Leaching of aluminium from cookwares -- a review

Concern over the possible relation between environmental aluminium exposure and Alzheimer's disease has prompted studies of all forms of human intake of this element including that from foods. Aluminium cookware, apart from other sources of dietary aluminium, is considered to be a potential source of this metal to human beings. Various research groups have carried out aluminium leaching experiments with food, beverages and water under different experimental conditions modified by varying the level of pH, chloride, fluoride, citrate, acetate etc. The results reported by different workers show marked discrepancies in levels of leached aluminum. The apparent reason for such discrepancy in levels of aluminum leached can be attributed to factors such as non-systematic and non-uniform experimental designs, non-standard conditions maintained during the experiments and choice of method for aluminium analysis. In order to assess accurately the contribution of aluminium ingestion by human beings through aluminium cookware, the present review emphasises the need of i) standard size aluminium plates obtained from the same lot for one set of experimentations; ii) real life cooking conditions to highlight the role of various complexing species present in food e.g. citrate, oxalate, acetate, tartrate etc.; iii) role of chemistry of aluminium in presence of acidic, basic and neutral cooking medium and iv) strict analytical control in the estimation of aluminium. Results of a systematic study by the authors conducted on the abovementioned lines are also described.     

Exergy analysis of the transcritical N2O refrigeration cycle with a vortex tube

In this article, a comparative study is presented for the transcritical cycle with expansion valve (TCEV) and transcritical cycle with vortex tube (TCVT) mainly based on the second law of thermodynamics. Natural refrigerant nitrous oxide (N₂O) is used in both the cycles for analysis. The evaporator and gas cooler temperatures are varied from ?55°C to 5°C and 35°C to 60°C, respectively. The effects of various operating and design parameters on the optimum heat rejection pressure, coefficient of performance (COP), exergy loss (irreversibility), and the exergetic efficiency are studied. Exergy analysis of each component in TCEV and TCVT is performed to identify the amount and locations of irreversibility. It is observed that the use of the vortex tube in place of the expansion valve reduces the total exergy losses and increases the exergetic efficiency as well as COP. The exergetic efficiency and COP of the TCVT are on average 10–12% higher compared to TCEV for the considered operating conditions. The computed values of the exergetic efficiency for TCVT using refrigerant N₂O are the highest at an evaporator temperature of ?55°C, and the corresponding values of exergetic efficiency and exergy losses varies between 25.35% and 15.67% and between 74.65% and 84.33%, respectively. However, COP at the same evaporator temperature of ?55°C varies between 0.83 and 0.51. Furthermore, the optimum heat rejection pressure in TCVT is lower compared to that in TCEV. The results offer significant help for the optimum design and operating conditions of TCVT with refrigerant N₂O.     

Transparency in global sustainability governance: to what effect?

ABSTRACT

Transparency in environmental governance is no longer an uncontroversial answer to problems of accountability and effectiveness. How to design effective transparency systems and in what policy contexts they are effective remain contested issues. This special section, consisting of this introduction and four research articles, interrogates complex and potentially conflicting links between transparency, accountability, empowerment and effectiveness in environmental governance. Building on existing literature and the four contributions, we discuss persisting diversity in varieties of transparency, the evolving dynamics of commodity chain transparency, and the consequences of emerging novel forms of digitalized transparency. As we show, the contributions to this special section interrogate in novel ways the transformative potential of transparency, through shedding light on the performative effects of transparency in ever more complex environmental governance contexts. These contexts may include, inter alia, the growing ubiquity of traceability in transnational commodity chains, the need for ever more anticipatory (ex-ante) forms of environmental governance, and an ever-broadening quest for digitally monitored environments. In particular, the impacts of the real-time ‘radical’ transparency engendered by use of novel digital technologies remain under-analyzed in the sustainability domain. We conclude by raising several critical concerns that deserve further scientific research and policy debate.     

