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1.
We investigated the e ects of environmental factors and properties of water-stable crystal fullerene (nC60) on the uptake of nC60
by Daphnia magna based on known accumulation in our laboratory. This study was performed for seven days using di erent
environmental factors including temperature, pH, water hardness, concentration (density of particle), and particle size. Results
demonstrated that body burden of C60 increased with time in all experiments. Body burden of C60 increased with increasing
concentration and particle size, and uptake of particles >100 nm reached their maximums more quickly than those <100 nm. Under
high hardness in aqueous systems with lower pH and high temperature, uptake was higher than those under opposite conditions. Uptake
in all batch tests reached balance within five days. Both nC60 properties and environmental factors influenced uptake of nC60 by D.
magna in an aqueous system. Additionally, environmental factors may have a ected accumulation by changing nC60 properties, which
are critical to understand the accumulation of fullerenes in aqueous systems. 相似文献
2.
3.
The feasibility of using anaerobic ba ed reactor (ABR) as onsite wastewater treatment system was discussed. The ABR consisted
of one sedimentation chamber and three up-flow chambers in series was experimented under di erent peak flow factors (PFF of 1
to 6), superficial gas velocities (between 0.6 and 3.1 cm/hr) and hydraulic retention times (HRT) (24, 36 and 48 hr). Residence time
distribution (RTD) analyses were carried out to investigate the hydraulic characteristics of the ABR. It was found that the PFF resulted
in hydraulic dead space. The dead space did not exceed 13% at PFF of 1, 2 and 4 while there was 2-fold increase (26%) at PFF of
6. Superficial gas velocities did not result in more (biological) dead space. The mixing pattern of ABR tended to be a completelymixed
reactor when PFF increased. Superficial gas velocities did not a ect mixing pattern. The e ects of PFF on mixing pattern could
be minimized by higher HRT (48 hr). The tank-in-series (TIS) model (N = 4) was suitable to describe the hydraulic behaviour of
the studied system. The HRT of 48 hr was able to maintain the mixing pattern under di erent flow patterns, introducing satisfactory
hydraulic e ciency. Chemical oxygen demand (COD) and total suspended solids (TSS) removals under all flow patterns were achieved
more than 85% and 90%, respectively. The standard deviation of e uent COD and TSS concentration did not exceed 15 mg/L. 相似文献
4.
Moisture distributions in municipal sewage sludge, printing and dyeing sludge and paper mill sludge were experimentally studied
based on four di erent methods, i.e., drying test, thermogravimetric-di erential thermal analysis (TG-DTA) test, thermogravimetricdi
erential scanning calorimetry (TG-DSC) test and water activity test. The results indicated that the moistures in the mechanically
dewatered sludges were interstitial water, surface water and bound water. The interstitial water accounted for more than 50% wet basis
(wb) of the total moisture content. The bond strength of sludge moisture increased with decreasing moisture content, especially when
the moisture content was lower than 50% wb. Furthermore, the comparison among the four di erent testing methods was presented.
The drying test was advantaged by its ability to quantify free water, interstitial water, surface water and bound water; while TG-DSC
test, TG-DTA test and water activity test were capable of determining the bond strength of moisture in sludge. It was found that the
results from TG-DSC and TG-DTA test are more persuasive than water activity test. 相似文献
5.
Most probable number (MPN) and colony-forming unit (CFU) estimates of fecal indicator bacteria (FIB) concentration are common
measures of water quality in aquatic environments. Thus, FIB intensively monitored in Yeongsan Watershed in an attempt to compare
two di erent methods and to develop a statistical model to convert from CFU to MPN estimates or vice versa. As a result, the significant
di erence was found in the MPN and CFU estimates. The enumerated Escherichia coli concentrations in MPN are greater than those in
CFU, except for the measurement in winter. Especially in fall, E. coli concentrations in MPN are one order of magnitude greater than
that in CFU. Contrarily, enterococci bacteria in MPN are lower than those in CFU. However, in general, a strongly positive relationship
are found between MPN and CFU estimates. Therefore, the statistical models were developed, and showed the reasonable converting
FIB concentrations from CFU estimates to MPN estimates. We expect this study will provide preliminary information towards future
research on whether di erent analysis methods may result in di erent water quality standard violation frequencies for the same water
sample. 相似文献
6.
