extensively performed. Samples from urban and rural North Carolina (NC), and Denver (CO), were collected and analyzed as the goal of this research. A study of PM₁₀ (<10 μm in aerodynamic diameter) and PM_2.5 (<2.5 μm in aerodynamic diameter) fractions of ambient bioaerosols was undertaken for a six month period to evaluate the potential for long-term concentrations. These airborne bioaerosols can induce irritational, allergic, infectious, and chemical responses in exposed individuals. Three separate sites were monitored, samples were collected and analyzed for mass and biological content (endotoxins, (1,3)-β-d-glucan and protein). Concentrations of these bioaerosols were reported as a function of PM size fraction, mass and volume of air sampled. The results indicated that higher concentrations of biologicals were present in PM₁₀ than were present in PM_2.5, except when near-roadway conditions existed. This study provides the characterization of ambient bioaerosol concentrations in a variety of areas and conditions.