The fate and transport of arsenic species in the aquatic ecosystem: a case study on Bestari Jaya,Peninsular Malaysia

The field of arsenic pollution research has grown rapidly in recent years. Arsenic constitutes a broad range of elements from the Earth’s crust and is released into the environment from both anthropogenic and natural sources due to its relative mobility under different redox conditions. The toxicity of arsenic is described in its inorganic form, as inorganic arsenic compounds can leach into different environments. Sampling was carried out in the Bestari Jaya catchment while using a land use map to locate the site, and experiments were conducted via sequential extraction and inductively coupled plasma optical emission spectroscopy to quantify proportions of arsenic in the sediment samples. The results show that metals in sediments of nonresidual fractions, which are more likely to be likely released into aquatic environments, are more plentiful than the residual sediment fractions. These findings support the mobility of heavy metals and especially arsenic through sediment layers, which can facilitate remediation in environments heavily polluted with heavy metals.     

Release,deposition and elimination of radiocesium (137Cs) in the terrestrial environment

Radionuclide contamination in terrestrial ecosystems has reached a dangerous level. The major artificial radionuclide present in the environment is ¹³⁷Cs, which is released as a result of weapon production related to atomic projects, accidental explosions of nuclear power plants and other sources, such as reactors, evaporation ponds, liquid storage tanks, and burial grounds. The release of potentially hazardous radionuclides (radiocesium) in recent years has provided the opportunity to conduct multidisciplinary studies on their fate and transport. Radiocesium’s high fission yield and ease of detection made it a prime candidate for early radio-ecological investigations. The facility setting provides a diverse background for the improved understanding of various factors that contribute toward the fate and transfer of radionuclides in the terrestrial ecosystem. In this review, we summarize the significant environmental radiocesium transfer factors to determine the damaging effects of radiocesium on terrestrial ecosystem. It has been found that ¹³⁷Cs can trace the transport of other radionuclides that have a high affinity for binding to soil particles (silts and clays). Possible remedial methods are also discussed for contaminated terrestrial systems. This review will serve as a guideline for future studies of the fate and transport of ¹³⁷Cs in terrestrial environments in the wake of the Fukushima Nuclear Power Plant disaster in 2011.     

Quality of tube well water intended for irrigation and human consumption with special emphasis on arsenic contamination at the area of Punjab,Pakistan

In the present study, the tube well water quality and the associated health risks, emphasizing on arsenic contamination, were investigated in rural and urban samples from Tehsil Mailsi located in Punjab, Pakistan. Arsenic concentrations (μg/L) were ranged from 12 to 448.5 and which exceeded the WHO recommended limit (10 μg/L) in all cases. The calculated average daily dose (3.3 × 10^?0.4 to 1.2 × 10^?0.2 mg/kg day) and hazard quotient (1.1–40) reflected the potential health risk to local population due to tube well water consumption as drinking purpose. Sodium percent (Na%), sodium absorption ratio, residual sodium carbonate, Kelly’s index and magnesium absorption ratio were also determined to assess the suitability of tube well water for irrigation purpose. The resulting piper plot revealed the Na–Ca–HCO₃ type water chemistry of the area and generally alkaline environment. The spatial distribution of arsenic in the tube well waters pinpoints the significant contribution of anthropogenic activities to arsenic pollution. Nevertheless, different statistical tools, including principal component analysis, hierarchical cluster analysis and correlation matrices, revealed the contribution of both natural and anthropogenic activities and alkaline type of aquifers toward the high level of arsenic contamination.     

Biodiesel synthesis and characterization using welted thistle plant (Carduus acanthoides) as source of new non-edible seed oil

In this work we applied base catalyzed transesterification to convert non-edible welted thistle oil (Carduus acanthoides) as new non-edible feedstock into biodiesel (Fatty acid methyl esters). The highest biodiesel yield of 88% was obtained using optimized reaction conditions of 70°C and 5:1 molar ratio (methanol:oil). The synthesized esters were characterize and confirmed by the application of NMR and FT-IR techniques. Gas chromatography and mass spectroscopy identified different fatty acids as palmatic acid (C16:0), oleic acid (C18:1), linoleic acid (18:2), arachidic acid (C20:0), eicosanic acid (C20:1), and erucic acid (C22:1) in the oil of welted thistle. Six corresponding methyl esters reported in welted thistle oil biodiesel includes 9-hexadecenoic acid, hexadecanoic acid, 9-octadecadienoic acid, 11-eicosanoic acid, eicosanoic acid and 13-docosenoicacid. Fuel properties, such as density @40°C Kg/L (0.8470), kinematic viscosity @ 40°C c St (4.37), flash point (95°C), cloud point (+4°C), pour point (?5°C), and sulfur contents (0.0112% wt) of the biodiesel produced were compatible with American Society for Testing and Materials D 6751 specifications.