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Pollution Load (pollution + load)
Selected AbstractsDECISION SUPPORT FOR ALLOCATION OF WATERSHED POLLUTION LOAD USING GREY FUZZY MULTIOBJECTIVE PROGRAMMING,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2006Ho-Wen Chen ABSTRACT: This paper uses the grey fuzzy multiobjective programming to aid in decision making for the allocation of waste load in a river system under versatile uncertainties and risks. It differs from previous studies by considering a multicriteria objective function with combined grey and fuzzy messages under a cost benefit analysis framework. Such analysis technically integrates the prior information of water quality models, water quality standards, wastewater treatment costs, and potential benefits gained via in-stream water quality improvement. While fuzzy sets are characterized based on semantic and cognitive vagueness in decision making, grey numbers can delineate measurement errors in data collection. By employing three distinct set theoretic fuzzy operators, the synergy of grey and fuzzy implications may smoothly characterize the prescribed management complexity. With the aid of genetic algorithm in the solution procedure, the modeling outputs contribute to the development of an effective waste load allocation and reduction scheme for tributaries in this subwatershed located in the lower Tseng-Wen River Basin, South Taiwan. Research findings indicate that the inclusion of three fuzzy set theoretic operators in decision analysis may delineate different tradeoffs in decision making due to varying changes, transformations, and movements of waste load in association with land use pattern within the watershed. [source] Bacterial community structure and function in a metal-working fluidENVIRONMENTAL MICROBIOLOGY, Issue 6 2003Christopher J. Van Der Gast Summary The diversity of bacterial populations colonizing spatially and temporally separated samples of the same metal-working fluid (MWF) formulation was investigated. Analyses were performed with a view to improve strategies for bioaugmentation of waste MWF in bioreactor systems and prevention of in-use MWF biodeterioration in engineering workshops. Significantly, complementary phenotypic, genotypic and in situ methods revealed that the bacterial communities in operationally exhausted MWFs had low diversity and were similar in species composition from different locations and uses. Of the 179 bacterial isolates studied, only 11 genera and 15 species were identified using fatty acid methyl ester (FAME) analysis, with culture independent analyses by 16S rDNA denaturing gradient gel electrophoresis (DGGE) and fluorescent in situ hybridization being congruent with these FAME data. In order to gain some insight into functional role of detected populations, we correlated the MWF chemical composition and potential pollution load with bacterial abundance and community composition detected within samples. [source] Subjective perceptions, symptom intensity and performance: a comparison of two independent studies, both changing similarly the pollution load in an officeINDOOR AIR, Issue 2 2002P. Wargocki First page of article [source] Effects of air pollution on natural enemies of the leaf beetle Melasoma lapponicaJOURNAL OF APPLIED ECOLOGY, Issue 2 2000Elena L. Zvereva Summary 1. ,Air pollution might have differential effects on herbivores and their natural enemies, thus changing population dynamics. Therefore, from 1993 to 1998 we studied mortality caused by parasitoids and predators to the willow-feeding leaf beetle Melasoma lapponica in the impact zone of the Severonikel nickel,copper smelter (Kola Peninsula, north-western Russia). 2. ,Densities of M. lapponica were very low at clean forest sites (below five beetles per 10-min count) but higher in polluted areas (10,340 beetles per count). There were, however, variations between study years. 3. ,Egg predation, mainly by syrphid larvae and zoophagous bugs, was higher at relatively clean sites (55·3%) than at polluted sites (22·2%). Similarly, predation on larvae by zoophagous bugs and wood ants was higher at clean sites (68·4%) than at polluted sites (32·9%). 4. ,In contrast to predation, mortality caused by the parasitoid flies Megaselia opacicornis (Phoridae) and Cleonice nitidiuscula (Tachinidae) was lower at clean sites (12·3%) than at polluted sites (35·3%). Total parasitism levels increased significantly with pollution load. 5. ,Total mortality caused by natural enemies was higher at clean sites (93·7%) than at polluted sites (79·4%) due to higher predation rates, which may partly explain increased leaf beetle density within the smelter's impact zone. The effects of predators in clean forests were confirmed by the extinction of adults of M. lapponica introduced to one of the forest sites. 