Environmental impact and diversity of protease-producing bacteria in areas of leather tannery effluents of Sialkot,Pakistan

Environmental Science and Pollution Research - Massive discharge of wastes produced by the processing of leather so far confers the most important environmental challenge facing the tanneries...     

Assessment of Hg accumulation in fish and scalp hair in fishing communities along river Swat,Pakistan

Environmental Science and Pollution Research - Mercury (Hg) bioaccumulation in fish poses severe threats to the food safety and human health. This study was conducted to assess Hg bioaccumulation...     

Possible options to slow down the advancement rate of Tarbela delta

The pivot point of delta in Tarbela dam has reached at about 10.6 km from the dam face which may result in blocking of tunnels. Tarbela delta was modeled from 1979 to 2060 using hec-6 model. Initially, the model was calibrated for year 1999 and validated for years 2000, 2001, 2002, and 2006 by involving the data of sediment concentration, reservoir cross sections (73 range lines), elevation-area capacity curves, and inflows and outflows from the reservoir. Then, the model was used to generate future scenarios, i.e., run-1, run-2, and run-3 with pool levels; 428, 442, and 457 m, respectively, till 2060. Results of run-1 and run-2 showed advancement to choke the tunnels by 2010 and 2030, respectively. Finally, in run-3, the advancement was further delayed showing that tunnels 1 and 2 will be choked by year 2050 and pivot point will reach at 6.4 km from the dam face.     

苍松点缀大漠三百年

提起黄山悬崖是的迎客松,人们无不为它挺拔的雄姿、别致的造型所感叹。然而,却很少有人闻知在内蒙古赤峰市克什克腾旗境内的浑善达克沙漠里竟然也生长着数十棵近似迎客松的奇特树种。     

Unregulated emissions from a diesel engine equipped with vanadium-based urea-SCR catalyst

The present work is aimed at the study of number-size distribution of particles,volatile organic compounds(VOCs),and carbonyl compounds(CC) or carbonyls emitted from a 4-cylinder turbocharged diesel engine equipped with a vanadium-based urea selective catalytic reduction catalyst.The engine was run on an electric dynamometer in accordance with the European steady-state cycle.Pollutants were analyzed using an electric low pressure impactor,a gas chromatograph/mass spectrometer,and a high performance liquid chromatography system for the number-size distribution of particles,VOCs,and CC emissions,respectively.Experimental results revealed that total number of particles were decreased,and their number-size distributions were moved from smaller sizes to larger sizes in the presence of the catalyst.The VOCs were greatly reduced downstream of the catalyst.There was a strong correlation between the conversion of styrene and ethyl benzene.The conversion rate of benzene increased with increase of catalyst temperature.Formaldehyde,acetaldehyde,acrolein and acetone were significantly reduced,resulting in a remarkable abatement in carbonyls with the use of the vanadium-based urea-SCR system.     

Distribution and leaching characteristics of trace elements in ashes as a function of different waste fuels and incineration technologies

Impact of waste fuels (virgin/waste wood, mixed biofuel (peat, bark, wood chips) industrial, household, mixed waste fuel) and incineration technologies on partitioning and leaching behavior of trace elements has been investigated. Study included 4 grate fired and 9 fluidized boilers. Results showed that mixed waste incineration mostly caused increased transfer of trace elements to fly ash; particularly Pb/Zn. Waste wood incineration showed higher transfer of Cr, As and Zn to fly ash as compared to virgin wood. The possible reasons could be high input of trace element in waste fuel/change in volatilization behavior due to addition of certain waste fractions. The concentration of Cd and Zn increased in fly ash with incineration temperature. Total concentration in ashes decreased in order of Zn > Cu > Pb > Cr > Sb > As > Mo. The concentration levels of trace elements were mostly higher in fluidized boilers fly ashes as compared to grate boilers (especially for biofuel incineration). It might be attributed to high combustion efficiency due to pre-treatment of waste in fluidized boilers. Leaching results indicated that water soluble forms of elements in ashes were low with few exceptions. Concentration levels in ash and ash matrix properties (association of elements on ash particles) are crucial parameters affecting leaching. Leached amounts of Pb, Zn and Cr in > 50% of fly ashes exceeded regulatory limit for disposal. 87% of chlorine in fly ashes washed out with water at the liquid to solid ratio 10 indicating excessive presence of alkali metal chlorides/alkaline earths.     

Synthesis of magnetite-based nanocomposites for effective removal of brilliant green dye from wastewater

Environmental Science and Pollution Research - The present study aims at evaluating the batch scale potential of cotton shell powder (CSP), Moringa oleifera leaves (ML), and magnetite-assisted...     

