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321.
322.
The speciation of titrated copper in a dissolved tannic acid (TA) solution with an initial concentration of 4 mmol organic carbon (OC)/l was investigated in a nine-step titration experiment (Cu/OC molar ratio = 0.0030–0.0567). We differentiated between soluble and insoluble Cu species by 0.45 μm filtration. Measurements with a copper ion selective electrode (ISE) and diffusive gradients in thin films (DGT) were conducted to quantify unbound Cu(II) cations (‘free’ Cu) and labile soluble Cu complexes. For the DGT measurements, we used an APA hydrogel and a Chelex 100 chelating resin (Na form). Insoluble organic Cu complexes (>0.45 μm) was the dominant Cu species for Cu/OC = 0.0030–0.0567 with a maximum fraction of 0.96 of total Cu. At Cu/OC > 0.0100, Cu-catalysed degradation of aggregate structures resulted in a strong increase of free Cu and (labile) soluble Cu complexes with a maximum fraction of 0.28 and 0.32 of total Cu, respectively. Labile (i.e. DGT-detectable) soluble Cu complexes had a relatively high averaged diffusion coefficient (D) in the APA hydrogel (3.50 × 10−6– 5.58 × 10−6 cm2 s−1). 相似文献
323.
324.
Bettinetti R Croce V Galassi S Volta P 《Environmental science and pollution research international》2006,13(1):59-66
- DOI: http://dx.doi.org/10.1065/espr2006.01.010
Background, Aims and Scope Although pp'DDT usage was strongly limited or banned in most parts of the world during the last three or four decades, the
parent compound, its homologues and their metabolites still occur at levels which might pose a risk for many ecosystem components.
A case of DDT pollution of industrial origin was discovered in 1996 in Lake Maggiore, the second largest (212 km2) and deepest
(370 m) lake in Italy, causing concern for wildlife and human health. The extensive monitoring of many biotic and abiotic
compartments which followed from 1998 in order to assess the pollution level and its trend in time, provided a great availability
of data referring to DDT contamination of the different fish species of the lake. In this study, the recent contamination
levels in selected fish species were compared to those measured in 1998 to evaluate the temporal pollution trend of the lake
and its natural recovery, given that no remediation measures were carried out on the contaminated soils and sediments in this
time span. Moreover, a modelling approach to test the equilibrium condition between water and pelagic fish species was used.
Analytical results of pp'DDT and pp'DDE concentrations in lake water were used as input data in the bioenergetic model by
Connolly & Pedersen (1988) to calculate concentrations in two fish species and to compare the predicted and the measured contamination.
Methods Sampling and analytical determination of DDT homologues in lake water: Five water sampling campaigns were carried out from
May 2002 to February 2004 in three sampling sites of Lake Maggiore. Suspended and dissolved pollutants were determined separately.
Quantitative DDT homologue analyses were performed by HRGC coupled with ECD detection by the external standard method. Single
water extracts were put together in correspondence with the stratification zones of the water column inferred on the basis
of the temperature profile to improve analytical sensitivity. Selection of fish data: Concentrations of DDT and DDE in fishes
were selected from recent literature (CIPAIS 2003, 2004). Bioaccumulation model: The bioenergetic model proposed by Connolly
& Pedersen (1988) was used to assess the bioaccumulation of pp'DDT and pp'DDE of Alosa fallax (landlocked shad) and Coregonus
spp. (whitefish), selected among the different species as representative of a secondary consumer level.
Results and Discussion The average concentrations of pp'DDT and pp'DDE in water to be used as input data in the bioenergetic model were obtained
considering all the concentrations measured at the three sampling stations in the epylimnion where the fish species considered
in this study spend most of their life. The resulting values were 0.05 and 0.16 ng/L for pp'DDT and pp'DDE, respectively.
Average measured pp'DDT and pp'DDE concentrations in landlocked shad were 0.81 +/- 0.39 and 1.69 +/- 0.71 mg/kg lipids, respectively,
and were 0.29 +/- 0.12 and 1.06 +/- 0.41 mg/kg lipids for the whitefish. Calculated and measured values turned out to be
in quite good agreement for pp'DDT, while measured pp'DDE concentrations were higher than expected on the basis of the bioenergetic
model in both species. Probably metabolic transformations of pp'DDT accumulated in fish tissues in the past are responsible
for the observed differences between calculated and expected pp'DDE concentrations in fish.
