Impact of Hazardous Exposure to Metals in the Nile and Delta Lakes on the Catfish, Clarias lazera

The impact of metal pollution in the Nile and Delta lakes was studied in Clarias lazera. Lake Edku is grouped as the site highest in metal concentrations. Compared to Lakes Maryût and Edku, the Nile stations displayed lower levels of metal contamination signifying their selection as reference sites. Metals were accumulated most by the liver, less by muscles and least by serum. Iron showed the highest bioconcentration factors (BCF) in liver, muscles or serum compared to other metals. Even after the refinement of the surrounding water, fish seem to uphold the metals that have been previously ingested. Mercury, in particular, seems to eventually reside in muscles rather than in liver. The positive relationship between total serum protein and metal contents may indicate the formation of specific metal-binding proteins. Meanwhile, serum hyperalbuminemia in polluted fish is probably a shock response towards the high stress index induced by metals. The hypothesis that most of serum copper is bound to ceruloplasmin is documented also in C. lazera. Moderate, but not extennsive, exposure to metals was quite stimulatory to liver alkaline phosphatase (AP) biosynthesis. AP could, thus, be considered as a promising bioindicator for assessing sublethal water intoxicosis.     

Adsorption of carbon dioxide using impregnated activated carbon promoted by Zinc

The effect of impregnation of activated carbon with Cr₂O and Fe₂O₃ and promotion by Zn²⁺ on its adsorptive properties of carbon dioxide was studied using a volumetric adsorption apparatus at ambient temperature and low pressures. Slurry and solution impregnation methods were used to compare CO₂ capture capacity of the impregnated activated carbon promoted by Zinc. The obtained adsorption isotherms showed that amount of CO₂ adsorbed on the samples impregnated by Cr₂O was increased about 20% in compare to raw activated carbon. The results also showed that Fe₂O₃ was not an effective impregnating species for activated carbon modification. Moreover slurry impregnation method showed higher CO₂ adsorption capacity in comparison with solution impregnation method. Samples prepared by co-impregnation of two metal species showed more adsorption capacity than samples impregnated by just one metal species individually. Washing the impregnated samples by metal oxide resulted in 15% increase in CO₂ adsorption capacities of activated carbons which can be attributed to the metal oxides removal covering the adsorption surface. Decreasing impregnation temperature from 95 to 25 °C in solution method showed a significant increase in CO₂ adsorption capacity. Sips equation was found a suitable model fitting to the adsorption data in the range studied.     

Synergistic Effect of TNPP and Carbon Black in Weathered XLPE Materials

Carbon black is one of the most widely used and most effective ultraviolet (UV) light stabilizers for plastics applications. Several important segments of the plastics industry rely on carbon black for UV stabilization of weather-resistant products, including telecommunications, power cable jacketing, and plastic pipes. In this research work a combination of Trisnonylphospate (TNPP) antioxidant and different size carbon black were applied in crosslinked polyethylene (XLPE) to improve its wetherability. The primary reason for cross-linking polyethylene (PE) is to raise the thermal stability of the material under load. This substantially improves environmental stress crack resistance and resistance to slow crack growth. The results achieved of this additive package combination show a synergism effect and improved weatherability of electrical cable. Increased weathering lifetime was also achieved. Further, we were able to confirm in this work, that the size and quality of the carbon black dispersion in a XLPE samples is an important component of both the UV-resistance and mechanical properties of the finished plastic article. Incremental improvements of carbon black dispersion can positively influence the expected life of plastic articles. Mechanical testing and FTIR were used to detect degradation of the accelerated weathered XLPE samples. The morphological considerations of UV energy absorption and presents laboratory data demonstrating the link between dispersion and weatherability as well as between morphology and weatherability     

The relative importance of factors influencing the adoption of sustainable agricultural practices: a factor approach for Malaysian vegetable farmers

