Groundwater resource management and environmental protection

Population and economic developmental pressures will continue to put increasing pressure on the environment, especially on scarce water resources. Meanwhile, large numbers of poor families in the developing countries still lack access to safe water. An integrated water resource planning and policy analysis framework is presented that permits the main issues and alternative options to be systematically considered and prioritized, especially problems arising from groundwater pollution. Basic principles of water resource economics are used to illustrate how the neglect of long-term environmental considerations jeopardizes the availability and quality of groundwater resources in the Greater Manila area. This paper contains a brief overview of drinking water and sanitation issues in developing countries, presents a policy-oriented analysis of a groundwater problem of great relevance worldwide, and demonstrates how the study conclusions might be implemented practically in a constrained developing country context.     

Water supply policies and issues in developing countries

The significant progress made during the UN International Water Decade is reviewed, eight years after its inception in 1981. Major issues remain, especially in rural areas. The advantages of an integrated water resource planning framework (IWRP) are explained, including the use of this process to develop a flexible strategy for the water and sewerage sector to meet national policy objectives. Economic efficiency in supply implies optimal service quality and least cost planning, while efficient pricing policy requires the implementation of long-run marginal cost based tariffs. Better sector organization, management, accountability, options for decentralization and innovative financing methods are also discussed.     

External synchronizers of tidal activity rhythms in the prawns Penaeus indicus and P. monodon

Phasing of persistent circatidal rhythmicity to an artificial tidal cycle was assessed in the prawns Penaeus indicus Milne Edwards and P. monodon (Fabricius) collected from the Vellar estuary, South India, in the period between June and December 1984. Simulated 6 h cycles of 20 and 30 S, and 6 h cycles of 20° and 30°C induced a persistent tidal rhythmicity after 20 cycles. The imposed 6 h cycles of 25 and 30 S, and 25° and 30°C induced tidal rhythms after 30 cycles. In both cases, re-established tidal activity rhythms were evident for at least 48 h — higher activity occurring during the higher salinity and lower temperature phases of the simulated tidal cycles. Artificial tidal cycles of still water and running water synchronized the tidal rhythm after 20 cycles. Combined 30 S, 20°C, for 6 h and 20 S and 30°C for 6 h established a persistent tidal rhythm after 10 cycles, whereas wave action had no influence on tidal synchronization. The influence of possible interactions of tidal rhythms and in situ tidal variables on circatidal activity is discussed.     

Long-term CO2 enrichment of a forest ecosystem: implications for forest regeneration and succession.

The composition and successional status of a forest affect carbon storage and net ecosystem productivity, yet it remains unclear whether elevated atmospheric carbon dioxide (CO2) will impact rates and trajectories of forest succession. We examined how CO2 enrichment (+200 microL CO2/L air differential) affects forest succession through growth and survivorship of tree seedlings, as part of the Duke Forest free-air CO2 enrichment (FACE) experiment in North Carolina, USA. We planted 2352 seedlings of 14 species in the low light forest understory and determined effects of elevated CO2 on individual plant growth, survival, and total sample biomass accumulation, an integrator of plant growth and survivorship over time, for six years. We used a hierarchical Bayes framework to accommodate the uncertainty associated with the availability of light and the variability in growth among individual plants. We found that most species did not exhibit strong responses to CO2. Ulmus alata (+21%), Quercus alba (+9.5%), and nitrogen-fixing Robinia pseudoacacia (+230%) exhibited greater mean annual relative growth rates under elevated CO2 than under ambient conditions. The effects of CO2 were small relative to variability within populations; however, some species grew better under low light conditions when exposed to elevated CO2 than they did under ambient conditions. These species include shade-intolerant Liriodendron tulipifera and Liquidambar styraciflua, intermediate-tolerant Quercus velutina, and shade-tolerant Acer barbatum, A. rubrum, Prunus serotina, Ulmus alata, and Cercis canadensis. Contrary to our expectation, shade-intolerant trees did not survive better with CO2 enrichment, and population-scale responses to CO2 were influenced by survival probabilities in low light. CO2 enrichment did not increase rates of sample biomass accumulation for most species, but it did stimulate biomass growth of shade-tolerant taxa, particularly Acer barbatum and Ulmus alata. Our data suggest a small CO2 fertilization effect on tree productivity, and the possibility of reduced carbon accumulation rates relative to today's forests due to changes in species composition.     

