Demonstration of sperm head shape abnormality and clastogenic potential of cypermethrin

Adult male Swiss albino mice were administered ip. suspension solution of cypermethrin in 0.15% DMSO at the doses of 30 mg, 60 mg and 90 mg/kg b. wt. daily for 5 days. Another group of animals was injected cyclophosphamide ip. (60 mg/kg b. wt.) in similar manner which served as positive control. Effect of cypermethrin on body and testes weight and sperm head morphology was studied. Clastogenic potential of cypermethrin was studied by using modified Allium test. The cytological changes were studied in the root tip cells of Allium cepa after 3 days treatment with three different concentration of cypermethrin (0.1, 1.0 and 10.0 microg/ml). The results revealed that body weight gain was considerably reduced in higher dose groups, but the testicular weight did not change significantly in any of the cypermethrin treated groups. However, a significant elevation in the number of abnormal shape of sperm head was noticed in higher dose groups as compared to control. It was observed that the abnormality in the shape of sperm head was dose-dependent. The cytological changes in the root tip cells of Allium cepa indicated that cypermethrin is having toxic effects on the root tip cells in the form of stickiness of chromosomes and also affect the mitotic activity. This study suggest that cypermethrin may have the potential to induce adverse effects on sperm head shape morphology of mouse as well as clastogenic effects on root tip cells of Allium cepa.     

Phosphorus release in aerobic sludge digestion.

The objectives of this study are to examine the phosphorus release in aerobic sludge digestion and to better understand its governing mechanisms. In this study, phosphorus release was examined using the secondary sludge from both conventional and biological nutrient removal processes. The experiments were carried out at room temperature (22 +/- 2 degrees C), with or without automatic control of pH (4.5 to 7.8), and under three aeration schemes: fully aerobic (dissolved oxygen [DO] at 3 to 4 mg/L), low DO (0.2 to 0.8 mg/L), and cyclic (with alternate on/off aeration). The released phosphorus concentrations were 20 to 80 mg/L for the conventional sludge and 60 to 130 mg/L for the biophosphorus sludge. Higher phosphorus release also occurred at low pH (<6.0). As for the effect of DO, fully aerobic digestion caused higher phosphorus release than the low-DO and cyclic operations. For better understanding, the solid phosphorus in sludge was conceptually categorized into three forms: inorganic phosphorus precipitates, organic cellular phosphorus, and polyphosphate (poly-P) in polyphosphate-accumulating organisms. Dissolution of inorganic phosphorus precipitates is controlled by physical and chemical conditions, with pH being the most important in this study. Lowering the pH to 4 to 6 clearly promoted the release of inorganic phosphorus. Polyphosphate hydrolysis, on the other hand, was found to be regulated biologically (sensitive to occurrence of anaerobic conditions) and was insignificant in the glutaraldehyde-fixed sludge. Phosphorus release from organic phosphorus should correlate with the volatile solid (VS) digestion, which lyses the cells and frees the phosphorus covalently bonded with the organic matters. The amounts of phosphorus released per unit VS digested (deltaP/deltaVS) were therefore calculated for experiments with long periods of constant pH (to minimize interferences from dissolution/precipitation of inorganic phosphorus). The results suggested that some poly-P was hydrolyzed and released accompanying the aerobic VS digestion, but at rates far lower than those under anaerobic conditions.     

Bench-scale biofilter for removing ammonia from poultry house exhaust

A bench-scale biofilter was evaluated for removing ammonia (NH3) from poultry house exhaust. The biofilter system was equipped with a compost filter to remove NH3 and calcium oxide (CaO) filter to remove carbon dioxide (CO2). Removal of NH3 and CO2 from poultry house exhaust could allow treated air with residual heat to be recirculated back into the poultry house to conserve energy during winter months. Apart from its use as a plant nutrient, NH3 removal from poultry house exhaust could lessen the adverse environmental impacts of NH3 emissions. Ammonia and CO2 were measured daily with gas detector tubes while temperatures in the poultry pen and compost filter were monitored to evaluate the thermal impact of the biofilter on treated air. During the first 37 days of the 54-day study, exhaust air from 33 birds housed in a pen was treated in the biofilter; for the final 17 days, NH3-laden exhaust, obtained by applying urea to the empty pen was treated in the biofilter. The biofilter system provided near-complete attenuation of a maximum short-term NH3 concentration of 73 ppm. During the last 17 days, with a mean influent NH3 concentration of 26 ppm, the biofilter provided 97% attenuation. The CaO filter was effective in attenuating CO2. Compared with a biofilter sized only for NH3 removal, an oversized biofilter would be required to provide supplemental heat to the treated air through exothermic biochemical reactions in the compost. The biofilter could conserve energy in poultry production and capture NH3 for use as plant nutrient. Based on this study, a house for 27,000 broilers would require a compost filter with a volume of approximately 34 m3.     