Changes in phototactic behavior of Daphnia magna clone C1 242 in response to copper, cadmium and pentachlorophenol 总被引:12,自引:0,他引:12
In order to develop a sound biotechnique for monitoring water quality that builds on the previous experiments carried out in our laboratory, a specific D. magna clone C1242 was used to study the effects of pollutants on phototactic behavior, in all experiments, the animals showed a stable and repeatable phototactic index approximated 0.2 in the presence and 0.4 in the absence of fish kairomenes, which decreased significantly in response to pollutants. There existed no pollutant x fish kairomone interaction, indicating the changes in phototactic behavior of animals imposed by pollutants were independent of the presence of fish kairomones. The detection limits for changes in phototactic behavior of D. magna clone C1 242 are 0.04 mg/L for copper, 0.02 mg/L for cadmium, and 0.80 mg/L for PCP, respectively, quite lowerthan LC50(48 h). The changes in phototactic behavior in presence to pollutants occurred quickly(3 h) compared to the period over whole acute toxicity tests. Therefore, D. magna clone C1 242 could be potentially used to monitor water quality. Moreover, the phototactic behavior did not decrease further in the pollutant mixtures employed in our experiments compared to individual pollutants, except in the Cd-PCP Lre.atme~t.This fact suggests that the formation of water quality criteria must be based upon pollutant mixture tests.Keywords: Daphnia; phototactic behavior; copper; cadmium; pentachlorophenol; fish kairomenes 相似文献
7.
Community analysis of ammonia-oxidizing bacteria in activated sludge of eight
wastewater treatment systems 总被引:9,自引:1,他引:8
Xiaohui Wang Xianghua Wen Craig Criddle George Wells Jie Zhang Yin Zhao 《环境科学学报(英文版)》2010,22(4):627-634
We investigated the communities of ammonia-oxidizing bacteria(AOB) in activated sludge collected from eight wastewater treatment systems using polymerase chain reaction(PCR) followed by terminal restriction fragment length polymorphism(T-RFLP),cloning,and sequencing of the α-subunit of the ammonia monooxygenase gene(amoA).The T-RFLP fingerprint analyses showed that different wastewater treatment systems harbored distinct AOB communities.However,there was no remarkable difference among the AOB TRFLP profiles from different parts of the same system.The T-RFLP fingerprints showed that a full-scale wastewater treatment plant(WWTP) contained a larger number of dominant AOB species than a pilot-scale reactor.The source of influent affected the AOB community,and the WWTPs treating domestic wastewater contained a higher AOB diversity than those receiving mixed domestic and industrial wastewater.However,the AOB community structure was little affected by the treatment process in this study.Phylogenetic analysis of the cloned amoA genes clearly indicated that all the dominant AOB in the systems was closely related to Nitrosomonas spp.not to Nitrosospira spp.Members of the Nitrosomonas oligotropha and Nitrosomonas communis clusters were found in all samples,while members of Nitrosomonas europaea cluster occurred in some systems. 相似文献
8.
微塑料(Microplastics,MPs)作为一种新兴环境污染物,其环境效应已引起了广泛关注.为揭示不同粒径微塑料对淡水生物摄食和抗氧化防御系统的影响规律,以100 nm、5 μm、50 μm聚苯乙烯(Polystyrene,PS)微塑料为研究对象,以大型溞(Daphnia magna)为受试生物,研究微塑料在大型溞体内的积累量、停留量,以及对大型溞滤水率、摄食率以及抗氧化防御系统的影响.结果表明:3种粒径的微塑料均可被大型溞摄入,100 nm和5 μm的微塑料在大型溞体内的积累量和停留量均高于50 μm的微塑料,50 μm的微塑料主要黏附在胸肢处,而100 nm和5 μm的微塑料能在大型溞肠道中积累.暴露于3种粒径的微塑料后,大型溞的滤水率和摄食率较对照组分别降低了50.7%±9.5%和39.2%±10.7%.3种粒径的微塑料均能促进大型溞体内超氧化物歧化酶、过氧化氢酶活性的升高,并诱导丙二醛含量升高,导致大型溞氧化损伤.研究显示,微塑料损伤大型溞的食物过滤器,堵塞消化道,降低其滤水率、摄食率,造成大型溞氧化损伤,微塑料暴露对大型溞的摄食和抗氧化防御系统造成了不利影响. 相似文献
9.
