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311.
健康风险暴露评价研究进展   总被引:2,自引:0,他引:2  
综述了国内外健康风险暴露评价的最新研究进展,重点讨论了对人体进行直接监测的生物监测技术和对环境中污染因子进行间接监测并利用数学模型进行暴露剂量计算的间接方法。生物监测方法通过测定人体生理介质(如血液、尿液)中的污染物质及其代谢产物含量确定人体对环境污染物的暴露情况,监测结果反映了风险因子通过所有暴露途径进入人体的总暴露剂量。为了利用生物监测结果评价人体暴露安全性,近几年建立了生物监测等效值的概念,推导确定化学物质的生物监测等效值发展迅速。环境监测和数学模型间接方法通过对不同暴露媒介中风险因子的浓度监测和特定暴露途径的量化研究,同时利用精确的暴露计算模型(如空气分散模型、地下水扩散模型)计算人体对污染物的暴露剂量。生物监测和环境监测技术及数学模型的发展使健康风险评价和管理的暴露参数更加精确,降低了风险评价的不确定性。还介绍了利用数学模拟和剂量重建等方法插补历史空白暴露数据的方法。  相似文献   
312.
Dissolved iron (Fe) distribution and speciation was determined in water samples (0–200?m) collected in a coastal area near Terra Nova Bay during the austral summer of 2014. Nutrients, dissolved oxygen, chlorophyll-a, phytoplankton composition and prokaryotic biomass distribution were investigated in combination with measurements of the physical properties of the water columns and its dynamics. The dFe value was above the limiting growth concentration, ranging from 0.52 to 4.51?nM, and it showed a spatial variability with a horizontal length scale of about 10?km, according to the variability of the water column physical properties and to iron sources. The organic ligands (L) maintained the concentrations of dFe at levels much higher than the inorganic solubility of Fe, keeping it available for phytoplankton and the log K’FeL values found (from 22.1 to 23.6) highlighted the presence of complexes of differing stabilities.  相似文献   
313.
Mercury (Hg) is a ubiquitous and a major environmental metal pollutant in the aquatic ecosystem. The present study was performed to evaluate the effect of mercury graded doses exposure on oxidative stress, redox status, metallothionein levels and genotoxicity in the intestine of sea cucumber Holothuria forskali. Specimens were exposed for 96?h to three concentrations of Hg (40, 80 and 160?µg/L). Exposure of H. forskali to Hg promoted oxidative stress with an increase in malondialdehyde (MDA), protein carbonyl (PCO) and advanced oxidation protein products (AOPP) levels. An increase of glutathione (GSH), vitamin C (ViteC) and non-protein thiols (NPSH) contents was also observed. Additionally, antioxidant activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) increased especially with the highest doses of Hg indicating a great defense of the antioxidant system. Our investigation revealed an increase in total Metallothionein (MT) content which was more pronounced at the sharpest concentrations of Hg. A significant decline of AChE activity was also observed. In the intestine of Hg-treated H. forskali genotoxicity was confirmed by DNA degradation.  相似文献   
314.
Marine protected areas (MPAs) are a critical defense against biodiversity loss in the world's oceans, but to realize near-term conservation benefits, they must be established where major threats to biodiversity occur and can be mitigated. We quantified the degree to which MPA establishment has targeted stoppable threats (i.e., threats that can be abated through effectively managed MPAs alone) by combining spatially explicit marine biodiversity threat data in 2008 and 2013 and information on the location and potential of MPAs to halt threats. We calculated an impact metric to determine whether countries are protecting proportionally more high- or low-threat ecoregions and compared observed values with random protected-area allocation. We found that protection covered <2% of ecoregions in national waters with high levels of abatable threat in 2013, which is ∼59% less protection in high-threat areas than if MPAs had been placed randomly. Relatively low-threat ecoregions had 6.3 times more strict protection (International Union for Conservation of Nature categories I–II) than high-threat ecoregions. Thirty-one ecoregions had high levels of stoppable threat but very low protection, which presents opportunities for MPAs to yield more significant near-term conservation benefits. The extent of the global MPA estate has increased, but the establishment of MPAs where they can reduce threats that are driving biodiversity loss is now urgently needed.  相似文献   
315.
