An improved method to study the impact of pesticide sprays on small song birds

Abstract

Four test groups of small songbirds (Zebra Finch, Poephila guttata) were sprayed in a chamber with varying concentrations of fenitrothion. Exposure levels were assessed by monitoring air concentrations, deposits of the active ingredient (AI) on glass plates and droplets/cm² on Kromekote® cards. All indices of exposure were linearly correlated and the mean AI deposit on glass plates for the four groups tested were equivalent to 38, 51, 139 and 255 g/ha or 14%, 18%, 50% and 91% of the highest permissible emitted rate for broadscale forest spraying in Canada. Significant depression in body weights and brain acetylcholinesterase levels were noted only for the highest exposure group. Fenitrothion residues in blood were detectable only at the highest exposure level, and in liver at the two higher levels. Carcass and feather residues were much higher than those in blood and liver, and were detectable at all exposure levels but the residues did not increase linearly with exposure. For one of the spray groups, we were able to compute an equivalent acute oral dose based on matching acetylcholinesterase inhibition.     

Thermodynamic and kinetic studies of As(V) removal from water by zirconium oxide-coated marine sand

Arsenic contamination of groundwater is a major threat to human beings globally. Among various methods available for arsenic removal, adsorption is fast, inexpensive, selective, accurate, reproducible and eco-friendly in nature. The present paper describes removal of arsenate from water on zirconium oxide-coated sand (novel adsorbent). In the present work, zirconium oxide-coated sand was prepared and characterised by infrared and X-ray diffraction techniques. Batch experiments were performed to optimise different adsorption parameters such as initial arsenate concentration (100–1,000 μg/L), dose (1–8 g/L), pH of the solution (2–14), contact time (15–150 min.), and temperature (20, 30, 35 and 40 °C). The experimental data were analysed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. Furthermore, thermodynamic and kinetic parameters were evaluated to know the mode of adsorption between ZrOCMS and As(V). The maximum removal of arsenic, 97 %, was achieved at initial arsenic concentration of 200 μg/L, after 75 min at dosage of 5.0 g/L, pH?7.0 and 27?±?2 °C. For 600 μg/L concentration, the maximum Langmuir monolayer adsorption capacity was found to be 270 μg/g at 35 °C. Kinetic modelling data indicated that adsorption process followed pseudo-second-order kinetics. The mechanism is controlled by liquid film diffusion model. Thermodynamic parameter, ΔH°, was ?57.782, while the values of ΔG° were ?9.460, ?12.183, ?13.343 and ?13.905 kJ/mol at 20, 30, 35 and 40 °C, respectively, suggesting exothermic and spontaneous nature of the process. The change in entropy, ΔS°?=??0.23 kJ/mol indicated that the entropy decreased due to adsorption of arsenate ion onto the solid adsorbent. The results indicated that the reported zirconium oxide-coated marine sand (ZrOCMS) was good adsorbent with 97 % removal capacity at 200 μg/L concentration. It is interesting to note that the permissible limit of arsenic as per World Health Organization is 10 μg/L, and in real situation, this low concentration can be achieved through this adsorbent. Besides, the adsorption capacity showed that this adsorbent may be used for the removal of arsenic from any natural water resource.     

Generation, storage, collection and transportation of municipal solid waste--a case study in the city of Kathmandu, capital of Nepal

Solid waste management (SWM) services have consistently failed to keep up with the vast amount of solid waste produced in urban areas. There is not currently an efficient system in place for the management, storage, collection, and transportation of solid waste. Kathmandu City, an important urban center of South Asia, is no exception. In Kathmandu Metropolitan City, solid waste generation is predicted to be 1091 m(3)/d (245 tons/day) and 1155 m(3)/d (260 tons/day) for the years 2005 and 2006, respectively. The majority (89%) of households in Kathmandu Metropolitan City are willing to segregate the organic and non-organic portions of their waste. Overall collection efficiency was 94% in 2003. An increase in waste collection occurred due to private sector involvement, the shutdown of the second transfer station near the airport due to local protest, a lack of funding to maintain trucks/equipment, a huge increase in plastic waste, and the willingness of people to separate their waste into separate bins. Despite a substantial increase in total expenditure, no additional investments were made to the existing development plan to introduce a modern disposal system due to insufficient funding. Due to the lack of a proper lining, raw solid waste from the existing dumping site comes in contact with river water directly, causing severe river contamination and deteriorating the quality of the water.     

