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.     

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.     

Sediment quality,elemental bioaccumulation and antimicrobial properties of mangroves of Indian Sundarban

Environmental Geochemistry and Health - Mangroves have wide applications in traditional medicines due to their several therapeutic properties. Potentially toxic elements (PTEs), in mangrove...     

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.     

Effects of herbicides on Odonata communities in a rice agroecosystem

The effects of the five herbicides propanil, quinclorac, molinate/propanil, 2,4-D amine, and bensulfuron on Odonata diversity and abundance at the experimental rice plots was investigated. A total of 13 Odonata morphospecies belonging to two families have been identified. Treated plots exhibited higher species richness (up to 12 species) than the control plot (8 species). Ishnura spp. was the most abundant species in the treated plots with a mean density of 194.2 individuals per m², (ind m^?2) followed by Brachythemis contaminata (152 ind m^?2) and Agriocnemis spp. (124 ind m^?2). In the control plots, Agrocnemis spp. was the dominant species (153 ind m^?2) followed by Ishnura spp. (143 ind m^?2) and Neurothemis fluctuans (59 ind m^?2). In the propanil-treated plot, the highest number of odonate species (10 species) was recorded followed by the plots treated with quinclorax and molinate/propanil (9 species). On the 2,4-D amine or bensulfuron-treated plots as well as the control plot, only eight odonate species were recorded. This study revealed that herbicide application had a positive effect on Odonata diversity. This seems reasonable as Odonata are non-target organisms for herbicides. Furthermore, the decomposed weeds resulting from herbicide application would enrich the water with necessary organic matter.     

Spatial variations in selected metal contents and particle size distribution in an urban and rural atmosphere of Islamabad, Pakistan

Spatial variations in total suspended particulate matter (TSP) were investigated for distribution of metals and particle size fractions in the urban and rural atmosphere of Islamabad, Pakistan. The metals Na, K, Fe, Mn, Pb, Cd, Cr, Zn, Ni and Co, and the particle fractions <2.5, 2.5-10, 10-100 and >100 microm were included in the study. TSP samples were trapped on glass fibre filters using high volume samplers and quantification of metals was done using Atomic Absorption Spectrometry employing HNO(3) based wet digestion. At the urban site, Na was dominant at 2.384 microg/m(3) followed by K, Fe and Zn with 0.778, 0.667 and 0.567 microg/m(3) as mean concentrations, respectively. The metal levels for the rural site ranged from 0.002 microg/m(3) for Cd to 1.077 microg/m(3) for Na. However, compared with the urban site, mean Pb concentration showed an almost two-fold enhancement, i.e., 0.163 Vs. 0.327 microg/m(3). Metals and particle size source identification was done using Principal Component Analysis and Cluster Analysis. Five sources were traced out for the urban site: industrial, soil, automobile emissions, metallurgical industries and excavation activities. For the rural site, four sources were recorded: agricultural, automotive emissions, excavation activities and metallurgical units. Collectively, for both the sites, PM(10-100) emerged as a major contributor to TSP, followed by PM(2.5-10), PM(<2.5) and PM(>100) in that order. The metals showed in general positive relationship with fine particulate fractions (PM(2.5-10), PM(<2.5)), and negative correlation with coarse fractions (PM(10-100), PM(>100)). Comparison with the corresponding data from various Asian sites revealed that the levels of Na, K, Fe, Mn, Co and Ni for the present study were lower than those reported for grossly polluted cities of the world.