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991.
de Figueiredo DR Ferreira RV Cerqueira M de Melo TC Pereira MJ Castro BB Correia A 《Environmental monitoring and assessment》2012,184(1):471-485
The information on bacterial community composition (BCC) in Portuguese water bodies is very scarce. Cértima River (central
western Portugal) is known to have high levels of pollution, namely organic. In the present work, the BCC from a set of 16
water samples collected from Cértima River Basin and its main tributaries was characterized using 16S rDNA–denaturing gradient
gel electrophoresis, a culture-independent molecular approach. Molecular data were related to environmental parameters through
multivariate analysis to investigate potential impact of water pollution along the river. Principal component analysis using
environmental data showed a water quality gradient from more pristine waters (at the mountain tributaries) to waters with
increasingly eutrophic potential (such as Fermentelos Lake). This gradient was mainly defined by factors such as organic and
inorganic nutrient sources, electrical conductivity, hydrogen carbonate concentration, and pH. Molecular results showed variations
in BCC along Cértima River Basin but in the main river section, a Bacteroidetes phylotype (Flavobacterium sp.) proved to be dominant throughout the river course. Multivariate analysis suggests that spatial variation of BCC along
the Cértima River Basin depended mainly on parameters such as Chl a, total suspended solid (TSS), total organic carbon, electrical conductivity, and HCO
_boxclose^-_{3}^{-} levels. Bacteroidetes phylotypes were all related to higher electrical conductivity and HCO3-_{3}^{-} levels although some of these were also correlated with high SO42-_{4}^{2-} and others with high soluble reactive phosphorus, nitrate, TN, and Kjeld-N levels. The Gammaproteobacteria occurrence was correlated with high SO42-_{4}^{2-} levels. One of the Betaproteobacteria phylotypes showed to correlate with low redox potential (Eh) and high temperature, pH, TSS, and Chl a levels while another one showed a negative correlation with Chl a values. 相似文献
992.
Fernandes CE Das A Nath BN Faria DG Loka Bharathi PA 《Environmental monitoring and assessment》2012,184(5):2677-2689
We investigated the influence on bacterial community and biochemical variables through mechanical disturbance of sediment-akin
to small-scale mining in Kalbadevi beach, Ratnagiri, a placer-rich beach ecosystem which is a potential mining site. Changes
were investigated by comparing three periods, namely phase I before disturbance, phase II just after disturbance, and phase
III 24 h after disturbance as the bacterial generation time is ≤7 h. Cores from dune, berm, high-, mid-, and low-tide were
examined for changes in distribution of total bacterial abundance, total direct viability (counts under aerobic and anaerobic
conditions), culturability and biochemical parameters up to 40 cm depth. Results showed that bacterial abundance decreased
by an order from 106 cells g − 1 sediment, while, viability reduced marginally. Culturability on different-strength nutrient broth increased by 155% during
phase II. Changes in sedimentary proteins, carbohydrates, and lipids were marked at berm and dune and masked at other levels
by tidal influence. Sedimentary ATP reduced drastically. During phase III, Pearson’s correlation between these variables evolved
from non-significant to significant level. Thus, simulated disturbance had a mixed effect on bacterial and biochemical variables
of the sediments. It had a negative impact on bacterial abundance, viability and ATP but positive impact on culturability.
Viability, culturability, and ATP could act as important indicators reflecting the disturbance in the system at short time
intervals. Culturability, which improved by an order, could perhaps be a fraction that contributes to restoration of the system
at bacterial level. This baseline information about the potential mining site could help in developing rational approach towards
sustainable harnessing of resources with minimum damage to the ecosystem. 相似文献
993.
