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271.
272.
几种萃取剂对土壤中重金属生物有效部分的萃取效果 总被引:1,自引:0,他引:1
采用6种萃取剂:pH=7的0.01mol/L CaCl_2、pH=7.3的0.005mol/L DTPA+0.1mol/L TEA(三乙醇胺)+0.01mol/L CaCl_2O.1mol/L NaNO_3、0.43mol/L HOAc、pH=7的0.05mol/L EDTA和pH=4.65的0.5mol/L NH_4OAc+0.02mol/L EDTA浸取液.对污染土壤中的重金属Cu、Zn、Cd、Pb、的进行了萃取,并比较了萃取剂的萃取能力。实验结果表明,HOAc、EDTA以及NH_4OAc-EDTA萃取各种重金属的能力远远大于其它几种萃取剂的萃取能力,是比较理想的萃取剂。 相似文献
273.
274.
单嘧磺隆在小麦田中的残留试验研究 总被引:2,自引:0,他引:2
研究了单嘧磺隆的残留分析方法 ,单嘧磺隆在土壤中的消解动态和在土壤、小麦中的最终残留 .土壤经甲醇 /氨水混合液提取 (小麦用丙酮 /水混合液 ) .液液分配及C1 8小柱净化、用带紫外检测器的高效液相色谱仪测定 .单嘧磺隆的最低检出量为 4ng ,在土壤和小麦中的最低检出浓度为 0 0 2mg·kg- 1 .本方法的平均添加回收率为 91 1 7— 1 0 3 8% ,变异系数为 1 47— 1 1 8% .应用上述方法 ,测定了单嘧磺隆在北京、山东两地土壤中的消解动态以及在土壤、小麦中的最终残留 .结果表明 :在北京土壤中的半衰期为 9 2 4d ;在山东土壤中的半衰期为 1 3 5 9d;当按推荐剂量施药 ,小麦收获时 ,在土壤和小麦中 ,北京、山东两地均未检出单嘧磺隆 相似文献
275.
文章论述了家庭生活水的氡浓度水平、生活用水对室内氡的贡献、水的使用过程中室内氡行为以及含氡水的使用与辐射照射剂量的关系等问题。指出家庭生活水的氡浓度高时,是室内氡的一个不可忽视的来源。对氡浓度特别高的家庭用水,建议先用活性炭等进行吸附后再使用。 相似文献
276.
苯噻草胺对土壤中过氧化氢酶活性及呼吸作用的影响 总被引:17,自引:0,他引:17
通过模拟实验研究了水稻除草剂苯噻胺对土壤中过氧化氢酶活性及对土壤呼唤作用强度的影响,并研究了其在不同条件下水解和光解的效果,结果表明,苯噻草胺的浓度对土壤中过氧化氢酶的活性有明显影响,浓度愈大,对土壤中过氧化氢酶活性的抑制愈大,苯噻草胺在实验条件下没有明显的水解和光解,苯噻草胺对土壤呼吸有明显的抑制作用,浓度愈高,土壤呼吸强度在初期抑制愈大,17d后各处理土样的呼吸强度基本恢复正常,试验结果还表明,苯噻草胺属于低毒或无明显实际危害的农药,对土壤微生物影响较小。 相似文献
277.
王之顺 《城市环境与城市生态》2002,15(2):19-20
文章综述了国内烟气脱硫技术及设备发展的历程和现状,分析了引进国外全套烟气脱硫技术装置对国内用户所造成的巨大经济压力,提出走转化高新技术发展国内烟气脱硫技术的道路,介绍了国内外脱硫技术与国内技术相结合,在天津市重点工程项目上实施的实例。 相似文献
278.
采用上流式厌氧污泥床(UASB)反应器,以精对苯二甲酸(PTA)废水为处理对象,研究了中温条件下反应器的启动、颗粒污泥的形态和产甲烷活性及微生物群落结构。实验结果表明:采用逐渐提高进水负荷和减少水力停留时间的运行方法,历时近200 d,可实现UASB 反应器的启动。此时,反应器对COD的去除率保持在80%以上,对应的容积负荷也达到4.0 kg·(m3·d)-1以上。反应器内污泥实现颗粒化,颗粒污泥的体积平均粒径为416.53 μm,产甲烷活性为121.2 mL·(g·d)-1 (以VSS计)。颗粒污泥表面存在大量菌胶团,杆菌和丝状菌镶嵌其中。菌胶团有助于微生物的聚集,加速污泥颗粒化过程。Syntrophorhabdus是降解PTA废水中苯类污染物的重要微生物,占细菌量的27.4%,而Methanosaeta则是主要的产甲烷菌,占古细菌总量的67.3%。该研究可为UASB 处理PTA废水的启动提供依据。 相似文献
279.
