干旱半干旱地区湖泊沉积物对Cu2+的吸附-解吸研究

吸附-解吸是重金属在沉积物中迁移转化的重要过程。本文研究干旱半干旱地区湖泊———乌梁素海不同区域沉积物对Cu2+的吸附-解吸过程。结果表明,吸附过程中,pH值逐渐降低;沉积物TOC含量越高,其对Cu2+的吸附能力也越强;生活污水和工业废水影响的S1样点及受农田退水影响的S2样点对Cu2+的吸附量相对较低,而相对较洁净的S3和S4样点具有较高的Cu2+吸附量。4个样点吸附量能力大小为S3>S4>S2>S1。解吸实验显示,沉积物吸附的Cu2+大部分都不能被解吸。试验结果符合Langmuir和Freundlich等温吸附方程,Langmuir方程的拟合效果要好于Freundlich方程,Langmuir方程拟合的饱和吸附量分别为3.31 mg/g、4.84 mg/g、8.39 mg/g和7.75 mg/g。     

玉滩湖表层沉积物重金属污染特征及潜在生态风险评价

为了掌握重庆玉滩湖表层沉积物重金属污染情况,监测了玉滩湖表层沉积物中Cr、Cd、Pb、Cu和Zn的相对含量,并采用地质累积指数法和潜在生态风险指数法对重金属的污染程度和潜在生态风险进行评价。结果表明,玉滩湖表层沉积物中重金属Cr、Cd、Pb、Cu和Zn的平均含量分别为28.41mg/kg、0.75mg/kg、46.04mg/kg、66.98mg/kg、131.55mg/kg,Pb和Cu受人为活动影响较大;重金属污染程度为Cu(轻度)Pb(轻微)Cd(轻微)Zn(轻微)Cr(无污染);有机质含量和重金属Pb、Cd含量显著正相关,是玉滩湖流域重金属污染防治的重点因子;玉滩湖总体的生态风险程度为轻微,重金属单项潜在生态风险程度为Cd(中等)Cu(轻微)Pb(轻微)Zn(轻微)Cr(轻微),Cd是主要的生态风险因子。     

固定化小球藻深度净化含重金属污水的特性研究

将小球藻包埋固定在海藻酸钙凝胶珠中,对人工污水进行深度净化,研究Cd,Cu对污水中氨氮和正磷酸盐的净化效率以及净化过程中藻类叶绿素a含量、过氧化物酶(POD)活性和去污过程中藻细胞富集Cd,Cu的情况。结果表明,低浓度Cd可促进藻细胞的生长与繁殖,低浓度Cu作为微量元素,可提高光合活性,使脱氮、除磷效率提高;高浓度Cd,Cu会对藻细胞有灭活作用,光合活性减弱,NH_4~+-N和正磷酸盐净化效率降低。     

铜、镉、汞单一及其复合污染对少根紫萍的毒害研究

通过实验室水培试验研究不同浓度处理水平下Cu、Cd、Hg单一及其复合污染对少根紫萍叶绿素及脯氨酸浓度的影响。经观察分析,培养4天后,各处理组均呈现出不同程度的受害症状。同一浓度处理水平下,单一重金属污染对少根紫萍叶绿素的生态毒性效应为Cd>Cu>Hg。复合污染中Cu+Cd和Hg+Cu+Cd对叶绿素的影响则表现为协同作用;Cd+Hg复合浓度≤6.0+4.0mg/L时表现为拮抗作用,复合浓度>6.0+4.0mg/L时表现为协同作用;Cu+Hg复合浓度≤0.4+4.0mg/L时表现为协同作用;复合浓度>0.4+4.0mg/L时表现为拮抗作用。随处理浓度的递增,脯氨酸含量均表现出一显著抗性峰,而后下降。     

4种拟除虫菊酯类杀虫剂对蜜蜂的毒性和安全性评价

参考《化学农药环境安全评价试验准则》的相关内容,通过接触法和摄入法测定甲氰菊酯、高效氯氰菊酯、高效氯氟氰菊酯、溴氟菊酯4种拟除虫菊酯类杀虫剂对蜜蜂的毒性。结果表明,甲氰菊酯、高效氯氰菊酯、高效氯氟氰菊酯、溴氟菊酯对蜜蜂的接触毒性(24h LD50)分别为0.0501μg/只、0.0102μg/只、0.0129μg/只、0.0147μg/只,经口毒性(24h LC50)分别为7.8261mg/L、4.9163mg/L、5.9678mg/L、7.7875mg/L。根据有关评价标准,甲氰菊酯、高效氯氰菊酯、高效氯氟氰菊酯、溴氟菊酯4种拟除虫菊酯类杀虫剂对蜜蜂的毒性均为高毒,应禁止在蜜蜂活动区域使用。     

