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991.
A hydroponic experiment was carried out to study the effect of cadmium (Cd) on growth, Cd accumulation, lipid peroxidation, reactive oxygen species (ROS) content and antioxidative enzymes in leaves and roots of Arabis paniculata F., a new Cd hyperaccumuator found in China. The results showed that 22-89 microM Cd in solution enhanced the growth of A. paniculata after three weeks, with 21-27% biomass increase compared to the control. Cd concentrations in shoots and roots increased with increasing Cd supply levels, and reached a maximum of 1662 and 8670 mg kg(-1) Cd dry weight at 178 microM Cd treatment, respectively. In roots, 22-89 microM Cd reduced the content of malondialdehyde (MDA), superoxide (O(2)(-1)) and H(2)O(2) as well as the activities of superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) and glutathione reductase (GR). In leaves, the contents of MDA, O(2)(-1) and H(2)O(2) remained unaffected by 22-89 microM Cd, while 178 microM Cd treatment significantly increased the MDA content, 69.5% higher than that of the control; generally, the activities of SOD, catalase (CAT), GPX and APX showed an increasing pattern with increasing Cd supply levels. Our present work concluded that A. paniculata has a great capability of Cd tolerance and accumulation. Moderate Cd treatment (22-89 microM Cd) alleviated the oxidative stress in roots, while higher level of Cd addition (178 microM) could cause an increasing generation of ROS, which was effectively scavenged by the antioxidative system. 相似文献
992.
993.
994.
典型河谷城市儿童土壤与灰尘铅暴露风险 总被引:1,自引:0,他引:1
为定量评价河谷型城市土壤与灰尘铅对城市儿童健康的影响与风险,结合野外调查的基础上,以陕西渭河谷地典型工业城市宝鸡、西安、渭南和铜川为研究区域,以定量分析河谷型城市儿童环境铅暴露为核心,收集4个城市土壤与灰尘分析样品总计243个。利用X射线荧光光谱法测定了4个城市土壤与灰尘铅的含量;采用BCR连续形态分级法探究了城市土壤与灰尘重金属铅地球化学形态分布与迁移特征;根据US EPA污染物暴露与健康风险评价模型对城市儿童铅暴露进行了评价。研究结果表明渭河谷地典型城市宝鸡、铜川、西安和渭南城市土壤与灰尘铅浓度(X±SD)分别为(409.2±52.54)和(624.70±66.15)mg·kg-1、(357.47±41.37)和(592.60±36.78)mg·kg-1、(61.4±13.31)和(78.42±14.89)mg·kg-1、(46.71±12.11)和(64.7±13.76)mg·kg-1,均高出陕西省土壤铅背景值;污染水平依次为宝鸡铜川西安渭南。4个河谷型城市土壤与灰尘重金属铅发生整体迁移的趋势为:宝鸡城市灰尘(90.71%)西安城市灰尘(84.74%)≥宝鸡城市土壤(83.12%)渭南城市灰尘(74.89%)≥西安城市土壤(74.50%)铜川城市灰尘(72.49%)铜川城市土壤(57.50%)渭南城市土壤(53.79%)。可见,铅在均在城市灰尘中的迁移趋势远大于相应的城市土壤。4个城市土壤与灰尘均表现出较大的儿童暴露致癌风险,宝鸡和铜川城市儿童土壤与灰尘铅暴露也分别存在非致癌风险,风险程度依次为宝鸡铜川西安渭南。儿童铅暴露致癌与非致癌风险程度与其城市土壤和灰尘中铅可氧化态分布呈相似的规律,表明碱性的城市土壤与城市灰尘(p H7)中可氧化态铅可能是导致河谷型城市儿童铅暴露风险和儿童血铅污染的主要形态和因素。由此,城市燃煤排放与含铅制品的加工等活动可能是渭河谷地河谷型城市儿童血铅与铅暴露最主要的贡献源,必须采取长期有效的监测与控制措施。 相似文献
995.
长三角地区农田化肥投入快速增长的经济学诱因分析 总被引:1,自引:0,他引:1
李洁 《生态与农村环境学报》2008,24(2):52-56
农田化肥大量投入是引起农业面源污染的重要原因.根据长三角地区1980-2005年种植业生产以及农产品市场的统计数据,从投入要素机会成本变化和农产品价格变化角度,探讨长三角地区农业生产中化肥投入快速增长的经济学诱因.研究结果表明,长三角地区土地密集型作物上化肥投入快速增长是由于土地机会成本增长远远高于化肥价格增长而产生的化肥对土地的替代;相对劳动密集型作物上化肥投入快速增长是由于劳动机会成本高速增长引发的化肥对劳动的替代,并且相对劳动密集型农产品市场价格波动对化肥投入量的影响也较为显著. 相似文献
996.
Epidemiological survey of 573 families, clinical examination of 2593 persons, and X-ray examination of 1136 persons (in 16 typical endemic villages) were conducted, based on the classification of endemiology for KBD disease areas, i.e, mountain type, loess plateau type, plateau type, and flatlands type. It was revealed that the KBD disease areas exhibited the regular pattern of corming-into-being, development and passing-away and the characteristics of growth and decline. Further, it was found clinically that the disease areas may be divided into 4 types, i.e., recent onset, developing, stable, and historical. This division is simple and easy, practical, scientific, and reliable and can be applied by medical personnel at different levels. 相似文献
997.
水厂排泥水的处理技术:分离水回用 泥饼综合利用及铝盐回收 总被引:1,自引:0,他引:1
介绍了水厂排泥水处理后,分离水的水质和回用、泥饼制砖和污泥用作水泥掺合料的方法和试验结果,以及铝盐回收的工艺。 相似文献
998.
采用柔性浮盖技术,以HDPE土工膜为浮盖材料,并以浙江台州黄岩废弃物生态处理场渗滤液调节池浮盖除臭系统为例,对建立垃圾填埋场调节池柔性浮盖膜除臭系统的设计与施工进行了阐述。 相似文献
999.
1000.
In large-scale and complex industrial systems, unplanned outages and hazardous accidents cause huge economic losses, environmental contamination, and human injuries, due to component degradation, exogenous changes, and operational mistakes. In order to ensure safety and increase operational performance and reliability of complex system, this study proposes an integrated method for safety pre-warning to analyze the current safety state of each component and the whole system indicating hidden hazards and potential consequence, and furthermore predict future degradation trends in the long term.The work presented here describes the rationale and implementation of the integrated method incorporating HAZOP study, degradation process modeling, dynamic Bayesian network construction, condition monitoring, safety assessment and prognosis steps, taking advantage of the priori knowledge of the interactions and dependencies among components and the environment, the relationships between hazard causes and effects, and the use of historical failure data and online real-time data from condition monitoring.The application of the integrated safety pre-warning approach described here to the specific example of the gas turbine compressor system demonstrates how each phase of the presented method contributes to completion of the safety pre-warning system development in a systematic way. 相似文献