Radon exhalation from building materials for decorative use

Long-term exposure to radon increases the risk of developing lung cancer. There is considerable public concern about radon exhalation from building materials and the contribution to indoor radon levels. To address this concern, radon exhalation rates were determined for 53 different samples of drywall, tile and granite available on the Canadian market for interior home decoration. The radon exhalation rates ranged from non-detectable to 312 Bq m⁻² d⁻¹. Slate tiles and granite slabs had relatively higher radon exhalation rates than other decorative materials, such as ceramic or porcelain tiles. The average radon exhalation rates were 30 Bq m⁻² d⁻¹ for slate tiles and 42 Bq m⁻² d⁻¹ for granite slabs of various types and origins. Analysis showed that even if an entire floor was covered with a material having a radon exhalation rate of 300 Bq m⁻² d⁻¹, it would contribute only 18 Bq m⁻³ to a tightly sealed house with an air exchange rate of 0.3 per hour. Generally speaking, building materials used in home decoration make no significant contribution to indoor radon for a house with adequate air exchange.     

Assessing of Environmental Quality in Six Areas in India,Sri Lanka and Bangladesh

Environmental quality for environmental health has been examined visually by describing general conditions and drinking water supply, sanitation and solid waste treatment conditions and practices in six South-East Asian villages with a dense population. The environmental review was supplemented by discussions with local people and political and administrative decision makers. Some drinking water analyses were done in order to show the water quality to the local people. The quality of the general conditions and the conditions and practices of drinking water supply, excreta disposal and solid waste treatment practices have been graded with the grading system presented below. The grading could be done in 1 or 2 days in each area by two persons, of which one was an environmental scientist and the other a social scientist, who also knew the local culture and worked as a translator.     

Modelling of water-ozone reaction system

Mass transfer and reaction kinetics of raw Nile water ozonation are examined. The contact system is a perfectly mixed reactor, and ozone is bubbled through a glass diffuser at different supply rates. The ozone residual is detected for different reaction time intervals. A simple mathematical model is proposed to describe the mechanism of the ozone reactions in the reactor. The proposed model quite accurately describes the mass transfer behaviour in the reactor and determines the ozone dissociation rate constant, together with the effect of the chemical reaction on the ozone transfer. A linear relationship is observed between the ozone feed rate and the ozone residual. First order reaction kinetics describes fairly well the autodecomposition and the global reaction rates of ozone in raw water. The mass transfer coefficient is about 0.18 min⁻¹. The dissociation and the reaction rate constants are evaluated to be 0.33 mg L⁻¹ and 0.19 mg L⁻¹min⁻¹.     

Prevalence of Rotaviruses Groups A and C in Egyptian Children and Aquatic Environment

The objective of this study is to compare the prevalence of rotaviruses groups A and C in Egyptian children and aquatic environment. From 110 stool specimens of children with acute diarrhea and using RT-PCR, 35 samples (31.8 %) were positive for human rotavirus group A and 15 samples (13.6 %) were positive for human rotavirus group C. From 96 samples collected from Zenin wastewater treatment plant over a 2-year period (November 2009–October 2011) and using RT-PCR, rotavirus group A was detected in (4/24) 16.7 %, (5/24) 20.8 %, (4/24) 16.7 %, and (4/24) 16.7 %, while rotavirus group C was detected in (2/24) 8.3 %, (3/24) 12.5 %, (3/24) 12.5 %, and (0/24) 0 % in raw sewage, after primary sedimentation, after secondary sedimentation, and after final chlorination, respectively. Moreover, from 96 samples collected from El-Giza water treatment plant over a 2-year period (November 2009–October 2011), rotavirus group A was detected in (7/24) 29.2 %, (6/24) 25 %, (5/24) 20.8 %, and (3/24) 12.5 %, while rotavirus group C was detected in (3/24) 12.5 %, (1/24) 4.2 %, (1/24) 4.2 %, and (0/24) 0 % in raw Nile water, after sedimentation, after sand filtration, and after final chlorination, respectively. Using SYBR Green real-time RT-PCR, the number of human rotavirus group A genome or infectious units was higher than rotavirus group C. VP6 sequence analysis of the RT-PCR positive rotavirus group C samples revealed that four clinical specimens and three environmental samples showed similar sequences clustered with Moduganari/Human Nigerian strain AF 325806 with 98 % homology, and two clinical specimens and one environmental sample showed similar sequences clustered with Dhaka CB/Human Bangladesh strain AY 754826 with 97 % homology.     

