Assessment of hydrothermally modified fly ash for the treatment of methylene blue dye in the textile industry wastewater

Dyes and pigments are one of the major water pollutants and if not discharged properly cause ecological disturbance. Considering this, the current study investigates the application of thermal power plant by-product, i.e., fly ash for the elimination of a hazardous methylene blue dye from its synthetic aqueous solution. Experiments were conducted in batch mode to study the effect of pH, temperature, adsorbent dose and contact time. Highest dye removal (94.3%) was achieved at pH 10 using adsorbent dose of 10 g/L in 90 min of contact time at 40 °C. However, for cost-effective operation at neutral pH and room temperature (30 °C), it yields 89.3% dye removal having similar dose and contact time. Equilibrium isotherms for adsorption were analyzed by Langmuir and Freundlich, Temkin and Dubinin–Radushkevich isotherm equations. The results revealed that the best fit model of adsorption closely followed Langmuir adsorption. Based on adsorption isotherm models, thermodynamics parameters ΔG, ΔH and ΔS were calculated. The negative value of ΔG and ΔH revealed that adsorption process was exothermic, spontaneous and physical. The present work suggests that through simple process hydrothermally modified fly ash has the potential to be used as cost-effective and efficient adsorbent for the treatment of wastewater from textile industries.     

Diversity of corals and benthic algae across the shallow-water reefs of Andaman Islands: managing the valuable ecosystems

The Andaman Islands characterize one of the relatively unexplored coral reef zones of the Indian subcontinent. A few benthic biodiversity studies have been carried out to date, but several coral and algal species still remain to be evaluated in terms of their abundance, vigour and conservation priority. In absence of a comprehensive, reliable dataset, inter-relationships between anthropogenic impacts and climate alterations with the coral reefs cannot be assessed authentically. This paper addresses the coupled themes of biodiversity and reef management in the Andaman Islands by examining the percentage cover of corals and benthic algae from shallow-water ecosystems across the coasts of Havelock, Neil, Ross, Jolly Buoy Islands and Chidiyatapu beach proximal to Port Blair. Four major reef types were observed: coral-dominated, algae-dominated, neutral setting and algae overgrowing dead reefs. Jolly Buoy Island had the highest percentage cover of scleractinian corals and crustose coralline algae. Turf algae were most abundant at the Ross Island, while other macroalgae showed highest abundance at Chidiyatapu. Overall species diversity values for corals and algae were highest at the Jolly Buoy and Chidiyatapu, respectively. Given that corals and algae are critical reef components, management paradigms must consider the abundance and frequency of both these biogenic entities in the seascape. The needs, expectations and objectives of the people dependent on coral reef ecosystems also need to be considered. Long-term monitoring is imperative in understanding the natural typology of reefs and managing the possible algal encroachments. Refined management efforts that include greater thrust on development of marine protected areas and reserves; establishment of connectivity between various coral ecosystems of the region; control of invasive algae; and increasing awareness among the local people as well as tourists will ensure continued support of ecosystem to maintain healthy reefs. Collectively, the results are used to promote some strategies to conserve the Andaman coral reefs and cope with the detrimental anthropogenic and climate changes in these coastal habitats.     

Livelihood vulnerability approach to assessing climate change impacts on mixed agro-livestock smallholders around the Gandaki River Basin in Nepal

Climate change vulnerability depends upon various factors and differs between places, sectors and communities. People in developing countries whose subsistence livelihood depends mainly upon agriculture and livestock production are identified as particularly vulnerable. Nepal, where the majority of people are in a mixed agro-livestock system, is identified as the world’s fourth most vulnerable country to climate change. However, there is limited knowledge on how vulnerable mixed agro-livestock smallholders are and how their vulnerability differs across different ecological regions in Nepal. This study aims to test two vulnerability assessment indices, livelihood vulnerability index and IPCC vulnerability index, around the Gandaki River Basin of central Nepal. A total of 543 households practicing mixed agro-livestock were surveyed from three districts, namely Dhading, Syangja and Kapilvastu representing three major ecological zones: mountain, mid-hill and Terai (lowland). Data on socio-demographics, livelihood determinants, social networks, health, food and water security, natural disasters and climate variability were collected and combined into the indices. Both indices differed for mixed agro-livestock smallholders across the three districts, with Dhading scoring as the most vulnerable and Syangja the least. Substantial variation across the districts was observed in components, sub-components and three dimensions (exposure, sensitivity and adaptive capacity) of vulnerability. The findings help in designing site-specific intervention strategies to reduce vulnerability of mixed agro-livestock smallholders to climate change.     

