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991.
992.
Gail Krantzberg 《The Environmentalist》2008,28(3):301-305
Some argue that a collective vision for the future of the Laurentian Great Lakes is embodied in the␣Great Lakes Water Quality
Agreement (GLWQA). The GLWQA is a binational agreement, first signed in 1972 by Prime Minister Pierre Trudeau and President
Richard Nixon, wherein the two countries (the Parties) commit to “restore and maintain the chemical, physical and biological
integrity of the waters of the Great Lakes Basin Ecosystem.” Article X of the Agreement states that the Parties shall conduct
a comprehensive review of the operation and effectiveness of this Agreement following every third biennial report of the [International
Joint] Commission (IJC). The IJC’s 12th Biennial Report, released in 2004, triggered this important science, program, and
policy review which commenced May 2006. This essay makes the case for a rigorous review, that explores deliberately the future
scope of the Agreement to protect the world’s largest surface freshwater resource, and calls for innovation in the governance
regime of this binational ecosystem. 相似文献
993.
Levels of perfluorochemicals in water samples from Catalonia,Spain: is drinking water a significant contribution to human exposure? 总被引:2,自引:0,他引:2
Ericson I Nadal M van Bavel B Lindström G Domingo JL 《Environmental science and pollution research international》2008,15(7):614-619
Background, aim, and scope In recent years, due to a high persistence, biomagnification in food webs, presence in remote regions, and potential toxicity,
perfluorochemicals (PFCs) have generated a considerable interest. The present study was aimed to determine the levels of perfluorooctane
sulfonate (PFOS), perfluorooctanoic acid (PFOA), and other PFCs in drinking water (tap and bottled) and river water samples
from Tarragona Province (Catalonia, Spain).
Materials and methods Municipal drinking (tap) water samples were collected from the four most populated towns in the Tarragona Province, whereas
samples of bottled waters were purchased from supermarkets. River water samples were collected from the Ebro (two samples),
Cortiella, and Francolí Rivers. After pretreatment, PFC analyses were performed by HPLC-MS. Quantification was done using
the internal standard method, with recoveries between 68% and 118%.
Results In tap water, PFOS and PFOA levels ranged between 0.39 and 0.87 ng/L (0.78 and 1.74 pmol/L) and between 0.32 and 6.28 ng/L
(0.77 and 15.2 pmol/L), respectively. PFHpA, PFHxS, and PFNA were also other detected PFCs. PFC levels were notably lower
in bottled water, where PFOS could not be detected in any sample. Moreover, PFHpA, PFHxS, PFOA, PFNA, PFOS, PFOSA, and PFDA
could be detected in the river water samples. PFOS and PFOA concentrations were between <0.24 and 5.88 ng/L (<0.48 and 11.8 pmol/L)
and between <0.22 and 24.9 ng/L (<0.53 and 60.1 pmol/L), respectively.
Discussion Assuming a human water consumption of 2 L per day, the daily intake of PFOS and PFOA by the population of the area under evaluation
was calculated (0.78–1.74 and 12.6 ng, respectively). It was found that drinking water might be a source of exposure to PFCs
as important as the dietary intake of these pollutants.
Conclusions The contribution of drinking water (tap and bottled) to the human daily intake of various PFCs has been compared for the first
time with data from dietary intake of these PFCs. It was noted that in certain cases, drinking water can be a source of exposure
to PFCs as important as the dietary intake of these pollutants although the current concentrations were similar or lower than
those reported in the literature for surface water samples from a number of regions and countries.
Recommendations and perspectives Further studies should be carried out in order to increase the knowledge of the role of drinking water in human exposure to
PFCs. 相似文献
994.