Real-world vehicle emissions: a summary of the Thirteenth Coordinating Research Council On-Road Vehicle Emissions Workshop

The Coordinating Research Council held its thirteenth Vehicle Emissions Workshop in April 2003, when results of the most recent on-road vehicle emissions research were presented. Ongoing work from researchers who are engaged in improving understanding of the contribution of mobile sources to ambient air quality and emission inventories is summarized here. Participants in the workshop discussed efforts to improve mobile source emission models, the role of on-board diagnostic systems in inspection and maintenance programs, light- and heavy-duty vehicle emissions measurements, on- and off-road emissions measurements, effects of fuels and lubricating oils on emissions, as well as topics for future research.     

Real-world vehicle emissions: a summary of the 14th coordinating research council on-road Vehicle Emissions Workshop

The Coordinating Research Council held its 14th Vehicle Emissions Workshop in March 2004, where results of the most recent on-road vehicle emissions research were presented. We summarize ongoing work from researchers who are engaged in improving our understanding of the contribution of mobile sources to ambient air quality and emission inventories. Participants in the workshop discussed efforts to improve mobile source emission models, light- and heavy-duty vehicle emissions measurements, on- and off-road emissions measurements, effects of fuels and lubricating oils on emissions, as well as topics for future research.     

Silver nanoparticles tolerant bacteria from sewage environment

Silver nanoparticle (SNP) is a threat to soil, water and human health. Protection of environment from silver nanoparticles is a major concern. A sewage isolate, Bacillus pumilus treated with SNPs showed similar growth kinetics to that without nanoparticles. A reduction in the amount of exopolysaccharides was observed after SNPs – B. pumilus culture supernatant interaction. The Fourier transform infrared spectroscopy (FT-IR) peaks for the exopolysaccharides extracted from the bacterial culture supernatant and the interacted SNPs were almost similar. The exopolysaccharide capping of the SNPs was confirmed by UV-Visible, FT-IR and X-ray di raction analysis. The study of bacterial exopolysaccharides capped SNPs with E. coli, S. aureus and M. luteus showed less toxicity compared to uncoated SNPs. Our studies suggested that the capping of nanoparticles by bacterially produced exopolysaccharides serve as the probable mechanism of tolerance.     

Removal of Diazo dye from aqueous phase by algae Spirogyra species

This communication presents a preliminary study conducted to investigate dye (Direct Brown 2‐Diazo) colour removal using viable algae Spirogyra species. The results indicate the ability of algae Spirogyra species to remove dye colour and found to be dependent on the contact time and biomass. Colour removal mechanism by algae Spirogyra species may be attributed to biosorption and/or bioconversion and/or biocoagulation.     

Freshwater Mussel,Lamellidens Marginalis (Lamarck) (Mollusca: Bivalvia: Unionidae) As an Indicator of River Pollution

Abstract

Analyses were made of heavy metals, manganese, nickel, copper, zinc and lead in water samples and soft body, shell and different tissues (gills, digestive glands, mantle and viscera) of the Unionid mussel, Lamellidens marginalis collected from two tributaries of the Cauvery river. Water samples from Station I contained higher concentrations of the metals than those from Station II. the concentration of metals in water at both stations were in the descending order: Mn > Zn > Pb > Ni > Cu. However, the concentrations of metals in the soft body were in the descending order: Zn > Mn > Pb > Ni > Cu at both stations in all size groups of mussels tested. the concentration of zinc maintained a linear relationship with the size of the mussels, but manganese showed a reverse trend. Small size (4-5 cm) mussels accumulated more manganese (105.5 μg.g^?1 dry wt.) than larger ones (7-8 cm; 6.5 μg.g^?1 dry wt.). Both young and old is accumulate the same level of lead, copper and nickel in the soft body. the order of concentrations of metals (Mn, Pb, Zn, Ni and Cu) in the shell of mussels from both stations coincided with the order of concentrations of background water except for lead. the accumulation of lead was higher in shell (30.4-36.2 μg.g^?1 dry wt.) than in soft body (6.4-12.0 μg.g^?1 dry wt.). the pattern of concentration of metals in the various tissues reveal that the digestive glands have greater ability than other tissues to concentrate most metals under study. the concentration factors for soft body, shell and different tissues are presented. the advantages in using the common mussel for biomonitoring of contaminants in water is also discussed.