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221.
Possible xenoestrogenic effects were investigated, for the first time, in two bivalve species from the Lagoon of Venice (Italy): the clam Tapes philippinarum and the cockle Cerastoderma glaucum. Bivalves were collected far from their reproductive phase at the very early stage of gametogenesis (January), and in the pre-spawning period (June) in six sites. Vitellogenin (Vg)-like proteins (a biomarker of exposure to estrogenic compounds) were measured by the alkali-labile phosphate method (ALP), in both haemolymph and digestive gland from males and females (when it was possible to distinguish sex by microscopic observation of gonadal tissue). Haemolymph calcium concentrations (a parameter considered closely related to the presence of Vg-like proteins) and the bivalve condition index (CI) were also measured. In both seasons, bivalves collected at Campalto (near a sewage treatment plant) and Marghera (a highly contaminated area) had higher Vg-like protein levels, particularly in haemolymph, than animals from the other sampling sites. Interestingly, CI had high values in these polluted sites. In June only, Vg-like proteins and Ca2+ levels in haemolymph exhibited similar trends in both bivalve species at most sampling sites. The responsiveness of bivalves to environmental xenoestrogens was higher in June, allowing better discrimination among sites. The present study demonstrates that animals from highly polluted areas have increased Vg-like protein levels. As endocrine disruption due to exposure to estrogenic compounds may cause fertility reduction, alterations in the sex ratio, and a decrease in reproductive rate, a condition of potential risk for bivalve populations in estuarine areas is highlighted. 相似文献
222.
In compilation of 1: 50 000 hydrogeological map, Some principles which are suitable for hydrogeological characteristics in China have been defined. Groundwater development and protection have been regarded as equally important. Some key problems such as classification of water-bearing formation, water yield property, color system and color scale of water yield property of water-bearing formation, expression of groundwater system, expression of hydrogeological parameters have been solved. This standardizing work can lay solid foundation for integration of 1: 50 000 synthetic hydrogeological map achievement and data, so as to broaden the service areas of hydrogeological survey. 相似文献
223.
ICP-AES测定海洋生物体中13种元素的微波消解条件优化 总被引:3,自引:1,他引:2
报道了微波密闭消解正交试验条件优化电感耦合等离子体发射光谱法(ICP-AES),同时测定8种海洋生物体中硒、铁、锰、锌、钙、镁、锶、砷、镉、铬、铜、铅和镍等13种元素含量的实验结果。优化后的样品消解条件为加入的HNO3V:H O2 2V=6.0 mL:1.0 mL,第二步程序升温温度为170℃,消解时间20 min;测定标准曲线相关系数大于0.999,相对标准偏差为0.30%~2.55%,加标回收率为92.0%~104.8%,方法检出限为0.0010~0.0468μg/g。结果表明,优化后方法测定操作简便、具有高的灵敏度、准确度和精密度,且能多元素同时测定,适合于海洋生物样品中这些元素含量的准确测定,并可为评估海产品食用安全提供科学依据。 相似文献
224.
DOM是国情普查内容的重要组成部分,是地理国情普查中调查的重要数据源。本文通过卫星影象纠正,控制点选取,全色波段影像正射纠正,多光谱影像与全色波段影像配准,多光谱影像与全色波段影像融合等技术手段,确保了DOM的精度,为国情普查的后续工作提供精确的基础资料。 相似文献
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Water resources play an important role in supporting the economic and social development of China. The impact of climate change on water resources has become a bottleneck in this process, especially for major projects, with surface water and groundwater systems experiencing considerable impacts. The annual natural recharge of fresh groundwater is 8 840×10~8 m~3, which accounts for approximately 31% of the water resources. Groundwater is the most significant water source for many cities and energy bases, and it is also the main source acting as a buffer against extreme climate events caused by climate change. However, most of the groundwater in China buried deeply and unevenly, which increases the difficulty of investigating and exploiting this resource.This paper illustrates the general conditions of China water resources and hydrogeological hazards, such as karst sinkholes, surface subsidence, and soil salinization, caused by climate change, El Nino, La Nina, other climate events and human activities and presents the regulatory measures enacted to mitigate these issues in China.The China Geological Survey(CGS) has organized professional teams to investigate and evaluate groundwater resources and the environment since 1999. Based on these investigations, the total quantity, expected exploitable quantity and current exploited quantity of groundwater in whole China have been evaluated. In addition, an evaluation of the groundwater pollution caused by climate change throughout China and key areas has been conducted. At present, the CGS is conducting national groundwater monitoring projects and establishing regional engineering and technical measures for water resource exploitation and utilization. 相似文献
227.
地理国情普查和监测为基础地理信息的及时更新提供了持续、可靠的参考数据。本文针对地理国情普查监测成果应用和基础地理信息数据更新的实际需求,从数据转换、要素匹配、变化识别和增量更新等方面设计了基于地理国情数据的基础地理信息数据更新技术框架。针对要素相似性匹配和变化识别难题,从距离、面积和形状相似性等方面设计了面向几何要素匹配与变化识别的系列指标、算法和知识规则。研究成果在山东莱芜某地进行了应用。实验结果表明,本文设计的方法对变化要素的识别精度达96.6%,极大地提高了基础地理信息更新的工作效率。研究成果不仅为基础地理信息增量式更新提供了技术支撑,同时也将提高地理国情数据成果的应用价值。 相似文献
228.
乐红铅锌矿矿床地质与成因分析 总被引:3,自引:0,他引:3
乐红铅锌矿,是滇东北地区既与上震旦统灯影组层位紧密相关、又受发育于灯影组中的主干断裂或派生的次一级构造严格控制的代表性矿床。但多年来对其成因众说纷云。本文从矿床地质特征入手,详细分析矿源层与构造对成矿的作用,及其内在影响因素,结合同位素成果,认为应属沉积改造类型。 相似文献
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230.
广饶县咸水入侵灾害的发生在于自然环境的脆弱性和社会经济环境的严峻性。本文分析了引起海(咸)水入侵的基本矛盾, 制定了防治咸水入侵灾害的对策和措施──水文地质环境调整方案。 相似文献