四川省马边磷矿区水环境中典型重金属污染分析

马边磷矿区磷矿资源丰富,区内磷矿开采企业较多。在开采的过程中难免会对当地的河水造成一定的影响。为了进一步了解马边磷矿区的环境影响问题,本文通过对磷矿区采集的水体样品和同一地点的水系沉积物样品进行分析测试,共检测了Cd、As、Cu、Cr、Pb、Zn六种重金属元素的含量,采用潜在生态危害指数法对沉积物中的重金属污染程度进行了综合评价。结果如下:马边磷矿区河水中的重金属元素的浓度较低,6种重金属元素含量均低于国家标准(GB3838-2002)。水系沉积物中的重金属元素含量较高,其中:Cd、Pb、Zn分别为2. 06mg/kg、182. 39mg/kg、479. 13 mg/kg。与四川省土壤元素背景值相比:Cd元素超标25. 7倍,Pb元素超标5. 9倍,Zn元素超标5. 5倍,其余元素未超标。与马边地区1∶20万区域水系沉积物背景值相比:Cd元素超标3. 12倍,Pb元素超标3. 3倍,Zn元素超标2. 5倍,As元素超标1. 6倍,Cu、Cr元素含量在背景值以内。与“中国土壤元素背景值”相比:Cd元素超标29. 4倍,Pb元素超标7. 7倍,Zn元素超标7. 1倍。潜在生态危害指数法评价结果表明:Cd的生态危害指数最大,其次为Pb和As,其余Cu、Cr、Zn等元素属于轻微生态风险。     

重金属的高分子捕集沉淀剂—DTCR

由陕西福天宝环保科技有限公司开发、陕西省环保局推荐的重金属的高分子捕集沉淀剂DTCR可应用于电镀、电子、石化、金属加工、皮革工业等行业的废水处理。主要技术内容该技术属化学沉淀法,DTCR是一种液体螯合树脂,在常温下与废水中Hg2+、Cd2+、Cu2+、Pb2+、Mn2+、Ni2+、Zn2+、Cr3+、Cr6+等重金属离子迅速反应,生成水不溶性的螯合盐,并形成絮状沉淀,达到捕集去除重金属离子的目的。含重金属废水中DTCR对离子的选择性:Hg2+>Ag+>Cu2+>Pb2+>Cd2+>Zn2+>Ni2+>Co2+>Cr3+>Fe2+>Mn2+。主要技术指标及条件要求一、主要技术指标:外观:棕红…     

重金属离子在二氧化锰上竞争/络合吸附行为的模拟

通过实验考察了Cu2+、Co2+、Cd2+、Zn2+和Ni2+五种重金属离子共存时各自在二氧化锰上的吸附边以及EDTA存在时Cu2+在二氧化锰上的吸附边。在改良型金属匹配模型的基础上,发展了多种重金属离子共存的竞争吸附模型和EDTA存在时的重金属离子络合吸附模型,利用所建立的吸附模型可以较好地模拟重金属离子的吸附行为,且利用模拟所得的参数可以预测EDTA存在时Cu2+在二氧化锰上的吸附边。     

我国南方桉树人工林区水库沉积物重金属垂向分布及污染评价

为研究我国南方桉树人工林区水库沉积物中重金属污染程度及垂向分布特征,选取南宁市那降水库和天雹水库为研究对象,采用ICP-AES测定沉积物中Cr、Cu、Zn、As、Cd、Hg和Pb 7种重金属在垂向上的含量分布,并采用地累积指数法对重金属污染进行风险评价。结果表明,天雹水库沉积物中重金属污染较那降水库严重,且7种重金属平均含量远远高于南宁市土壤重金属元素背景值。重金属垂向分布特征显示,重金属Cu和Pb平均含量呈波动增长趋势,Zn和Cd呈持续增长趋势,而Cr、As和Hg呈波动下降趋势。由重金属含量变异系数垂向变化来看,重金属Hg含量变异系数最大,不同深度处均大于0.45,离散程度较高。地累积指数法评价结果表明,重金属污染程度由大到小顺序为:HgCdZnCuPbCrAs,重金属Hg累积最严重,属于中度污染程度,且有逐年加重趋势,两个水库的相似点是重金属Hg和Cd也有明显累积,处于中度污染水平。     