Nutrient-impregnated charcoal: an environmentally friendly
slow-release fertilizer 总被引:20,自引:0,他引:20
Modabber Ahmed Khan Ki-Wook Kim Wang Mingzhi Bu-Kug Lim Weon-Hee Lee Jong-Yoon Lee 《The Environmentalist》2008,28(3):231-235
The widespread contamination of surface and ground water quality from the heavy use of fertilizer in modern agriculture is
the current concern. Therefore, this study was carried out to develop a slow-release fertilizer using charcoal. The morphology
of the charcoal impregnated fertilizer was investigated by scanning electron microscopy (SEM). This study also evaluated the
release patterns of N, P, and K from impregnated charcoal using a simulated soil solution and distilled water as leaching
solutions. The patterns of N, P, and K releases were examined in both static and continuous-flow conditions for 360 h. Releases
of N, P, and K from impregnated charcoal were found to be slow and steady. However, the release trends of N, P, and K were
higher in soil solution than distilled water under both the above conditions. Dissolution occurred when N, P, and K were released
in the above leached solutions. As a result, the fertilizer impregnated charcoal could be developed as slow-release type fertilizer
to minimize the contamination. 相似文献
995.
996.
Influence of Riparian Seepage Zones on Nitrate Variability in Two Agricultural Headwater Streams 下载免费PDF全文
Mark R. Williams Anthony R. Buda Herschel A. Elliott Kamini Singha James Hamlett 《Journal of the American Water Resources Association》2015,51(4):883-897
Riparian seeps have been recognized for their contributions to stream flow in headwater catchments, but there is limited data on how seeps affect stream water quality. The objective of this study was to examine the effect of seeps on the variability of stream NO3‐N concentrations in FD36 and RS, two agricultural catchments in Pennsylvania. Stream samples were collected at 10‐m intervals over reaches of 550 (FD36) and 490 m (RS) on 21 occasions between April 2009 and January 2012. Semi‐variogram analysis was used to quantify longitudinal patterns in stream NO3‐N concentration. Seep water was collected at 14 sites in FD36 and 7 in RS, but the number of flowing seeps depended on antecedent conditions. Seep NO3‐N concentrations were variable (0.1‐29.5 mg/l) and were often greater downslope of cropped fields compared to other land uses. During base flow, longitudinal variability in stream NO3‐N concentrations increased as the number of flowing seeps increased. The influence of seeps on the variability of stream NO3‐N concentrations was less during storm flow compared to the variability of base flow NO3‐N concentrations. However, 24 h after a storm in FD36, an increase in the number of flowing seeps and decreasing streamflow resulted in the greatest longitudinal variability in stream NO3‐N concentrations recorded. Results indicate seeps are important areas of NO3‐N delivery to streams where targeted adoption of mitigation measures may substantially improve stream water quality. 相似文献
997.
Resolution and Analysis of Spatial Variations and Patterns in an Urban Lake with Rapid Profiling Instrumentation 下载免费PDF全文
Anthony R. Prestigiacomo Steven W. Effler David A. Matthews 《Journal of the American Water Resources Association》2015,51(1):200-213
Rapid response vertical profiling instrumentation was used to document spatial variability and patterns in a small urban lake, Onondaga Lake, associated with multiple drivers. Paired profiles of temperature, specific conductance (SC), turbidity (Tn), fluorometric chlorophyll a (Chlf), and nitrate nitrogen (NO3?) were collected at >30 fixed locations (a “gridding”) weekly, over the spring to fall interval of several years. These gridding data are analyzed (1) to characterize phytoplankton (Chlf) patchiness in the lake's upper waters, (2) to establish the representativeness of a single long‐term site for monitoring lake‐wide conditions, and (3) to resolve spatial patterns of multiple tracers imparted by buoyancy effects of inflows. Multiple buoyancy signatures were resolved, including overflows from less dense inflows, and interflows to metalimnetic depths and underflows to the bottom from the plunging of more dense inputs. Three different metrics had utility as tracers in depicting the buoyancy signatures as follows: (1) SC, for salinity‐enriched tributaries and the more dilute river that receives the lake's outflow, (2) Tn, for the tributaries during runoff events, and (3) NO3?, for the effluent of a domestic waste treatment facility and from the addition of NO3? solution to control methyl mercury. The plunging inflow phenomenon, which frequently prevailed, has important management implications. 相似文献
998.
