Eco-Friendly, Vascular Shape and Interpenetrating Poly (Acrylic Acid) Grafted Pectin Hydrogels; Biosorption and Desorption Investigations

The synthesis and characterization of poly (acrylic acid) grafted pectin hydrogel followed by biosorption and desorption characteristics of cadmium, as a model heavy metal, have been studied. The grafted eco-friendly pectin based interpenetrating hydrogel was prepared in the presence of gluteraldehyde crosslinker under N₂ atmosphere and characterized using ¹H-NMR, FTIR, TGA and SEM techniques. Gluteraldehyde was found to form one-arm and two-arm crosslinks in the copolymer. Upon grafting, two-dimensional sheet structures bounded to tubular and vascular cylindrical rods were observed. The biosorption and desorption data, determined experimentally, were fitted to pseudo-second order reaction kinetics. At higher ionic strength values, the maximum metal uptake value (q _max) was lowered and pseudo-second order rate constant (k ₂) was increased. Whereas, at higher pH values the maximum metal uptake value (q _max) was increased and Pseudo-second order rate constant (k ₂) was decreased. 0.1?M HCl solution was a suitable eluent to regenerate the hydrogel surface and recover the adsorbed cadmium metal ions. Pectin based copolymer could be used as an efficient candidature biosorbent for the recovery of cadmium metal ions from aqueous solutions.     

Uranium biosorption by <Emphasis Type="Italic">Padina</Emphasis> sp. algae biomass: kinetics and thermodynamics

Introduction  

Kinetic, thermodynamic, and equilibrium isotherms of the biosorption of uranium ions onto Padina sp., a brown algae biomass, in a batch system have been studied.     

Chronic exposure of arsenic via drinking water and its adverse health impacts on humans

Worldwide chronic arsenic (As) toxicity has become a human health threat. Arsenic exposure to humans mainly occurs from the ingestion of As contaminated water and food. This communication presents a review of current research conducted on the adverse health effects on humans exposed to As-contaminated water. Chronic exposure of As via drinking water causes various types of skin lesions such as melanosis, leucomelanosis, and keratosis. Other manifestations include neurological effects, obstetric problems, high blood pressure, diabetes mellitus, diseases of the respiratory system and of blood vessels including cardiovascular, and cancers typically involving the skin, lung, and bladder. The skin seems to be quite susceptible to the effects of As. Arsenic-induced skin lesions seem to be the most common and initial symptoms of arsenicosis. More systematic studies are needed to determine the link between As exposure and its related cancer and noncancer end points.     

Monitoring and assessment of seasonal land cover changes using remote sensing: a 30-year (1987–2016) case study of Hamoun Wetland,Iran

The availability of Landsat data allows improving the monitoring and assessment of large-scale areas with land cover changes in rapid developing regions. Thus, we pretend to show a combined methodology to assess land cover changes (LCCs) in the Hamoun Wetland region (Iran) over a period of 30-year (1987–2016) and to quantify seasonal and decadal landscape and land use variabilities. Using the pixel-based change detection (PBCD) and the post-classification comparison (PCC), four land cover classes were compared among spring, summer, and fall seasons. Our findings showed for the water class a higher correlation between spring and summer (R²?=?0.94) than fall and spring (R²?=?0.58) seasons. Before 2000, ~?50% of the total area was covered by bare soil and 40% by water. However, after 2000, more than 70% of wetland was transformed into bare soils. The results of the long-term monitoring period showed that fall season was the most representative time to show the inter-annual variability of LCCs monitoring and the least affected by seasonal-scale climatic variations. In the Hamoun Wetland region, land cover was highly controlled by changes in surface water, which in turn responded to both climatic and anthropogenic impacts. We were able to divide the water budget monitoring into three different ecological regimes: (1) a period of high water level, which sustained healthy extensive plant life, and approximately 40% of the total surface water was retained until the end of the hydrological year; (2) a period of drought during high evaporation rates was observed, and a mean wetland surface of about 85% was characterized by bare land; and (3) a recovery period in which water levels were overall rising, but they are not maintained from year to year. After a spring flood, in 2006 and 2013, grassland reached the highest extensions, covering till more than 20% of the region, and the dynamics of the ecosystem were affected by the differences in moisture. The Hamoun wetland region served as an important example and demonstration of the feedbacks between land cover and land uses, particularly as pertaining to water resources available to a rapidly expanding population.     

Effects of water shortage in Kabul River network on the plain areas of Khyber Pakhtunkhwa,Pakistan

Kabul River is a shared resource of Pakistan and Afghanistan and is a major source of economy for both countries. It is used for irrigation, power generation, fishery, hunting, and recreation. This study explored human-induced impact on Kabul River and its associated wetlands. For an in-depth study, the area situated between the two tributaries of Kabul River, i.e., Shalam and Naguman Rivers, was selected. The focus of the study was to find out reduction in the wetland areas, its causes, and associated impacts. For this purpose, a survey was conducted in 10 villages selected randomly in 10 union councils. The study revealed that anthropogenic activities, such as wetland farming, grazing residential encroachment, and industrial development, have caused severe alteration in the wetland of the study areas. The results revealed that before the 1990s, 33.55% area of the study area was wetland. Due to regular decrease in the flow of the Kabul River System and human encroachment, it has engulfed 68.40% of the total wetland leaving behind only 10.60% wetland. This can be termed as a big ecological disturbance. In the long run, this will have negative effects on both the countries. It is therefore recommended to give proper attention to this important wetland, positioning between Shalam and Naguman Rivers and to conserve it. One of the solutions is to regulate the natural flow of Kabul River.     

Persistence of 4-chloro-O-cresol and 5-chloro-3-methylcatechol in soil

Two typical neutral soils were treated with 10, 200 and 2000 ppm 4-chloro-o-cresol and 5-chloro-3-methylcatechol under field capacity condition, and incubated for 12 weeks at room temperature. The samples were collected after 0, 2, 4, 8 and 12 weeks to study the fate of the compounds by gas chromatography. The two compounds were rapidly degraded and degradation was almost complete (90–96 %) after 4 weeks with a level of 10 ppm. The rate of persistence was similar in the two soils after different periods of incubation.     

Organophosphate dichlorvos induced dose-related differential alterations in lipid levels and lipid peroxidation in various regions of the fish brain and spinal cord

The effect of dichlorvos (DDVP) (0-0, dimethyl 2:2-dichlorovinyl phosphate), on various lipid fractions and lipid peroxidation in the discrete areas of the brain and spinal cord were studied in the fresh water teleost (Heteropneustes fossilis). Fishes were exposed to three different doses (3.0, 6.0 and 9.0 ppm) of DDVP daily for 7 days. Dose-related increase in the levels of total lipids, cholesterol and esterified fatty acids was detected in the fore brain, optic lobes, cerebellum, medulla oblongata and spinal cord. However, phospholipids were significantly decreased in the aforementioned regions of the central nervous system. The rate of lipid peroxidation was significantly increased in all the regions of the CNS.