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11.
水体中锰离子对酚类有机物的光化学降解的影响 总被引:3,自引:3,他引:0
通过对不同锰离子浓度下三种酚在三种不同介质中的光降解情况的研究,来确定水体中的锰离子对酚类有机物的光化学降解的影响。实验结果表明,在不同条件下,不同浓度的锰离子对实验中所选的三种酚的影响有所不同。对邻硝基苯酚的光降解几乎不产生影响,对对甲基苯酚的光降解起到抑制作用,而对2,4-二硝基苯酚的光降解则起到促进作用。 相似文献
12.
Sunlu U 《Environmental monitoring and assessment》2006,114(1-3):273-286
Bio-monitoring of some heavy metal levels (Cd, Pb, Zn, Cu) in whole edible soft parts of Mytilus galloprovincialis (L. 1758) was conducted in Turkish Aegean Sea coast during the period of September 2002–August 2003 seasonally. Moreover, some physico-chemical environmental parameters, also have been analysed in the same region. The values of some physico-chemical environmental parameters in coastal waters of Turkish Aegean Sea were changed between; 9.0–27.0 ∘C for temperature, 31.93–40.45 psu for salinity, 7.35–8.48 for pH and 4.05–9.50 mg/l for dissolved oxygen. The levels of trace elements in whole edible soft parts including interstitial fluids of Mediterranean mussels M. galloprovincialis (L. 1758), sampled from 6 different regions of Turkish Aegean Sea coast have ranged between; 0.04–0.52 μg Cd/g wet weight, 0.49–1.72 μg Pb/g w.w., 0.95–1.85 Cu/g w.w., 16.11–37.15 μg Zn/g w.w. The highest values for all trace metals (Cd, Pb, Zn, Cu) were measured in inner part of Izmir Bay (station 3) and lowest in Sigacik and Gulluk Bay (station 5, 6). Generally heavy metal levels are lower than the results in soft mussel tissues reported from Mediterranean regions. 相似文献
13.
14.
Van Hoecke K De Schamphelaere KA Van der Meeren P Smagghe G Janssen CR 《Environmental pollution (Barking, Essex : 1987)》2011,159(4):970-976
The influence of pH (6.0-9.0), natural organic matter (NOM) (0-10 mg C/L) and ionic strength (IS) (1.7-40 mM) on 14 nm CeO2 NP aggregation and ecotoxicity towards the alga Pseudokirchneriella subcapitata was assessed following a central composite design. Mean NP aggregate sizes ranged between 200 and 10000 nm. Increasing pH and IS enhanced aggregation, while increasing NOM decreased mean aggregate sizes. The 48 h-ErC20s ranged between 4.7 and 395.8 mg CeO2/L. An equation for predicting the 48 h-ErC20 (48 h-ErC20 = −1626.4 × (pH) + 109.45 × (pH)2 + 116.49 × ([NOM]) − 14.317 × (pH) × ([NOM]) + 6007.2) was developed. In a validation study with natural waters the predicted 48 h-ErC20 was a factor 1.08-2.57 lower compared to the experimental values. 相似文献
15.
Jussi Kosonen Leif Kronberg 《Environmental science and pollution research international》2009,16(5):555-564
Background, aim and scope Each year, large quantities of pharmaceuticals are consumed worldwide for the treatment and prevention of human and animal
diseases. Although the drugs and the metabolites observed in the wastewaters and in the environment are present at concentrations
several orders of magnitude lower than the concentrations required to exert their effects in humans or animals, their long-term
impact on the environment is commonly not known. In this study, the occurrence of six antihistamines, which are used for the
relief of allergic reactions such as hay fever, was determined in sewage treatment plants wastewaters and in recipient river
waters.
Materials and methods The occurrence of the antihistamines cetirizine, acrivastine, fexofenadine, loratadine, desloratadine and ebastine in sewage
treatment plants wastewaters and in recipient river waters was studied. The analytical procedure consisted of solid-phase
extraction of the water samples followed by liquid chromatography separation and detection by a triple-quadrupole mass spectrometer
in the multiple reaction mode.
Results Cetirizine, acrivastine and fexofenadine were detected in both influent and effluent wastewater samples at concentration levels
ranging from about 80 to 220 ng/L, while loratadine, desloratadine and ebastine could not be detected in any samples. During
sewage treatment, the concentration of the antihistamines dropped by an average of 16–36%. Furthermore, elevated concentrations
of antihistamines were observed in samples collected during the season of most intensive plant pollen production, i.e. in
May. In the river water samples, the relative pattern of occurrence of cetirizine, acrivastine and fexofenadine was similar
to that in the wastewater samples; although the concentration of the compounds was substantially lower (4–11 ng/L). The highest
concentrations of the studied drugs were observed near the discharging point of the sewage treatment plant.