Mayack DT 《Environmental monitoring and assessment》2012,184(4):2497-2516
Many non-linear processes link atmospheric emissions to the bioavailability of metals; consequently, the monitoring of metals
in ecosystem components is required to model their ecodynamics. American mink (Neovison vison) and river otter (Lontra canadensis) have the potential to serve as an upper-level-consumer component in monitoring metals bioavailability. However, the relationship
of bioaccumulated metals to various environmental factors has not been explored nor have the effects of demographic factors
been resolved. To address these limitations, mink and otter, collected throughout New York State during 1998–2002, were analyzed
for hepatic concentrations of total mercury (Hg), cadmium (Cd), and lead (Pb). Relationships were investigated between metals
concentrations and landscape-level factors (physiographic zone, hydrologic unit, and elevation) and demographic factors (gender
and age). Considerable variation in Hg and Cd concentrations was observed relative to both physiographic zone and hydrologic
unit for both species. In contrast with Hg, Cd concentration increased predictably with increasing elevation. Mercury concentrations
were greater, but for Cd less, in otter than mink. Lead concentrations showed little landscape heterogeneity and were independent
of elevation. Age-related bioaccumulation was evident for Hg and Cd, but not for Pb, in both species. Mercury and Cd concentrations
were greater in female than male mink; however, Pb concentrations were greater in males than females. Inverse relationships
of relative growth (weight/length) to metals concentrations explained gender differences in Hg and Cd in mink. For otter,
no gender-related differences in metals concentrations were apparent. The suitability of mink and otter for monitoring programs
is discussed. 相似文献
994.
Scheepers PT Cremers R van Hout SP Anzion RB 《Journal of environmental monitoring : JEM》2012,14(2):429-439
During periods of two weeks in February and June 2010 the performance of portable air treatment units (PATUs) was evaluated in a primary school classroom using indicators of indoor air quality. Air samples were collected in an undisturbed setting on weekend days and in an occupied setting during teaching hours. In the first week PATUs were turned off and in the second week they were turned on. On weekend days PATUs reduced indoor levels of PM-10 by 87% in February and by 70% in June compared to weekend days when PATUs were turned off. On schooldays, indoor PM-10 was increased by 6% in February and reduced by 42% in June. For PM-2.5 reductions on weekend days were 89% in February and 80% in June. On school days PM-2.5 was increased by 15% in February and reduced by 83% in June. Turning on the PATUs reduced total VOC by 80% on weekend days and by 57% on school days (but not in June). No influence on formaldehyde, NO(2), O(3) and molds was observed. PATUs appeared to be less effective in removal of air pollutants when used in an occupied classroom compared to an unoccupied setting. Our study suggests that such devices should be tested in real-life settings to evaluate their influence on indoor air quality. 相似文献
995.
Direct-reading aerosol measurement usually uses the optical properties of airborne particles to detect and measure particle concentration. In the case of occupational hygiene, mass concentration measurement is often required. Two aerosol monitoring methods are based on the principle of light scattering: optical particle counting (OPC) and photometry. The former analyses the light scattered by a single particle, the latter by a cloud of particles. Both methods need calibration to transform the quantity of scattered light detected into particle concentration. Photometers are simpler to use and can be directly calibrated to measure mass concentration. However, their response varies not only with aerosol concentration but also with particle size distribution, which frequently contributes to biased measurement. Optical particle counters directly measure the particle number concentration and particle size that allows assessment of the particle mass provided the particles are spherical and of known density. An integrating algorithm is used to calculate the mass concentration of any conventional health-related aerosol fraction. The concentrations calculated thus have been compared with simultaneous measurements by conventional gravimetric sampling to check the possibility of field OPC calibration with real workplace aerosols with a view to further monitoring particle mass concentration. Aerosol concentrations were measured in the food industry using the OPC GRIMM? 1.108 and the CIP 10-Inhalable and CIP 10-Respirable (ARELCO?) aerosol samplers while meat sausages were being brushed and coated with calcium carbonate. Previously, the original OPC inlet had been adapted to sample inhalable aerosol. A mixed aerosol of calcium carbonate and fungi spores was present in the workplace. The OPC particle-size distribution and an estimated average particle density of both aerosol components were used to calculate the mass concentration. The inhalable and respirable aerosol fractions calculated from the OPC data are closely correlated with the results of the particle size-selective sampling using the CIP 10. Furthermore, the OPC data allow calculation of the thoracic fraction of workplace aerosol (not measured by sampling), which is interesting in the presence of allergenic particles like fungi spores. The results also show that the modified COP inlet adequately samples inhalable aerosol in the range of workplace particle-size distribution. 相似文献
996.
