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Influence of soil properties and aging on Cu partitioning and toxicity was assessed on 10 artificial soils constituted using a statistical design considering pH (5.5 and 7.5), organic matter (1-30% [w/w]), and clay content (5-35% [w/w]). Total Cu as well as water-, CaCl2-, and diethylene triamine pentaacetic acid (DTPA)-extracted Cu fractions were determined for each soil mixture. Ecotoxic effect was assessed by determining growth inhibition of barley (Hordeum vulgare L.) and compost worm (Eisenia fetida) mortality. Analyses were repeated after a 16-wk aging period of the soils at pH 7.5 (8 x 2-wk wetting and drying cycle). Results indicated that pH was the main factor controlling Cu partitioning, ahead of organic matter and clay content. Calcium chloride (0.5 M)-extracted Cu fractions showed the best correlation with toxic responses (r = 0.55-0.66; p < 0.05), while total and DTPA-extracted Cu concentrations could not explain differences in toxicity. Direct regressions between toxicity and soil properties (pH, organic matter, and clay content) provided better explanation of variance: r2= 0.50 (p = 0.00006) for compost worm mortality, r2= 0.77 (p < 0.00001) for barley shoot inhibition, and r2= 0.92 (p < 0.00001) for barley root inhibition. Copper toxicity was mainly influenced by pH and, to a lesser extent, by organic matter and clay content. Aging in organic soils revealed a slight reduction in ecotoxicity while an increase was observed in soils with low organic matter content. Further investigation using longer aging periods would be necessary to assess the significance of this observation. 相似文献
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The effect of the triazine herbicides Etazine and Bladex on coliform and fecal streptococci groups was studied in Nile river water, Nile water seeded with sewage, and autoclaved Nile water. The results indicate the fecal streptococci were able to persist and multiply in Nile water containing Bladex or Etazine and seeded with sewage. The successive addition of Bladex and Etazine (up to 10 mg/liter) increased its degradation rate and had no inhibitory effect on the bacterial parameters. 相似文献
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镍的作物效应及临界值研究 总被引:11,自引:0,他引:11
在三种紫色土(酸性,中性,石灰性)上添加Ni(0,10,30,60,100,200mg/kg土)进行莴笋盆栽试验,结果表明:低浓度的Ni能刺激作物生长,而高浓度的Ni则阻碍作物生长,使叶片黄化。三种土因性质及本身肥力水平的差异,使酸性紫色土上作物Ni最敏感,石灰性紫色土上次之,中性紫色土上最不敏感,且Ni在作物体内分配规律也有所不同,比较了土壤全Ni,有效Ni,植株根Ni作为的临界值的优越性,结果 相似文献
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基于RS和GIS的技术方法,运用景观格局指数对赛里木湖流域近25a来的景观格局变化综合分析。结果表明:1986-2010年,赛里木湖流域疏林地、灌木林地和中覆盖度草地面积增加,有林地、高覆盖度草地面积减小。整体上,景观斑块总数增加,景观破碎化指数、景观类型形状指数和景观多样性指数升高,均匀度指数有所减少。由此可以看出,该区域内由于自然或人为因素干扰所导致的景观斑块类型逐渐变得复杂,景观遭到破坏,土地利用向着多样化和非均匀化的方向发展,景观斑块分布变得很不均匀。 相似文献
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表面活性剂及酸处理对污泥脱水性能影响的研究 总被引:12,自引:0,他引:12
研究表面活性剂和酸处理对污泥脱水性能的影响,并探讨其作用机理。对采用最优加药量的各种加药方案进行了从污泥性质到脱水行为的一系列横向比较。污泥性质的比较依据为絮体颗粒的宏观(目测)和微观(光学和电子显微镜)变化以及在结合水含量(DSC法测)方面的变化。脱水行为的比较依据为过滤脱水速率(比阻)、离心脱水速率(1800rpm-2min离心后的泥饼含固率)、脱水程度(4800rpm~45min离心后的泥饼含固率)及脱水清液的性质(目测及测定SS、COD、TP)。实验结果表明:除了表面活性剂与Fe^3 和CaO联用外,投加表面活性剂或酸处理对提高污泥脱水速率的意义不大,但却能有效提高污泥的机械脱水程度。表面活性剂的作用机理是:分散作用使污泥絮体结构分散解体,释放出原絮体内部的结合水;增溶作用可溶解有高度水合作用的ECP。酸处理的作用机理是:H^ 与污泥的结合,改变了污泥的表面电荷特性,促进了污泥絮体间进一步的絮凝;使ECP水解,降低了絮体对水的亲和力。 相似文献
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市政污泥与生活垃圾掺烧工艺探讨 总被引:1,自引:0,他引:1
本文概括介绍了国内市政污泥处理处置的现状和目前不同类型的市政污泥处理处置技术,根据国外经验和国内情况做了市政污泥与生活垃圾掺烧的探讨,并总结了通过掺烧试验进行的工程应用实践。 相似文献