排序方式: 共有14条查询结果,搜索用时 78 毫秒
1.
不同母质发育的水稻土中铁、锰对甲烷排放的影响 总被引:1,自引:0,他引:1
盆栽结果表明,不同土壤类型铁、锰含量的差异是造成不同土壤类型间甲烷排放量差异甚大的重要因素之一。土壤中铁、锰通过对土壤氧化还原电位及根膜形成的影响而影响甲烷的排放。 相似文献
2.
Xu Su Gong Ping Ding Wen Wu Shengchun Yu Xinwei Liang Peng 《Environmental science and pollution research international》2021,28(47):66990-66997
Environmental Science and Pollution Research - Paspalum distichum L. was tested to evaluate their phytoremediation capacity for Hg contaminated soil through analyzing the dissipation of Hg in soil... 相似文献
3.
Shao D Liang P Kang Y Wang H Cheng Z Wu S Shi J Lo SC Wang W Wong MH 《Chemosphere》2011,83(4):443-448
This study investigated total mercury (THg) and methylmercury (MeHg) concentrations in five species of freshwater fish and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The concentrations of THg and MeHg in fish pond surface sediments were 33.1-386 ng g(-1) dry wt and 0.18-1.25 ng g(-1) dry wt, respectively. The age of ponds affected the surface sediment MeHg concentration. The vertical distribution of MeHg in sediment cores showed that MeHg concentrations decreased with increasing depth in the top 10 cm. In addition, a significant correlation was observed between %MeHg and DNA from Desulfovibrionacaea or Desulfobulbus (p<0.05) in sediment cores. Concentrations of THg and MeHg in fish muscles ranged from 7.43-76.7 to 5.93-76.1 ng g(-1) wet wt, respectively, with significant linear relationships (r=0.97, p<0.01, n=122) observed between THg and MeHg levels in fish. A significant correlation between THg concentrations in fish (herbivorous: r=0.71, p<0.05, n=7; carnivorous: r=0.77, p<0.05, n=11) and corresponding sediments was also obtained. Risk assessment indicated that the consumption of largemouth bass and mandarin fish would result in higher estimated daily intakes (EDIs) of MeHg than reference dose (RfD) for both adults and children. 相似文献
4.
为研究改性生物炭对砷镉复合污染水体中镉和砷的吸附特征。本研究以牛粪、污泥、竹屑三种不同原料制备生物炭,利用镧(La)对生物炭进行改性,并采用元素分析、扫描电镜、傅里叶变换红外光谱和X射线光电子能谱等分析手段对改性前后的生物炭进行表征,结合等温吸附实验及吸附动力学实验,对比各生物炭对As (V)、Cd (II)的吸附性能并探讨其内在机理。结果表明,竹屑炭(BB)的芳香性大于牛粪炭(CB)和污泥炭(SB)。La改性使三种生物炭在热解过程中形成了酮类、酯类、羰基等含氧官能团,并在表面引入羟基。X射线光电子能谱结果显示La以氢氧化物的形式负载在生物炭表面。各生物炭对Cd (II)、As (V)的吸附符合准二级吸附动力学和Langmuir等温吸附方程。La改性生物炭对As (V)的最大拟合吸附量达到3.47~4.51 mg/g,显著高于未改性生物炭(1.82~2.50 mg/g)(p<0.05)。在As (V)、Cd (II)吸附过程中,La改性生物炭表面的La与As (V)发生络合反应,同时Cd (II)与镧基氢氧化物发生配体交换,生成Cd (OH)2沉淀。本研究证明了La改性有效提高了生物炭对As (V)、Cd (II)同时吸附的能力。 相似文献
5.
