Metallic components of traffic-induced urban aerosol, their spatial variation, and source apportionment

This study proposes a practical method to estimate elemental composition and distribution in order to attribute source and quantify impacts of aerosol particles at an urban region in Kolkata, India. Twelve-hour total particulates were collected in winter (2005–2006) and analyzed by energy-dispersive X-ray fluorescence technique to determine multi-elemental composition, especially trace metals. The aerosols consist of various elements including K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, and Pb which exhibit significant concentration at various sites (p?<?0.05). The concentration of different metallic elements were found in the order of Zn ?> ?Pb ?> ?Ni ?> ?Cu ?> ?Cr ?>? Co. Statistical multivariate analysis and correlation matrix analyses were performed for factor identification and consequent source apportionment. Contour profiles demonstrate spatial variation of elemental compositions indicating possible source contribution along with meteorological influences. Spatial differences were clearly most significant for Zn, Ni, Pb, and Cu reflecting the importance of anthropogenic inputs, primarily from automobile sources.     

APPLICATION OF THE CONTINUOUS STORMWATER POLLUTION SIMULATION SYSTEM (CSPSS): PHILADELLPHIA CASE STUDY1

ABSTRACT: This paper describes the Continuous Stormwater Pollution Simulation System (CSPSS) as well as a site-specific application of CSPSS to the Philadelphia urban area and its receiving water, the Delaware Estuary. Conceptually, CSPSS simulates the quantity and quality or urban stormwater runoff, combined sewer overflow, municipal and industrial waste water effuent, and upstream flow on a continuous basis for each time step in the simulation period. In addition, receiving water dissolved oxygen, suspended solids, and lead concentrations resulting from these pollutant sources may be simulated. However, only rceiving water dissolved oxygen (DO) response is considered in this paper. The continuous Do receiving water response model was calibrated to existing conditions usinv observed data at Chester, Pennsylvnia, located on the Delaware Estuary approximately 10 miles down stream from the study area. Average annual pollutant loads to the receiving water were estimated for all major sources and receiving water quality improvements resulting from removal of various portions of these pollutant loads were estimated by application of the calibrated stimultion model. It was found that the removal of oxygen-demanding pollutants from combined sewer overflow and urban stormwater runoff would result in relatively minor improvements in the overall dissoved oxygen resources of the Delaware Estuary; whereas. removal of oxygen demanding pollutants from waste water treatment plant effluent would result in greater improvemens. The results of this investigation can be used along with appropriate economic techniques to identify the most cost-effective mix of point and nonpoint source pollution control measures.     

Economic rent : Incidence in selected metals and minerals

The magnitude of the ‘economic rent’ and its distribution among producing countries, mineral exploitation companies and consumers has become a dominant issue in national and international policy formulation, but the difficulties in measuring the rent add to the problems of determining its equitable distribution. This paper examines the nature of the rent and estimates its incidence in bauxite, copper, iron ore, phosphate rock, tin and petroleum. Rents were found to be low for bauxite and iron ore. Bauxite, phosphates and petroleum producers have increased their share of the rent, though this trend now seems to be reversing for bauxite and phosphates. Only in tin, and to a lesser extent petroleum, have the exporting countries captured significant shares in total rent. Otherwise, the rent is largely concentrated at the processing stage, which suggests that processing plant would have to shift to the producing countries if they are to claim a larger share.     

WATER TREATMENT PLANT STAGING POLICY1

Economics of treatment plant staging or capacity expansions is governed by the initial water demand rate, Q₀; the anticipated demand growth rate, G; the discount rate, D; the cost of operation, maintenance, and repair (OMR); the useful plant life, T, as a function of the quality of design, construction, and OMR; the treatment plant load factor, L_f; the salvage value of the plant at the end of the project period; the efficiency of the plant-staging design, eta; and the length of the project period, T_s. Various staging policies are investigated to find an optimal policy. The desirability of adopting a staging policy is governed by the magnitude of percent savings that can be achieved by adopting this policy instead of a no-staging policy. A detailed analysis of the problem shows that the percent savings because of staging increase with an increase in Q, G, D, T, and eta;. A reduction in the plant load factor increases the total costs. Information about the effect of variation in the parameters should help the planner and designer to work out an economical schedule of treatment plant capacity expansions.     

Women and community water supply programmes: An analysis from a socio-cultural perspective

Community water supply programmes are seen as instrumental in achieving the goal of ‘safe’ water for all. Women, a principal target group of these programmes, are to be benefited with greater convenience, enhanced socio‐cultural opportunities and better health for themselves and their families, provided through improved water facilities. Water supply programmes largely consist of three essential components, namely: technology, people and institutions. Although such programmes are intended to benefit women members of local communities, scant attention is paid to the impacts of the socio‐cultural context of the community on these programmes. This article explores the influence of social and cultural intricacies on the implementation of community water supply programmes, and assesses their effectiveness. The article offers important lessons for the design and implementation of this type of programme. It concludes that the local socio‐cultural context sets the stage for programme implementation, being a dynamic factor that determines actual access to water sources, more so than mere physical availability, which is often used as a criterion for programme performance. The article stresses the urgent need to integrate socio‐cultural factors as a fourth dimension in designing community water supply programmes, and suggests practical measures for enhancing the effectiveness of such programmes.     

Vent sizing for gas-generating runaway reactions

Exothermic runaway reactions that generate non-condensible gas as the temperature increases, as is typical of decompositions for example, can reach extremely high rates of pressure rise necessitating emergency relief of the process vessel containing the reactant. Sizing of a relief device using presently recommended methods (e.g. DIERS) frequently leads to extremely large and expensive vents. This paper presents a methodology that leads to a simple but much improved method for vent sizing, fully allowing for two-phase release of the gas—liquid mixture. A number of examples are presented which lead to interesting conclusions about the influence of plant variables.     

The eighth world conservation lecture

The World Conservation Lecture is an annual event organised by the World Wide Fund for Nature (WWF), United Kingdom, to draw attention to the World Conservation Strategy. This lecture was presented at the Commonwealth Institute in London on 20 April 1989. Full copies of the lecture, in booklet form, are available from the Public Relations Department, WWF - UK, Panda House, Weyside Park, Godalming, Surrey, GU7 1XR.     

COMPARING SOME METHODS OF ESTIMATING MEAN AREAL RAINFALL1

ABSTRACT: A comparison of 13 different methods of estimating mean areal rainfall was made on two areas in New Mexico, U.S.A., and one area in Great Britain. Daily, monthly and yearly rainfall data were utilized. All methods, in general, yielded comparable estimates, especially for yearly values. This suggested that a simpler method would be preferable for estimating mean areal rainfall in these areas.     

DERIVATION OF THE GAMMA DISTRIBUTION BY USING THE PRINCIPLE OF MAXIMUM ENTROPY (POME)1

The principle of maximum entropy (POME) was used to derive the two-parameter gamma distribution used frequently in synthesis of instantaneous or finite-period unit hydrographs. The POME yielded the minimally prejudiced gamma distribution by maximizing the entropy subject to two appropriate constraints which were the mean of real values and the mean of the logarithms of real values of the variable. It provided a unique method for parameter estimation. Experimental data were used to compare this method with the methods of moments, cumulants, maximum likelihood estimation, and least squares.