Organic carbon accumulation capability of two typical tidal wetland soils in
Chongming Dongtan, China 总被引:3,自引:1,他引:2
Shiping Zhang Lei Wang Jiajun Hu Wenquan Zhang Xiaohua Fu Yiquan Le Fangming Jin 《环境科学学报(英文版)》2011,23(1):87-94
We measured organic carbon input and content of soil in two wetland areas of Chongming Dongtan (Yangtze River Estuary) to
evaluate variability in organic carbon accumulation capability in di erent wetland soils. Observed di erences were investigated based
on the microbial activity and environmental factors of the soil at the two sites. Results showed that the organic carbon content of wetland
soil vegetated with Phragmites australis (site A) was markedly lower than that with P. australis and Spartina alterniflora (site B). Sites
di erences were due to higher microbial activity at site A, which led to higher soil respiration intensity and greater carbon outputs.
This indicated that the capability of organic carbon accumulation of the site B soils was greater than at site A. In addition, petroleum
pollution and soil salinity were di erent in the two wetland soils. After bio-remediation, the soil petroleum pollution at site B was
reduced to a similar level of site A. However, the culturable microbial biomass and enzyme activity in the remediated soils were also
lower than at site A. These results indicated that greater petroleum pollution at site B did not markedly inhibit soil microbial activity.
Therefore, di erences in vegetation type and soil salinity were the primary factors responsible for the variation in microbial activity,
organic carbon output and organic carbon accumulation capability between site A and site B. 相似文献
10.
Nitrification potentials of Chinese tea orchard soils and their adjacent
wasteland and forest soils 总被引:1,自引:0,他引:1
To investigate the nitrifying activities of di erent soil types, soil samples collected from 8-, 50- and 90-year old tea orchards, the
adjacent wasteland, and 90-year old forest were measured for their nitrification potentials using the conventional soil incubation and the
liquid incubation method. Among di erent soil types, the nitrification potential of soil in tea orchards was higher than that of wasteland
and forest soils. The slurry shaken liquid incubation method was confirmed to be more accurate and have reliable results than the
soil incubation. Interestingly, experimental result revealed that the generally applied pH value of 7.2 for the liquid media was not the
optimal pH for these acid soils with a strong bu er capacity. This suggested that tea orchard soils may have nitrifiers requiring pHneutral
condition for the best activity. Our data also showed that treatment with the commonly used nitrogen fertilizer urea significantly
improved nitrification potential of the soils; such enhancement e ect was stronger on all of three tea orchard soils than on wasteland
and forest soils, and also stronger on the younger (8- and 50-year old) tea orchard soils than on the older one (90-year old). 相似文献
11.
In vivo activity of cholinesterase (ChE) in Daphnia magna was measured at di erent time points during 21-day exposure to triazophos
and chlorpyrifos ranging from 0.05 to 2.50 g/L and 0.01 to 2.00 g/L, respectively. For exposure to triazophos, ChE was induced up
to 176.5% at 1.5 g/L and day 10 when measured by acetylthiocholine (ATCh), whereas it was induced up to 174.2% at 0.5 g/L
and day 10 when measured by butyrylthiocholine (BTCh). For exposure to chlorpyrifos, ChE was induced up to 134.0% and 160.5%
when measured by ATCh and BTCh, respectively, with both maximal inductions detected at 0.1 g/L and day 8. Obvious induction
in terms of ChE activity was also detected in daphnia removed from exposures 24 hr after their birth and kept in a recovery culture
for 21 days. Results indicated that the enzyme displayed symptoms of hormesis, a characteristic featured by conversion from low-dose
stimulation to high-dose inhibition. In spite of that, no promotion in terms of reproduction rate and body size was detected at any tested
concentrations regardless of whether the daphnia were collected at end of the 21-day exposure or at end of a 21-day recovery culture.
