Chemical Behaviour of Calcium in Stabilized Oil Ash Reef Blocks After Five Years in the Ocean

Reef blocks made from stabilized oil ash were taken from the sea after five years in the ocean to examine the chemical behaviour of calcium. Experiments included (1) determination of the calcium leaching rate and a comparison with the rate for unexposed blocks to test the validity of a diffusion model for predicting long term (5 years) leaching rates, (2) determination of the effect of biological cover (shell) on the leaching rate, (3) determination of the leaching rate of the core of exposed reef blocks, (4) determination of the calcium content in 'ring areas' - regions of discoloration observed in sectioned exposed reef blocks, and (5) determination of the leachable fraction of the total calcium in exposed reef blocks. Results showed the presence of a pronounced calcium discontinuity zone located 3-7 cm from the outside surface of the reef blocks. Cumulated calcium release rates ranged from 2.81-3.14 μmol cm^-2 day^-1 for original unexposed reef blocks and the core of exposed (in the ocean for five years) blocks, respectively, to 0.47-0.50 μmol cm^-2 day^-1 for outside (facing sea water) surfaces of exposed reef blocks. Tank leaching studies also showed that the presence or absence of hard biological cover (shells) had little or no effect on the calcium release rate. the diffusion model normally used in modelling the chemical behaviour of calcium cannot be used to predict the long term (five years) leaching of calcium. the core of the exposed blocks released calcium at a rate similar to new, unexposed reef block material. Overall, it appears that the calcium discontinuity zone is probably responsible for restricting the release of calcium and hence the failure of the diffusion model.     

SUBSURFACE QUALITY TRANSFORMATIONS DURING THE INITIATION OF A NEW STABILIZATION LAGOON1

ABSTRACT Raw sewage was metered into a newly-constructed lagoon of the Pima County Department of Sanitation, Tucson, Arizona. Seepage losses were calculated from data on inflow, evaporation and change in storage. Water samples were obtained from shallow suction cups, a 40 ft. and a 60 ft. PVC well and a 100 ft. access tube, all located inside the lagoon. Samples from these wells, together with water samples from the lagoon, were examined for conform organisms and various physical and chemical constituents. Of special concern were transformations in nitrogen. Estimated seepage rates in the lagoon during inundation ranged from 0.20 ft. per day to 0.10 ft. per day. Water level observations in wells reflected the percolation of effluent to the water table, 70 ft. below land surface. Initially, the nitrate ion levels in the suction cup samples were high, manifesting the leaching of indigenous soil nitrogen. With the onset of anaerobic conditions at the base of the lagoon, nitrification was inhibited at the soil surface and ammonia became the predominant form of nitrogen in the soil solution. Sorption of ammonium ion appeared to occur on clay particles in a soil zone of high cation exchange capacity. There were no undesirable microbial or chemical effects of recharge from lagoon seepage on native groundwater quality.     

Alkaline leaching of metal melting industry wastes and separation of zinc and lead in the leach solution

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｍｅｔａｌｍｅｌｔｉｎｇｉｎｄｕｓｔｒｙｉｓｏｎｅｏｆｔｈｅｌａｒｇｅｒｉｎｄｕｓｔｒｉｅｓｗｏｒｌｄ ｗｉｄｅ ,ｉｎｃｌｕｄｉｎｇｉｒｏｎａｎｄｓｔｅｅｌｆｏｕｎｄｒｉｅｓａｎｄｍｉｌｌｓ,ａｓｗｅｌｌａｓｂｒａｓｓａｎｄｂｒｏｎｚｅｆｏｕｎｄｒｉｅｓ (Ｍｏｒｇａｎ ,1 977;Ｇｉｌｌ,1 981 ;Ｂｒｏｏｋｓ,1 991 ;Ｃｏｌｌｉｅ ,1 984;Ｓｗａｒｎｋａｒ,1 996 ;Ｐｅｔｅｒｓ,1 992 ;Ｅｌｇｅｒｓｍａ,1 992 ) .Ｄｕｒｉｎｇｔｈｅｍｅｔａｌｍｅｌｔｉｎｇｐｒｏｃｅｓｓ,ｔｈｅｅｌｅ…     

稀土矿废弃地植被恢复过程中土壤微生物演变

以福建长汀典型离子型稀土矿堆浸冶炼废弃地作为研究对象，采取"空间代时间"的方法，对堆浸废弃地不同植物恢复年限样地土壤理化性质及微生物进行调查测定，分析植物恢复对稀土矿堆浸废弃地土壤理化特性及微生物的影响.结果表明：在植被恢复第3a和4a土壤理化性质显著高于未治理废弃地，但仍显著低于矿区周边未开采对照（P<0.05）.植被恢复年4a以后，长汀稀土矿废弃地土壤理化性质则呈下降趋势，但仍显著高于未治理废弃地（P<0.05）.长汀稀土矿堆浸废弃地不同植被恢复年限土壤细菌丰度及多样存在一定差异.随植被恢复年限的增加，土壤细菌多样性及丰度降低，但一些特殊细菌群如γ-变形菌纲（Gammaproteobacteria）、a-变形杆菌纲（Alphaproteobacteria）、酸杆菌门（Acidobacteria）、蓝藻菌门（Cyanobacteria）等在不同植被恢复年限样地中其相对丰度明显增加.具有固氮作用的蓝藻菌门（Cyanobacteria）随着植被恢复年限的增加，其相对丰度降低.广古菌门（Euryarchaeota）仅存在于未开采对照样地；土壤寡营养细菌酸杆菌门（Acidobacteria）随植被恢复年限的增加，相对丰度呈增大趋势.土壤中优势菌群广古菌门（Euryarchaeota）、厚壁菌门（Firmicutes）、β-变形菌门（Proteobacteria）、Methanobacterium属、罗尔斯通菌属（Ralstonia）与土壤pH、全磷、全钾、速效磷等呈正相关.土壤pH值、全磷、全钾等是影响广古菌门（Euryarchaeota）、厚壁菌门（Firmicutes）等细菌菌群多样性及相对丰度变化的重要因素.以上结果表明，离子型稀土矿堆浸废弃地植被恢复治理到3~4a时，应采取防治措施对其进行人工抚育管理，否则可能会出现前期恢复后期退化的问题.     

