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261.
Effect of incubation temperature and wet-dry cycle on the availabilities of Cd, Pb and Zn in soil 总被引:1,自引:0,他引:1
The effect of incubation temperature and wet-dry cycle on the availabilities of Cd, Pb and Zn was studied. Three soils with pH ranging from 3.8 to 7.3, organic carbon (OC) from 0.7% to 2.4%, and clay from 12.3% to 35.6% were selected. Soils were spiked with reagent grade Cd(NO3)2, Pb(NO3)2, and Zn(NO3)2 at concentrations of 30 mg Cd/kg soil, 300 mg Zn/kg soil and 2000 mg Pb/kg soil. The soils were incubated at 35, 60, 105℃, respectively and went through four wet-dry cycles. Metal availability in soils was estimated by soil extraction with 0.1 mol/L Ca(NO3)2. According to this study, the effect of the spiking temperature on the metal availabilities was different among the metals, soils and wet-dry cycles. Mostly, 35 ~C was the first recommended spiking temperature for Cd and Pb while no spiking temperature was obviously better than others for Zn. Three wet-dry cycles was recommended regardless of the type of metals and incubation temperature. 相似文献
262.
Assessing availability, phytotoxicity and bioaccumulation of lead to ryegrass and millet based on 0.1 mol/L Ca(NO3)2 extraction 总被引:1,自引:1,他引:0
SI Ji-tao TIAN Bao-guo WANG Hong-tao Nicholas Bast Jackie Schroder Mark Casillas 《环境科学学报(英文版)》2006,18(5):958-963
This study was conducted to assess availability, phytotoxicity and bioaccumulation of lead (Pb) to ryegrass (Lolium perenne L.) and millet (Echinochloa crusgalli) based on the 0.1 mol/L Ca(NO3)2 extraction. Effect of soil properties on availability, phytotoxicity and bioaccumulation of Pb to the two plants was also evaluated. Five soils with pH values varying from 3.8 to 7.3, organic carbon (OC) contents from 0.7% to 2.4%, and clay contents from 11.6% to 35.6% were selected. Soils were spiked with Pb to achieve a range of concentrations: 250, 500, 1000, 3000 and 5000 mg/kg. Pb availability in the spiked soils was estimated by extracting soil with 0.1 mol/L Ca(NO3)2. The results indicate that plants yield decreased with decreasing soil pH and increased with increasing soil clay and OC content. Negative relationship between available Pb and the relative dry matter growth (RDMG) of the two plants were significantly related. Available Pb used to assess EC20 (20% effective concentration) and EC50 (50% effective concentration) of millet was 119 and 300 mg/kg, respectively. Available Pb used to assess EC20 and EC50 of ryegrass was 63 and 157 mg/kg, respectively. Bioaccumulation, expressed as bioconcentration factors of Pb, was inversely related to soil pH, soil OC and clay content. Strong relationships were found between available lead and uptake by the two plants (P was 0.92 and 0.95 respectively). In general, 0.1 mol/L Ca(NO3)2 available Pb may be used to assess the availability, phytotoxicity and bioaccumulation of lead to the two plants tested. 相似文献
263.
在实验室条件下,研究了Shewanella oneidensis MR-1对磺胺甲噁唑(Sulfamethoxazole,SMX)的降解特性以及低分子有机酸强化Fe(Ⅲ)还原介导的S.oneidensis MR-1对SMX的降解.结果表明,S.oneidensis MR-1对不同浓度SMX的降解能力与体系中的有机酸和Fe(Ⅲ)密切相关.低浓度SMX对其生长影响不大,高浓度时细菌生长则受到抑制,进而抑制SMX的降解率.当低分子有机酸单独加入体系后,S.oneidensis MR-1对SMX的最大降解率为58.5%;Fe(Ⅲ)单独加入体系后,S.oneidensis MR-1对SMX的最大降解率为67.6%.此外,当柠檬酸和Fe(OH)3同时加入体系后,S.oneidensis MR-1对SMX生物降解和铁还原作用促进效果最显著,培养5 d后SMX降解率为90.3%.最后,采用液相色谱-质谱联用仪(LC-MS)对SMX的降解中间产物进行了分析,推测SMX的可能降解途径是由S-N键断裂引起的.本研究以期为地下水污染场地修复提供理论依据. 相似文献
264.
265.
随着燃煤、工业、扬尘等大气污染源的治理力度不断加强,机动车和非道路移动机械等移动源的排放贡献率逐步增加,已成为城市最主要的大气污染源之一。《江苏省机动车和非道路移动机械排气污染防治条例》已于2022年11月25日通过江苏省第十三届人民代表大会常务会员会第三十三次会议审议, 自2023年5月1日起施行。该条例的施行将为协同开展机动车和非道路移动机械排气监管,深入打好污染防治攻坚战提供有力的法规支撑。介绍了这部法规的背景、立法修订的必要性、制度设计的主要内容及创新亮点,分析了存在的不足并提出建议,为未来移动源立法工作提供地方经验和参考。 相似文献
266.
267.
本文提出一种基于注意力机制的像素级海陆语义分割网络A-Unet用来提取水边线,并通过条件随机场对A-Unet分类结果进行细化。以天津沿海地区的人工海岸与威海地区的基岩海岸为例,对所提方法进行了验证,实验表明,与其他水边线分割方法相比,本文提出的方法能够得到更精细的结果,实现对遥感图像水边线的像素级语义分割。该方法提取了天津地区近10年海岸线并对其变化趋势进行了定性和定量分析,可为城市海洋资源的合理开发、海洋生态环境的保护提供更好的决策与参考依据。 相似文献
268.