Polycyclic aromatic hydrocarbon removal from water by natural fiber sorption.

The use of two natural sorbents, kapok and cattail fibers, were investigated for polycyclic aromatic hydrocarbon (PAH) removal from water. Naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, and fluoranthene were the PAHs studied. For comparative purposes, a commercial polyester fiber sorbent was included in the investigation. The PAH sorption and retention capabilities of the three fibers were determined through batch and continuous-flow experiments under non-competitive and competitive conditions. In the batch experiments, cattail fiber was the most effective sorbent. Kapok fiber provided the lowest PAH retention, while cattail fiber had slightly less PAH retention than polyester fiber. When two PAHs were present in the same system, a competitive effect on the much less hydrophobic PAH was observed. Similar results were obtained in the column experiments, except that polyester fiber performed much poorer on naphthalene. Cattail fiber is a promising sorbent for treating PAH-contaminated water, such as urban runoff.     

Recilia banda Kramer (Hemiptera: Cicadellidae), a vector of Napier stunt phytoplasma in Kenya

Napier grass (Pennisetum purpureum) is the most important fodder crop in smallholder dairy production systems in East Africa, characterized by small zero-grazing units. It is also an important trap crop used in the management of cereal stemborers in maize in the region. However, production of Napier grass in the region is severely constrained by Napier stunt disease. The etiology of the disease is known to be a phytoplasma, 16SrXI strain. However, the putative insect vector was yet unknown. We sampled and identified five leafhopper and three planthopper species associated with Napier grass and used them as candidates in pathogen transmission experiments. Polymerase chain reaction (PCR), based on the highly conserved 16S gene, primed by P1/P6-R16F2n/R16R2 nested primer sets was used to diagnose phytoplasma on test plants and insects, before and after transmission experiments. Healthy plants were exposed for 60 days to insects that had fed on diseased plants and acquired phytoplasma. The plants were then incubated for another 30 days. Nested PCR analyses showed that 58.3% of plants exposed to Recilia banda Kramer (Hemiptera: Cicadellidae) were positive for phytoplasma and developed characteristic stunt disease symptoms while 60% of R. banda insect samples were similarly phytoplasma positive. We compared the nucleotide sequences of the phytoplasma isolated from R. banda, Napier grass on which these insects were fed, and Napier grass infected by R. banda, and found them to be virtually identical. The results confirm that R. banda transmits Napier stunt phytoplasma in western Kenya, and may be the key vector of Napier stunt disease in this region.     

Conversion of Mixed Low-Density Polyethylene Wastes into Liquid Fuel by Novel CaO/SiO<Subscript>2</Subscript> Catalyst

Plastic wastes disposal can be done by various methods such as landfill, incineration, mechanical and chemical recycling but these are restricted due to some environmental, economic and political problems. Conversion of these plastic wastes into valuable products by degradation is the best option. In the present work waste low density polyethylene was degraded by catalytic process using CaO/SiO₂ as mixed catalyst. The conditions for catalytic degradation were optimized for the production of maximum liquid fuel. It was found that the yield of liquid product was up to 69.10 wt% at optimum condition of temperature (350 °C), time (90 min) and catalyst feed ratio (1:0.4). Liquid fuels obtained from the catalytic degradation were further separated into various fractions by fractional distillation. Composition of liquid fuels was analyzed by FTIR spectroscopy, which showed that the liquid fuels mostly consist of paraffinic and naphthenic hydrocarbons. Different fuel properties such as density, specific gravity, American petroleum institute gravity (API gravity), viscosity, kinematic viscosity, refractive index, refractive intercept and flash point of both the parents and various fractional fuels were determined. All the properties of the obtained fuels are in close agreement with the fuel properties of gasoline, kerosene and diesel. It was found that our catalyst is very much efficient in terms of time, degradation temperature and amount of catalyst.     

The nexus of environment-related technologies and consumption-based carbon emissions in top five emitters: empirical analysis through dynamic common correlated effects estimator

Environmental Science and Pollution Research - Climate action got attention from the United Nation’s Sustainable Development Goals (SDGs). Although a large number of studies are investigating...     

Consumption of energy from conventional sources a challenge to the green environment: evaluating the role of energy imports,and energy intensity in Australia

Environmental Science and Pollution Research - Conventional energy consumption such as coal, natural gas, and oil is a source of deteriorating environmental sustainability as well as a severe...     