Growth and metal accumulation response of <Emphasis Type="Italic">Vigna radiata</Emphasis> L. var PDM 54 (mung bean) grown on fly ash-amended soil: effect on dietary intake

Plants of Vigna radiata L. var. PDM 54 (mung bean) were grown in soil amended with different amounts (10 and 25%) of fly ash (FA). Although total metal content increased with increasing FA amendment, DTPA-extractable metals were higher for 10% FA. Accumulation of metals by the plants increased with increasing FA amendment and was greater in shoots than in roots (except for Mn and Cu) and seeds (except Mn). The total daily intake (TDI) of all the tested metals in seeds was within the recommended dietary allowance (RDA)/provisional tolerable daily intake (PTDI) for adults, except for Cd, which was higher than recommended values. Principal-components analysis (PCA) based on studies of physicochemical properties, DTPA-extractable metals, and metal accumulation in the different parts of V. radiata showed that physicochemical properties such as cation-exchange capacity, organic carbon, and organic matter had significant positive effects on accumulation of Cd, Co, Ni, and Pb by the plant, whereas EC had a significant negative effect. Although addition of fly ash (10%) initially increased the rate of growth, toxic symptoms were observed for 25% FA. Results from analysis of antioxidants (carotenoids, ascorbic acid, non-protein thiol, and free proline) revealed that these increased more in plants grown in 10% FA than in those grown in garden soil. Cysteine and malondialdehyde (MDA) content increased with increasing FA amendment. PCA also showed that all the antioxidants studied behaved similarly except cysteine, for which there was a close relationship with MDA content. Thus, the results obtained during this study revealed that V. radiata L. var. PDM 54 may be grown in 10% FA and/or contaminated agricultural soil.     

Arsenic accumulation in root and shoot vis-a-vis its effects on growth and level of phytochelatins in seedlings of Cicer arietinum L

Arsenic (As) contamination of water and soil has become a subject of prime interest due to its direct effect on human health through drinking water and food. In present study two varieties (CSG-8962 and C-235) of chickpea, Cicer arietinum L., which is a major supplementary food in many parts of India and a valuable source of protein, has been selected to estimate the level of arsenate in root and shoot of five day old seedlings vis-à-vis effect of arsenate on seedling growth and induction of thiols including glutathione (GSH) and phytochelatins (PCs) and their homologues. Both varieties accumulated arsenate to similar levels and most of the metalloid was confined to roots, only about 2.5% was translocated to shoot. Plant growth was also not affected significantly in both the varieties. Arsenate exposure significantly induced the levels of thiols including PCs and homophytochelatins (hPCs). The induction of thiols was much higher in roots than shoots and was greater in var C-235 between the two tested ones. Thus, both varieties tolerated and detoxified arsenic through chelation with GSH, PCs and hPCs, primarily in roots, however var C-235 performed better     

Air quality mapping using GIS and economic evaluation of health impact for Mumbai City,India

Mumbai, a highly populated city in India, has been selected for air quality mapping and assessment of health impact using monitored air quality data. Air quality monitoring networks in Mumbai are operated by National Environment Engineering Research Institute (NEERI), Maharashtra Pollution Control Board (MPCB), and Brihanmumbai Municipal Corporation (BMC). A monitoring station represents air quality at a particular location, while we need spatial variation for air quality management. Here, air quality monitored data of NEERI and BMC were spatially interpolated using various inbuilt interpolation techniques of ArcGIS. Inverse distance weighting (IDW), Kriging (spherical and Gaussian), and spline techniques have been applied for spatial interpolation for this study. The interpolated results of air pollutants sulfur dioxide (SO₂), nitrogen dioxide (NO₂) and suspended particulate matter (SPM) were compared with air quality data of MPCB in the same region. Comparison of results showed good agreement for predicted values using IDW and Kriging with observed data. Subsequently, health impact assessment of a ward was carried out based on total population of the ward and air quality monitored data within the ward. Finally, health cost within a ward was estimated on the basis of exposed population. This study helps to estimate the valuation of health damage due to air pollution.

Implications: Operating more air quality monitoring stations for measurement of air quality is highly resource intensive in terms of time and cost. The appropriate spatial interpolation techniques can be used to estimate concentration where air quality monitoring stations are not available. Further, health impact assessment for the population of the city and estimation of economic cost of health damage due to ambient air quality can help to make rational control strategies for environmental management. The total health cost for Mumbai city for the year 2012, with a population of 12.4 million, was estimated as USD8000 million.     