Analysis of elemental concentration using ICP-AES and pathogen indicator in drinking water of Qasim Abad, District Rawalpindi, Pakistan

The present study was conducted to investigate drinking water quality (groundwater) from water samples taken from Qasim Abad, a locality of approximately 5,000 population, situated between twin cities Rawalpindi and Islamabad in Pakistan. The main sources of drinking water in this area are water bores which are dug upto the depth of 250–280 ft in almost every house. The study consists of the determination of physico-chemical properties, trace metals, heavy metals, rare earth elements and microbiological quality of drinking water. The data showed the variation of the investigated parameters in samples as follows: pH 6.75 to 8.70, electrical conductivity 540 to 855 μS/cm, total dissolved solids 325.46 to 515.23 ppm and dissolved oxygen 1.50 to 5.64 mg/L which are within the WHO guidelines for drinking water quality. The water samples were analysed for 30 elements (aluminium, iron, magnesium, manganese, silicon, zinc, molybdenum, titanium, chromium, nickel, tungsten, silver, arsenic, boron, barium, beryllium, cadmium, cobalt, copper, gallium, mercury, lanthanum, niobium, neodymium, lead, selenium, samarium, tin, vanadium and zirconium) by using inductively coupled plasma atomic emission spectroscopy. The organic contamination was detected in terms of most probable number (MPN) of faecal coliforms. Overall, elemental levels were lower than the recommended values but three water bores (B-1, B-6, B-7) had higher values of iron (1.6, 2.206, 0.65 ppm), two water bores (B-1, B-6) had higher values of aluminium (0.95, 1.92 ppm), respectively, and molybdenum was higher by 0.01 ppm only in one water bore (B-11). The total number of coliforms present in water samples was found to be within the prescribed limit of the WHO except for 5 out of 11 bore water samples (B-2, B-3, B-4, B-8, B-11), which were found in the range 5–35 MPN/100 mL, a consequence of infiltration of contaminated water (sewage) through cross connection, leakage points and back siphoning.     

Degradation characteristics and metabolic pathway of 17alpha-ethynylestradiol by Sphingobacterium sp. JCR5

A 17alpha-ethynylestradiol (EE2)-degrading bacterium was isolated from the activated sludge of the wastewater treatment plant (WWTP) of an oral contraceptives producing factory in Beijing, China. On the basis of its morphology, biochemical properties and the 16S rDNA sequence analysis, this strain was identified as Sphingobacterium sp. JCR5. This strain grew on EE2 as sole source of carbon and energy, and metabolized up to 87% of the substrate added (30 mgl-1) within 10 d at 30 degrees C. In addition to EE2 the strain could be cultivated on steroidal estrogens like estrone (E1), 17beta-estradiol (E2), estriol (E3) and mestranol (MeEE2), the intermediates of contraceptive medicine processing and on some aromatic compounds. Mass spectrum analysis of the EE2 degradation showed that in the first step it is oxygenized to E1, 2-hydroxy-2,4-dienevaleric acid and 2-hydroxy-2,4-diene-1,6-dioic acid, which are the main catabolic intermediates. The former was analogous to the pathway of a previously reported testosterone-degrading bacterium Comamonas testosteroni TA441 and the latter is a metabolite with a different cleavage position of 3-hydroxy-4,5-9,10-disecoestrane-1(10),2-diene-5,9,17-trione-4-oic acid from the former.     

Characterization of polycyclic aromatic hydrocarbon emissions from diesel engine retrofitted with selective catalytic reduction and continuously regenerating trap

Two after treatment units, selective catalytic reduction (SCR) and continuously regenerating trap (CRT), were independently retrofitted to a diesel engine, with the objective to investigate their impact on the conversion/reduction (CR) of polycyclic aromatic hydrocarbons (PAHs). The experiments were conducted under the European steady state cycle (ESC) first without any retrofits to get baseline emissions, and then with SCR and CRT respectively, on the same engine. The particulate matter (PM)-phase PAHs were trapped in fiberglass filters, whereas gas-phase PAHs were collected in cartridges, and then analyzed using a gas chromatograph-mass spectrometer (GC-MS). Both PM-phase and gas-phase PAHs were greatly reduced with CRT showing respective CR of 90.7% and above 80%, whereas only gas-phase PAHs were abated in the case of SCR, with CR of above 75%. Lower molecular weight (LMW) PAHs were in abundance, while naphthalene exhibited a maximum relative contribution (RC) to LMW-PAHs for all three cases. Further, the CR of naphthalene and anthracene were increased with increasing catalyst temperature of SCR, most likely due to their conversion to solid particles. Moreover, the Benzo[a]Pyrene equivalent (BaP_eq) of PAHs was greatly reduced with CRT, owing to substantial reduction of total PAHs.