6. ,Although some individual sources of mortality appeared to be density dependent (direct or inverse), the joint effect of all natural enemies was not. 7. ,Our data show that a decrease in predation can contribute to increased leaf beetle density at polluted sites. However, the overall effects of natural enemies in this case were not sufficient to account for all density variations between sites. To our knowledge this is the first study to assess how pollution affects the partitioning of mortality in herbivorous insects between predators and parasitoids. [source] Studies on internal and external water treatment at a paper and cardboard factoryJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2003Mamdouh M Nassar Abstract The treatment of effluent from a paper/board factory that produced 280 tons of cardboard and consumed 1200 m3 of water per day was carried out. Wastewater analysis showed that the mill effluent contained 3000 mg dm,3 suspended solids, 1400 mg dm,3 COD (chemical oxygen demand) and 500 mg dm,3 BOD (biochemical oxygen demand). An internal treatment cycle is suggested that involves recirculation of paper-machine wastewater (white-water) and may be accomplished by installing a flotation saveall (fiber recovery) unit. This arrangement reduced fresh water use by about 90%, reduced fiber loss by 80,90%, and increased board production by 13%. An external treatment process for the effluent was assessed by conducting laboratory coagulation tests (alum, ferric chloride, ferrous sulfate, and polyelectrolyte) on the whole mill effluent. Oxidation of the mill effluent using calcium hypochlorite before discharging the effluent to a lagoon offers the benefits of killing the harmful bacteria and reducing the pollution load. Copyright © 2003 Society of Chemical Industry [source] Physicochemical parameters and magnetic speciation of Iron in Nakivubo Channel and Lake Victoria watersLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 2 2009Naziriwo Betty Bbosa Abstract Magnetic speciation technique was used for the determination of iron species in Nakivubo Channel and Lake Victoria waters. The method consisted of a column of supported Dowex 1-X18, 20,50 US mesh (Cl) surrounded by movable permanent magnets. Dowex was supported by a porous material to permit adequate passage of the eluent through the column. In the presence of an external magnetic field, enhanced capacity for adsorption of iron III was observed. The enhanced capacity is primarily due to the magnetic field produced and ion exchange sorption mechanism. The results show that, most of the Iron in Nakivubo Channel waters is in reduced ferrous form while, in the Lake Victoria waters, it exists in the oxidized ferric form. Physicochemical parameters for the field samples are discussed in this study. Turbidity levels in catchments with substantial vegetation were significantly lower than those without. pH values up to 13 was observed for some of the point source. The physicochemical parameters along Nakivubo Channel waters were relatively higher than the Lake Victoria waters indicating slow increasing pollution load along the Nakivubo Channel. [source] Heavy metal pollution in a sewage-fed lake of Bhopal, (M. P.) IndiaLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 1 2003Pradeep Shrivastava Abstract Shahpura Lake receives untreated domestic sewage from residential areas in Bhopal city. Analysis of water, plankton, fish and sediment reveals that the lake is contaminated by certain heavy metals. The concentrations of some of these metals including iron and manganese were within acceptable limits, whereas others including chromium, nickel, zinc and lead were not within acceptable water quality limits. Metal concentrations in the sewage inlet drain and lake sediment were compared with published criteria. The comparison revealed that the metals in the sediment ranged from the ,non-polluted' to the ,heavy pollution' categories. The reference dose was calculated by the adoption of the United States Environmental Protection Agency reference dose factor, and the result reveals that the local population is not exposed to undue health risks. Concentrations of heavy metals in the water increased during the second year of the study, indicating an increase in the pollution load on the system. This might increase the bioaccumulation levels in fish and increase the actual dose of metals to which the local population will be exposed. [source] | |||||||||||||