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431.
建立适合我国国情的饮用水水质指数   总被引:6,自引:0,他引:6  
目前一般利用各指标合格率评价饮用水水质,由于指标繁杂,不利于消费者了解水质整体概况,也不利于对外发布公报。本文建议采用水质指数法来对饮用水水质进行综合评价。本文介绍了目前采用的水质指数的不同评价方法,综述了不同的水质指数的原理和计算方法,根据我国国情,对我国城市供水的饮用水水质指数进行了修正,首次在水质指数中增加了超标项目“惩罚项”。修正后的饮用水水质指数具有很强的科学性和可操作性,可以从整体上对饮用水水质进行综合评价。  相似文献   
432.
Agricultural practices can lead to copper accumulation in soils and at high concentration it can become toxic for plants. One common toxic effect of copper on plants is a decrease of crop yield. Here, we studied 1) the crop yield of maize grown on plots of a soil intentionally enriched with copper sulphate and 2) the possible relationship between the copper concentration in chemical soil fractions and the maize crop yield. Anthropogenic copper is mainly bound to manganese oxides, to iron oxides and to the organic matter. Maize (Zea maize L.) was grown on outdoor experimental plots. The crop yield was evaluated for three development stages: the 6–10 leaf stage, the female flowering stage and the maturity stage, 2, 4 and 6 years after the soil copper enrichment. Strong crop yield reductions, proving a toxic effect of copper on maize growth were noted 2 years after the copper input at the maturity stage and 4 years after the copper input at the 6–10 leaf stage. Variations in maize crop yield are described with linear multiple regression equations including the variable copper content in soil, and other variables when needed such as soil pH, soil organic carbon level and the climatic variables, the precipitation rate and the ambient temperature. The crop yield study at the 6–10 leaf stage and at the female flowering stage does not provide significant regression equations, while the crop yield study at the maturity stage does. Request variables for the models are the total copper content or the copper bound to the organic matter and the meteorological data. Electronic Publication  相似文献   
433.
把一个新鸡贫血病毒(CAV)的vp1基因通过PCR扩增,然后克隆到质粒载体pUC18上.vp1基因包含1347个碱基对,并且推定的VP1蛋白氨基酸序列含有449个氨基酸.通过DNA BLAST软件把该基因的序列数据与在GenBank中发表的其他vp1基因比较显示,克隆的vp1基因与已发表的其他vp1基因之间存在许多核甘酸差异.核甘酸的变异导致其编码蛋白质的某些氨基酸发生改变.氨基酸的改变主要集中在VP1蛋白的29、75、125、141、144、251、254、447位.在这些变异中,许多氨基酸的电荷和/或疏水性发生了改变,例如:Gly→Glu、Val→Glu、Ala→Thr、Leu→Gln、Cys→Trp、Leu→Arg、Arg→Ala、Gly→Ser、Ser→Ala、Glu→Gly、Gly→Thr等.通过CLUSTAL X软件比较了6个不同的vp1基因.该vp1基因已被GenBank登录(登录编号:AF448446).VP1蛋白是CAV的唯一衣壳蛋白,因此VP1的氨基酸变异可能影响该蛋白质的抗原特征.对该vp1基因进一步进行免疫学研究具有重要意义,并且有可能应用该基因构建CAV基因工程疫苗.图1表3参20  相似文献   
434.