Conclusions Pelagic fishes of Lake Maggiore seem to maintain the DDT accumulated during their life time and the most efficient mechanism
responsible for the fish population recoveries is probably their generation changes; for this reason, equilibrium models cannot
be used until negligible pp'DDT concentrations are reached in fish tissues.
Recommendations and Outlook The limit proposed for pp'DDT in water by the EU Directive 2000/60, which will come in force in 2008, is 0.2 ng/L, four times
higher than the average concentration measured in Lake Maggiore waters. Nevertheless, concentrations measured in Lake Maggiore
fish were very close and sometimes exceeded the Maximum residue limits (MRLs) settled by the Italian legislation for foods
(0.1 mg/kg w.w. for fish containing 5–20% lipid). It seems, therefore, that the 'environmental quality standard' of 0.2 ng/L
cannot guarantee the suitability of fish for human consumption. 相似文献
325.
丁孝泉 《安全.健康和环境》2004,4(6):12-14
根据目前油库泵站内存在可燃气体经常泄漏的实际情况,提出并应用计算机信息处理系统解决可燃气体泄漏监控问题。 相似文献
326.
江苏沿江开发研究 总被引:10,自引:2,他引:8
随着中国加入WTO和经济全球化进程的加快,长江三角洲以其独特的滨江临海的区位和发达的制造业基础,正在成为新的投资热点地区。江苏省沿江地区是长江三角洲重要的组成部分,拥有800多km的长江岸线和8个经济发达、人才资源优势明显的经济中心城市。传统的制造业基础和相对低廉的加工成本、商务成本,使江苏沿江开发既有对外来资本的吸引力,又有自我发展的内生机制。重点研究了全球化背景下江苏沿江开发的战略问题,主要包括:①江苏沿江地区开发的环境和条件比较分析;②沿江产业带重组与实施跨江开发;③再造新战略据点;④打破行政区界限沿江联动实施区域一体化,等等。最后指出:加快江苏沿江开发,必须科学规划、统筹安排,做到空间合理、时间有序,同时考虑沿江的环境容量有限,应实施可持续发展和南北联动的开发战略,拓展沿江的开发空间,提升沿江的产业发展水平。 相似文献
327.
概略地分析了武钢安全生产目标责任状制度的内容、作用和目的 ,以及实施和管理该责任制的一些主要做法、措施。通过实施签订安全生产目标责任状制度 ,促使各级领导、各部门落实安全生产责任制 ,取得了成效 ,确保了安全生产 相似文献
328.
王志安 《安全.健康和环境》2004,4(1):13-15
介绍了在石油生产设备设施的建设安装和检修动火过程中 ,工程技术人员创造发明的防护盲板、防护接地、加装管道扫线接口和绝缘螺栓4种防护方法 ,简要叙述它们的结构、用途和适用范围 ,为油田施工单位进行动火作业提供技术参考。 相似文献
329.
邻苯二甲酸酯(Phthalate esters, PAEs)是环境介质中的一类典型的有机污染物。已有研究表明,PAEs具有明显的内分泌干扰毒性,并会对动物和人体的生殖发育与神经系统造成损伤。体外细胞评价模型因具有高通量、测试周期短、成本低和毒性效应易于探明等技术优点,被广泛应用到PAEs毒理学效应的研究中。本文从内分泌干扰毒性、胚胎发育毒性、神经毒性、免疫毒性、遗传毒性以及致癌作用等方面,对PAEs的一些体外细胞毒性评价模型进行了分类和总结,并对其相应的研究进展进行了综述。本文旨在为体外细胞毒性评价模型的有效利用提供借鉴,并对PAEs毒性作用机制的深入研究提供思路和依据。 相似文献
330.
为提高巷道超前支架迈步前移过程的稳定性和安全性,建立一种基于液压油液体积平均释放原则的迈步稳定控制方法。用软件仿真及样机实测的方法,检验所提出控制方法的控制效果。结果表明,与传统的直线、对数曲线、指数曲线的阀芯位移控制方法相比,应用所建立的方法,设备迈步过程支撑力波动最小,稳定过程耗时最短,为2.2 s,顶板变形量最小,最大值约为4.74 mm。而采用对数曲线控制方式效果最差,稳定过程耗时3.8 s,顶板变形量最大值达到9.48 mm。 相似文献