溶解性有机质(DOM)对水生环境中汞的赋存形态及转化过程具有极其重要的影响.但从更加微观的角度,如DOM的组成部分及其官能团特征等,却缺乏相关研究以阐明DOM影响汞形态转化的机制.为探究渔业养殖区来源于不同有机物(如残饵、鱼粪和底泥)的DOM各亚组分对水体中汞甲基化的影响,应用多级树脂联用技术,将渔业养殖区不同来源的DOM分离出6种亚组分,利用室内培养方式进行Hg2+的甲基化试验.傅里叶红外光谱分析结果表明,DOM中含有各种不同的官能团.亲水性组分主要包含羟基、羧基等极性较强的官能团;疏水性组分则包含一些无极性或者弱极性官能团如甲基、亚甲基和酚羟基等.疏水性亚组分是DOM的主要组成成分,其中又以疏水性碱性物质(HOB)为最,在有机物腐解过程中一直占有最大的比重.总体而言,疏水性有机组分对汞甲基化的促进作用显著高于亲水性有机组分;这主要是因为亲水性有机组分含有大量的羧基、羟基等官能团,可以更好地与活性Hg2+结合,降低甲基化反应的底物浓度,从而抑制甲基化发生.而疏水性组分对汞亲和性较弱,而且所含酚羟基以及还原性含硫基团等都可作为电子供体,从而促进汞甲基化的发生.从总体来说,在有机质腐解过程中,各种非同源有机质所形成的HOB对汞甲基化的促进作用不断增强. 相似文献
6.
分别以厌氧污泥、脱氮硫杆菌菌悬液和厌氧污泥并添加脱氮硫杆菌菌悬液为接种物,以硫化物和硝酸盐为进水基质,考察不同接种物条件下,各反应器的硫化物氧化特性、反硝化特性、生化反应机理及微生物特性。结果表明,在无菌条件下,硫化物不能被硝酸盐化学氧化。接种脱氮硫杆菌菌悬液的2#反应器的硫氧化速率为1.98 g S/(m3.h),停留24 h硫化物的去除率高达97%,脱硫能力最强,该接种条件下以硝酸盐氧化硫化物为主反应,优势菌为杆菌,进水的NO3--N/S应控制在0.4以下,可以实现高效生物脱硫。接种厌氧污泥的1#和3#反应器的脱氮效果比2#反应器好,停留时间为24 h时,硝酸盐的平均去除率为96%。单独接种厌氧污泥的1#反应器的硫氧化速率为1.78 g S/(m3.h),其优势菌为球菌,该接种条件下以硝酸盐氧化硫化物和硝酸盐氧化单质硫为主反应,进水的NO3--N/S应控制在0.8左右。以厌氧污泥联合脱氮硫杆菌为接种物时,硫氧化速率为1.71 g S/(m3.h),反应器以硝酸盐氧化硫化物、硝酸盐氧化单质硫以及异养反硝化为主反应,驯化后优势菌为球形、卵圆形和短杆状,应控制进水NO3--N/S为1.2,可以实现同步脱硫反硝化,该工艺既可以用于含硫废水的处理,也可以用于C/N低的硝酸盐废水的处理。 相似文献
7.
结合粉煤灰的性质及化学成分组成,综述了粉煤灰在制备白炭黑、沸石、水处理和在稀有金属回收方面的高值应用的新途径和应用现状。粉煤灰目前主要应用在建筑、交通等行业,虽然能在短时间内快速提高利用率,但均为低附加值产品,并未充分发挥潜在的价值,大力开发粉煤灰的高附加值产品是今后粉煤灰资源化利用技术研究的主要方向。 相似文献
8.