Feasibility study of rainwater harvesting system in Sylhet City

In rural areas in Bangladesh, groundwater is the principal source of water supply. This underground water is available in considerable amount in shallow aquifers. It is free from pathogenic microorganisms and hence water-borne diseases. In plain lands, other than hilly areas, water supply to 97% rural population comes from tube-wells, which is regarded to be a phenomenal achievement in preserving public health. Besides, a dependable water supply system all throughout the country is offset by two factors: (a) high salinity in surface plus groundwater in coastal areas; (b) want of suitable groundwater aquifers in hilly areas and the high cost of setting up tube-wells due to deep underground water table and stony layers. However, presence of arsenic in underground water now poses a serious threat to the success once made in water supply by setting up of manually operated tube-wells in the village areas—the achievement is now on the brink of total collapse. In about 61 districts out of 64, presence of arsenic exceeds a quantity of 0.05 mg/1, a permissible limit as per Bangladeshi water quality standard. Harvesting rainwater can be a pragmatic solution to this problem, which is common in many places in Sylhet especially in the hilly areas on the north eastern part of the city. This can be an alternative source of drinking water because of availability of rainwater from March to October. Heavy rain occurs from end of May till mid September, which is commonly known as the rainy season. This paper focuses on the possibility of harvesting rainwater in rural communities and thickly populated urban areas of Sylhet. It also demonstrates the scopes of harvesting rainwater using simple and low-cost technology. With setting up of a carefully planned rainwater storage tank, a family can have all of its drinking water from rain. Planned use of rainwater through rainwater harvesting in the roof catchments may fulfill the entire annual domestic water demand of a family in the rural areas of Bangladesh.     

Exposure assessment and associated lung deposition calculations for vehicular exhaust in four metropolitan cities of Pakistan

Ambient aerosol concentrations along the roadside of metropolitan cities of Pakistan were measured using a Grimm 1.109 dust monitor. Considering the high ambient aerosol concentrations, regional lung deposition of aerosol particles in the human respiratory tract was calculated to assess extent of exposure. Lung deposition was computed in terms of mass concentration and the associated surface area for 12 male traffic wardens using the latest version of the stochastic lung deposition code Inhalation, Deposition, and Exhalation of Aerosols in the Lung. The results have revealed 4 to 10 times higher concentrations than recommended by WHO guidelines. The deposition results derived from the model disclose that extrathoracic deposition is in the range of 22 to 28 % with total lung deposition ranging from 40 to 44 % for the scanned particle window of 0.25–10 μm. Considering an average 8-h shift per day and an average breathing rate of 1.3 m³?h^?1, it is approximated that in a worker, up to 1.6 mg of inhalable particle mass can deposit per day.     

Wastewater quality of natural gas fertilizer factory, Fenchuganj and water quality of Kushiara River at the down stream

The physical, chemical and biological characteristics of the wastewater of Natural Gas Fertilizer Factory Ltd. Fenchuganj, Sylhet were determined through extensive laboratory tests in the months of March, July, October and December of the year 2005. Concentration of Suspended Solids was within the range of 445 to 950 mg/L. Bangladesh Industrial Effluent Standards for Suspended Solids is 100 mg/L. Suspended Solids were found above the limit in all the samples. Concentration of Dissolved Solids was found to vary from 576 to 1,456 mg/L. Bangladesh Industrial Effluent Standards, for Dissolved Solids is 2,100 mg/L. Dissolved Solids were found within the limit. Concentration of BOD(5) was found to vary from 4.5 to 8.4 mg/L. Bangladesh Industrial Effluent Standards for BOD(5) is 50 mg/L. For the year 2005, the BOD(5) was found below the limit in all the samples. Dissolved Oxygen of the wastewater was found to be between 2.0 to 3.0 mg/L, which do not satisfy the standard (4.5-8 mg/L). Oil and grease concentration were found in the range of 28 to 68 mg/L, whereas the standard is 10 mg/L for discharge into the inland surface water. In 2005, concentration of Cr(+ 6) was found to vary from 0.01 to 0.156 mg/L in the wastewater. Bangladesh Industrial Effluent Standards, for Cr(+6) is 0.1 mg/L. The concentration of chromium was found above the limit in three samples. Concentration of NO(3) was found to vary from 4.5 to 15.2 mg/L in the wastewater. Bangladesh Industrial Effluent Standards for nitrate is 10 mg/L. The nitrate was found above the limit in three samples. Maximum concentration of ammonia in lagoon 1 was found 1,710 mg/L in month of December. Bangladesh Industrial Effluent Standards for ammonia nitrogen is 100 mg/L. For the year 2005, the ammonia nitrogen was found above the limit in all samples.     