Chemical characteristics and source apportionment of PM<Subscript>2.5</Subscript> using PCA/APCS,UNMIX, and PMF at an urban site of Delhi,India

The present study investigated the comprehensive chemical composition [organic carbon (OC), elemental carbon (EC), water-soluble inorganic ionic components (WSICs), and major & trace elements] of particulate matter (PM_2.5) and scrutinized their emission sources for urban region of Delhi. The 135 PM_2.5 samples were collected from January 2013 to December 2014 and analyzed for chemical constituents for source apportionment study. The average concentration of PM_2.5 was recorded as 121.9 ± 93.2 μg m^?3 (range 25.1–429.8 μg m^?3), whereas the total concentration of trace elements (Na, Ca, Mg, Al, S, Cl, K, Cr, Si, Ti, As, Br, Pb, Fe, Zn, and Mn) was accounted for ～17% of PM_2.5. Strong seasonal variation was observed in PM_2.5 mass concentration and its chemical composition with maxima during winter and minima during monsoon seasons. The chemical composition of the PM_2.5 was reconstructed using IMPROVE equation, which was observed to be in good agreement with the gravimetric mass. Source apportionment of PM_2.5 was carried out using the following three different receptor models: principal component analysis with absolute principal component scores (PCA/APCS), which identified five major sources; UNMIX which identified four major sources; and positive matrix factorization (PMF), which explored seven major sources. The applied models were able to identify the major sources contributing to the PM_2.5 and re-confirmed that secondary aerosols (SAs), soil/road dust (SD), vehicular emissions (VEs), biomass burning (BB), fossil fuel combustion (FFC), and industrial emission (IE) were dominant contributors to PM_2.5 in Delhi. The influences of local and regional sources were also explored using 5-day backward air mass trajectory analysis, cluster analysis, and potential source contribution function (PSCF). Cluster and PSCF results indicated that local as well as long-transported PM_2.5 from the north-west India and Pakistan were mostly pertinent.     

Nickel accumulation and its effect on growth,physiological and biochemical parameters in millets and oats

With the boom in industrialization, there is an increase in the level of heavy metals in the soil which drastically affect the growth and development of plants. Nickel is an essential micronutrient for plant growth and development, but elevated level of Ni causes stunted growth, chlorosis, nutrient imbalance, and alterations in the defense mechanism of plants in terms of accumulation of osmolytes or change in enzyme activities like guiacol peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD). Ni-induced toxic response was studied in seedlings of finger millet, pearl millet, and oats in terms of seedling growth, lipid peroxidation, total chlorophyll, proline content, and enzymatic activities. On the basis of germination and growth parameters of the seedling, finger millet was found to be the most tolerant. Nickel accumulation was markedly lower in the shoots as compared to the roots, which was the highest in finger millet and the lowest in shoots of oats. Plants treated with a high concentration of Ni showed significant reduction in chlorophyll and increase in proline content. Considerable difference in level of malondialdehyde (MDA) content and activity of antioxidative enzymes indicates generation of redox imbalance in plants due to Ni-induced stress. Elevated activities of POD and SOD were observed with high concentrations of Ni while CAT activity was found to be reduced. It was observed that finger millet has higher capability to maintain homeostasis by keeping the balance between accumulation and ROS scavenging system than pearl millet and oats. The data provide insight into the physiological and biochemical changes in plants adapted to survive in Ni-rich environment. This study will help in selecting the more suitable crop species to be grown on Ni-rich soils.

     

Applicability of sustainable urban drainage systems: an evaluation by multi-criteria analysis

Urban flooding has become more serious and worldwide in recent years, especially in the big cities of developing countries. This study uses a multi-criteria analysis (MCA) approach to evaluate the applicability of sustainable urban drainage systems (SUDS), a flood control measure, in the central part of Ho Chi Minh City, Vietnam. The output of the personal computer storm water management model along with interviews with 140 households was used to assess the efficacy and acceptability of four SUDS alternatives: rainwater harvesting, green roof, urban green space and pervious pavement. On technical performance, green roof was the best alternative, followed by pervious pavement, urban green space and rainwater harvesting. Results of the social survey, however, diverged largely from the results of the technical assessments. In particular, people generally prefer public SUDS such as urban green space and pervious pavements to household solutions. With respect to the MCA, we applied four different procedures: Borda count, pair-wise voting, range of value and analytic hierarchy process. Despite some differences, the integrated results from MCA largely agree that urban green space is the most favourable type of SUDS, followed by green roof, pervious pavement and rainwater harvesting.