AI-based runoff simulation based on remote sensing observations: A case study of two river basins in the United States and Canada

Data-driven techniques are used extensively for hydrologic time-series prediction. We created various data-driven models (DDMs) based on machine learning: long short-term memory (LSTM), support vector regression (SVR), extreme learning machines, and an artificial neural network with backpropagation, to define the optimal approach to predicting streamflow time series in the Carson River (California, USA) and Montmorency (Canada) catchments. The moderate resolution imaging spectroradiometer (MODIS) snow-coverage dataset was applied to improve the streamflow estimate. In addition to the DDMs, the conceptual snowmelt runoff model was applied to simulate and forecast daily streamflow. The four main predictor variables, namely snow-coverage (S-C), precipitation (P), maximum temperature (T_max), and minimum temperature (T_min), and their corresponding values for each river basin, were obtained from National Climatic Data Center and National Snow and Ice Data Center to develop the model. The most relevant predictor variable was chosen using the support vector machine-recursive feature elimination feature selection approach. The results show that incorporating the MODIS snow-coverage dataset improves the models' prediction accuracies in the snowmelt-dominated basin. SVR and LSTM exhibited the best performances (root mean square error = 8.63 and 9.80) using monthly and daily snowmelt time series, respectively. In summary, machine learning is a reliable method to forecast runoff as it can be employed in global climate forecasts that require high-volume data processing.     

Effects of β-cyclodextrin on adsorption and desorption of carbofuran in soils of divergent texture

Laboratory studies were conducted to determine the adsorption/desorption equilibrium of carbofuran between four divergently textured soils and distilled water and an aqueous solution of 0.01?mol?L^?1 β-cyclodextrin using a batch equilibrium technique. The determined adsorption isotherms for silt loam soils were of L-shaped, for sandy loam soil S-shaped, in agreement with a Freundlich isotherm. In the presence of β-cyclodextrin, the adsorption of carbofuran to the four soils was lower than with distilled water. Positive hysteresis was observed in all soils with distilled water, negative hysteresis when using a solution of β-cyclodextrin as desorbent. The results indicate the potential use of β-cyclodextrin for remediation of pesticide-contaminated soils.     

Assessing the Removal Efficiency of Murine Norovirus 1, Hepatitis A Virus,and Human Coronavirus 229E on Dish Surfaces Through General Wash Program of Household Dishwasher

Food and Environmental Virology - The performance of dishwashers in removing live viruses is an important informative value in practical applications. Since foodborne viruses are present in...     

Limitation of communal latrines in changing the prevalence of parasites and diarrhoeal attack rate in Dhaka Peri-urban slums

A study of the effects of communal latrines on diarrhoeal incidence and parasite prevalence rates was conducted in 1983 at Tongi, which had five communal Oxfam latrines with a manual flushing system for 924 people; and at Kalsi, which had 39 open fit latrines for 823 people. Inhabitants' stool samples were tested initially and also after twelve months to see the reinfection rates. All inhabitants were dewormed with pyrantel, and were visited weekly to obtain diarrhoea histories. In both communities, there were high prevalence rates of roundworm, hookworm, Trichuris trichiura, Entamoeba histolytica, Giardia lambia and Strongyloides stercoralis. Following the dewormings, the prevalence rates of roundworm, hookworm and Trichuris infection came down significantly, in both areas. The prevalence or reinfection rates remained identical in both communities. There was also no difference in diarrhoea incidence rate for the two areas. It is found that keeping all other variables unchanged, use of communal latrines, without strict disposal of everyone's excreta, does not affect parasite prevalence and diarrhoea rates. People must be educated about the use of communal latrines and the safe disposal of all excreta, including that of children.     

Impact of water control projects on fisheries resources in Bangladesh

Bangladesh is a very flat delta built up by the Ganges—Brahmaputra—Meghna/Barak river systems. Because of its geographical location, floods cause huge destruction of lives and properties almost every year. Water control programs have been undertaken to enhance development through mitigating the threat of disasters. This structural approach to flood hazard has severely affected floodplain fisheries that supply the major share of protein to rural Bangladesh, as exemplified by the Chandpur Irrigation Project. Although the regulated environment of the Chandpur project has become favorable for closed-water cultured fish farming, the natural open-water fishery loss has been substantial. Results from research show that fish yields were better under preproject conditions. Under project conditions per capita fish consumption has dropped significantly, and the price of fish has risen beyond the means of the poor people, so that fish protein in the diet of poor people is gradually declining. Bangladesh is planning to expand water control facilities to the remaining flood-prone areas in the next 15–20 years. This will cause further loss of floodplain fisheries. If prices for closed-water fish remain beyond the buying power of the poor, alternative sources of cheap protein will be required.