龙湾涌沉积物重金属污染现状评价

本文根据广州市番禺区龙湾涌沉积物重金属的调查结果,分析了沉积物重金属含量的空间分布,表明龙湾涌沉积物重金属含是沿河分布的差异与水流速度、工业排污位置有关,采用重金属潜在生态危害指数法评价了龙湾涌重金属对水生态系统的潜在危害,结果表明：产生生态危害的主要重金属污染物为Hg;其次为Cd、Cu、Pb、Cr、Zn。污染最严重断面是龙湾闸口,龙湾涌重金属潜在污染除龙湾闸口沉积物Cd属中等生态危害外,龙湾涌生态危害属于轻微。     

针铁矿对重金属Pb^2＋、Cd^2＋的吸附特征

本文采用平衡振荡法,主要探讨了重金属铅和镉在针铁矿上的环境行为。研究结果表明针铁矿对重金属有较强的吸附作用。在pH一定时,针铁矿对Pb^2＋和Cd^2＋的吸附率随着初始浓度的增加而增大。随着介质pH升高,针铁矿对Pb^2＋和Cd^2＋的吸附量与吸附率均增大,最大吸附率可达到99．71％和99．46％,而解吸量则随之降低。在高pH条件下,针铁矿对Pb^2＋和Cd^2＋的结合牢固,且与Pb^2＋的稳定度大于Cd^2＋。研究表明,环境中针铁矿对铅、镉等重金属的环境化学行为具有重要的影响。利用针铁矿处理含Pb^2＋和Cd^2＋的污水具有良好的应用潜力。     

不同因素对黄山贡菊叶中过氧化氢酶活性的影响

以黄山贡菊离体叶片中过氧化氢酶为研究对象,采用室内模拟方法,研究不同因素处理对黄山贡菊离体叶片中过氧化氢酶活力的影响。结果表明,在30℃时酶活力较高,高温或低温时酶活力均减小;低浓度的K^＋和Ca^2＋对过氧化氢酶有激活作用,高浓度的K^＋和Ca^2＋对过氧化氢酶有抑制作用;Mg^2＋、Pb^2＋、Cu^2＋对过氧化氢酶均具有抑制作用,生长素和赤霉素对过氧化氢酶活性的影响不明显。     

利用缺氧反硝化处理难降解有机物的探讨

本文研究了厌氧、缺氧实验夺件下难降解苯、甲苯、乙苯、二甲苯的同分异构体（BTEX）的生物降解性能。得出了不同底物的厌氧降解变化情况和缺氧降解条件下不同底物适宜的C／N比。通过对实验结果的分析，初步确定了不同底物具有各不相同的C／N比的原因，同时得出了缺氧反硝化与厌氧生物降解过程有可能同时发生的结论。     

水淬渣处理废水的研究进展

水淬渣的微观结构特殊,比表面积大,表面能高。国内外研究表明,水淬渣吸附去除废水中的Cu2+、Zn2+、Ni2+、Pb2+、Cr6+、As3+及磷等效果良好,而且对废水中的COD、大分子有机物、油类、苯酚等也有比较好的去除率;并研究了吸附去除的机理,对水淬渣在水处理领域的应用起到了推动作用。     

铁元素对有机物厌氧降解的影响研究

不同价态的铁元素氧化还原性不同,对有机物的厌氧生物降解过程的影响也不同。以邻氟苯酚和硝基苯为目标污染物,投铁量为20～100mg／L的条件下,单质铁能加速硝基苯的厌氧降解,对2-氟酚降解的影响则很小;二价铁和三价铁对两种物质都表现出一定的抑制作用,投加浓度越高,抑制作用越明显。     

生物法处理含酚废水的研究

为了降低炼油厂污水处理场的酚负荷,对催化裂化汽提塔所排含酚废水的预处理进行了研究。进行了煤渣吸附实验,酚的生物降解动力学实验及酚在兼氧条件下的处理实验;采用４－氨基安替比林光度法测定酚浓度。实验结果表明采用煤渣填料－生物膜反应器,酚的去除率可达９０％,酚的生物降解符合一级反应动力学,酚类物质可在兼氧条件下降解     

