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91.
92.
Precipitation Chemistry and Occurrence of Acid Rain Over Dhanbad, Coal City of India 总被引:1,自引:0,他引:1
Singh AK Mondal GC Kumar S Singh KK Kamal KP Sinha A 《Environmental monitoring and assessment》2007,125(1-3):99-110
The present study investigated the chemical composition of wet atmospheric precipitation over Dhanbad, coal city of India.
The precipitation samples were collected on event basis for three years (July 2003 to October 2005) at Central Mining Research
Institute. The precipitation samples were analyzed for pH, conductivity, major anions (F, Cl, NO3, SO4) and cations (Ca, Mg, Na, K, NH4). The pH value varied from 4.01 to 6.92 (avg. 5.37) indicating acidic to alkaline nature of rainwater. The pH of the rainwater
was found well above the reference pH (5.6), showing alkalinity during the non-monsoon and early phase of monsoon, but during
the late phase of monsoon, pH tendency was towards acidity (<5.6~pH) indicating the non-availability of proper neutralizer
for acidic ions. The observed acidic events at this site were 91, (n = 162) accounting 56% for the entire monitoring months. The (NO3 + Cl)/SO4 ratio in majority of samples was found below 1.0, indicating that the acidity is greatly influenced by SO4. The calculated ratio of (Ca + NH4)/(NO3 + SO4) ranges between 0.42–5.13 (average 1.14), however in most of the samples, the ratio is greater than unity (>1.0) indicating
that Ca and NH4 play an important role in neutralization of acidic ions in rainwater. Ca and SO4 dominate the bulk ionic deposition and these two ions along with NH4 accounts 63% of the annual ionic deposition. 相似文献
93.
R. Srikanth Anil Gautam Suresh Chandra Jaiswal Pavitra Singh 《Environmental monitoring and assessment》2013,185(3):2343-2350
Endemic fluorosis was detected in 31 villages in the Dhar district of Madhya Pradesh, Central India. Out of the 109 drinking water sources that were analyzed, about 67 % were found to contain high concentration of fluoride above the permissible level of 1.0 mg/l. Dental fluorosis among the primary school children in the age between 8 and 15 served as primary indicator for fluoride intoxication among the children. Urinary fluoride levels among the adults were found to be correlated with drinking water fluoride in 10 villages affected by fluoride. Intervention in the form of alternate safe water supply in five villages showed significant reduction in the urinary fluoride concentration when compared to the control village. Urinary fluoride serves as an excellent marker for assessing the effectiveness of intervention program in the fluoride-affected villages. 相似文献
94.
We relate the historical (1850–2000) spatial and temporal changes in cropland cover in the conterminous United States to several socio-economic and biophysical determinants using an eco-region based spatial framework. Results show population density as a major determinant during the nineteenth century, and biophysical suitability as the major determinant during the twentieth century. We further examine the role of technological innovations, socio-economic and socio-ecological feedbacks that have either sustained or altered the cropland trajectories in different eco-regions. The cropland trajectories for each of the 84 level-III eco-regions were analyzed using a nonlinear bi-analytical model. In the Eastern United States, low biophysically suitable eco-regions, e.g., New England, have shown continual decline in the cropland after reaching peak levels. The cropland trajectories in high biophysically suitable regions, e.g., Corn Belt, have stabilized after reaching peak levels. In the Western United States, low-intensity crop cover (<10 %) is sustained with irrigation support. A slower rate of land conversion was found in the industrial period. Significant effect of Conservation Reserve Program on planted crop area is found in last two decades (1990–2010). 相似文献
95.
Jitendra Kumar N. A. Shakil M. A. Khan Kamlesh Malik Suresh Walia 《Journal of environmental science and health. Part. B》2013,48(8):678-682
Controlled release (CR) formulations of carbofuran and imidacloprid were prepared employing polyvinyl chloride and carboxymethyl cellulose (CMC) and their bioefficacy was evaluated against the aphid, Aphis gossypii and leafhopper, Amrasca biguttula biguttula Ishida on potato crop. The CR formulations of carbofuran and imidacloprid provided better or equal control of the pests than commercial formulations. CMC-based formulation provided a superior control of both the pests. The Imida-CMC, which showed the lowest population of leaf hopper (10.50 leafhopper/100 cl), provided significantly superior control among all treatments after 35 days after germination (DAG). The residue of carbofuran and imidacloprid in potato tuber and soils were not detectable at the time of harvesting in any one of the formulations. 相似文献
96.
Lignocellulosic biomass can be converted into ethanol through either biochemical or thermochemical conversion processes. Biochemical
conversion involves hydrolysis and fermentation while thermochemical conversion involves gasification and catalytic synthesis.