Kuang YW Zhou GY Da Wen Z Liu SZ 《Environmental science and pollution research international》2007,14(4):270-275
Goal, Scope and Background Rapid urbanization and the expansion of industrial activities in the past several decades have led to large increases in emissions
of pollutants in the Pearl River Delta of south China. Recent reports have suggested that industrial emission is a major factor
contributing to the damages in current natural ecosystem in the Delta area. Tree barks have been used successfully to monitor
the levels of atmospheric metal deposition in many areas, but rarely in China. This study aimed at determining whether atmospheric
heavy metal deposition from a Pb-Zn smeltery at Qujiang, Guangdong province, could be accurately reflected both in the inner
bark and the outer bark of Masson pine (Pinus massoniana L.). The impact of the emission from smeltery on the soils beneath the trees and the relationships of the concentrations
between the soils and the barks were also analyzed.
Methods Barks around the bole of Pinus massoniana from a pine forest near a Pb-Zn smeltery at Qujiang and a reference forest at Dinghushan natural reserve were sampled with
a stainless knife at an average height of 1.5 m above the ground. Mosses and lichens on the surface barks were cleaned prior
to sampling. The samples were carefully divided into the inner bark (living part) and the outer bark (dead part) in the laboratory,
and dried and ground, respectively. After being dry-ashed, the powder of the barks was dissolved in HNO3. The solutions were analyzed for iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), chromium (Cr), nickel (Ni) and cobalt
(Co) by inductively coupled plasmas emission spectrometry (ICP, PS-1000AT, USA) and Cadmium (Cd) and lead (Pb) by graphite
furnace atomic absorption spectrometry (GFAAS, ZEENIT 60, Germany). Surface soils (0–10 cm) beneath the sample trees were
also collected and analyzed for the selected metals.
Results and Discussion Concentrations of the selected metals in soils at Qujiang were far above their environmental background values in the area,
except for Fe and Mn, whilst at Dinghushan, they were far below their background values, except for Cd and Co. Levels of the
metals, in particular Pb and Zn, in the soils beneath the sample trees at Qujiang were higher than those at Dinghushan with
statistical significance. The result suggested that the pine forest soils at Qujiang had a great input of heavy metals from
wet and dry atmospheric deposition, with the Pb-Zn smeltery most probably being the source.
Levels of Cu, Fe, Mn, Zn, Ni and Pb at Qujiang, both in the inner and the outer bark, were statistically higher than those
at Dinghushan. Higher concentrations of Pb, Fe, Zn and Cu may come from the stem-flow of elements leached from the canopy,
soil splash on the 1.5 m height and sorption of metals in the mosses and lichens growing on the bark, which were direct or
indirect results from the atmospheric deposition. Levels of heavy metals in the outer barks were associated well with the
metal concentrations in the soil, reflecting the close relationships between the metal atmospheric deposition and their accumulation
in the outer bark of Masson pine. The significant (p<0.01) correlations of Fe-Cu, Fe-Cr, Fe-Pb, Fe-Ni, Pb-Ni, and Pb-Zn in
the outer barks at Qujiang again suggested a common source for the metals. The correlation only occurred between Pb and Ni,
Cd and Co in the outer barks at Dinghushan, which suggested that those metals must possibly have other uncommon sources.
Conclusions Atmospheric deposition of the selected metals was great at Qujiang, based on the levels in the bark of Pinus massoniana and on the concentrations in the soils beneath the trees compared with that at Dinghushan. Bark of Pinus massoniana, especially the outer bark, was an indicator of metal loading at least at the time of sampling.
Recommendations and Perspectives The results from this study and the techniques employed constituted a new contribution to the development of biogeochemical
methods for environmental monitoring particularly in areas with high frequency of pollution in China. The method would be
of value for follow up studies aimed at the assessment of industrial pollution in other areas similar with the Pearl River
Delta. 相似文献
280.