Persistence of metaflumizone on cabbage (Brassica oleracea Linne) and soil, and its risk assessment

Metaflumizone is a novel sodium channel blocker insecticide of semicarbazone class. It provides good to excellent control of most of the economically important lepidopterous pests and certain pests in the orders Coleoptera, Hemiptera, Hymenoptera, Diptera, Isoptera, and Siphonaptera. Although metaflumizone has been marketed globally for several years and got registered in India in the year 2009, specifically for the control of DBM on cabbage, to our knowledge, no food safety aspects of metaflumizone residue on cabbage have ever been reported in the literature in India or elsewhere. The present study was undertaken to evaluate the persistence of metaflumizone on cabbage and soil, vis-a-vis its risk assessment, following two spray applications of metaflumizone 220 SC (Verismo®), each at recommended and double dose of 200 and 400 g?a.i.?ha^?1 respectively. Initial residue deposits of metaflumizone on cabbage were 0.46 and 0.51 mg?kg^?1 at recommended and 0.76 and 0.85 mg?kg^?1 at double the recommended dose following the first spray and second spray application. The residues persisted beyond 5 days from both the treatments and dissipated with the half-life ranging from 1.7–2.1 days. Initial deposits of metaflumizone on soil ranged from 0.23–0.37 mg?kg^?1 and degraded with a half life ranging from 4.0–4.8 days. No degradation product of metaflumizone was detected in cabbage and soil at any point of time. Soil samples collected from the treated field after 7 days were free from any residue of metaflumizone or its metabolites. A pre-harvest waiting period of 3 days after application was suggested based on calculation of theoretical maximum daily intake.     

Top-down and bottom-up inventory approach for above ground forest biomass and carbon monitoring in REDD framework using multi-resolution satellite data

This study deals with the future scope of REDD (Reduced Emissions from Deforestation and forest Degradation) and REDD+ regimes for measuring and monitoring the current state and dynamics of carbon stocks over time with integrated geospatial and field-based biomass inventory approach. Multi-temporal and multi-resolution geospatial synergic approach incorporating satellite sensors from moderate to high resolution with stratified random sampling design is used. The inventory process involves a continuous forest inventory to facilitate the quantification of possible CO₂ reductions over time using statistical up-scaling procedures on various levels. The combined approach was applied on a regional scale taking Himachal Pradesh (India), as a case study, with a hierarchy of forest strata representing the forest structure found in India. Biophysical modeling implemented revealed power regression model as the best fit (R ²?=?0.82) to model the relationship between Normalized Difference Vegetation Index and biomass which was further implemented to calculate multi-temporal above ground biomass and carbon sequestration. The calculated value of net carbon sequestered by the forests totaled to 11.52 million tons (Mt) over the period of 20 years at the rate of 0.58 Mt per year since 1990 while CO₂ equivalent reduced from the environment by the forests under study during 20 years comes to 42.26 Mt in the study area.     

