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1.
大沽排污河内持久性有机氯农药的检测   总被引:2,自引:0,他引:2  
为调查大沽排污河表层底泥持久性有机氯农药(OCPs)污染状况以及河流流动后水体中溶解态、悬浮态OCPs的时空分布,研究了前处理方法对检测的影响,结果表明,超声波萃取和索氏萃取两种方法萃取底泥中的HCB、α-HCH、β-HCH、γ-HCH、δ-HCH、p,p′-DDE、p,p′-DDD、o,p′-DDT、p,p′-DDT的萃取效果相当.选定超声波萃取方法后,继而对比了不同萃取剂、不同超声波萃取时间及不同洗脱液用量对回收率的影响,结果表明,正己烷-二氯甲烷萃取效果最好,最佳萃取时间为90 min,洗脱剂用量为20 mL.并分析了大沽排污河上12个站位的表层底泥以及从开闸到闭闸期间万年桥站位河水中OCPs浓度变化,结果表明,表层底泥中的HCHs、DDTs分别为12.50~99.65 ng/g和1.56~46.26 ng/g,HCB浓度为17.50~189.13 ng/g;河流流动造成底泥悬浮是导致大沽排污河水体持久性OCPs浓度增高的因素,残留有OCPs的底泥是河流水体中持久性OCPs的主要来源之一.  相似文献   

2.
根据太湖梅梁湾有机氯农药(OCPs)污染情况,采用GC/ECD分析了梅梁湾沉积物,并对4种鱼及螺狮为代表的水生生物中有机氯农药的残留现状进行了风险评估.结果表明:沉积物(干重)中OCPs浓度范围在8.45~48.54 ng/g之间,生物样品(湿重)中的浓度范围在2.68~31.34 ng/g之间.人类食用OCPs污染的水产品的潜在健康风险评估显示,从非致癌风险角度滴滴涕(DDTs)、六氯苯(HCB)、氯丹(CHL)和七氯环氧的危险商RHQ均小于1;从致癌风险角度,除CHL外,DDTs、HCB、六六六(HCHs)、七氯环氧的危险比RHR均大于1,长期癌症风险不容忽视.根据淡水沉积物质量导则标准估算,太湖梅梁湾沉积物中OCPs残留对水生生态系统的影响较小.  相似文献   

3.
应用紫外–可见吸收光谱、三维荧光光谱对大沽排污河及大沽沙航道水体中有色溶解有机物(CDOM)的空间分布、组成、来源进行了分析.结果显示吸收系数a_(355)变化范围为1.73~23.62,m~(-1),CDOM丰度空间分布为大沽排污河下游最高,上游次之,大沽沙航道最低,表明大沽排污河下游水体有机污染负荷最大.CDOM荧光物质包括类蛋白质(T1、T2)和类腐殖质(A、C、M)两类组分,以类蛋白质组分的百分比最高,但相关性分析表明类腐殖质组分与CDOM的吸收相关性更好.A峰和C峰对应的最大发射波长及紫外–可见吸收光谱参数E253/203结果显示,大沽排污河下游水体CDOM芳香性较高,且芳香环取代基中含有较多的羟基、羰基、羧基、酯基.荧光指数HIXb显示大沽排污河下游水体CDOM来源以陆源输入(工业废水)为主,而排污河上游及航道水体CDOM主要由生物活动产生.  相似文献   

4.
单剂量口灌呋喃唑酮在草鱼体内消除及组织残留研究   总被引:2,自引:0,他引:2  
按60 mg/kg的剂量给草鱼灌服呋喃唑酮,用高效液相色谱法检测用药后不同时间的血浆、肝脏、肾脏及肌肉中药物浓度,然后用MCPKP药代动力学软件处理药时数据,对药物在草鱼体内消除及组织残留进行研究.结果表明单剂量口灌呋喃唑酮在草鱼血液中主要药动学参数为 AUC 3.756 9 μg*h/mL, Cmax 0.517 6 μg/mL, t1/2α1.524 9 h,t1/2β22.863 2 h,Tpeak 2.229 6 h,k10 1.015 8 h-1,k12 0.124 9 h-1,k210.0654 7 h-1;给药后72 h肌肉和血浆中检测不到药物,7 d后肝、肾中药物消除.  相似文献   

