应用模糊数学法综合评价营口石门水库水质级别

应用模糊数学法综合了5项主要污染指标评价了2008-2012年营口石门水库的水质级别,改变了仅凭单因子评价水质级别的方法,评价更合理,更符合实际情况。     

GIS支持下乡镇域土壤肥力评价与分析

在地理信息系统支持下,以鄂南典型红壤丘陵区为例,研究了乡镇域土壤肥力评价的方法和过程,分析了土壤肥力变化原因。结果表明,应用GIS对乡镇域土壤肥力进行评价能克服速度慢、数据更新不方便的缺点,避免乡镇农业决策者主观判断土壤肥力等级的弊病,为生产布局和用地决策提供准确的科学依据。试区土壤肥力与土壤养分、土地利用和区域经济有关,肥力等级有向中等级变化的趋势。     

三峡蓄水前后宜昌–城陵矶水情多尺度变化特征分析

采用Morlet小波分解重构和频谱分析等方法,对宜昌、枝城、沙市、监利和城陵矶1997~2014年水位和流量及三峡水库2003~2014年入库、出库流量和库水位数据进行了统计分析,探究了各水文站在三峡建坝前后水情的变化特征及原因。结果表明:各观测站的水位和流量沿程递减,水位的年内波动处同一水平,研究河段内上游河段流量年内和年际变化比下游河段剧烈;各水文站水位和流量变化的显著周期为6.05、11.78、21.2、30.29和53个月,各水文站水位1 a周期变化幅度均在2 m以上,其他周期上的变化幅度为0.08~0.82 m;三峡水库蓄水活动对下游水文站水位和流量等水情的影响有限,主要反映在对水情趋势项的影响上,三峡大坝蓄水后,各水文站水位和流量受到一定程度影响,呈波动性递减变化。     

咸阳地裂缝成因分析

咸阳地裂缝出现于1992年,以近东西向为主,局部发育为近南北向,水平拉张位移最明显,垂直位移次之,水平扭动位移最小,为拉张兼具左旋地裂缝。咸阳地裂缝的出现位置与区域构造线吻合,说明与区域地质构造环境密切相关,构造带的存在与活动为地裂缝的发育提供了空间条件和力学薄弱界面,而承压水头的急剧下降,最终使地裂缝的出现成为可能。     

浅谈县级环境监测质量管理工作现状及对策

当前环保系统垂直改革稳步推进,县级环境监测质量管理工作也迎来新的机遇与挑战。从县级环境监测站质量管理工作现状着手,分析新形势下存在质量管理体系有效性缺乏、现场监测过程质量管理薄弱、质量管理意识尚待提高等问题。提出,应从加强体系建设、提高现场监测水平、强化考核培训力度等方面改进县级环境监测质量管理工作水平。     

Variation of radiation level and radionuclide enrichment in high background area

Significantly high radiation level and radionuclide concentration along Quilon beach area of coastal Kerala have been reported by several investigators. Detailed gamma radiation level survey was carried out using a portable scintillometer. Detailed studies on radionuclides concentration in different environmental matrices of high background areas were undertaken in the coastal areas of Karunagapalli, Kayankulam, Chavara, Neendakara and Kollam to study the distribution and enrichment of the radionuclides in the region. The absorbed gamma dose rates in air in high background area are in the range 43-17,400 nGyh⁻¹. Gamma radiation level is found to be maximum at a distance of 20 m from the sea waterline in all beaches. The soil samples collected from different locations were analysed for primordial radionuclides by gamma spectrometry. The activity of primordial radionuclides was determined for the different size fractions of soil to study the enrichment pattern. The highest activity of ²³²Th and ²²⁶Ra was found to be enriched in 125-63 μ size fraction. The preferential accumulation of ⁴⁰K was found in <63 μ fraction. The minimum ²³²Th activity was 30.2 Bq kg⁻¹, found in 1000-500 μ particle size fraction at Kollam and maximum activity of 3250.4 Bq kg⁻¹ was observed in grains of size 125-63 μ at Neendakara. The lowest ²²⁶Ra activity observed was 33.9 Bq kg⁻¹ at Neendakara in grains of size 1000-500 μ and the highest activity observed was 482.6 Bq kg⁻¹ in grains of size 125-63 μ in Neendakara. The highest ⁴⁰K activity found was 1923 Bq kg⁻¹ in grains of size <63 μ for a sample collected from Neendakara. A good correlation was observed between computed dose and measured dose in air. The correlation between ²³²Th and ²²⁶Ra was also moderately high. The results of these investigations are presented and discussed in this paper.     