灭幼脲Ⅲ号在土壤中的吸附与淋溶

用批量平衡法研究了昆虫生长调节剂灭幼脲Ⅲ号在四种不同类型土壤中的吸附行为,测定其吸附常数,给出吸附等温线;并研究了它在上述四种土壤中的淋溶行为.结果表明,Freun-dlich经验公式能较好地描述灭幼脲Ⅲ号在土壤中的吸附状况.试验表明,该农药在土壤中的迁移能力较差。     

北京市工业固体有害废物浸出毒性研究

本文介绍了北京市工业固体废物和有害废物产生及利用情况 ,对采集的有害废物样品进行预处理后 ,用超声波浸提法制备浸出液进行浸出毒性实验 ,并对浸出毒性的影响因素进行研究 ,确定最佳浸提条件     

煤矸石中重金属的淋滤特征研究

以内蒙古某矿区的煤矸石为研究对象,采用试验模拟法对煤矸石中的重金属的淋滤特征进行研究.结果表明:经过8 d的淋滤试验,重金属淋滤强度达到稳定,各个样品中各元素的最大淋出率平均值为:Cd＞Cr＞Pb＞Cu＞Hg＞As;Hg,Cr,Cd元素的最大淋出率与样品中元素背景值负相关;淋滤液中的As来源于硫化物的风化;煤矸石中重金属对环境的影响主要发生在淋滤初期,且重金属在自然条件下的淋滤过程对环境的影响较小,只有Cr和Cd的浓度超过了国家地表水Ⅲ类水质标准.     

Complexation of arsenate with humic substance in water extract of compost

The interactions of environmental toxicants with organic substances affect the speciation and dynamics, and subsequent toxicity, mobility, and fate of toxicants in the environment. For the purpose of understanding the complexation of As(V) with humic substances, arsenate-containing solutions with As concentrations from 1 to 8 mg l⁻¹ were prepared to react with the water extract of compost (WEC). All the reaction systems including the control were incubated for 48 h at 25 °C. The complexation of As(V) with humic substance was examined by dialysis and ion exchange techniques. From 30% to 51% of added As(V) reacted with organic substance in WEC to form an As–metal–organic complex. This was verified as a hydrophobic organic fraction after separation of As–metal–organic complex fraction from the hydrophilic fraction by XAD-8 resin. The complex substance was also identified as a humic substance by the method of proton binding formation function determination. This suggests that cations, such as Ca and Mg, and especially Fe, Al, and Mn act in cation bridging in the complexation of As(V) with humic substance. The role of metals in the complexation of As(V) with humic substance in terrestrial and especially aquatic environments thus merits close attention.     

表面活性剂对采油区土壤装填土柱中PAHs迁移渗透的影响

以阴离子表面活性剂十二烷基苯磺酸钠(LAS)对采油区土壤(MGP)中PAHs的淋洗效果进行研究．结果表明，5CMC(临界胶束浓度)LAS促进了土柱中PAHs的迁移渗透，土柱中PAHs的淋溶率较低，而且仅土柱上层5cm的土样中PAHs发生了较为明显的淋溶．与Br^-离子穿透曲线相比，土柱中PAHs的淋溶均有滞后现象，而且随着环数的增加，PAHs的淋溶滞后现象愈加明显．PAHs的迁移渗滤性与其辛醇／水分配系数之间具有显著负相关性，说明随着辛醇／水分配系数的增加，PAHs的淋溶率逐渐降低．     

三峡库区生活垃圾总磷的分布特征和溶出规律研究

了解垃圾堆放场堆存生活垃圾的污染物含量及浸泡条件下污染物的溶出规律，有助于正确评价垃圾堆放场所带来的环境影响，从而为政府部门的决策提供依据。文章以三峡库区为例，通过测定三峡库区主要垃圾堆放场堆存生活垃圾总磷的含量，分析它们的分布特征，并且进行生活垃圾浸泡条件下总磷的溶出实验，分析它们的溶出规律，为三峡库区的环境保护提供帮助。结果表明，(1)三峡库区生活垃圾总磷的含量位于50-3290mg／kg之间，总磷分布集中于100-1600mg／kg之间，且区域差异较大；(2)生活垃圾淹没条件下总磷的释放规律为开始较慢，逐渐增大，达到最大值以后减少，最后趋于稳定；(3)生活垃圾淹没条件下总磷的单位溶出量与时间的关系满足逻辑斯特模型w=α／[1 βexp(-kt)]，且垃圾单位可溶出量α随质量增加而减少，利用本模型可以预测垃圾进入水体后总磷溶出的初期行为。