Elie Gaget  Diego Pavón-Jordán  Alison Johnston  Aleksi Lehikoinen  Wesley M. Hochachka  Brett K. Sandercock  Alaaeldin Soultan  Hichem Azafzaf  Nadjiba Bendjedda  Taulant Bino  Luka Božič  Preben Clausen  Mohamed Dakki  Koen Devos  Cristi Domsa  Vitor Encarnação  Kiraz Erciyas-Yavuz  Sándor Faragó  Teresa Frost  Clemence Gaudard  Lívia Gosztonyi  Fredrik Haas  Menno Hornman  Tom Langendoen  Christina Ieronymidou  Vasiliy A. Kostyushin  Lesley J. Lewis  Svein-Håkon Lorentsen  Leho Luigujõe  Włodzimierz Meissner  Tibor Mikuska  Blas Molina  Zuzana Musilová  Viktor Natykanets  Jean-Yves Paquet  Nicky Petkov  Danae Portolou  Jozef Ridzoň  Samir Sayoud  Marko Šćiban  Laimonas Sniauksta  Antra Stīpniece  Nicolas Strebel  Norbert Teufelbauer  Goran Topić  Danka Uzunova  Andrej Vizi  Johannes Wahl  Marco Zenatello  Jon E. Brommer 《Conservation biology》2021,35(3):834-845
Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993–2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTISD). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTISD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTISD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming.  相似文献   
435.
贺兰山高山草甸生物多样性和地上生物量的关系   总被引:2,自引:0,他引:2  
在对贺兰山高山草甸进行群落调查的基础上,研究高山草甸生物多样性和地上生物量与环境因子之间的关系,进而分析生物多样性和地上生物量的关系.结果表明:(1)地上生物量主要与土层深度成正相关关系.(2)海拔高度与生物多样性成负相关关系,而其它影响物种丰富度或Shannon指数的环境因子仅在个别群落类型中起作用.(3)生物多样性与地上生物量主要呈单峰曲线关系.  相似文献   
436.
蔡信德  仇荣亮 《生态环境》2007,16(6):1705-1709
采用室内盆栽试验方法,研究了外源镍污染土壤的植物吸收修复对土壤镍形态和土壤主要化学性质的影响。试验用水稻土添加NiSO4·6H2O(100~1600mgkg-1)经过12周的驯化培养后,种植了镍超累积植物Alyssu mmurale,110 d后收获植物并进行了试验土壤镍的形态和主要化学性质的分析,采用再分配系数和结合强度系数对植物修复效果进行了定量分析。结果表明,根区土壤中DTPA提取态镍的数量明显减少,根区土壤DTPA-Ni与非根区土壤DTPA-Ni之比的范围在0.33~0.61之间。每盆植物提取镍量为6.61~31.18mg,植物提取量随着添加镍量增加而增加,地上部分最大镍含量达到12454.1mgkg-1。根区的再分配系数在2.17~4.19之间,而非根区的再分配系数在6.87~15.91之间,再分配系数随着镍添加量的增加而增大;根区的结合强度系数为0.84~0.39,而非根区的则为0.88~0.26,随着土壤中镍添加量的增加,结合强度系数逐渐减小。植物吸收修复后,根区土壤镍的再分配系数降低、结合强度系数增大,表明土壤镍各形态之间的稳定性增加,因此植物修复可以加快外源镍在土壤中的稳定。试验结果也表明,根区土壤中pH随着镍添加量的增加呈下降趋势、但较非根区土壤的高;根区土壤有机碳亦较非根区的高。  相似文献   
437.
The distribution and enrichment of selected trace metals (Cd, Cr, Cu, Ni, Pb, Sn, Zn) in benthic sediments of the Southport Broadwater, a semi-enclosed coastal body of water adjacent to the Gold Coast city, south-eastern Queensland, Australia, was studied with the objective of assessing the extent and degree of sediment contamination. Sediment samples from the 0–10 cm and 10–20 cm depth intervals of 32 sites within the Southport Broadwater and surrounding residential canals were analysed for particle size distribution, pH, organic C and ‘near-total’ major (Al, Ca, Fe, Mn) and trace (Cd, Cr, Cu, Ni, Pb, Sn, Zn) metal contents. Sediment contamination for each trace metal was assessed by (1) comparison with Australian sediment quality guidelines, (2) calculation of the index of geoaccumulation based on regional background values, and (3) geochemical normalisation against Al (i.e. the abundance of alumino-silicate clay minerals). Based on this approach, the results indicate that submerged sediments in the study area are not presently enriched with Cd, Cr or Ni, with the spatial distribution of these metals being very well explained by the abundance of alumino-silicate clay minerals. However, several sites were strongly enriched with Cu, Pb, Sn and Zn, arising from sources related to either urban runoff or vessel maintenance activities. The study indicates that several varying approaches are needed for a satisfactory assessment of contaminant enrichment in estuarine sediments.  相似文献   
438.
