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1.
Dibyendu Rakshit Sejuti Naha Biswas Santosh Kumar Sarkar Bhaskar Deb Bhattacharya Nallamuthu Godhantaraman Kamala Kanta Satpathy 《Environmental monitoring and assessment》2014,186(5):3063-3078
The study is the first documentation of seasonal variations in species composition, abundance and diversity of tintinnid (Ciliata: Protozoa), in relation to water quality parameters along the stretch of the Hooghly (Ganges) River Estuary (HRE), eastern coastal part of India. A total of 26 species (22 agglomerated and 4 non-agglomerated) belonging to 8 genera has been identified from 8 study sites where Tintinnopsis (17 species) represented the most dominant genera, contributing up to 65 % of total tintinnid community followed by Tintinnidium (2 species), Leprotintinnus (2 species) and Dadayiella, Favella, Metacylis, Eutintinnus and Helicostomella (each with solitary species). The maximum (1,666 ind.?l?1) and minimum (62 ind.?l?1) abundance of tintinnids was recorded during post-monsoon and monsoon, respectively. A distinct seasonal dynamics in terms of biomass (0.005–2.465 μg C l?1) and daily production rate (0.04–3.13 μg C l?1 day?1) was also noticed, accounting highest value during pre-monsoon. Chlorophyll a and nitrate were found to be potential causative factors for the seasonal variations of tintinnids as revealed by a stepwise multiple regression model. The result of ANOVA showed a significant variation between species abundance and months (F?=?2.36, P?≤?0.05). k-dominance curves were plotted to determine the comparison of tintinnid dominance between the investigated stations. Based on a principal component analysis (PCA), three main groups were delineated with tintinnid ciliates and environmental parameters. The changes in lorica morphology in terms of temperature and salinity, recorded for three dominant species, provided information on the ecological characteristics of the species assemblage in this estuarine system. 相似文献
2.
Modeling Streamflow and Water Quality Sensitivity to Climate Change and Urban Development in 20 U.S. Watersheds 下载免费PDF全文
T. Johnson J. Butcher D. Deb M. Faizullabhoy P. Hummel J. Kittle S. McGinnis L.O. Mearns D. Nover A. Parker S. Sarkar R. Srinivasan P. Tuppad M. Warren C. Weaver J. Witt 《Journal of the American Water Resources Association》2015,51(5):1321-1341
Watershed modeling in 20 large, United States (U.S.) watersheds addresses gaps in our knowledge of streamflow, nutrient (nitrogen and phosphorus), and sediment loading sensitivity to mid‐21st Century climate change and urban/residential development scenarios. Use of a consistent methodology facilitates regional scale comparisons across the study watersheds. Simulations use the Soil and Water Assessment Tool. Climate change scenarios are from the North American Regional Climate Change Assessment Program dynamically downscaled climate model output. Urban and residential development scenarios are from U.S. Environmental Protection Agency's Integrated Climate and Land Use Scenarios project. Simulations provide a plausible set of streamflow and water quality responses to mid‐21st Century climate change across the U.S. Simulated changes show a general pattern of decreasing streamflow volume in the central Rockies and Southwest, and increases on the East Coast and Northern Plains. Changes in pollutant loads follow a similar pattern but with increased variability. Ensemble mean results suggest that by the mid‐21st Century, statistically significant changes in streamflow and total suspended solids loads (relative to baseline conditions) are possible in roughly 30‐40% of study watersheds. These proportions increase to around 60% for total phosphorus and total nitrogen loads. Projected urban/residential development, and watershed responses to development, are small at the large spatial scale of modeling in this study. 相似文献
3.
Das Suchismita Nath Moumita Laskar Agniv Kumar DebRoy Satabdi Deb Swarupa Barhai Akan Choudhury Atiya Parveen 《Environmental science and pollution research international》2021,28(22):28133-28145
Environmental Science and Pollution Research - To investigate the complex Pb-Cd exposure network in school-going children, a thorough investigation of the probable exposure means (diet, water, and... 相似文献
4.