This suggested that induction of ChE caused by anticholinesterases had nothing to do with the prosperity of the daphnia population. 相似文献
12.
We investigated the effects of environmental factors and properties of water-stable crystal fullerene (nC60) on the uptake of nC60 by Daphnia magna based on known accumulation in our laboratory. This study was performed for seven days using different environmental factors including temperature, pH, water hardness, concentration (density of particle), and particle size. Results demonstrated that body burden of C60 increased with time in all experiments. Body burden of C60 increased with increasing concentration and particle size, and uptake of particles >100 nm reached their maximums more quickly than those <100 nm. Under high hardness in aqueous systems with lower pH and high temperature, uptake was higher than those under opposite conditions. Uptake in all batch tests reached balance within five days. Both nC60 properties and environmental factors influenced uptake of nC60 by D. magna in an aqueous system. Additionally, environmental factors may have affected accumulation by changing nC60 properties, which are critical to understand the accumulation of fullerenes in aqueous systems. 相似文献
13.
Soluble protein and acid phosphatase exuded by ectomycorrhizal fungi and
seedlings in response to excessive Cu and Cd 总被引:1,自引:0,他引:1
Fungi and their symbionts can alleviate heavy metal stress by exuding soluble proteins and enzymes. This study examined the role
of soluble protein and acid phosphatase (APase) exuded by Xerocomus chrysenteron, an ectomycorrhizal fungus, and the seedlings
of its symbiont, Chinese pine (Pinus tabulaeformis), under conditions of excessive Cu and Cd. The growth type showed that this
poorly studied ectomycorrhizal fungus was capable of tolerating high concentrations of Cu, and may be useful in phytoremediation.
X. chrysenteron grew well at 80 mg/L Cu, and the EC50 for Cd was 17.82 mg/L. X. chrysenteron also showed enhanced exudation
of soluble protein in both isolated and inoculated cultivations under the influence of Cu and Cd. Soluble protein exudation, however,
di ered under Cu and Cd stress in isolates. In mediums containing Cu, soluble protein exudation increased with concentration, but in
mediums containing Cd the content of soluble protein increased to a comparable level at all concentrations. This study demonstrated
that soluble protein was related to heavy metal tolerance, although the di erent ions played di erent roles. While APase activity in
exudates of fungi and seedlings decreased under Cu and Cd stress in comparison to the control, the APase activity in seedlings was
maintained by inoculation. Thus, X. chrysenteron facilitated the ability of plant to maintain a normal nutrient uptake, and therefore to
protect it from heavy metal toxicity. 相似文献
14.
研究了除草剂精□唑禾草灵和染料中间体1-氨基-2,4-二溴蒽醌对大型□(Daphnia magna)的光致急性毒性作用机制. 精□唑禾草灵(EC50 95%置信区间为4.62~6.63 mg/L)光解生成光稳定性以及急性毒性更大的产物□唑酚(EC50 95%置信区间为1.49~1.64 mg/L),推测精□唑禾草灵通过光修饰作用机制对大型□发挥光致毒性作用. 1-氨基-2,4-二溴蒽醌通过光化学转化生成二聚体,光修饰作用降低了其母体化合物的光致毒性. 在1-氨基-2,4-二溴蒽醌和模拟日光单独存在的条件下,大型□体内的活性氧物种(ROS)没有明显变化;在1-氨基-2,4-二溴蒽醌和模拟日光共同存在的条件下,生物体内的ROS呈先增加后降低的趋势. 另外,添加抗氧化剂可以减弱1-氨基-2,4-二溴蒽醌对大型□的光致毒性. 结果表明,光敏化作用是1-氨基-2,4-二溴蒽醌对大型□产生光致毒性的主要作用机制. 含时-密度泛函理论(TD-DFT)的计算结果表明,1-氨基-2,4-二溴蒽醌在水溶液中能够通过能量传递和电子转移2种方式发生光敏化反应. 相似文献
15.