Even though these routes produce comparable amounts of ethanol and have similar energy efficiency at the plant level, little
is known about their relative environmental performance from a life cycle perspective. Especially, the indirect impacts, i.e.
emissions and resource consumption associated with the production of various process inputs, are largely neglected in previous
studies. This article compiles material and energy flow data from process simulation models to develop life cycle inventory
and compares the fossil fuel consumption, greenhouse gas emissions, and water consumption of both biomass-to-ethanol production
processes. The results are presented in terms of contributions from feedstock, direct, indirect, and co-product credits for
four representative biomass feedstocks i.e., wood chips, corn stover, waste paper, and wheat straw. To explore the potentials
of the two conversion pathways, different technological scenarios are modeled, including current, 2012 and 2020 technology
targets, as well as different production/co-production configurations. The modeling results suggest that biochemical conversion
has slightly better performance on greenhouse gas emission and fossil fuel consumption, but that thermochemical conversion
has significantly less direct, indirect, and life cycle water consumption. Also, if the thermochemical plant operates as a
biorefinery with mixed alcohol co-products separated for chemicals, it has the potential to achieve better performance than
biochemical pathway across all environmental impact categories considered due to higher co-product credits associated with
chemicals being displaced. The results from this work serve as a starting point for developing full life cycle assessment
model that facilitates effective decision-making regarding lignocellulosic ethanol production. 相似文献
97.
98.
G. Hariharan C. Suresh Kumar S. Laxmi Priya A. Paneer Selvam D. Mohan R. Purvaja 《毒物与环境化学》2013,95(8):1571-1582
Metal pollution produces damage to marine organisms at the cellular level possibly leading to ecological imbalance. The present investigation focused on the acute and chronic toxicity of lead (Pb) and zinc (Zn) by examining the effects of biomarker enzymes in post-larvae of Penaeus monodon (Tiger prawn). Antioxidant biomarker responses such as lipid peroxidation (LPO) and catalase (CAT) activity for Pb and Zn were determined following chronic exposure. Acute Lethal Concentration 50 (LC50) values observed in the study at 96?h for Pb and Zn at 5.77?±?0.32?mg?L?1 and 3.02?±?0.82?mg?L?1, respectively. The estimated No Observed Effect Concentration and Lowest Observed Effect Concentration values for Pb were 0.014 and 0.029?mg?L?1 and that recorded for Zn was 0.011 and 0.022?mg?L?1, respectively. Among the two metals studied, toxicity of Zn was found to be greater to P. monodon than Pb. The activities of antioxidant defense enzymes and total protein content differed significantly from control following exposure to both metals. Overall, the biomarker studies demonstrated that alterations in antioxidant enzymes and induction of LPO reflect the consequences of heavy metal exposure in P. monodon. 相似文献
99.
Kumar KS Suvardhan K Rekha D Kiran K Jayaraj B Janardhanam K Chiranjeevi P 《Environmental monitoring and assessment》2007,127(1-3):67-72
Facile, selective and sensitive spectrophotometric method has been developed for the determination of bendiocarb in its insecticidal
formulations, fortified water, food grains, agriculture wastewater and agriculture soil samples with prepared reagents. The
method was based on alkaline hydrolysis of the bendiocarb pesticide, and the resultant hydrolysis product of bendiocarb was
coupled with 2,6-dibromo-4-methylaniline to give a yellow color product with λmaxof457 nmorcouplingwith2, 6−dibromo−4−nitroanilinetoproducearedcoloredproductwithλmax
of474~nmorcouplingwith2, 4, 6−tribromoanilinetoformorangeredcoloredproducthasaλmax
of465 nm.Underoptimalconditions, Beer'slawrangefor2, 6−dibromo−4−methylaniline(DBMA)wasfoundtobe0.6−−14.0~μgmL
-1, 0.8−−10.0 μgmL
-1
for2, 6−dibromo−4−nitroaniline(DBNA)and0.4−−10.0 μgmL
-1
for2, 4, 6−tribromoaniline(TBA).Themolarabsorptivityofthecolorsystemswerefoundtobe4.126~×~104
lmol
-1 cm
-1
forDBMA, 3.254×104
l~mol
-1 cm
-1
forDBNAand2.812×104
lmol
-1 cm
-1
forTBA.Sandell'softhecolorreactionsare0.018 μgcm
-2(DBMA), 0.052 μgcm
-2(DBNA)and0.065 μgcm
-2$ (TBA) respectively. The effect of the non-target species on the determination of bendiocarb was studied. The formation of
colored derivatives with the coupling agents is instantaneous and stable for 18 h, 30 h, and 12 h. Performance of the proposed
methods were compared statistically in terms Student's F and t-tests with the reported methods. 相似文献
100.
The equilibrium distributions, between water and coal-tar contaminated sediment, of 16 monocyclic and polycyclic aromatic hydrocarbons were measured and evaluated for consistency with a Raoult's Law-based quantitative relationship. The quantitative relationship calculates the pore water concentration as the product of the aqueous solubility (or for compounds that are solid at room temperature, the aqueous super-cooled liquid solubility) and the mole fraction concentration of the compound within the liquid coal tar. Sediment was collected at five locations at two depths within a 120 m stretch of a river adjacent to a former manufactured gas plant, and all samples contained non-aqueous phase liquid (NAPL) coal tar. Although the amount of coal tar varied between samples by over an order of magnitude, the Raoult's Law-based NAPL-water partition coefficients for each monocyclic or 2- or 3-ring polycyclic aromatic hydrocarbon measured in this study generally varied within a factor of 2 over all sediments. 相似文献