Levels of selected essential and toxic elements in the foodstuffs of Islamabad as analyzed by DPASV

Typical dietary components such as vegetables, wheat flour, milk, chicken and drinking water samples have been analyzed for the quantification of essential trace elements like Zn and Cu and potentially toxic trace elements like Pb and Cd. The sensitivity, selectivity and cost effectiveness of Differential Pulse Anodic Stripping Voltammetric method at Hanging Mercury Drop Electrode has been evaluated and used for the analysis. A database covering the adequacy and safety of trace elements through common food articles was first contrived for the Islamabad region. This was followed by assessment of the mobility rate of the heavy metals in the soil, plant system for evaluation of the environmental impact. The method used was also validated using appropriate certified reference materials.     

Effects of anthropogenic nitrogen deposition on soil nitrogen mineralization and immobilization in grassland soil under semiarid climatic conditions

Earlier studies by the authors on English soils under grassland strongly supported their hypothesis that soil/plant systems have naturally evolved to conserve nitrogen (N) by having a close match between the dynamics of mineral-N production in soils and the dynamics of plant N requirements. Thus, maximum mineral-N production in soils occurred in spring when plant N requirements were greatest and were very low in mid to late summer. Low temperature and a high C:N ratio of senescing material helped to conserve N in winter, but mobile N was associated with pollution inputs. We test the hypothesis that under the much more arid conditions of Pakistan, soil/plant systems naturally have evolved to conserve mineral-N, especially over the very dry and cooler months between October and February. When soils from a grassland site were incubated at ambient temperatures after removal of plant roots and exclusion of atmospheric N inputs, there was consistent evidence of immobilization of nitrate and immobilization and possibly volatilization of ammonia/ammonium. In the wetter months of July and August, the soil at 0–10 cm depth showed no evidence of significant ammonium-N production in July and only small ammonium production at 10–20 cm depth in August, but was associated with significant nitrate-N immobilization in August. Nitrate leaching only appeared likely towards the end of the rainy season in September. The results strongly suggest that, under grass, the retention of atmospheric N inputs over the long dry periods is regulating the pools of available N in the soils, rather than the N produced by mineralization of soil organic matter.     

Correction to: Increasing water productivity,nitrogen economy,and grain yield of rice by water saving irrigation and fertilizer-N management

Environmental Science and Pollution Research - The original publication of this paper contains a mistake.     

Vertical distributions of 210Pb excess, 7Be and 137Cs in selected grass covered soils in Southeast Queensland, Australia

Net accumulated areal activity densities and profiles of (210)Pb(ex), (7)Be and (137)Cs in the surface 10 cm of the soil are reported for eight sites in Southeast Queensland, Australia. Areal activity densities of (210)Pb(ex) and (7)Be varied from 1,080 to 4,100 Bqm(-2) and from 176 to 778 Bqm(-2), respectively. A significant (p < 0.001) portion of the variance (R(2) > 0.99) in their vertical distributions was explained by depth in the profile using an exponential function. Around 85% of accumulated (210)Pb(ex) was present in the surface 10 cm of the soil. Beryllium-7 was mainly confined to the grass and surface 2 cm of the soil. Average penetration half-depths of 3.6 +/- 0.2 and 0.3 +/- 0.1cm were determined for (210)Pb(ex) and (7)Be, respectively. Areal activity densities of global fallout (137)Cs varied from 10 to 361 Bqm(-2). Its signal was well mixed within the surface 10 cm. Comparison of the measured (137)Cs values to the estimated input value for the region ( approximately 490 Bqm(-2)) and profiling of a 1m deep soil core suggests a vertical migration of (137)Cs over the past decades. The paleo-radon activity flux determined from the (210)Pb(ex) areal activity density (5.1 +/- 0.9 mBqm(-2) s(-1)) was not statistically different to that measured using activated charcoal cups (5.5 +/- 0.4 mBqm(-2) s(-1)), tending to suggest that Southeast Queensland is neither a net source nor a net sink of (210)Pb-bearing aerosols.     

Toxic effect of some heavy metals on hematology and histopathology of major carp (Catla catla)

Environmental Science and Pollution Research - The current study was conducted to assess the hematological and histopathological changes in major carp (Catla catla) exposed to different...     

Landfill site selection by integrating fuzzy logic,AHP, and WLC method based on multi-criteria decision analysis

Environmental Science and Pollution Research - Rapid population growth integrated with poor governance and urban planning is highly challenging resulting key for the selection of unsuitable...     

Visible–light driven photocatalytic degradation of bisphenol-A using ultrasonically synthesized polypyrrole/K-birnessite nanohybrids: Experimental and DFT studies

Although manganese oxides are known for their semiconductor characteristics, the photocatalytic performance of conducting polymer intercalated K-Birnessite(K-Bi) has not been explored till date. With the view to design a visible light driven organic–inorganic hybrid photocatalyst for rapid degradation of Bisphenol A(BPA), the present work reports the ultrasound-assisted green synthesis of K-Bi/polypyrrole(Ppy) nanohybrids. The loading of Ppy in K-Bi was confirmed by thermogravimetric analysis while the formation of organic–inorganic hybrid was confirmed by infrared spectroscopy. K-Bi revealed a band gap of 2.8 e V while for the nanohybrids it was found to be ranging between 2.4 and 1.6 e V. X-ray diffraction studies confirmed partial intercalation of Ppy chains in the inter-layer space of K-Bi. High resolution transmission electron microscopy and scanning electron microscopy studies showed mixed morphology of K-Birnessite/Ppy nanohybrids. Rapid degradation of BPA was observed under visible irradiation in presence of K-Bi/Ppy nanohybrids and almost90% degradation of 20 mg/L BPA solution was achieved within 120 min. The degradation was found to follow pseudo-first order kinetics and the degraded fragments were identified using liquid chromatography-mass spectrometry. Degradation pathway was proposed based on density-functional theory calculations of fukui index predicting the radical easyattacking(f0) and(f-) sites in BPA.     

Trace metals accumulation in soil irrigated with polluted water and assessment of human health risk from vegetable consumption in Bangladesh

Trace metals accumulation in soil irrigated with polluted water and human health risk from vegetable consumption was assessed based on the data available in the literature on metals pollution of water, soil, sediment and vegetables from the cites of Bangladesh. The quantitative data on metal concentrations, their contamination levels and their pollution sources have not been systematically gathered and studied so far. The data on metal concentrations, sources, contamination levels, sample collection and analytical tools used were collected, compared and discussed. The USEPA-recommended method for health risk assessment was used to estimate human risk from vegetable consumption. Concentrations of metals in water were highly variable, and the mean concentrations of Cd, Cr, Cu and As in water were found to be higher than the FAO irrigation water quality standard. In most cases, mean concentrations of metals in soil were higher than the Bangladesh background value. Based on geoaccumulation index (I _geo) values, soils of Dhaka city are considered as highly contaminated. The I _geo shows Cd, As, Cu, Ni, Pb and Cr contamination of agricultural soils and sediments of the cities all over the Bangladesh. Polluted water irrigation and agrochemicals are identified as dominant sources of metals in agricultural soils. Vegetable contamination by metals poses both non-carcinogenic and carcinogenic risks to the public. Based on the results of the pollution and health risk assessments, Cd, As, Cr, Cu, Pb and Ni are identified as the priority control metals and the Dhaka city is recommended as the priority control city. This study provides quantitative evidence demonstrating the critical need for strengthened wastewater discharge regulations in order to protect residents from heavy metal discharges into the environment.