基于3S信息技术,通过建立水环境和部分重点污染源的在线监测系统,对水环境污染事故实施有效监控。采用航天卫星、低空遥感、地面监视监测相结合的技术,实现水污染事故的应急监视监测;构建基于3S技术的大辽河(营口段)水质自动在线实时监控与污染事故应急处理系统。 相似文献
16.
17.
Characterization of disinfection byproduct formation potential in 13 source
waters in China 总被引:3,自引:1,他引:2
Junzhi Zhang Jianwei Yu Wei An Juan Liu Yongjing Wang Youjun Chen Jia Tai Min Yang 《环境科学学报(英文版)》2011,23(2):183-188
The formation potential of four trihalomethanes (THMFP) and seven haloacetic acids (HAA7FP) in 13 source waters taken from
four major water basin areas in China was evaluated using the simulated distribution system (SDS) chlorination method. The specific
ultraviolet absorbance (SUVA254: the ratio of UV254 to dissolved organic carbon (DOC)), which ranged between 0.9 and 5.0 L/(mg m),
showed that the organic compounds in di erent source waters exhibited di erent reactivities with chlorine. The HAA7FP of source
waters ranged from 20 to 448 g/L and the THMFP ranged from 29 to 259 g/L. The HAA7FP concentrations were higher than the
THMFP concentrations in all but one of the samples. Therefore, the risks of haloacetic acids (HAAs) should be of concern in some
source waters. TCM (chloroform) and BDCM (bromodichloromethane) were the major THM constituents, while TCAA (trichloroacetic
acid) and DCAA (dichloroacetic acid) were the major HAA species. Br-THM (brominated THM species) were much higher than Br-
HAA (brominated HAA species), and the formation of Br-DBP (Br-THM and Br-HAA) should be of concern when the bromide
concentration is over 100 g/L. 相似文献
18.
The acute toxic effect of the pesticide cypermethrin to Daphnia magna HB was examined. D. magna HB was exposed to cypermethrin at concentrations of 0, 1, 3, 5, 7, and 9 mg/L for 24 h. Data showed that the 24 h-LG50 of cypermthrin on D. magna HB was 4.81 mg/L. In contrast, the 24 h-LC50 of K2Cr2O7 (the national standard toxicant) to Daphnia magna was 0.38 mg/L in the current study. Results indicated that the Daphnia magna was very sensitive to pesticides. In addition, the effects of the culture condition(such as hardness, temperature and DO etc. ) on Daphnia magna HB was also studied. 相似文献
19.
对燃煤机组脱硫信息的实时监测进行了研究,详细探讨了脱硫现场各种数据的采集方式、数据上送监测主站的方式,并结合实际项目开发了脱硫在线实时监测系统,系统运用测控技术、现代通讯、数据库等技术,通过对火电厂燃煤机组脱硫系统监测数据的采集、传输、处理、分析等,实现了对火电厂脱硫设施运行状况的在线监测。 相似文献
20.
Aerobic granules seeded with activated sludge flocs and pellets (obtained from activated sludge flocs) were cultivated in two
sequencing batch reactors and their characteristics were compared. Compared with granules seeded with activated sludge flocs,
those seeded with pellets had shorter start-up time, larger diameter, better chemical oxygen demand removal e ciency, and higher
hydrophobicity, suspended solid concentration, and Mg2+ content. The di erent inocula led the granule surface with di erent microbial
morphologies, but did not result in di erent distribution patterns of extracellular polymeric substances and cells. The anaerobic
bacterium Anoxybacillus sp. was detected in the granules seeded with pellets. These results highlighted the advantage of pellet over
activated sludge floc as the seed for aerobic granulation and wastewater treatment. 相似文献