5.
γ辐照降解HCB的机理及动力学研究   总被引:1,自引:0,他引:1  
研究了1.2%的H2O2以及10-2mol/L的NaNO3溶液体系中,γ辐照技术降解六氯苯的降解效果的差异,分析研究了其反应动力学方程;反应前后溶液体系的Cl-浓度;另外对γ辐照降解HCB的降解产物进行了研究.研究结果表明,5%的异丙醇和10-2mol/L的NaNO3溶液体系对γ辐照降解HCB具有抑制作用,而在低剂量下1.2%的H2O2对γ辐照降解HCB具有促进作用,空白采用一级动力学方程拟合效果最佳,异丙醇溶液体系拟合效果最差;γ辐照降解HCB的降解产物主要为氯苯类化合物,且反应体系中Cl-浓度是随着辐照剂量的增加而增加的,γ辐照技术能够有效地对六氯苯进行脱氯.  相似文献   

6.
为有效控制六氯苯污染水体对生态环境的影响,分析零价铁修复HCB污染水体的可行性,探讨各影响因素的作用机制.研究结果表明:随着反应时间延长,HCB去除率增加;反应体系的最佳初始pH值范围为3~6,最佳点在4.5左右;增加零价铁的投加量有利于HCB去除率的提高,但是当投加量大于35 mg后,HCB去除率增势不十分显著;反应体系的温度在20~30℃之间时对HCB去除效果影响不大.反应动力学研究表明,HCB去除速率对于HCB的物质的量浓度为一级反应,其反应速率常数K为-0.013 5 min-1.该方法设备简单,易于下一步实现工业放大,是一种有较好开发前景的污染水体修复工艺.  相似文献   

7.
系统探讨了新乡市道路灰尘中有机氯农药(OCPs)的含量、分布,解析了道路灰尘中OCPs的来源,评价了新乡市道路灰尘中OCPs的生态风险.结果表明,新乡市道路灰尘中16种OCPs的总量范围为2.37724.74ng/g,平均含量为155.54ng/g.DDTs,HCB,HCHs是新乡市道路灰尘中检出的主要OCPs,检出率均为100%,含量分别为32.26ng/g(1.09724.74ng/g,平均含量为155.54ng/g.DDTs,HCB,HCHs是新乡市道路灰尘中检出的主要OCPs,检出率均为100%,含量分别为32.26ng/g(1.09165.31ng/g),114.96ng/g(0.58165.31ng/g),114.96ng/g(0.58693.28ng/g),4.51ng/g(0.36693.28ng/g),4.51ng/g(0.3614.10ng/g),占总OCPs的比例分别为39.07%,45.16%,10.98%.通过对HCHs,DDTs,氯丹组成特征的分析,表明新乡市道路灰尘中的OCPs主要来源于历史上OCPs的使用.根据沉积物风险评估值,新乡市道路灰尘中的OCPs存在较高的生态风险.  相似文献   

8.
本文研究应用通量箱 (FluxChamber)方法研究Hg在湖水表现挥发性汞的流通释放量 ,研究在贵州红枫湖进行 ,当水温在 2 0 - 2 4℃时 ,湖面汞的释放量在 89- 196ng·h- 1·m- 2 。平均 12 3ng·h- 1·m- 2 。汞的释放通量白天达到最大值 ,而夜间降到最小 ,湖泊表面挥发性汞的释放通量均具有显著的昼夜变化规律 ,湖面汞的流通量与太阳辐射相关 ,与底泥中汞含量也明显相关  相似文献   

9.
采用批处理等温吸附-解吸试验,研究了初始Cu2+浓度、壳聚糖用量、吸附时间、pH值和温度等单因子对壳聚糖吸附Cu2+的影响,在此基础上采用正交试验获得最优吸附条件为:壳聚糖用量0.025g/L,温度35℃,吸附时间60min,初始Cu2+浓度1 000mg/L,得出最大吸附量为256mg/g;因子影响排序由大到小为:壳聚糖用量,温度,初始Cu2+浓度,吸附时间.吸附铜后的壳聚糖,制作壳聚糖载铜灭藻剂(CCA),其Cu2+释放动力学特征可用Elovich方程、Langmuir方程和二级动力学方程加以描述.pH值和CCA的初始用量对Cu2+释放量有显著影响.  相似文献   

10.
利用GC-ECD分析了京杭运河(宿迁-扬州)8个断面上的底泥样品中的12种PCBs同系物的含量.实验结果表明,PCBs含量范围为3.00~81.81ng/g(干重),平均浓度为40.01ng/g(干重).京杭运河(宿迁-扬州)表层底泥中的PCBs的平均含量高于国内一些水体如,黄河、长江等的底泥中PCBs的平均含量.其中,宿迁段的含量明显高于下游的淮安段和扬州段.在利用潜在生态危害指数法和加拿大环境委员会制定的SQG评价方法对其进行了初步风险评价后,两种评价方法的结构都表明京杭运河(宿迁-扬州)表层底泥中的PCBs在宿迁段的皂河船闸、宿迁水上加油站、仰化镇和泗阳船闸四个监测断面显示出较强的潜在生态风险.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

18.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

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