Groundwater vulnerability assessment using DRASTIC and Pesticide DRASTIC models in intense agriculture area of the Gangetic plains,India

Delineating areas susceptible to contamination from anthropogenic sources form an important component of sustainable management of groundwater resources. The present research aims at estimating vulnerability of groundwater by application of DRASTIC and Pesticide DRASTIC models in the southern part of the Gangetic plains in the state of Bihar. The DRASTIC and Pesticide DRASTIC models have considered seven parameters viz. depth to water level, net recharge, aquifer material, soil material, topography, impact of vadose zone and hydraulic conductivity. A third model, Pesticide DRASTIC LU has been adopted by adding land use as an additional parameter, to assess its impact on vulnerability zonation. The DRASTIC model indicated two vulnerable categories, moderate and high, while the Pesticide DRASTIC model revealed moderate, high and very high vulnerable categories. Out of the parameters used, depth to water level affected the vulnerability most. The parameter caused least impact was topography in DRASTIC, while in case of Pesticide DRASTIC and Pesticide DRASTIC LU models, the parameter was hydraulic conductivity. A linear regression between groundwater NO₃ concentrations and the vulnerability zonation revealed better correlation for Pesticide DRASTIC model, emphasising the effectiveness of the model in assessing groundwater vulnerability in the study region. Considering all three models, the most vulnerable areas were found to be concentrated mainly in two zones, (i) in the south-western part along Ekangarsarai-Islampur patch and (ii) around Biharsharif-Nagarnausa area in the central part. Both zones were characterised by intensive vegetable cultivation with urban areas in between.     

Impacts of climate change on savannah woodland biomass carbon density and water-use: a modelling study of the Sudanese gum belt region

This paper analyzes potential impacts of climate change on biomass carbon (C) density and water-use (actual evapotranspiration, AET) of savannah woodlands in Sudan. Climate change scenarios were developed from five General Circulation Models (GCMs; CGCM2, CSIRO2, ECHam4, HadCM3 and PCM) under two IPCC (Intergovernmental Panel on Climate Change) emission scenarios (A1FI and B1). Baseline (1961-90) climate and climate change scenarios for 2080s for eight map sheet grids (1° latitude x 1.5° longitude) were constructed. Compared to baseline values, mean annual precipitation (MAP) showed both increases (+112 to +221 mm) and decreases (?13 to ?188 mm) but mean annual temperature (MAT) only showed increases (+1.2 to +8.3 °C). Baseline biomass C densities showed an exponential relationship with MAP (y?=?6.798 e ^0.0054x, R²?=?0.70). Depending on climate change MAP, biomass C densities increased (+14 to +241 g C m^?2) or decreased (?1 to ?148 g?C m^?2). However, because of uncertainty in biomass C density estimates, the changes were only significant (P <0.05) for some of the climate change scenarios and for grids with MAP >260 mm. Under A1FI emission scenarios, only HadCM3 did not have a significant effect while under B1 emission scenarios, only CGCM2 and ECHam4 had a significant effect on biomass C density. AET also showed both increases (+100 to +145 mm for vertisols and +82 to +197 mm for arenosols) and decreases (?12 to ?178 mm for vertisols and ?12 to ?132 mm for arenosols). The largest relative changes in AET (up to 31 %) were associated with grids receiving the lowest rainfall. Thus, even if MAP increases across the study region, the increase will have little impact on biomass levels in the driest areas of the region, emphasizing the need for improved management and use of savannah woodlands.