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441.
Cindoruk SS 《Chemosphere》2011,82(1):78-87
Air concentrations of organochlorine pesticides (OCPs) were measured at four different sites in Bursa, Turkey to determine current levels. For this purpose, about 35 samples were collected from June 2008 to June 2009 using a high volume air sampler (HVAS) equipped with particle and gas-phase units. Ten OCP compounds (alpha-, beta-, gamma-, delta-hexachlorocyclohexane, Heptachlor epoxide, Endrin, Endosulfan beta, Endrin aldehyde, p,p′-DDT and Methoxychlor) were reported within the scope of this study. The average concentrations of total (particle + gas) ∑OCPs were 550.9 ± 277.6 pg m−3 (coastal), 1030.7 ± 453.5 pg m−3 (urban/traffic), 519.7 ± 277.5 pg m−3 (semi-rural) and 722.8 ± 351.8 pg m−3 (urban/residential). The individual OCP concentrations were in line with reported concentrations. The maximum particle and gas-phase concentrations were determined for Endosulfan beta and beta-HCH for all sites, respectively. Available gas/particle partitioning models were applied in order to investigate the compatibility of the experimental data and the significant relationships were observed. 相似文献
442.
Occurrence, distribution and seasonal variation of antibiotics in the Huangpu River, Shanghai, China 总被引:13,自引:0,他引:13
Water samples were collected from 19 sampling sites along the Huangpu River in June and December 2009. The occurrence, distribution and seasonal variation of 22 antibiotics, including four tetracyclines, three chloramphenicols, two macrolides, six fluoroquinolones, six sulfonamides and trimethoprim were investigated. It was found that all 19 sampling sites were contaminated by antibiotics. Four antibiotics (sulfamerazine, norfloxacin, fleroxacin and sarafloxacin) were not detected. The detection frequencies of the other 18 antibiotics were in the range of 5.3-100%. The median concentrations of the detected antibiotics ranged from quantification limits to 36.71 ng L−1 (tetracycline) in June and to 313.44 ng L−1 (sulfamethazine) in December. The number of detected antibiotics and the overall antibiotic concentrations were higher in December than in June due to the different river flow conditions. Different dominant antibiotics were observed for each group of antibiotics between June and December. Higher total concentrations of veterinary antibiotics such as tetracyclines were observed in suburban sampling sites than in unban sites, indicating the role of livestock and agricultural activities as an important source of antibiotic contamination. 相似文献
443.
Testing the limits of social resilience in ant colonies 总被引:4,自引:0,他引:4
Sarah J. Backen A. B. Sendova-Franks Nigel R. Franks 《Behavioral ecology and sociobiology》2000,48(2):125-131
Social resilience is the ability of Leptothorax ant colonies to re-assemble after dissociation, as caused, for example, by an emigration to a new nest site. Through social
resilience individual workers re-adopt their spatial positions relative to one another and resume their tasks without any
time being wasted in worker respecialisation. Social resilience can explain how an efficient division of labour can be maintained
throughout the trials and tribulations of colony ontogeny including the, often substantial, period after the queen dies when
the ability to conserve worker social relationships may be essential for efficiency to be maintained. The mechanism underlying
social resilience is, therefore, expected to be robust even in the absence of many of the colony’s components, such as the
queen, the brood and even a large proportion of the workers. Such losses are likely, given the ecology of this genus. Using
sociotomy experiments, we found that social resilience can occur in the absence of the queen. Furthermore, the spatial component
of social resilience can occur even when the queen, the brood, as well as a large proportion of the workers, are all absent
simultaneously and hence many of the tasks are missing. We conclude, therefore, that social resilience is indeed robust. This
does not, however, preclude worker flexibility in response to changes in task supply and demand. We propose a possible sorting
mechanism based on worker mobility levels which might explain the robustness underlying this phenomenon.
Received: 25 October 1999 / Accepted: 1 April 2000 相似文献
444.