Informal Institutional Responses to Government Interventions: Lessons from Madhupur National Park,Bangladesh

Madhupur National Park is renowned for severe resource ownership conflicts between ethnic communities and government authorities in Bangladesh. In this study, we applied the Institutional Analysis and Development framework to identify: (i) past and present informal institutional structures within the ethnic Garo community for land resource management; (ii) the origin of the land ownership dispute; (iii) interaction mechanisms between formal and informal institutions; and (iv) change in land management authority and informal governance structures. We identify that the informal institutions of the traditional community have undergone radical change due to government interventions with implications for the regulation of land use, informal institutional functions, and joint-decision-making. Importantly, the government’s persistent denial of the role of existing informal institutions is widening the gap between government and community actors, and driving land ownership conflicts in a cyclic way with associated natural resource degradation.     

Insecticide substitutes for DDT to control mosquitoes may be causes of several diseases

Malaria continues to be a public health problem in Bangladesh, despite efforts in the 1960s to eradicate the vectors through the use of DDT. At one point, eradication of malaria was acclaimed but later on it reappeared. The use of DDT is no more legally allowed in Bangladesh, which has been officially replaced by a number organophosphates and/or synthetic pyrethroids and their combinations in addition to the integrated vector management (IVM) package. IVM being a community approach is still to go a long way to be mass popular. Adulticides, larvicides, residual sprays, mosquito coil, insecticide-impregnated curtain, aerosol, etc. still serve as the major weapons of mosquito control. Thus, mosquito control still mostly depends on chemical insecticides. Although the use of DDT is banned in Bangladesh, there are reports on its illegal use in different forms. Moreover, there is tons of leftover DDT in Bangladesh, which is likely to cause several diseases. As per one report, about 500 MTs of DDT stockpiles are lying in the Medical Sub-Depots at Chittagong for over a period of 26 years. DDT is a persistent organic pollutant pesticide, which can cause diseases like cancer, endocrine disorder, disruption of immune system, embryonic abnormality, reproductive disorder, etc. Other chemical insecticides, which are replacing DDT, are also not free of hazardous impacts. IVM thus appears to be a wise approach requiring concerted efforts for the management of mosquito to control malaria. Such an IVM comprises use of Bacillus thuringiensis Berliner var. israelensis, methoprene, biocontrol agents, cleaning of breeding sites, pyrethroid-impregnated curtain, etc. Therefore, a wise effort should be adopted to completely stop the use of DDT, eliminate its stockpiles wherever they are in Bangladesh and to popularise the IVM, not the chemicals-based alternatives throughout the country.     

A framework for integrated resource planning in the electric power sector

A framework is presented showing the process of integrated resource planning in the electric power sector. This takes into account the traditional utility planning process, and shows how the use of advanced decision analysis tools would facilitate the integration of demand-side management (DSM) and environmental factors. The concept of influence diagram is introduced in the utility planning arena. Using the interdependent data analysis (IDA) technique, a way is shown to provide the probability estimates necessary for the influence diagram. The IDA technique allows the use of expert opinions and intuitive judgements to develop the necessary probability estimates. A sample case study is presented where the issue of environmental impact from stack emissions is incorporated. A base case coal option is compared against a gas turbine combined cycle (GTCC) alternative. Energy costs from these two options are compared by taking into account the capital, licensing, fuel, operation and maintenance, and emissions related costs.     

Toxicological study of plant extracts on termite and laboratory animals

Toxic activity of leaf extracts of Polygonum hydropiper L. and Pogostemon parviflorus Benth. were tested in the laboratory against tea termite, Odontotermes assamensis Holm. Both the tested extracts caused mortality of the termite. The highest toxic activity (100%) was found in the 2.0% chloroform extracts of P. hydropiper. The chloroform extract of P. hydropiper was explored for possible mammalian toxicological effects. The LD50 was 758.58 mg/kg in male albino mice. Subcutaneous injection of sub-lethal dose of extract into male mice once a week for 6 weeks failed to express any significant influence on WBC, RBC count and blood cholesterol.     

Zingiber officinale ethanolic extract attenuates oxidative stress,steroidogenic gene expression alterations,and testicular histopathology induced by sodium arsenite in male rats

Environmental Science and Pollution Research - Arsenic (As) indelibly exists in the environment and may reach to a food chain. Flavors and herbs are recognized sources of natural antioxidants that...