外加镍在土壤中的形态与再分配   总被引:6,自引:1,他引:6  
镍处理土壤经室内培养12周后,采用连续提取技术对试验土壤中镍的形态与再分配方式进行了研究。研究结果表明,外加的水溶性镍进入土壤后的主要存在形态与添加的剂量有关:低剂量时,以铁锰氧化态为主,这一形态在100mg·kg-1处理土壤中占比例最大,达到31.6%;高剂量时,以交换态为主,这一形态在1600mg·kg-1处理土壤中占比例最大,达到48.4%。随着镍添加剂量由0(对照)增加到1600mg·kg-1,再分配系数逐渐由1.00增大到30.65;金属结合强度系数则由0.90减小至0.25,也反映出进入土壤中镍的剂量较大时,镍是以不稳定的形态占优。试验结果也证实了土壤具有减小镍的环境危害的作用,但这种缓冲能力是有限的。随着时间的推移,镍的形态会继续发生变化,但这一转化过程是缓慢的。因此,一旦土壤发生重金属污染,其对土壤环境的影响将是长期的。  相似文献   
439.
取代芳烃对绿藻、斜生栅列藻急性毒性的自相关拓扑指数   总被引:6,自引:0,他引:6  
冯长君  唐自强 《环境化学》2002,21(4):371-375
本文提出新的原子生物活性值 (ai) ,由其建构自相关拓扑指数 ( mL) . 1 6种氯代芳烃对绿藻的急性毒性 ( -lgEC50 )与其0 L ,1L的回归方程为 :-lgEC50 =0 6 1 99+2 6 1 6 3× 1 0 - 6 1L2 5+ 0 0 0 92 0 L ,r=0 936 3. 1 8种苯酚、苯胺类化合物对斜生栅列藻的急性毒性 ( -lgEC50 )可以表示为 :-lgEC50 =1 1 374 + 0 1 4 4 71L0 6+ 0 0 0 2 70 L,r=0 95 35 .用Jackknife法检验 ,以上模型具有总体稳健性 .  相似文献   
440.
This study investigated geochemical characteristics of the acid mine drainage (AMD) discharged from the abandoned mine adits in the vicinity of the Dogye coal mine in Korea. Acid mine drainage discharged from Jeoncha pit adit of the Dogye coal mine, which is the main source of the AMD in the study area, had a pH value of 3.0 and concentrations of 2148mg SO4 2– L–1, 229mg Fe L–1, 71mg A1 L–1 and 11mg Mn L–1. The reduction of some metal concentrations downstream from the discharge point could be explained on the basis of dilution and precipitation. The order of removal of metal ions downstream from the discharge point was Fe>A1, Cu>Zn, Mn. Acidity could be used as a good determining factor offering comprehensive and quantitative values for the polluting extent of acid mine drainage. The acidities existing in all acidic water samples in the Gunahan district originated primarily from mineral acidity, especially in the upper Nahan Creek from dissolved Fe and Al and in the middle and down Nahan Creek from dissolved Al. From the application of the WATEQ4F program, it was determined that predominant species of dissolved Fe in all water samples was Fe2+, and those of dissolved Al were AlSO4 + and Al3+ except for IW2 sample which was associated with white precipitates. The species of dissolved Al in IW2 sample include also AlOH2+ and Al(OH)2 +. The saturation indices of goethite and haematite were positive in the water samples associated with ochrous precipitates (usually called Yellow Boy), therefore these solids might be precipitated. For the IW2 sample, the saturation indices of amorphous Al(OH)3 and gibbsite were positive, so theoretically these solids might also be precipitated. By XRD analysis, it was found that goethite occurs in ochrous precipitates, and gibbsite in white precipitates.  相似文献   
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