南通地区地下水中砷的形态分布特征研究 总被引:1,自引:0,他引:1
2012年开展南通市1∶50000水文地质调查,对监测网内地下水进行采样分析,建立了基于液相色谱-电感耦合等离子体质谱联用测定地下水中砷形态的方法,该方法检出限为0.1μg/L。样品分析表明,南通地区地下水中砷的形态以三价无机砷为主,有机砷以砷胆碱(AsB)和乙基砷(DMA)为主,样品中未检出五价无机砷。通过砷形态研究表明,南通近海地区地下水中砷的质量浓度较低(<0.5μg/L),主要以 As(Ⅲ)为主,不存在其他砷的形态;近长江地区地下水中砷的质量浓度较高(>1.0μg/L),砷形态以 As(Ⅲ)和 DMA为主。 相似文献
445.
446.
福建泉州市东、西湖水体中氮的空间分布研究 总被引:1,自引:0,他引:1
初步探讨了东湖和西湖水体中氯的空间分布特征以及3种不同形态的氮与溶解氧的相关性.结果表明,(1)泉州东湖、西湖水体中总氮的平均含量分别为3.396、3.929mg/L,氨氮的平均含量分别为1.927、2.182mg/L,硝酸盐氮的平均含量分别为1.061、1.236mg/L,亚硝酸盐氮的平均含量分别为0.084、0.059 mg/L,东湖和西湖水体的主要氮素形式均是氨氮.(2)东湖出水口和位于动物园附近的采样点总氮、氨氮和亚硝酸盐氮浓度较其它采样点高,入水口、湖区北部及湖心区采样点的氨氤和硝酸盐氮的分布趋势基本一致.西湖东南部采样点总氮、氨氯、硝酸盐氯和亚硝酸盐氮的含量都较其它采样点高.(3)东湖水体的DO浓度与氨氛、硝酸盐氮和亚硝酸盐氯的含量都不具有相关性,而西湖水体的DO浓度与这3种形态氮显著相关. 相似文献
447.
Zhao Y Xu X Sun W Huang B Darilek JL Shi X 《Environmental monitoring and assessment》2008,138(1-3):343-355
Accurate characterization of heavy-metal contaminated areas and quantification of the uncertainties inherent in spatial prediction
are crucial for risk assessment, soil remediation, and effective management recommendations. Topsoil samples (0–15 cm) (n = 547) were collected from the Zhangjiagang suburbs of China. The sequential indicator co-simulation (SIcS) method was applied
for incorporating the soft data derived from soil organic matter (SOM) to simulate Hg concentrations, map Hg contaminated
areas, and evaluate the associated uncertainties. High variability of Hg concentrations was observed in the study area. Total
Hg concentrations varied from 0.004 to 1.510 mg kg−1 and the coefficient of variation (CV) accounts for 70%. Distribution patterns of Hg were identified as higher Hg concentrations
occurred mainly at the southern part of the study area and relatively lower concentrations were found in north. The Hg contaminated
areas, identified using the Chinese Environmental Quality Standard for Soils critical values through SIcS, were limited and
distributed in the south where the SOM concentration is high, soil pH is low, and paddy soils are the dominant soil types.
The spatial correlations between Hg and SOM can be preserved by co-simulation and the realizations generated by SIcS represent
the possible spatial patterns of Hg concentrations without a smoothing effect. Once the Hg concentration critical limit is
given, SIcS can be used to map Hg contaminated areas and quantitatively assess the uncertainties inherent in the spatial prediction
by setting a given critical probability and calculating the joint probability of the obtained areas. 相似文献
448.
