Global Emissions of Nitrogen and Sulfur Oxides from 1860 to 1980

Statistical models have been developed that relate the rate of emissions of a pollutant to the rate of fuel consumption. These relations may be used to estimate emissions in other regions, or at other times, if fuel consumption data are available. This approach has been used to estimate global emissions of nitrogen and sulfur oxides in fossil fuel combustion at ten year intervals from 1860 to 1980. Emissions from each of the populated continents, i.e., North America, South America, Asia, Europe, Africa and Oceania from 1930 to 1980 are also presented. When averaged globally over the 1860 to 1980 period, sulfur emissions increased at the rate of 2.9 percent per year and the nitrogen emissions at the rate of 3.4 percent per year. The ratio of global sulfur emissions to nitrogen emissions has declined steadily; it was nearly 5 in the 19th century and became 3 by 1980. After the second world war, the most rapid increases in emissions have been registered in Asia, South America, and Africa.     

Immobilization of some metals in contaminated sludge by zeolite prepared from local materials

In this study, zeolite was prepared from cheap local Egyptian clay (kaolin) and characterized by X-ray diffraction, X-ray fluorescence spectroscopy, SEM. The prepared zeolite was used as a binder for immobilization of the metals Cd²⁺, Cu²⁺, Ni²⁺, Pb²⁺, and Zn²⁺ in contaminated sewage sludge. Different leaching tests were conducted to determine the efficiency of the prepared zeolite for metal stabilization. The leaching of the metals from stabilized sludge decreased as the zeolite amount increased. It was found that 10% of zeolite is sufficient for the stabilization of all metal ions under investigation. It was suggested that the metal uptake mechanism by zeolite was by an ion-exchange mechanism. Examination of the solidified sample for its compressive strength after curing for 28 days yielded a value of 0.83?MPa, which indicates that the treated sludge was well solidified and safe to be used in a wide variety of applications, for instance as a raw material for pavement blocks.     

The Freshwater Mussel Parreysia Favidens (Benson) As A Biological Indicator of Polonium - 210 in A Riverine System

The concentration of ²¹⁰Po, an alpha emitter from the natural uranium series was measured in the soft tissues (total), shell, and different organs - digestive glands, gills, mantle and foot - of the freshwater mussel, Parreysia favidens (Benson), collected from the river Kaveri, at Tiruchirapalli in South India. the analyses were made in three size groups based on shell length (Group 1: 2-4 cm; Group 2: 4-5 cm; Group 3: 5-6 cm). the soft tissues of the mussel accumulated higher concentrations of ²¹⁰Po (74.0-125.5 Bq kg^-1 fresh) than the shell (2.9-3.9 Bq kg^-1 fresh). Further, younger mussels (1 group) showed higher concentrations (125.5+2.0 Bq kg^-1 fresh) in total soft tissues than older ones (III Group) (74.0+1.6 Bq kg^-1 fresh); concentration factors were 1.59x 10⁵ in I group and 9.37 × 10⁴ in III group. the ²¹⁰Po was observed to be non-uniformly distributed among the internal organs, which maintained the following descending order with reference to ²¹⁰Po accumulation: digestive glands, ranging from 286.2+3.5 Bq kg^-1 fresh to 43+1.3 Bq kg^-1 fresh. the concentration of ²¹⁰Po in the mussels was distinctly higher than that in the grass, Echinochloa colonum (J. Koenig), and carp, Cirrhinus cirrhosa (Bloch), from the same river. These data indicate that younger mussels could be used as an excellent biological indicator of ²¹⁰Po and among soft tissues, digestive glands are preferable to other tissues to monitor the distribution of ²¹⁰Po in the riverine system.     

Assessment of public vs private MSW management: a case study

Public-private partnerships in urban environmental services have witnessed increased interest in recent years primarily to reform the weak performance of the public sector, reduce cost, improve efficiency, and ensure environmental protection. In this context, successful public-private partnerships require a thorough analysis of opportunities, a deliberate attention to process details, and a continuous examination of services to determine whether they are more effectively performed by the private sector. A comparative assessment of municipal solid waste collection services in the two largest cities in Lebanon where until recently municipal solid waste collection is private in one and public in the other is conducted. While quality of municipal solid waste collection improved, due to private sector participation, the corresponding cost did not, due to monopoly and an inadequate organizational plan defining a proper division of responsibilities between the private and the public sector.     

A comparative study of various grains from the different cities of Pakistan

The fate of trace elements (like Ca, Fe, Al, Pb, K, and Cu) in various pulses (mash, mung, lentils and red kidney beans) of Pakistan has been studied. Samples were collected from two districts (Mansehra and Rawalpindi) and analyzed by wet acid digestion method using atomic absorption spectrophotometry. Experimental results show that the intensity of heavy metal accumulation in plants depends upon the type of the soil, the species of plants, the physicochemical properties of heavy metals, and their content in the soil. The obtained values were compared with the World Health Organization (WHO) standards for food quality. The grains from District Mansehra contained greater amount of trace metals as compared to those collected from District Rawalpindi. However, those values did not exceed the upper limits described by the WHO in nearly all the cases. Based on these findings, the consumption of pulses in larger amounts may easily be recommended.     

Modelling temporal and spatial changes of PCBs in fish tissue from Lake Huron

A model has been developed to assess temporal and spatial changes in the concentration of polychlorinated biphenyl (PCB) contaminant in whole fish from Lake Huron during the years 1980 to 2004. The model uses log PCB concentration as the response variable and includes time trend, within-lake variability and dependence on age, weight and length as explanatory variables. A preliminary examination of the data revealed that some values are recorded as below detection limits (thus leading to the left censoring), and the PCB concentration appears to show declines in latter years. To this end, parametric log-location-scale regression models used in survival analysis were employed. It has been found that the Weibull model yields a better fit than the log-logistic or the log-normal models. The analysis provides strong evidence that, starting in 1996, the level of PCB concentration showed steady decline, which is most contributed by the Canadian and US governments?? actions carried out earlier to reduce the load of toxic contaminants to the Great Lakes. Spatially, fish from the north of the lake is less contaminated than fish from the south. The pattern and magnitude of the estimated spatial and temporal trends can provide useful information regarding the safety of fish consumption, the setting of regularity limits, the identifiability of PCB sources and the effects of remedial actions in the future. In addition, the developed model is not restricted to the current application but could be used for the analysis of other contaminants.     

Engineered magnetic oxides nanoparticles as efficient sorbents for wastewater remediation: a review

The rapid urbanization and industrialization is causing worldwide water pollution, calling for advanced cleaning methods. For instance, pollutant adsorption on magnetic oxides is efficient and very practical due to the easy separation from solutions by an magnetic field. Here we review the synthesis and performance of magnetic oxides such as iron oxides, spinel ferrites, and perovskite oxides for water remediation. We present structural, optical, and magnetic properties. Magnetic oxides are also promising photocatalysts for the degradation of organic pollutants. Antimicrobial activities and adsorption of heavy metals and radionucleides are also discussed.