Emissions of organic compounds and trace metals in fine particulate matter from motor vehicles: a tunnel study in Houston, Texas

Fine particulate matter (PM) samples collected in a highway tunnel in Houston, TX, were analyzed to quantify the concentrations of 14 n-alkanes, 12 polycyclic aromatic hydrocarbons, and nine petroleum biomarkers, as well as 21 metals, with the ultimate aim of identifying appropriate tracers for diesel engines. First, an exploratory multivariate dimensionality reduction technique called principal component analysis (PCA) was employed to identify all potential candidates for tracers. Next, emission indices were calculated to interpret PCA results physically. Emission indices of n-heneicosane, n-docosane, n-tricosane, n-tetracosane, n-pentacosane, fluoranthene, and pyrene were correlated highly and increased strongly with percentage carbon present in the tunnel emanating from diesel vehicles. This suggests that these organic compounds are useful molecular markers to separate emissions from diesel and gasoline engines. Additionally, the results are the first quantification of the metal composition of PM with aerodynamic diameters smaller than 2.5 microm (PM2.5) emissions from mobile sources in Houston. PCA of trace metal concentrations followed by emission index calculations revealed that barium in fine airborne particles can be linked quantitatively to diesel engine emissions, demonstrating its role as an elemental tracer for heavy-duty trucks.     

Human chromosomes in prenatal diagnosis: A one step high resolution technique

A simple high resolution technique for human chromosomes is described for fibroblasts obtained from amniotic fluid cell cultures. The application and clinical significance of this technique in prenatal diagnosis is discussed.     

Is the environment becoming more hazardous?—A global survey 1947 to 1980

This paper examines the assertion that natural disasters are increasingly destructive using evidence from disaster reports during the period 1947–1980. The criteria for judging the impact of a given natural disaster are chiefly loss of life and the extent of the geographical area affected. In spite of uneveness and bias in the reporting of sudden impact disasters the conclusions are that both the frequency of disasters and number of people killed are increasing. Further research into the social consequences of disasters and the need for disaster preparedness training programmes are recommended.     

Capital assets and institutional constraints to implementation of greenhouse gas mitigation options in agriculture

Agriculture is one of the major sources of greenhouse gas (GHG) emission. It accounts for approximately 15% of the total global anthropogenic emissions of GHGs. Emissions could be twice as much if indirect emissions are also taken into the consideration. However, unlike other high emitting sectors such as transport or energy, agriculture is potentially a significant carbon “sink”. It has high technical potential as a carbon sink and if tapped, can substantially enhance global sequestration efforts. The technical potential, however, may not translate into actual GHG reduction because of the capital assets and institutional constraints faced by the smallholder farmers in the developing countries. In this paper we develop a capital assets based framework of physical, financial, social, human and natural barriers to agricultural carbon mitigation initiatives and through analysis of current initiatives, we set out policy based options to reduce each of these barriers. Fundamentally, barrier removal will entail designing agricultural carbon mitigation initiatives in collaboration with farmer communities, through strengthening local institutions, understanding land tenure and natural resource cultures, ensuring legitimacy and equity in payments and fast tracking training and information. We provide a framework that simultaneously aids the dual objectives of alleviating poverty in the poor farming communities of developing countries and lowering global greenhouse gas emissions.     

Using circuit theory to model connectivity in ecology, evolution, and conservation

Connectivity among populations and habitats is important for a wide range of ecological processes. Understanding, preserving, and restoring connectivity in complex landscapes requires connectivity models and metrics that are reliable, efficient, and process based. We introduce a new class of ecological connectivity models based in electrical circuit theory. Although they have been applied in other disciplines, circuit-theoretic connectivity models are new to ecology. They offer distinct advantages over common analytic connectivity models, including a theoretical basis in random walk theory and an ability to evaluate contributions of multiple dispersal pathways. Resistance, current, and voltage calculated across graphs or raster grids can be related to ecological processes (such as individual movement and gene flow) that occur across large population networks or landscapes. Efficient algorithms can quickly solve networks with millions of nodes, or landscapes with millions of raster cells. Here we review basic circuit theory, discuss relationships between circuit and random walk theories, and describe applications in ecology, evolution, and conservation. We provide examples of how circuit models can be used to predict movement patterns and fates of random walkers in complex landscapes and to identify important habitat patches and movement corridors for conservation planning.