T. R. Gireeshkumar P. M. Deepulal N. Chandramohanakumar 《Environmental monitoring and assessment》2013,185(3):2535-2552
Sequential chemical extraction using chelating agents were used to study the P dynamics and its bioavailability along the surface sediments of the Cochin estuary (southwest coast of India). Sediments were analyzed for major P species (iron bound P, calcium bound P, acid soluble organic P, alkali soluble organic P and residual organic P), Fe, Ca, total carbon, organic carbon, total nitrogen and total sulfur contents. An abrupt increase in the concentration of dissolved inorganic P with increasing salinity was observed in the study region. Iron-bound P exhibited a distinct seasonal pattern with maximum values in the monsoon season when fresh water condition was prevailed in the estuary. As salinity increased, the percentage of iron-bound P decreased, while that of calcium-bound P and total sedimentary sulfur increased. C/P and N/P ratios were low which indicate that large amounts of organic matter enriched with P tend to accumulate in surface sediments. The high organic P contribution in the sedimentary P pool may indicate high organic matter load with incomplete mineralization, as well as comparatively greater percentage of humic substance and resistant organic compounds. Principal component analysis is employed to find the possible processes influencing the speciation of P in the study region and indicate the following processes: (1) the spatial and seasonal variations of calcium bound P and acid soluble organic P was mainly controlled by sediment texture and organic carbon content, (2) sediment redox conditions control the distribution of iron bound P and (3) the terrigenous input of organic P is a significant processes controlling total P content in surface sediments. The bioavailable P was very high in the surface sediments which on an average accounts for 59 % in the pre-monsoon, 65 % in the monsoon and 53 % in the post-monsoon seasons. The surface sediments act as a potential internal source of P in the Cochin estuary. 相似文献
997.
Groundwater recharge and available groundwater resources in Chithar River basin, Tamil Nadu, India spread over an area of 1,722 km2 have been estimated by considering various hydrological, geological, and hydrogeological parameters, such as rainfall infiltration, drainage, geomorphic units, land use, rock types, depth of weathered and fractured zones, nature of soil, water level fluctuation, saturated thickness of aquifer, and groundwater abstraction. The digital ground elevation models indicate that the regional slope of the basin is towards east. The Proterozoic (Post-Archaean) basement of the study area consists of quartzite, calc-granulite, crystalline limestone, charnockite, and biotite gneiss with or without garnet. Three major soil types were identified namely, black cotton, deep red, and red sandy soils. The rainfall intensity gradually decreases from west to east. Groundwater occurs under water table conditions in the weathered zone and fluctuates between 0 and 25 m. The water table gains maximum during January after northeast monsoon and attains low during October. Groundwater abstraction for domestic/stock and irrigational needs in Chithar River basin has been estimated as 148.84 MCM (million m3). Groundwater recharge due to monsoon rainfall infiltration has been estimated as 170.05 MCM based on the water level rise during monsoon period. It is also estimated as 173.9 MCM using rainfall infiltration factor. An amount of 53.8 MCM of water is contributed to groundwater from surface water bodies. Recharge of groundwater due to return flow from irrigation has been computed as 147.6 MCM. The static groundwater reserve in Chithar River basin is estimated as 466.66 MCM and the dynamic reserve is about 187.7 MCM. In the present scenario, the aquifer is under safe condition for extraction of groundwater for domestic and irrigation purposes. If the existing water bodies are maintained properly, the extraction rate can be increased in future about 10 % to 15 %. 相似文献
998.