Characterization of particulate matter and its related metal toxicity in an urban location in South West India

This study reports the quantification of the toxicity of particulate matter (PM)-bound metals and their possible associated risks to human health. For assessment of PM, 24-h samples of PM₁₀ and PM_2.5 were collected by Mini Vol-TAS sampler at an urban site of Pune. Samples were sequentially extracted with ultrapure water and concentrated HNO₃ and analyzed for “soluble” and “total” metals. Factor analysis identified the resuspension of road dust due to traffic, biomass burning, construction activities, and wind-blown dust as possible sources that played an important role for overall pollution throughout the year. Water-soluble proportion was found to be ≤20 % for Cr, Co, Fe, and Al; ≥50 % for Sr, Cd, Ca, and Zn; and a substantial proportion (～25–45 %) for Mn, Ba, K, Na, Ni, Mg, Cu, and Pb metals in PM₁₀. For PM_2.5, the water-soluble proportion was ≤20 % for Fe, Co, Ni, Cr, and Al, while Sr, K, and Cd were mostly soluble (>50 %) and Cu, Ba, Mn, Ca, Zn, Pb, Na, and Mg were substantially soluble (～25–45 %). In the present study, among the toxic metals, Cd and Pb show higher concentration in the soluble fraction and thus represent the higher bioavailability index and especially are harmful to the environment and exposed person. Risk calculations with a simple exposure assessment method showed that the cancer risks of the bioavailable fractions of Cr, Cd and Ni were greater than the standard goal.     

Antioxidants in Capsicum chinense: Variation among countries of origin

The main objective of this investigation was to evaluate fruits of C. chinense accessions for their concentration of β -carotene, ascorbic acid, and phenols for use as parents in breeding for these phytochemicals. Mature fruits of 63 accessions of C. chinense originally acquired from Belize, Brazil, Colombia, Ecuador, Mexico, Peru, Puerto Rico, and the United States were analyzed for their chemical composition. Fruits of C. chinense accessions PI-152452 (Brazil) and PI-360726 (Ecuador) contained the greatest concentrations of ascorbic acid (1.2 and 1.1 mg g^?1 fresh fruit, respectively), while PI-438648 (Mexico) contained the greatest concentration of total phenols content (349 μ g g^?1 fresh fruit) among the other 63 accessions tested. Accession PI-355817 from Ecuador contained the greatest concentrations of β -carotene (8 mg g^?1fresh fruit). These accessions were identified as potential candidates for mass production of antioxidants with health-promoting properties.     

Evaluating climatic and non-climatic stresses for declining surface water quality in Bagmati River of Nepal

Both climatic and non-climatic factors affect surface water quality. Similar to its effect across various sectors and areas, climate change has potential to affect surface water quality directly and indirectly. On the one hand, the rise in temperature enhances the microbial activity and decomposition of organic matter in the river system and changes in rainfall alter discharge and water flow in the river ultimately affecting pollution dilution level. On the other hand, the disposal of organic waste and channelizing municipal sewage into the rivers seriously worsen water quality. This study attempts to relate hydro-climatology, water quality, and impact of climatic and non-climatic stresses in affecting river water quality in the upper Bagmati basin in Central Nepal. The results showed that the key water quality indicators such as dissolved oxygen and chemical oxygen demand are getting worse in recent years. No significant relationships were found between the key water quality indicators and changes in key climatic variables. However, the water quality indicators correlated with the increase in urban population and per capita waste production in the city. The findings of this study indicate that dealing with non-climatic stressors such as reducing direct disposal of sewerage and other wastes in the river rather than emphasizing on working with the effects from climate change would largely help to improve water quality in the river flowing from highly populated urban areas.     

Estimating the uncertainty of pesticide residue analysis from mango using multi-residue analysis and validation of method

Validation of method was performed for various pesticides on mango matrix involving the processing of sample at ambient and cryogenic conditions. The linearity, limits of detection, repeatability, matrix effect, and recovery were studied as the aspects of method validation. The effect of matrix on recovery was found to be medium (20–50%) and strong (>50%). After correction by matrix-matched calibration curves, the recovery was calculated to be in the range of 80–107% and 80–105% at ambient and cryogenic processing, respectively. The precision estimated for the recovery of pesticides obtained from both solvent- and matrix-matched calibration curves and at both the processing conditions was determined to be >20% except for chlorpyrifos and atrazine. The uncertainty established for the methodology was >20%, which substantiates the efficiency and reliability of methodology used for pesticide residue analysis in mango in this study.