Oxidative stress in the blood of pregnant rats and reduction of organ weights caused by the polychlorinated biphenyl congener 77

3,3′,4,4′-Tetrachlorobiphenyl (PCB 77), one of the environmentally persistent polychlorinated biphenyls that have been used for industrial purposes, was repeatedly administered to pregnant rats by gavage at a dose of minimal, non-lethal toxicity in order to study its effects on routine blood variables, parameters of oxidative stress and hematopoietic organs in pregnant female rats. Of the routine blood parameters, PCB 77 reduced the mean corpuscular hemoglobin concentration and platelet counts; the levels of malondialdehyde and glutathione peroxidase in the blood were higher during the first days of gestation (1–7), as compared to the respective controls. In the subsequent period between days 8 and 18, these parameters did not show any significant change after PCB 77 treatment. Routine blood parameters and oxidative stress parameters indicated a moderate degree of oxidative stress which alone could not bring about the serious weight reduction of the thymus, pituitary, and kidneys. The extent of oxidative stress did not correlate with the weight reduction of some of the blood-forming organs.     

EKC analysis for studying economic growth and environmental quality: a case study in China

Compared with the extensive research on the relationship between economic growth and environmental quality in developed countries, there is a paucity of an empirical research on studying the relation for developing countries. Based upon the Environmental Kuznets Curve (EKC) theory, this paper develops regression models for investigating the relationship between economic growth and environmental quality in China. The EKC analysis based on six pollution indices is illustrated with a case study in Jiaxing of Zhejiang, China.     

Removal of emerging contaminants from wastewater using advanced treatments. A review

Environmental Chemistry Letters - The rise of emerging contaminants in waters challenges the scientific community and water treatment stakeholders to design remediation techniques that are simple,...     

Cyclodextrin-enabled green environmental biotechnologies

Environmental Science and Pollution Research - Most of the organic compounds contaminating the environment can form inclusion complexes with cyclodextrins resulting in enhanced solubility (a...     

Observational and modeling studies of chemical species concentrations as a function of raindrop size

The Guttalgor method has been used to determine the chemical species concentrations in size-selected raindrops in nine rain events at Hong Kong from 1999 to 2001. The curve (concentration against raindrop radius) patterns for all the species are similar but depend on the starting time of sampling within a rain event. In these plots, the maximum concentration occurs at the same range of droplet radius, irrespective of the species, and this indicates the importance of coalescence and breakup processes. The maximum is located at a smaller droplet radius than was found in previous studies in Germany. All results show almost constant concentrations with size for large raindrops, and these indicate the in-cloud contributions. The pH of raindrops of similar size is linearly correlated with a function of the sulfate, nitrate, acetate, formate, calcium and ammonium ion species concentrations. Within a single raindrop, chloride depletion is not significant, and sulfate, ammonium and hydrogen ions are found in ratios compatible with the precursor solid-phase mixture of ammonium sulfate and ammonium bisulphate. When simulated by a below-cloud model, good agreement between the modeled and measured sodium and sulfate concentrations has been found. Below-cloud sulfur dioxide scavenging contributes at most 60% of the sulfate concentration in a single raindrop.     

Cross-cultural comparison of concrete recycling decision-making and implementation in construction industry

Waste management is pressing very hard with alarming signals in construction industry. Concrete waste constituents major proportions of construction and demolition waste of 81% in Australia. To minimize concrete waste generated from construction activities, recycling concrete waste is one of the best methods to conserve the environment. This paper investigates concrete recycling implementation in construction. Japan is a leading country in recycling concrete waste, which has been implementing 98% recycling and using it for structural concrete applications. Hong Kong is developing concrete recycling programs for high-grade applications. Australia is making relatively slow progress in implementing concrete recycling in construction. Therefore, empirical studies in Australia, Hong Kong, and Japan were selected in this paper. A questionnaire survey and structured interviews were conducted. Power spectrum was used for analysis. It was found that “increasing overall business competitiveness and strategic business opportunities” was considered as the major benefit for concrete recycling from Hong Kong and Japanese respondents, while “rising concrete recycling awareness such as selecting suitable resources, techniques and training and compliance with regulations” was considered as the major benefit from Australian respondents. However, “lack of clients’ support”, “increase in management cost” and “increase in documentation workload, such as working documents, procedures and tools” were the major difficulties encountered from Australian, Hong Kong, and Japanese respondents, respectively. To improve the existing implementation, “inclusion of concrete recycling evaluation in tender appraisal” and “defining clear legal evaluation of concrete recycling” were major recommendations for Australian and Hong Kong, and Japanese respondents, respectively.     

Repeated use of two Chlorella species, C. vulgaris and WW1 for cyclic nickel biosorption.

Two living Chlorella species were used to remove nickel from solution containing 30 micrograms Ni ml-1 in 10 successive cycles. The present study also examined the continued viability of these two algal species after repeated exposure to nickel. The two species of Chlorella were Chlorella vulgaris (commercially available) and WW1 (indigenous species isolated from domestic sewage and was tentatively identified as Chlorella miniata). The nickel removal percentage of WW1 cells was maintained at around 85% in the first five cycles, then declined slightly from the fifth cycle onwards, and finally achieved around 70% removal at the end of the 10th cycle. On the contrary, the removal efficiency of C. vulgaris declined from 50 to 30% during the 10 cycles of nickel bisorption. At the end of these 10 successive cycles, WW1 accumulated a substantial amount of Ni2+ (the cumulative cellular Ni concentration was 0.92% dry w.), while the value was only 0.17% in the case of C. vulgaris. These results suggest that the local isolate, WW1, had more consistent and satisfactory ability for removing Ni than the commercial C. vulgaris. Both algal species were still capable of dividing after each nickel treatment cycle, suggesting that the cells were not killed even when significant amounts of nickel were adsorbed/absorbed. However, Ni exposure adversely affected the physiological activity of algal cells as reflected by the decline in division rate and chlorophyll-a activity in both species. Such negative effects became more obvious as the number of cyclic treatments was increased. Nevertheless, WW1 cells appeared to recover from nickel treatment when re-cultivated in commercial medium for 2 weeks.