This study develops the understanding of the adoption of sustainable agricultural practices (SAPs) by investigating the relative importance of a set of multidimensional factors in the Malaysian vegetable production sector. A factor approach is deployed to identify explanatory indicators within an integrative framework that is synthesized from the theory of interpersonal behavior and the theory of diffusion of innovation. We achieved this by analyzing a logistic regression model for the adoption of six individual SAPs (conservation tillage, intercropping, cover crops/mulches, crop rotation, organic fertilizers/composts, and integrated pest management). The findings indicate that adoption depends on a range of socio-economic, agro-ecological, institutional, informational, and psychological factors, as well as the perceived attributes of SAPs. Fundamental policy understanding of the issue should, therefore, be multidisciplinary. In addition, standardized coefficients reveal that the impact of statistically significant factors on adoption is unequal. In general, the most influential factor is the asymmetric distribution of resources across geographical locations. This is followed by financial capital and a number of factors, including the workforce size, the usefulness of information, Chinese ethnicity, and the perceived relative advantage of SAPs. Guided by this prioritization understanding, future SAPs promotion now has a better opportunity to target the more important areas. Similar research effort should be made to steer sustainable agriculture internationally.     

Sequential photochemical-biological degradation of chlorophenols

UV/TiO₂/H₂O₂, UV/TiO₂ and UV/H₂O₂ were compared as pre-treatment processes for the detoxification of mixtures of 4-chlorophenol (4CP), 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP) prior to their biological treatment. When each chlorophenol was initially supplied at 50 mg l⁻¹, UV/TiO₂/H₂O₂ treatment supported the highest pollutant removal, COD removal, and dechlorination efficiencies followed by UV/TiO₂ and UV/H₂O₂. The remaining toxicity to Lipedium sativum was similar after all pre-treatments. Chlorophenol photodegradation was always well described by a first order model kinetic (r² > 0.94) and the shortest 4CP, DCP, TCP and PCP half-lives of 8.7, 7.1, 4.5 and 3.3 h, respectively, were achieved during UV/TiO₂/H₂O₂ treatment. No pollutant removal was observed in the controls conducted with H₂O₂ or TiO₂ only. Inoculation of all the photochemically pre-treated mixtures with activated sludge microflora was followed by complete removal of the remaining pollutants. Combined UV/TiO₂/H₂O₂-biological supported the highest detoxification, dechlorination (99%) and COD removal (88%) efficiencies. Similar results were achieved when each chlorophenol was supplied at 100 mg l⁻¹. COD and Cl mass balances indicated UV, UV/H₂O₂, and UV/TiO₂ treatments lead to the formation of recalcitrant photoproducts, some of which were chlorinated.     

Remotely-Sensed Active Fire Data for Protected Area Management: Eight-Year Patterns in the Manas National Park, India

The Terai-Duar savanna and grasslands, which once extended along most of the Himalayan foothills, now only remain in a number of protected areas. Within these localities, grassland burning is a major issue, but data on frequency and distribution of fires are limited. Here, we analysed the incidence of active fires, which only occur during the dry season (Nov.–Mar.), within a significant area of Terai grasslands: the Manas National Park (MNP), India. We obtained locations of 781 fires during the 2000–2008 dry seasons, from the Fire Information for Resource Management System (FIRMS) that delivers global MODIS hotspot/fire locations using remote sensing and GIS technologies. Annual number of fires rose significantly from around 20 at the start of the study period to over 90 after 2002, with most (85%) detected between December and January. Over half of the fires occurred in tall grasslands, but fire density was highest in wetland and riverine vegetation, dry at the time. Most burning took place near rivers, roads and the park boundary, suggesting anthropogenic origins. A kernel density map of all recorded fires indicated three heavily burnt areas in the MNP, all within the tall grasslands. Our study demonstrates, despite some technical caveats linked to fire detection technology, which is improving, that remote fire data can be a practical tool in understanding fire concentration and burning temporal patterns in highly vulnerable habitats, useful in guiding management.     