A. O. Oyeyiola C. M. Davidson K. O. Olayinka T. O. Oluseyi B. I. Alo 《Environmental monitoring and assessment》2013,185(3):2167-2177
Surface sediments collected from the Lagos Lagoon, Nigeria, and three adjoining rivers were analysed for their physicochemical properties and pseudo-total concentration of the potentially toxic metals (PTM) Cd, Cr, Cu, Pb and Zn. The concentration of the PTM varied seasonally and spatially. Odo-Iyaalaro was observed to be the most polluted river, with highest concentrations of 42.1 mg kg?1, 102 mg kg?1, 185 mg kg?1, 154 mg kg?1 and 1040 mg kg?1 of Cd, Cr, Cu, Pb and Zn, respectively, while Ibeshe River was the least contaminated, apart from a site affected by Cu from the textile industry. Some of the sediments were found to be above the consensus-based probable effect concentrations and Dutch sediment guideline for metals. Overall metal concentrations were similar to those reported for other tropical lagoon and estuarine systems affected by anthropogenic inputs as a result of rapid urbanisation. Due to the large number of samples, principal component analysis was used to examine relationships within the data set. Generally, sediments collected during the dry season were observed to have higher concentration of PTM than those collected during the rainy season. This means that PTM could accumulate over a prolonged period and then be released relatively rapidly, on an annual basis, into tropical lagoon systems. 相似文献
999.
Azadeh Taghinia Hejabi H. T. Basavarajappa 《Environmental monitoring and assessment》2013,185(2):1273-1283
Cu, Cr, Fe, Mn, Ni, Pb, and Zn in the sediments of the Kabini River, Karnataka, India was studied to determine the association of metal with various geochemical phases by sequential extraction. The variations of heavy metal concentration depend on the lithology of the river basin and partly on anthropogenic activities. The Kabini River sediments are dominated by Sargur supracrustals with amphibolites, gneisses, carbonates, and ultrabasic rocks weathering into gneissic and serpentine soils carrying a natural load of cationic heavy metals. The source of heavy metals in the Kabini riverbed sediments is normally envisaged as additional inputs from anthropogenic over and above natural and lithogenic sources. Geochemical study indicates the metals under study were present mostly in the least mobilizable fraction in the overlying water and it is concluded that heavy metals in these sediments are to a great extent derived from multisource anthropogenic inputs besides geochemical background contributions The results show that lead and chromium have higher potential for mobilization from the sediment due to higher concentration at the exchangeable ion and sulfide ion bounded, also Cu and Pb have the greatest percentage of carbonate fraction, it means that the study area received inputs from urban and industrial effluents. Association of the Fe with organic matter fraction can be explained by the high affinity of these elements for the humic substances. Further, Zn and Ni reveal a significant enrichment in sediment and it is due to release of industrial wastewater into the river. These trace metals are possible contaminants to enter into aquatic and food chain. 相似文献
1000.
C. Kesavachandran B. S. Pangtey V. Bihari M. Fareed M. K. Pathak A. K. Srivastava N. Mathur 《Environmental monitoring and assessment》2013,185(2):1265-1272
The World Health Organization has estimated that air pollution is responsible for 1.4 % of all deaths and 0.8 % of disability-adjusted life years. NOIDA, located at the National Capital Region, India, was declared as one of the critically air-polluted areas by the Central Pollution Control Board of the Government of India. Studies on the relationship of reduction in lung functions of residents living in areas with higher concentrations of particulate matter (PM) in ambient air were inconclusive since the subjects of most of the studies are hospital admission cases. Very few studies, including one from India, have shown the relationship of PM concentration and its effects of lung functions in the same location. Hence, a cross-sectional study was undertaken to study the effect of particulate matter concentration in ambient air on the lung functions of residents living in a critically air-polluted area in India. PM concentrations in ambient air (PM1, PM2.5) were monitored at residential locations and identified locations with higher (NOIDA) and lower concentrations (Gurgaon). Lung function tests (FEV1, PEFR) were conducted using a spirometer in 757 residents. Both air monitoring and lung function tests were conducted on the same day. Significant negative linear relationship exists between higher concentrations of PM1 with reduced FEV1 and increased concentrations of PM2.5 with reduced PEFR and FEV1. The study shows that reductions in lung functions (PEFR and FEV1) can be attributed to higher particulate matter concentrations in ambient air. Decline in airflow obstruction in subjects exposed to high PM concentrations can be attributed to the fibrogenic response and associated airway wall remodeling. The study suggests the intervention of policy makers and stake holders to take necessary steps to reduce the emissions of PM concentrations, especially PM1, PM2.5, which can lead to serious respiratory health concerns in residents. 相似文献