Assessment of tap water quality and corrosion scales from the selected distribution systems in northern Pakistan

Corrosion deposits formed within drinking water distribution systems deteriorate drinking water quality and resultantly cause public health consequences. In the present study, an attempt was made to investigate the concurrent conditions of corrosion scales and the drinking water quality in selected water supply schemes (WSS) in districts Chitral, Peshawar, and Abbottabad, northern Pakistan. Characterization analyses of the corrosion by-products revealed the presence of α-FeOOH, γ-FeOOH, Fe₃O₄, and SiO₂ as major constituents with different proportions. The constituents of all the representative XRD peaks of Peshawar WSS were found insignificant as compared to other WSS, and the reason could be the variation of source water quality. Well-crystallized particles in SEM images indicated the formation of dense oxide layer on corrosion by-products. A wider asymmetric vibration peak of SiO₂ appeared only in Chitral and Abbottabad WSS, which demonstrated higher siltation in the water source. One-way ANOVA analysis showed significant variations in pH, turbidity, TDS, K, Mg, PO₄, Cl, and SO₄ values, which revealed that these parameters differently contributed to the source water quality. Findings from this study suggested the implementation of proper corrosion prevention measures and the establishment of international collaboration for best corrosion practices, expertise, and developing standards.     

Temporal variation in leachate composition of a newly constructed landfill site in Lahore in context to environmental pollution and risks

Environmental Science and Pollution Research - This study investigated the seasonal and temporal variations in the extent and source of physiochemical and toxic trace elements in the Lakhodair...     

Selective removal of some polyhydric phenols from aqueous solution by ferric antimonate

Ferric antimonate, a cation-exchanger, has been investigated as an adsorbent for the removal of phenol and polyhydric phenols from aqueous solution. It has been found that ferric antimonate in H+ form selectively adsorbs polyhydric phenols having hydroxyl groups on adjacent positions. While phenol, resorcinol, and quinol did not show any appreciable adsorption, catechol, pyrogallol, and gallic acid having hydroxyl groups on adjacent positions exhibited considerable adsorption on ferric antimonate. Batch equilibrium experiments were carried out to study the effect of contact time, initial concentration of phenolic compounds, and temperature on the adsorption of phenolic compounds on ferric antimonate. The equilibrium time was found to be 1.5 hours for gallic acid and pyrogallol and 2 hours for catechol and salicylic acid. The adsorption data of the phenols at temperatures of 30 degrees, 40 degrees, and 50 degrees C have been described by Langmuir and Freundlich isotherm models. The best fit was obtained with the Langmuir model in the whole range of concentrations studied at all temperatures, indicating a monolayer adsorption onto a homogeneous adsorption surface. On the basis of the Langmuir isotherm, the maximum adsorption capacity of ferric antimonate for gallic acid, pyrogallol, catechol, and salicylic acid was found to be 3.915, 3.734, 2.397, and 2.758 mg/g, respectively at 30 degrees C. The maximum sorption capacity of ferric antimonate for the phenolic compounds studied is in the following order: gallic acid > pyrogallol > salicylic acid > catechol. The adsorption of phenolic compounds was found to decrease with an increase in temperature. Thermodynamic parameters like free energy, enthalpy, and entropy changes were calculated and discussed. The adsorption of polyhydric phenols on ferric antimonate is exothermic and spontaneous in nature.     

A new challenge to child and adolescent survival in urban Africa: an increasing burden of road traffic injuries

OBJECTIVES: To develop an epidemiological profile and present the burden of urban road-traffic injuries (RTI) in children and adolescents in urban Sub-Saharan Africa. METHOD: A systematic review of published and gray literature of children and adolescents < or =19 years old involved in RTI in urban regions in Sub-Saharan Africa from January 1980-December 2003. RESULTS: The mean annual incidence for urban road-traffic injuries was 109.8 per 100,000 children, and males were twice as involved as their female counterparts. Children between 10 to 14 years constitute the most frequent group involved in road crashes (36%) while pedestrians represent an average of 68% of all childhood RTI cases. Twenty Healthy Life Years per 1,000 children and adolescents are being lost annually in the region from RTI. CONCLUSIONS: There is an urgent need to develop a regional health research agenda to generate an accurate estimate of the burden of road-traffic injuries on children. This is a new challenge for child health and there is a need to raise awareness among policy makers to promote appropriate interventions.     

Mapping green technologies literature published between 1995 and 2019: a scientometric review from the perspective of the manufacturing industry

Environmental Science and Pollution Research - This study presents a comprehensive literature review and gives an insight into the increasing research trends that are based on the discipline of...     

Analysis of daily and seasonal variation of fine particulate matter (PM2.5) for five cities of China

Environment, Development and Sustainability - Monitoring of air quality is demanding, especially in poor air quality regions. China has been suffering from PM2.5 pollution associated with the fast...