The International Union for Conservation of Nature (IUCN) Red List Index (RLI) is used to measure trends in extinction risk of species over time. The development of 2 red lists for Spanish vascular flora during the past decade allowed us to apply the IUCN RLI to vascular plants in an area belonging to a global biodiversity hotspot. We used the Spanish Red Lists from 2000 and 2010 to assess changes in level of threat at a national scale and at the subnational scales of Canary Islands, Balearic Islands, and peninsular Spain. We assigned retrospective IUCN categories of threat to 98 species included in the Spanish Red List of 2010 but absent in the Spanish Red List of 2000. In addition, we tested the effect of different random and taxonomic and spatial Spanish samples on the overall RLI value. From 2000 to 2010, the IUCN categories of 768 species changed (10% of Spanish flora), mainly due to improved knowledge (63%), modifications in IUCN criteria (14%), and changes in threat status (12%). All measured national and subnational RLI values decreased during this period, indicating a general decline in the conservation status of the Spanish vascular flora. The Canarian RLI value (0.84) was the lowest, although the fastest deterioration in conservation status occurred on peninsular Spain (from 0.93 in 2000 to 0.92 in 2010). The RLI values based on subsamples of the Spanish Red List were not representative of RLI values for the entire country, which would discourage the use of small areas or small taxonomic samples to assess general trends in the endangerment of national biotas. The role of the RLI in monitoring of changes in biodiversity at the global and regional scales needs further reassessment because additional areas and taxa are necessary to determine whether the index is sufficiently sensitive for use in assessing temporal changes in species’ risk of extinction.  相似文献   
316.
安全生产标准是规范企业安全生产工作的基础性规范,是安全生产法律体系的重要组成部分,也是安全生产监管监察执法的重要依据。为掌握安全生产标准现状,收集、梳理了已发布的安全生产标准603项和正在研制阶段的标准385项,对标准发布年份、在研标准计划年份、标准领域分布、标准级别和标准性质多个维度进行分析,总结标准工作存在的问题,提出安全生产标准制(修)订及发展建议,为安全生产标准工作的持续完善提供参考。  相似文献   
317.
海南鹦哥岭的外来植物与生态环境影响评价   总被引:5,自引:0,他引:5  
通过对鹦哥岭外来植物的调查,以及外来植物区系的种类组成、原产地、生长型、生境和危害程度等的分析,阐明鹦哥岭的外来植物现状及其对当地生态环境的影响。分析表明:共有53种外来植物,约占鹦哥岭种子植物总数的2.73%,主要来自新大陆热带地区(35种)。其中草本(36种)和灌木(13种)占优势,藤本(3种)和小乔木(2种)相对不明显。外来种对鹦哥岭自然生态系统的影响较小,对人为干扰严重的生态系统影响较大。最后对外来植物进行评估,并提出防控措施。  相似文献   
318.
本文阐述了加强野生动物保护管理的重要性,并对衡阳市野生动物管理的现状及存在的问题进行了认真的分析,提出相应的对策与措施,藉以推动衡阳市野生动物保护事业的发展.  相似文献   
319.
循环载体生物过滤工艺融三相流化、悬浮曝气、移动接触等几种不同工艺于一体,具有独特的工作原理和工艺特征。动态实验结果表明,循环载体生物过滤工艺容积负荷高,耐冲击负荷能力强,处理效果好,是一种比较理想的生物处理工艺。  相似文献   
320.
西藏自治区自然保护区事业的现状和展望   总被引:1,自引:0,他引:1  
介绍了西藏自治区保护区事业的发展概况和现状,指出了目前保护区建设与管理中存在的主要问题,对今后保护区的规划与发展提出了意见和建议。  相似文献   
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