Bayramin I Basaran M Erpul G Canga MR 《Environmental monitoring and assessment》2008,140(1-3):249-265
There has been increasing concern in highlands of semiarid Turkey that conversion of these systems results in excessive soil
erosion, ecosystem degradation, and loss of sustainable resources. An increasing rate of land use/cover changes especially
in semiarid mountainous areas has resulted in important effects on physical and ecological processes, causing many regions
to undergo accelerated environmental degradation in terms of soil erosion, mass movement and reservoir sedimentation. This
paper, therefore, explores the impact of land use changes on land degradation in a linkage to the soil erodibility, RUSLE-K,
in Cankiri–Indagi Mountain Pass, Turkey. The characterization of soil erodibility in this ecosystem is important from the
standpoint of conserving fragile ecosystems and planning management practices. Five adjacent land uses (cropland, grassland,
woodland, plantation, and recreational land) were selected for this research. Analysis of variance showed that soil properties
and RUSLE-K statistically changed with land use changes and soils of the recreational land and cropland were more sensitive
to water erosion than those of the woodland, grassland, and plantation. This was mainly due to the significant decreases in
soil organic matter (SOM) and hydraulic conductivity (HC) in those lands. Additionally, soil samples randomly collected from
the depths of 0–10 cm (D
1) and 10–20 cm (D
2) with irregular intervals in an area of 1,200 by 4,200 m sufficiently characterized not only the spatial distribution of
soil organic matter (SOM), hydraulic conductivity (HC), clay (C), silt (Si), sand (S) and silt plus very fine sand (Si + VFS)
but also the spatial distribution of RUSLE-K as an algebraically estimate of these parameters together with field assessment
of soil structure to assess the dynamic relationships between soil properties and land use types. In this study, in order
to perform the spatial analyses, the mean sampling intervals were 43, 50, 64, 78, 85 m for woodland, plantation, grassland,
recreation, and cropland with the sample numbers of 56, 79, 72, 13, and 69, respectively, resulting in an average interval
of 64 m for whole study area. Although nugget effect and nugget effect–sill ratio gave an idea about the sampling design adequacy,
the better results are undoubtedly likely by both equi-probable spatial sampling and random sampling representative of all
land uses. 相似文献
449.
选取2015年珠海市国控监测站ρ(PM_(2.5))数据,分析PM_(2.5)中有机碳(OC)、元素碳(EC)、水溶性离子组分等化学组成,ρ(PM_(2.5))时空分布特征,以及与气象因素的相互关系。结果表明,2015年珠海市PM_(2.5)年均值为31.0μg/m3,表现出显著的时间分布规律,月均值呈现"V"型趋势,PM_(2.5)中主要化学组分是有机物(OM),占总质量的34.0%,其次是硫酸根(SO2-4),占总质量的26.9%,具有明显的季节分布特征,呈现冬高夏低分布;ρ(PM_(2.5))日变化呈现双峰型分布,其值工作日显著高于非工作日;ρ(PM_(2.5))与平均温度、相对湿度、风速呈现负相关关系,与气压呈现显著正相关关系;珠海市ρ(PM_(2.5))空间分布总体呈现"东高西低,北重南轻"变化趋势,有机物、SO2-4和NH+4空间分布呈现东部高于西部趋势,颗粒物浓度受地形、气候因素和海域环境等影响呈现多样化分布趋势。 相似文献
450.
We tested the precision and accuracy of the Trimble GeoXT™ global positioning system (GPS) handheld receiver on point and
area features and compared estimates of stream habitat dimensions (e.g., lengths and areas of riffles and pools) that were
made in three different Oklahoma streams using the GPS receiver and a tape measure. The precision of differentially corrected
GPS (DGPS) points was not affected by the number of GPS position fixes (i.e., geographic location estimates) averaged per
DGPS point. Horizontal error of points ranged from 0.03 to 2.77 m and did not differ with the number of position fixes per
point. The error of area measurements ranged from 0.1% to 110.1% but decreased as the area increased. Again, error was independent
of the number of position fixes averaged per polygon corner. The estimates of habitat lengths, widths, and areas did not differ
when measured using two methods of data collection (GPS and a tape measure), nor did the differences among methods change
at three stream sites with contrasting morphologies. Measuring features with a GPS receiver was up to 3.3 times faster on
average than using a tape measure, although signal interference from high streambanks or overhanging vegetation occasionally
limited satellite signal availability and prolonged measurements with a GPS receiver. There were also no differences in precision
of habitat dimensions when mapped using a continuous versus a position fix average GPS data collection method. Despite there
being some disadvantages to using the GPS in stream habitat studies, measuring stream habitats with a GPS resulted in spatially
referenced data that allowed the assessment of relative habitat position and changes in habitats over time, and was often
faster than using a tape measure. For most spatial scales of interest, the precision and accuracy of DGPS data are adequate
and have logistical advantages when compared to traditional methods of measurement. 相似文献