The influence of radiopharmaceutical isotope production on the global radioxenon background

Radioxenon isotopes play a major role in confirming whether or not an underground explosion was nuclear in nature. It is then of key importance to understand the sources of environmental radioxenon to be able to distinguish them from those of a nuclear explosion.     

区域性煤矿百万吨死亡率指标的宏观预测研究

为了对煤矿安全状况进行宏观预测,提出区域性煤矿安全状况评价指标体系并建立了以煤矿百万吨死亡率指标标征区域性煤矿安全状况的灰色预测模型。在对煤矿综合机械化采煤率、大型煤矿产量比例、原煤全员效率指标预测分析的基础上,利用多元回归法综合预测煤矿百万吨死亡率指标。实例计算证明:建立的预测模型具有输入数据少、建模简单、计算快捷等优点;客观地反映出区域性的煤矿安全状况;该模型可进行煤矿安全的短期预测,并为制定煤矿安全控制指标提供理论依据。     

Impact of Sea Level Rise on Groundwater Salinity in a Coastal Community of South Florida1

Guha, Hillol and Sorab Panday, 2012. Impact of Sea Level Rise on Groundwater Salinity in a Coastal Community of South Florida. Journal of the American Water Resources Association (JAWRA) 48(3): 510-529. DOI: 10.1111/j.1752-1688.2011.00630.x Abstract: Freshwater resources of coastal communities in the United States and world over are threatened by the rate of sea level rise. According to recent estimates by various governmental agencies and climate researchers, the global sea level rise is likely to be between 0.6 and 2.1 m by the year 2100. South Florida is a coastal community and much of its coastline is subject to sea level rise and potential impacts to wetlands and the water resources of the area. To understand what the impact of sea level rise would cause to the groundwater level and salinity intrusion, an integrated groundwater and surface water model was developed for North Miami-Dade and Broward Counties of South Florida. The model was calibrated against daily groundwater heads, base flows in canals, and chloride concentrations for a period of one year and six months. Three separate sensitivity analyses were conducted by increasing the sea level by 0.6, 0.9, and 1.22 m. Results of the simulations shows increase of groundwater heads in some areas from 4 to 15%; whereas the average relative chloride concentrations increased significantly by 100-600% in some wells. The increase in groundwater elevations and chloride concentrations varies from location of the wells and its proximity to the coast. The model results indicate that even a 0.6 m increase in sea level (which is the conservative estimate) is likely to impair the vital freshwater resources in many parts of South Florida.     

Effect of humic acids on physicochemical property and Cd(II) sorption of multiwalled carbon nanotubes

Zinc pyrithione is used as an antifouling agent. However, the environmental impacts of zinc pyrithione have recently been of concern. Zinc induces diverse actions during oxidative stress; therefore, we examined the effect of zinc pyrithione on rat thymocytes suffering from oxidative stress using appropriate fluorescent probes. The cytotoxicity of zinc pyrithione was not observed when the cells were incubated with 3 μM zinc pyrithione for 3 h. However, zinc pyrithione at nanomolar concentrations (10 nM or more) significantly increased the lethality of cells suffering from oxidative stress induced by 3 mM H₂O₂. The application of zinc pyrithione alone at nanomolar concentrations increased intracellular Zn²⁺ level and the cellular content of superoxide anions, and decreased the cellular content of nonprotein thiols. The simultaneous application of nanomolar zinc pyrithione and micromolar H₂O₂ synergistically increased the intracellular Zn²⁺ level. Therefore, zinc pyrithione at nanomolar concentrations may exert severe cytotoxic action on cells simultaneously exposed to chemicals that induce oxidative stress. If so, zinc pyrithione leaked from antifouling materials into surrounding environments would be a risk factor for aquatic ecosystems. Alternatively, zinc pyrithione under conditions of oxidative stress may become more potent antifouling ingredient.