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Geo-accumulation index and contamination factors of heavy metals (Zn and Pb) in urban river sediment 总被引:1,自引:0,他引:1
Hazzeman Haris Ley Juen Looi Ahmad Zaharin Aris Nor Farhanna Mokhtar Nur Ain Ayunie Ayob Fatimah Md. Yusoff Abu Bakar Salleh Sarva Mangala Praveena 《Environmental geochemistry and health》2017,39(6):1259-1271
The aim of the present study was to appraise the levels of heavy metal contamination (Zn and Pb) in sediment of the Langat River (Selangor, Malaysia). Samples were collected randomly from 15 sampling stations located along the Langat River. The parameters measured were pH, redox potential, salinity, electrical conductivity, loss of ignition, cation exchanges capacity (Na, Mg, Ca, K), and metal ions (Zn and Pb). The geo-accumulation index (I geo) and contamination factor (C f) were applied to determine and classify the magnitude of heavy metal pollution in this urban river sediment. Results revealed that the I geo of Pb indicated unpolluted to moderately polluted sediment at most of the sampling stations, whereas Zn was considered to be within background concentration. The I geo results were refined by the C f values, which showed Pb with very high C f at 12 stations. Zinc, on the other hand, had low to moderate C f values. These findings indicated that the sediment of the Langat River is severely polluted with Pb. The Zn concentration at most sampling points was well below most sediment quality guidelines. However, 40% of the sampling points were found to have a Pb concentration higher than the consensus-based probable effect concentration of 128 mg/kg (concentrations above this value are likely to cause harmful effects). This result not only highlights the severity of Pb pollution in the sediment of the Langat River, but also the potential risk it poses to the environment. 相似文献
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Joshi BB Bhatt RP Bahukhandi D 《Journal of environmental biology / Academy of Environmental Biology, India》2010,31(6):921-928
The genus Trichoderma is rapidly growing colonies bearing tufted or postulate, repeatedly branched conidiophores with lageniform phialides and hyaline or green conidia born in slimy heads. 62 isolates of Trichoderma species were isolated from different rhizospheric soil samples collected from different places located in Western Himalayas region. Out of these only two species were found i.e. Trichoderma hazianum and Trichoderma viride. Their efficacy against soil borne plant pathogens like Sclerotium rolfsii, Rhizoctonia solani and Sclerotinia sclerotiorum revealed that only three isolates amounting to 5% of the total collected isolates of this region were found highly antagonist. Among them 5% isolates were found against S. rolfsii, 13% isolates against R. solani, 10% against sclerotium caused above 80% inhibition of mycelial growth respectively. 6% isolates out of twenty seven utilized chitin by more than 80 and 16% isolates consumed cellulose by above 80% and therefore are producers of chitinase and cellulases. 58% isolates produced colonies having cottony texture and 41% produced dark green colonies. Pigmentation as observed from reverse side of the colony revealed that 70% of them did not produced pigment in the medium. Plant growth promotion measured as root and shoot lengths were significantly higher than in control. The maximum root length and shoot length were recorded when seeds were treated with isolates were recorded at Srinagar Garhwal was 4.70 and 4.75 cm out of all the isolates in which isolate recorded from Srinagar no 3 caused maximum percent seed germination which was significantly higher 79.49%. 相似文献
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Mishra AK Tiwari HS Bhatt RK 《Journal of environmental biology / Academy of Environmental Biology, India》2010,31(6):987-993
The growth, biomass production and photosynthesis of Cenchrus ciliaris was studied under the canopies of 17 yr old Acacia tortilis trees in semi arid tropical environment. On an average the full grown canopy of A. tortilis at the spacing of 4 x 4 m allowed 55% of total Photosynthetically Active Radiation (PAR) which in turn increased Relative Humidity (RH) and reduced under canopy temperature to -1.75 degrees C over the open air temperature. C. ciliaris attained higher height under the shade of A. tortilis. The tiller production and leaf area index decreased marginally under the shade of tree canopies as compared to the open grown grasses. C. ciliaris accumulated higher chlorophyll a and b under the shade of tree canopies indicating its shade adaptation potential. The assimilatory functions such as rate of photosynthesis, transpiration, stomatal conductance, photosynthetic water use efficiency (PN/TR) and carboxylation efficiency (PN/CINT) decreased under the tree canopies due to low availability of PAR. The total biomass production in term of fresh and dry weight decreased under the tree canopies. On average of 2 yr C. ciliaris had produced 12.78 t ha(-1) green and 3.72 -t ha(-1) dry biomass under the tree canopies of A. tortilis. The dry matter yield reduced to 38% under the tree canopies over the open grown grasses. The A. tortilis + C. ciliaris maintained higher soil moisture, organic carbon content and available N P K for sustainable biomass production for the longer period. The higher accumulation of crude protein, starch, sugar and nitrogen in leaves and stem of C. ciliaris indicates that this grass species also maintained its quality under A. tortilis based silvopastoral system. The photosynthesis and dry matter accumulation are closely associated with available PAR indicating that for sustainable production of this grass species in the silvopasture systems for longer period about 55% or more PAR is required. 相似文献
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Mrdakovic Popic J Bhatt CR Salbu B Skipperud L 《Journal of environmental monitoring : JEM》2012,14(1):193-201
The present study was done in the Fen Complex, a Norwegian area rich in naturally occurring radionuclides, especially in thorium ((232)Th). Measurement of radioactivity levels was conducted at the decommissioned iron (Fe) and niobium (Nb) mining sites (TENORM) as well as at the undisturbed wooded sites (NORM), all open for free public access. The soil activity concentrations of (232)Th (3280-8395 Bq kg(-1)) were significantly higher than the world and the Norwegian average values and exceeded the Norwegian screening level (1000 Bq kg(-1)) for radioactive waste, while radium ((226)Ra) was present at slightly elevated levels (89-171 Bq kg(-1)). Terrestrial gamma dose rates were also elevated, ranging 2.6-4.4 μGy h(-1). Based on long-term surveys, the air concentrations of thoron ((220)Rn) and radon ((222)Rn) reached 1786 and 82 Bq m(-3), respectively. Seasonal variation in the outdoor gamma dose rates and Rn concentrations was confirmed. Correlation analyses showed a linear relationship between air radiation levels and the abundance of (232)Th in soil. The annual outdoor effective radiation doses for humans (occupancy 5 h day(-1)) were estimated to be in the range of 3.0-7.7 mSv, comparable or higher than the total average (summarized indoor and outdoor) exposure dose for the Norwegian population (2.9 mSv year(-1)). On the basis of all obtained results, this Norwegian area should be considered as enhanced natural radiation area (ENRA). 相似文献
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