Plant species affect colonization patterns and metabolic activity of associated endophytes during phytoremediation of crude oil-contaminated soil

Plants coupled with endophytic bacteria hold great potential for the remediation of polluted environment. The colonization patterns and activity of inoculated endophytes in rhizosphere and endosphere of host plant are among the primary factors that may influence the phytoremediation process. However, these colonization patterns and metabolic activity of the inoculated endophytes are in turn controlled by none other than the host plant itself. The present study aims to determine such an interaction specifically for plant-endophyte systems remediating crude oil-contaminated soil. A consortium (AP) of two oil-degrading endophytic bacteria (Acinetobacter sp. strain BRSI56 and Pseudomonas aeruginosa strain BRRI54) was inoculated to two grasses, Brachiaria mutica and Leptochloa fusca, vegetated in crude oil-contaminated soil. Colonization patterns and metabolic activity of the endophytes were monitored in the rhizosphere and endosphere of the plants. Bacterial augmentation enhanced plant growth and crude oil degradation. Maximum crude oil degradation (78 %) was achieved with B. mutica plants inoculated with AP consortium. This degradation was significantly higher than those treatments, where plants and bacteria were used individually or L. fusca and endophytes were used in combination. Moreover, colonization and metabolic activity of the endophytes were higher in the rhizosphere and endosphere of B. mutica than L. fusca. The plant species affected not only colonization pattern and biofilm formation of the inoculated bacteria in the rhizosphere and endosphere of the host plant but also affected the expression of alkane hydroxylase gene, alkB. Hence, the investigation revealed that plant species can affect colonization patterns and metabolic activity of inoculated endophytic bacteria and ultimately the phytoremediation process.     

Multiple Interactive Pollutants in Water Quality Trading

Efficient environmental management calls for the consideration of multiple pollutants, for which two main types of transferable discharge permit (TDP) program have been described: separate permits that manage each pollutant individually in separate markets, with each permit based on the quantity of the pollutant or its environmental effects, and weighted-sum permits that aggregate several pollutants as a single commodity to be traded in a single market. In this paper, we perform a mathematical analysis of TDP programs for multiple pollutants that jointly affect the environment (i.e., interactive pollutants) and demonstrate the practicality of this approach for cost-efficient maintenance of river water quality. For interactive pollutants, the relative weighting factors are functions of the water quality impacts, marginal damage function, and marginal treatment costs at optimality. We derive the optimal set of weighting factors required by this approach for important scenarios for multiple interactive pollutants and propose using an analytical elasticity of substitution function to estimate damage functions for these scenarios. We evaluate the applicability of this approach using a hypothetical example that considers two interactive pollutants. We compare the weighted-sum permit approach for interactive pollutants with individual permit systems and TDP programs for multiple additive pollutants. We conclude by discussing practical considerations and implementation issues that result from the application of weighted-sum permit programs.     

How to Quantify Sustainable Development: A Risk-Based Approach to Water Quality Management

Since the term was coined in the Brundtland report in 1987, the issue of sustainable development has been challenged in terms of quantification. Different policy options may lend themselves more or less to the underlying principles of sustainability, but no analytical tools are available for a more in-depth assessment of the degree of sustainability. Overall, there are two major schools of thought employing the sustainability concept in managerial decisions: those of measuring and those of monitoring. Measurement of relative sustainability is the key issue in bridging the gap between theory and practice of sustainability of water resources systems. The objective of this study is to develop a practical tool for quantifying and assessing the degree of relative sustainability of water quality systems based on risk-based indicators, including reliability, resilience, and vulnerability. Current work on the Karoun River, the largest river in Iran, has included the development of an integrated model consisting of two main parts: a water quality simulation subroutine to evaluate Dissolved Oxygen Biological Oxygen Demand (DO-BOD) response, and an estimation of risk-based indicators subroutine via the First Order Reliability Method (FORM) and Monte Carlo Simulation (MCS). We also developed a simple waste load allocation model via Least Cost and Uniform Treatment approaches in order to consider the optimal point of pollutants control costs given a desired reliability value which addresses DO in two different targets. The Risk-based approach developed herein, particularly via the FORM technique, appears to be an appropriately efficient tool for estimating the relative sustainability. Moreover, our results in the Karoun system indicate that significant changes in sustainability values are possible through dedicating money for treatment and strict pollution controls while simultaneously requiring a technical advance along change in current attitudes for environment protection.