Assessment of the Water Quality and Ecosystem Health of the Great Barrier Reef (Australia): Conceptual Models 总被引:3,自引:0,他引:3
Haynes D Brodie J Waterhouse J Bainbridge Z Bass D Hart B 《Environmental management》2007,40(6):993-1003
Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities
is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World
Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation
of contaminants and decreased photosynthetic capacity to major shifts in community structure and health of mangrove, coral
reef, and seagrass ecosystems. A detailed conceptual model underpins and illustrates the links between the main anthropogenic
pressures or threats (dry-land cattle grazing and intensive sugar cane cropping) and the production of key contaminants or
stressors of Great Barrier Reef water quality. The conceptual model also includes longer-term threats to Great Barrier Reef
water quality and ecosystem health, such as global climate change, that will potentially confound direct model interrelationships.
The model recognises that system-specific attributes, such as monsoonal wind direction, rainfall intensity, and flood plume
residence times, will act as system filters to modify the effects of any water-quality system stressor. The model also summarises
key ecosystem responses in ecosystem health that can be monitored through indicators at catchment, riverine, and marine scales.
Selected indicators include riverine and marine water quality, inshore coral reef and seagrass status, and biota pollutant
burdens. These indicators have been adopted as components of a long-term monitoring program to enable assessment of the effectiveness
of change in catchment-management practices in improving Great Barrier Reef (and adjacent catchment) water quality under the
Queensland and Australian Governments’ Reef Water Quality Protection Plan. 相似文献
5.
6.
This article suggests that Asia’s groundwater socio‐ecology is at an impasse. Rapid growth in groundwater irrigation in South Asia and the North China plains during the period 1970–95 has been the main driver of the agrarian boom in these regions. India, Pakistan, Bangladesh and China account for the bulk of the world’s use of groundwater in agriculture. On the plus side, groundwater development has provided sustenance to agrarian economies and millions of rural livelihoods. On the downside, it has created chronic problems of resource depletion and quality deterioration. While problems of groundwater depletion, pollution and quality deterioration are indeed serious, so are the consequences of the degradation of the resource for those that have come to precariously depend upon groundwater irrigation. Three problems currently afflict groundwater use: depletion due to overdraft; water logging and salinization; and pollution due to agricultural, industrial and other human activity. The pathology of the decline in groundwater socio‐ecology reflects a remarkably similar pattern across regions. The critical issue for Asia now is: what might be done to sustain and revive these groundwater socio‐ecologies vital to the region’s economy? This article reviews a variety of techno‐institutional approaches. However, transposing lessons from the industrialized world uncritically in the Asian context may not work. A more nuanced understanding of the peculiarities of Asia’s groundwater socio‐ecology is needed. 相似文献
7.
Warne MS Heemsbergen D McLaughlin M Bell M Broos K Whatmuff M Barry G Nash D Pritchard D Penney N 《Environmental pollution (Barking, Essex : 1987)》2008,156(3):707-714
Laboratory-based relationships that model the phytotoxicity of metals using soil properties have been developed. This paper presents the first field-based phytotoxicity relationships. Wheat (Triticum aestivum L.) was grown at 11 Australian field sites at which soil was spiked with copper (Cu) and zinc (Zn) salts. Toxicity was measured as inhibition of plant growth at 8 weeks and grain yield at harvest. The added Cu and Zn EC10 values for both endpoints ranged from approximately 3 to 4760 mg/kg. There were no relationships between field-based 8-week biomass and grain yield toxicity values for either metal. Cu toxicity was best modelled using pH and organic carbon content while Zn toxicity was best modelled using pH and the cation exchange capacity. The best relationships estimated toxicity within a factor of two of measured values. Laboratory-based phytotoxicity relationships could not accurately predict field-based phytotoxicity responses. 相似文献
8.