Discussion The highest concentrations of antihistamines in STP wastewaters correlate with the outbreak of allergic reaction caused by
high amounts of plant pollens in the air. The analysis results of the river water samples show that the antihistamines are
carried far away from the effluent discharge points. They may account for a part of the mix of pharmaceuticals and of pharmaceutical
metabolites that occur downstream of STPs.
Conclusions Antihistamines are poorly degraded/eliminated under the biological treatment processes applied in the wastewater treatment
plants and, consequently, they are continuously being discharged along with other drugs to the aquatic environment.
Recommendations and perspectives As a huge quantity and variety of drugs and their metabolites are continuously discharged to rivers and the sea, the compounds
should be considered as contaminants that may possess risks to the aquatic ecosystem. Further studies are urgently needed
on the environmental fate of the antihistamines and other pharmaceuticals in the aquatic environment. These studies should
be concerned with the stability of the compounds, their transformation reactions and the identity of the transformation products,
the distribution of drugs and their uptake and effects in organisms. On the basis of these studies, the possible environmental
hazards of pharmaceuticals may be assessed. 相似文献
16.
The Sambhar Salt Lake hydrological system, including river waters, groundwaters, evaporating pans and sub-surface brines, has been analyzed for the salt content (TDS) and naturally occurring radionuclides (210Po, 210Pb and 226,228Ra). The abundance of these radionuclides and their activity ratios show a wide variation in different hydrological regimes, which helps to geochemically characterize the lake system. A significantly lower Ra to total dissolved solids (TDS) ratio in the brines (by two to three orders of magnitude), when compared to the groundwaters and river waters, suggests removal of dissolved Ra by co-precipitation with Ca–Mg minerals at an early stage of the brine evolution. The concentration of Ra in evaporating lake/pan waters saturates at a value of about 35 Bq L−1 over the salinity range of 100–370 g L−1; attributable to its equilibration with the clay minerals. The two distinct regimes, saline lake system (lake water, evaporating pans and sub-surface brines) and groundwaters have been identified based on their differences in the distribution of 226,228Ra isotopes. This observation points to the conclusion that the groundwaters and the lake brines are not intimately coupled in terms of their origin and evolution. The abundances of 210Po and 210Pb along with their activity ratios (210Po/210Pb) are markedly different among the surface lake waters/evaporating pans, sub-surface lake brines and groundwaters. These differences are explained in terms of different geochemical behaviour of these nuclides in presence of algae and organic matter present in these water regimes. 相似文献
17.
L. León Vintró P.I. Mitchell A. Omarova M. Burkitbayev H. Jiménez Nápoles N.D. Priest 《Journal of environmental radioactivity》2009
New data are reported on the concentrations, isotopic composition and speciation of americium, plutonium and uranium in surface and ground waters in the Sarzhal region of the Semipalatinsk Test Site, and an adjacent area including the settlement of Sarzhal. The data relate to filtered water and suspended particulate from (a) streams originating in the Degelen Mountains, (b) the Tel′kem 1 and Tel′kem 2 atomic craters, and (c) wells on farms located within the study area and at Sarzhal. The measurements show that 241Am, 239,240Pu and 238U concentrations in well waters within the study area are in the range 0.04–87 mBq dm−3, 0.7–99 mBq dm−3, and 74–213 mBq dm−3, respectively, and for 241Am and 239,240Pu are elevated above the levels expected solely on the basis of global fallout. Concentrations in streams sourced in the Degelen Mountains are similar, while concentrations in the two water-filled atomic craters are somewhat higher. Suspended particulate concentrations in well waters vary considerably, though median values are very low, at 0.01 mBq dm−3, 0.08 mBq dm−3 and 0.32 mBq dm−3 for 241Am, 239,240Pu and 238U, respectively. The 235U/238U isotopic ratio in almost all well and stream waters is slightly elevated above the ‘best estimate’ value for natural uranium worldwide, suggesting that some of the uranium in these waters is of test-site provenance. Redox analysis shows that on average most of the plutonium present in the microfiltered fraction of these waters is in a chemically reduced form (mean 69%; 95% confidence interval 53–85%). In the case of the atomic craters, the proportion is even higher. As expected, all of the americium present appears to be in a reduced form. Calculations suggest that annual committed effective doses to individual adults arising from the daily ingestion of these well waters are in the range 11–42 μSv (mean 21 μSv). Presently, the ground water feeding these wells would not appear to be contaminated with radioactivity from past underground testing in the Degelen Mountains or from the Tel′kem explosions. 相似文献
18.