Drying of an inland river’s terminal lake in arid regions is an important signal of environmental degradation in downstream regions. A long-term, high-resolution understanding of the lake’s retreat and expansion and the driving mechanisms will inform future adaptive water management strategies, ecosystem restoration, and government decision-making in the context of a growing water scarcity in the inland river basin. The shrubs that grow along the shore of a lake often provide evidence of lake retreat or expansion. The chronological results showed that the earliest germination dates of the lakeshore shrubs, tamarisk, were in 1901, 1943, 1966, 2009, and 1990 from the higher terrace to the lower terrace of East Juyan Lake, a terminal lake of China’s Heihe River. Coupled with river and lake hydrological data, six obvious lake’s fluctuations were identified: shrinkage from 1900 to 1940s and during the early 1990s, expansion and retreat in the late 1950s and early 1970s, continued expansion from 2002 to 2008, and stabilization at a water area of around 40 km2 from 2009 to the present. The water elevation in the 1900s was below 905 m a.s.l., resulting in a water area <80 km2, but decreased to 40 km2 after 1960 and dried up completely by the 1990s. By analysing climatic and hydrological records since 1950, tree-ring climate proxy data, river runoff outside the observation period, and water resource consumption in the middle and lower reaches of the Heihe River, we found that the periodic expansion and retreat of East Juyan Lake was influenced by both climate change and human activities, but especially by human activities. The lake’s recent recovery and stability was achieved by government policy designed to provide environmental flows to the lake. 相似文献
9.
为阐明诺氟沙星和土霉素对汞(Hg)在鱼体内积累和转化的影响机制,探究了Hg单一暴露、诺氟沙星-Hg和土霉素-Hg复合暴露条件下,鱼体内各器官和组织中总汞(THg)和甲基汞(MeHg)的积累特征.结果表明:Hg单一暴露条件下,鱼体肌肉THg含量随着暴露时间呈先增加后降低的趋势,鱼头和内脏组织的THg含量随暴露时间增加而逐渐增加,内脏组织积累量高于鱼头(p<0.01).鱼体内的MeHg含量随着暴露时间的增加而不断增加,其中肌肉和内脏组织增加显著(p<0.05),鱼头无明显差异(p>0.05).在诺氟沙星-Hg和土霉素-Hg复合暴露条件下,鱼体内的THg和MeHg含量与Hg单一暴露处理相比均产生显著变化,诺氟沙星和土霉素均能促进THg在鱼体内的积累及抑制MeHg的形成(p<0.01).然而,无论对THg积累的促进作用还是对MeHg形成的抑制作用,诺氟沙星比土霉素作用都更为显著. 相似文献
10.
Junli Hu Jintian Li Fuyong Wu Shengchun Wu Zhihong Ye Xiangui Lin Ming Hung Wong 《Environmental science and pollution research international》2013,20(12):8457-8463
A post-harvest experiment was conducted further to our previous greenhouse pot study on upland kangkong (Ipomoea aquatica Forsk.) and Alfred stonecrop (Sedum alfredii Hance) intercropping system in Cd-contaminated soil inoculated with arbuscular mycorrhizal (AM) fungi. Previously, four treatments were established in the intercropping experiment, including monoculture of kangkong (control), intercropping with stonecrop (IS), and IS plus inoculation with Glomus caledonium (IS?+?Gc) or Glomus versiforme (IS?+?Gv). Both kangkong and stonecrop plants were harvested after growing for 8 weeks. Then, the tested soils were reclaimed for growing post-harvest kangkong for 6 weeks. In the post-harvest experiment, there were no significant differences between the IS and control treatments, except for a significantly decreased (p?<?0.05) soil available P concentration with IS treatment. Compared with IS, both IS?+?Gc and IS?+?Gv significantly decreased (p?<?0.05) soil DTPA-extractable (phytoavailable) Cd concentrations, but not total Cd, by elevating soil pH, causing significantly lower (p?<?0.05) Cd concentrations in both the root and shoot of kangkong. In addition, both Gc and Gv significantly increased (p?<?0.05) soil acid phosphatase activities and available P concentrations and hence resulted in significantly higher (p?<?0.05) plant P acquisitions. However, only Gv significantly increased (p?<?0.05) kangkong yield, while Gc only significantly elevated (p?<?0.05) the shoot P concentration. It suggested that AM fungi have played key roles in Cd stabilization and P mobilization in the intercropping system, and such positive responses seemed to be sustainable and valuable in post-harvest soils. 相似文献