Chatterjee M Massolo S Sarkar SK Bhattacharya AK Bhattacharya BD Satpathy KK Saha S 《Environmental monitoring and assessment》2009,150(1-4):307-322
This paper presents a comprehensive account regarding concentration, distribution and possible sources of trace elements (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in 20-30 cm sediment cores (<63 microm particle size) collected at the confluence of the Ganges River and Bay of Bengal (Sunderban wetland, India). This work aims to evaluate the fluvio-marine and geochemical processes influencing the metal distribution. The most interesting features are the downward increase of concentrations of majority of the elements reaching overall maximum values at a depth of 10-15 cm observed in station Lot No.8 located along the main stream of the Ganges estuary as well as an overall elevated concentration of all the elements in the lower littoral zone. The interelemental relationship revealed the identical behaviour of elements during its transport in the estuarine environment. The overall variation in concentration can be attributed to differential discharge of effluents originating from industrial and agricultural as well as from domestic sewage. Arsenic exceeded effects range - low (ER - L) concentrations, implying occasional or frequent adverse biological effects. For Cu, Ni and Cr a smaller proportion of samples had exceeded the ER - L values indicating that the dataset would be suitable for future use in evaluating predictive abilities of SQGs. 相似文献
9.
Large‐Scale Fine‐Resolution Hydrological Modeling Using Parameter Regionalization in the Missouri River Basin 下载免费PDF全文
Prasad Daggupati Debjani Deb Raghavan Srinivasan Dhanesh Yeganantham Vikram M. Mehta Norman J. Rosenberg 《Journal of the American Water Resources Association》2016,52(3):648-666
This study simulated crop and water yields in the Missouri River Basin (MRB; 1,371,000 km2), one of the largest river basins in the United States, using the Soil and Water Assessment Tool (SWAT) at a fine resolution of 12‐digit Hydrological Unit Codes (HUCs) using the regionalization calibration approach. Very few studies have simulated the entire MRB, and those that have developed were at a coarser resolution of 8‐digit HUCs and were minimally calibrated. The MRB was first divided into three subbasins and was further divided into eleven regions. A “head watershed” was selected in each region and was calibrated for crop and water yields. The parameters from the calibrated head watershed were extrapolated to other subwatersheds in the region to complete comprehensive spatial calibration. The simulated crop yields at the head watersheds were in close agreement with observed crop yields. Spatial validation of the aggregated crop yields resulted in reasonable predictions for all crops except dryland corn in a few regions. Simulated and observed water yields in head watersheds and also in the validation locations were in close agreement in naturalized streams and poor agreement in streams with high groundwater‐surface water interactions and/or reservoirs found upstream of the gauges. Overall, the SWAT model was able to reasonably capture the hydrological and crop growth dynamics occurring in the basin despite some limitations. 相似文献
10.
PW Kok HY Ong MK Wong WK Au KT Tan WH Phoon CN Ong 《Environmental monitoring and assessment》1997,44(1-3):425-431
Occupational exposure to benzene was measured in two gasoline marketing terminals and five major refineries in Singapore. A total of 280 workers were monitored over two years. This assessment was carried out with two primary objectives: (1) To find out the extent of occupational exposure to benzene in the petroleum industry in Singapore, (2) To identify suitable biomarkers for monitoring of low levels of benzene exposure. The exposure was measured in five different categories of petroleum and petrochemical workers, i.e., truck drivers, despatch assistant, process operators, oil movements operators and laboratory technicians. The results revealed wide variations in exposure, from 0.01 to 13.6 ppm for personal time weighted average (TWA) exposure over the whole workshift. The exposure of truck drivers appeared to be the highest, with geometric mean (GM) of 1.98 ppm (ranged from 0.25 to 13.6 ppm). The average benzene exposure for process operators was relative low with a GM of 0.04 ppm. Lowest benzene exposure was found in the laboratory technicians, with a GM of 0.02 ppm. As cigarette smoking is known to affect metabolism of benzene, data analyses on the relationships with environmental exposure were conducted only on the 190 nonsmokers. The results showed that urinary trans, trans-muconic acid (ttMA), unmetabolized benzene in urine (UBZ) and benzene in blood (BBZ) were better biomarkers for low level benzene exposure as compared to urinary phenolic metabolites in urine, such as hydroquinone, phenol and catechol. 相似文献