This study quantifies the disruption of zooplankton population fluctuations in relation to two magnitudes of fire retardant contamination events using artificial ponds as model systems. Population time series were analysed using redundancy analysis where time was modelled with a principal coordinate of neighborhood matrices approach that identified relevant scales of fluctuation frequencies. Analyses of temporal coherence provided insight whether population fluctuations correlated with system intrinsic or extrinsic forces. Responses to stress were species-specific and context-dependant. Contamination changed temporal structure in some species. These alterations were associated with an increased intrinsic control of dynamics. In some cases the magnitude of impact was unrelated to contamination severity. Some populations were less tolerant of pollution in the low relative to the high concentration treatment. Results suggest that population-level monitoring of degraded sites may be suboptimal because disparate population responses complicate the selection of specific sentinel organisms to monitor stress. 相似文献
19.
Cielo Emar M. Paraoan Windell L. Rivera 《Journal of environmental science and health. Part. B》2017,52(5):306-313
Contaminated irrigation water may greatly affect not only the quality of produce but also the people exposed to it. In this study, agricultural irrigation waters in Bulacan, Philippines were assessed and found to be contaminated with Escherichia coli (E. coli) ranging from 0.58 to 4.51 log10 CFU/mL. A total of 79 isolates of E. coli were confirmed through polymerase chain reaction (PCR) amplifying the uidA gene and were tested for phenotypic resistance using 10 antimicrobials through the Kirby–Bauer disc diffusion method. Forty-six isolates (58.22%) were noted to be multidrug resistant (MDR) with high resistance rate to cephalothin, tetracycline, streptomycin, ampicillin, trimethoprim, nalidixic acid, and chloramphenicol. Moreover, this study also examined the prevalence of Class I and II integrons accounting to 67.39% and 17.39%, respectively, of the MDR E. coli strains using multiplex PCR. The results imply that the agricultural water used in Bulacan is contaminated with the fecal material of man or other animals present in the area, and the presence of MDR bacteria, which pose a potential threat to individuals in these areas, is alarming. In addition, detection of integrons could be a good marker for the identification of MDR isolates. Lastly, this study could develop strategies for the proper management of farming sites leading to the detection of food-borne pathogens and prevention of infectious diseases. 相似文献
20.
Abundance of fecal caliform bacteria is a weak index of the presence of human pathogens in wastewater entering coastal waters.
In spite of this, use of fecal caliform indices for management purposes is widespread. To gain insight into interpretation
of fecal coliform data, we evaluated size of stocks of fecal coliforms in water, sediments, and sea wrack, in Buttermilk Bay,
a coastal embayment in Massachusetts. Sediments contained most of the fecal coliforms. Fecal coliforms in sediments were as
much as one order of magnitude more abundant than in the water column or in sea wrack. The fecal coliforms in sediments of
Buttermilk Bay were so abundant that resuspension of fecal coliforms from just the top 2 cm of muddy sediments could add sufficient
cells to the water column to have the whole bay exceed the federal limit of fecal coliforms for shellfishing.
The major sources of fecal coliforms to the bay were water-fowls, surface runoff, groundwater, and streams. Waterfowl were
the largest source of fecal coliforms during cold months; surface runoff, streams, and groundwater were most important during
warm months. Redirection of surface runoff pipes is unlikely to be a very successful management action since contributions
via this source are insufficient to account for the measured increases in concentrations of fecal coliforms in water. Removal
of waterfowl is also unlikely to be useful, since fecal coliform concentrations leading to closures of shellfish beds and
swimming areas are most frequent during warm months when waterfowl are rarest. Rates of loss of fecal caliform cells from
the water column by death and tidal exchange were high. Mortality of cells was about an order of magnitude larger than losses
by tidal exchange.
The amounts of fecal coliforms brought into the bay by waterfowl, surface runoff, groundwater, and streams are an order of
magnitude smaller than the losses by mortality and tidal removal. This implies that there is an additional source of fecal
coliforms within the bay. We suggest that resuspension of the upper layers of sediments can easily account for the fecal coliforms
present in the water.
Fecal coliform content of water and shellfish were not correlated. In contrast, sediment and shellfish fecal coliform abundances
were significantly related. Monitoring of fecal coliforms in sediments may provide a better assessment of shellfish than sampling
of water.
The large fecal coliform stock in sediments should be the first priority for management. Efforts ought to be directed toward
the reduction of sediment fecal coliform stocks. Lowering nutrient additions to coastal water bodies may be one practical
approach. 相似文献