CO2 from waste to resource by developing novel mixed matrix membranes

Environmental Science and Pollution Research - Mixed matrix membranes (MMMs) were fabricated by the hydrothermal synthesis of ordered mesoporous KIT-6 type silica and incorporating in polyimide...     

Detection and removal of heavy metal ions: a review

Environmental Chemistry Letters - In aqueous systems, heavy metal ions, when present in excess than permissible limits, are dangerous for human beings and aquatic life. Heavy metals cannot be...     

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...     

Investigating global surface temperature from the perspectives of environmental,demographic, and economic indicators: current status and future temperature trend

Environmental Science and Pollution Research - Anthropogenic activities have increased atmospheric concentrations of greenhouse gas emissions, which have observably increased global temperature....     

Cattle egrets as a biosentinels of persistent organic pollutants exposure

We investigated selected chlorinated pollutants (β-HCH, γ-HCH, DDDs, DDEs, o,p′-DDT, p,p′-DDT, heptachlor, aldrin, dieldrin, and endrin) in the Lahore and the Sialkot districts of Pakistan, using eggs of cattle egret (Bubulcus ibis) collected during May and June 2007. The pollutant with highest level and frequency was ΣDDT, followed by β-HCH, γ-HCH, heptachlor, aldrin, dieldrin, and endrin in descending order. The concentration(s) were significantly higher in Sialkot heronry for all the pollutants (except p,p′-DDT) than in Lahore. The values for DDTs, β-HCH, γ-HCH, and heptachlor were significantly higher (p < 0.05) in the egg(s) than in sediment(s) and in the chicks’ diet, due to biomagnification. Among DDTs analogues, p,p′-DDD was the major contaminant with >60 % of total DDT burden, reflecting the widespread aged as well as recent use of DDT as well as anaerobic degradation (DDD/DDE > 1 in many cases) in the nearby paddy soils. In few samples, p,p′-DDT/(DDD + DDE) > 0.5 suggested the recent emission patterns from surrounding contaminated areas of demolished DDT units and obsolete pesticide stores. The higher levels of HCHs (i.e., β-HCH) in the samples collected from Sialkot indicate exposure from long-term agricultural use. Overall, concentrations of all studied POPs were less than the threshold levels known to affect reproduction. Nevertheless, total DDTs and/or HCHs burdens in some eggs contained concentrations of greater than what would educe adverse effects on birds. This is among few studies on OCPs exposure to avian species, which provide the evidence of Pakistan’s contribution toward the Global POPs emission.     

Application of Zr(IV) tungstate for removal of metal ions from aqueous solutions

A heteropolyacid Zr(IV) tungstate-based cation exchanger has been synthesized. An amorphous sample, prepared at pH 1.2 and having a Na⁺ ion exchange capacity of 0.92?meq?g^?1, was selected for further studies. Its physicochemical properties were determined using Fourier transform infrared spectrometer, X-ray diffraction, thermogravimetric, and scanning electron studies. To understand the cation exchange behavior of the material, distribution coefficients (K _d) for metal ions in various solvent systems were determined. Some important binary separations of metal ions, namely Mg²⁺–Bi³⁺, Cd²⁺–Bi³⁺, Fe³⁺–Bi³⁺, Th⁴⁺–Bi³⁺, and Fe³⁺–Zn²⁺, were achieved on such columns. The practical utility of these separations was demonstrated by separating Fe³⁺ and Zn²⁺ ions quantitatively in commercial pharmaceutical formulation. The cation exchanger has been successfully applied also for the treatment of industrial wastewater and a synthetic mixture. All the results suggests that Zr(IV) tungstate has excellent potential for the removal of metals from aqueous systems using packed columns of this material.     

Sol-gel immobilisation of methyl parathion degrading bacteria isolated from agricultural areas of Pakistan

The following areas are discussed in this paper: immobilisation of bacterial consortium in sol-gel; methyl parathion degradation and bioremediation applications; evaluation of indigenous bacterial isolates of contaminated soils. Bacterial strains were isolated from agricultural areas of Pakistan which were contaminated with methyl parathion. A bacterial consortium of seven (out of 64) Enterobacteriaceae isolates including Citrobacter, Enterobacter and Proteus vulgaris capable of degrading methyl parathion (enzyme activity ranging 410–675 mU mL^?1 for individual isolates and 982 mU/mL for consortium) was selected and subsequently immobilised in tetraethyl orthosilicate (TEOS) and sodium-silicate-based sol-gel matrices. Cell viability of suspended and immobilised bacterial consortium was monitored using a minimal salt medium supplemented with methyl parathion. The results indicate that sol-gel immobilisation can be helpful to increase the shelf life of methyl parathion degrading bacterial strains along with preservation of biological activity for bioremediation applications in field.     

Selenium and hazardous elements distribution in plant–soil–water system and human health risk assessment of Lower Cambrian,Southern Shaanxi,China

The natural selenium poisoning due to toxic Se levels in food chain had been observed in humans and animals in Lower Cambrian outcrop areas in Southern Shaanxi, China. To find out the distribution pattern of selenium and other hazardous elements in the plant, soil and water of Lower Cambrian in Southern Shaanxi, China, and their possible potential health risk, a total of 30 elements were analyzed and the health risk assessment of 18 elements was calculated. Results showed that the soil, plant and natural water of Lower Cambrian all had relatively high Se levels. In Lower Cambrian, the soil was enriched with Se, As, Ba, Cu, Mo, Ni, Zn, Ga, Cd and Cr (1.68 < I_geo < 4.48, I_geo; geo-accumulation index). In same plants, the contents of Se, Cd and Zn (except Cd in corn and rice, Zn in potato and corn) of Lower Cambrian were higher than that of the other strata. Ba and Ga in natural water were higher than that of the other strata, while K and Cs were opposite. The health risk assessment results showed that the people living in outcrop areas of Lower Cambrian had both high total non-carcinogenic risk of 18 elements (HI = 16.12, acceptable range: < 1) and carcinogenic risk of As (3.98E−04, acceptable range: 10⁻⁶–10⁻⁴). High contents of Se, As, Mo and Tl of Lower Cambrian may pose a health risk to local people, and food intake was the major pathway. For minimizing potential health risk, the local inhabitants should use the mix-imported food with local growing foods.

     

Metal contamination of surface soils of industrial city Sialkot,Pakistan: a multivariate and GIS approach

In this study concentrations of selected metals viz., Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Na, Ni, Pb and Zn in surface soils of Sialkot city known worldwide for tanneries and pharmaceutical industries were measured to assess the status of urban soil pollution and to identify sources of contamination. Hierarchical cluster analysis (HACA) indicated concentrations of Mg and Ca related to parent rock material, Cd, Co, and Pb with traffic related activities, Cr, Cu, Ni and Zn either associated with automobiles activities or industrial pollution and Fe, K and Na related with anthropogenic activities or lithogenous materials. Correlation analyses and principal component analysis based on factor analysis confirmed the results of HACA. Spatial distribution maps exhibited relatively higher concentrations of Cd, Co, Cu, Ni, Pb, Cr and Zn along traffic routes in the city and streams. The results highlighted concentration of Cd, Ni, Cr, Zn, and Pb measured in urban soil exceeded the permissible limit of surface soils and advocated an imperative need for detailed baseline investigations of spatial distribution of heavy metals and other contaminants for the formulation of geochemical database that should be made available to stakeholder involved in monitoring, assessment and conservation of soil contamination for future planning and management of the Sialkot city.