999.
Waled Morsy El-Senousy Ahmed Mohammed El-Sayed Ragab Eman Mohammed Abd El Hamed Handak 《Food and environmental virology》2015,7(2):132-141
The objective of this study is to compare the prevalence of rotaviruses groups A and C in Egyptian children and aquatic environment. From 110 stool specimens of children with acute diarrhea and using RT-PCR, 35 samples (31.8 %) were positive for human rotavirus group A and 15 samples (13.6 %) were positive for human rotavirus group C. From 96 samples collected from Zenin wastewater treatment plant over a 2-year period (November 2009–October 2011) and using RT-PCR, rotavirus group A was detected in (4/24) 16.7 %, (5/24) 20.8 %, (4/24) 16.7 %, and (4/24) 16.7 %, while rotavirus group C was detected in (2/24) 8.3 %, (3/24) 12.5 %, (3/24) 12.5 %, and (0/24) 0 % in raw sewage, after primary sedimentation, after secondary sedimentation, and after final chlorination, respectively. Moreover, from 96 samples collected from El-Giza water treatment plant over a 2-year period (November 2009–October 2011), rotavirus group A was detected in (7/24) 29.2 %, (6/24) 25 %, (5/24) 20.8 %, and (3/24) 12.5 %, while rotavirus group C was detected in (3/24) 12.5 %, (1/24) 4.2 %, (1/24) 4.2 %, and (0/24) 0 % in raw Nile water, after sedimentation, after sand filtration, and after final chlorination, respectively. Using SYBR Green real-time RT-PCR, the number of human rotavirus group A genome or infectious units was higher than rotavirus group C. VP6 sequence analysis of the RT-PCR positive rotavirus group C samples revealed that four clinical specimens and three environmental samples showed similar sequences clustered with Moduganari/Human Nigerian strain AF 325806 with 98 % homology, and two clinical specimens and one environmental sample showed similar sequences clustered with Dhaka CB/Human Bangladesh strain AY 754826 with 97 % homology. 相似文献
1000.
Jinxue Luo Jinsong Zhang Xiaohui Tan Diane McDougald Guoqiang Zhuang Anthony G.Fane Staffan Kjelleberg Yehuda Cohen Scott A.Rice 《环境科学学报(英文版)》2015,(3):115-123
Biofilm formation, one of the primary causes of biofouling, results in reduced membrane flux or increased transmembrane pressure and thus represents a major impediment to the wider implementation of membrane bioreactor(MBR) technologies for water purification. Most studies have focused on the role of bacteria in membrane fouling as they are the most dominant and best studied organisms present in the MBR. In contrast, there is limited information on the role of the archaeal community in biofilm formation in MBRs. This study investigated the composition of the archaeal community during the process of biofouling in an MBR. The archaeal community was observed to have lower richness and diversity in the biofilm than the sludge during the establishment of biofilms at low transmembrane pressure(TMP). Clustering of the communities based on the Bray–Curtis similarity matrix indicated that a subset of the sludge archaeal community formed the initial biofilms. The archaeal community in the biofilm was mainly composed of Thermoprotei, Thermoplasmata,Thermococci, Methanopyri, Methanomicrobia and Halobacteria. Among them, the Thermoprotei and Thermoplasmata were present at higher relative proportions in the biofilms than they were in the sludge. Additionally, the Thermoprotei, Thermoplasmata and Thermococci were the dominant organisms detected in the initial biofilms at low TMP, while as the TMP increased, the Methanopyri, Methanomicrobia, Aciduliprofundum and Halobacteria were present at higher abundances in the biofilms at high TMP. 相似文献