Effects of suspended sediment on the biodegradation and mineralization of phenanthrene in river water

High suspended sediment (SPS) concentration commonly exists in many Asian rivers. Furthermore, climate change can cause high floods and lead to the resuspension of sediments and soil erosion, resulting in high SPS concentration in many natural waters. This research studied the impact of the presence of SPS and organic C composition of SPS on the biodegradation and mineralization of phenanthrene (PHE). Three sediments, including original sediment (OS), 375 degrees C (S375), and 600 degrees C (S600) combusted sediment, were studied. A flask-based 14C-respirometer system was applied to study the mineralization of [14C]PHE by Agrobacterium sp. The mineralization rate of PHE in the absence of SPS was significantly lower than that with the presence of OS and S600 but higher than that with S375, suggesting that the effect of the presence of sediment on PHE mineralization depended on its organic C composition. The residual levels of PHE in the S375 and OS systems were about 1.5 times that of the S600 system after incubation for 2 d. After 26-d incubation, the mineralization rates of PHE were 34.64, 29.40, and 14.00% in the OS, S600, and S375 systems, respectively. The first-order rate constants of the OS and S600 systems were about three times that of the S375 system. The net influence of SPS on the biodegradation and mineralization rates of PHE was dependent on its effects on compound bioavailability and bacteria population. This study suggested that black C played a key role in reducing the mineralization rates of PHE in sediments-even without aging.     

Estimation of the effect of the degree of sewage treatment on the status of pollution along the coastline of the Mediterranean Sea using broad scale modelling

A preliminary investigation was performed to estimate the effect of the degree of treatment in Sewage Treatment Plants (STPs) on the status of pollution along the coastlines of the Mediterranean Sea. Data from questionnaires and the literature were collected and processed (a) to identify 18 approximate 1D surface coastal currents, (b) to estimate their prevailing direction and average flow velocity and (c) to estimate the water pollution loads and identify their locations of discharge. Then, a simplified 1D water quality model was formulated and applied for the existing conditions and two hypothetical scenarios: (1) all coastal cities have STPs with secondary treatment and (2) all coastal cities have STPs with tertiary treatment to determine BOD(5), TN and TP concentrations in the 18 surface coastal currents. Calculated concentrations were compared and discussed. A main conclusion is that, to reduce pollution in the Mediterranean Sea measures should be adopted for upgrading the water quality of the rivers discharging into the Mediterranean Sea, along with the construction of STPs for all the coastal cities.     

DISTRIBUTION OF SEDIMENT PHOSPHORUS POOLS AND FLUXES IN RELATION TO ALUM TREATMENT1

ABSTRACT: The distribution of sediment physical characteristics, sediment phosphorus (P) pools, and laboratory‐based rates of P release from the sediments were used to identify regions and dosage for alum treatment in Wind Lake, Wisconsin. Using variations in sediment moisture content, we identified an erosional zone at depths < 1.4 m and an accumulation zone at depths > 2.6 m. Mean concentrations of porewater P, loosely‐bound P, iron‐ and aluminum‐bound P, and mean rates of P release from sediments under anoxic conditions were high in the accumulation zone compared to sediment P characteristics in the erosional zone, indicating focusing of readily mobilized sediment P pools from shallow regions and accumulation to deep regions. We determined that a future alum treatment for control of internal P loading would be most effective at depths > 2.6 in the accumulation zone. The mean rate of anoxic P release from sediments encountered in the accumulation zone (8.3 mg m^‐2 d^‐1) was used in conjunction with a summer anoxic period of 122 d, and a treatment area of 1.6 km² to estimate an internal P load of 1,600 kg to be controlled. Our results suggest that an understanding of the distribution of sediment P pools and P fluxes in lakes provides a strategy for estimating alum dosage and application areas.     

Applying the principle of sustainability to coastal sand mining: The case of Pakiri-Mangawhai Beach,New Zealand

The purpose of New Zealand's Resource Management Act (1991) is to promote the sustainable management of natural and physical resources. Coastal sand mining may be consistent with this purpose where: (1) extractions occur from sediment systems open to inputs of sediment, and the volumes extracted do not limit the natural development, physical characteristics, and ecological diversity of the coastal environments affected; or (2) extractions from palimpsest or relict sedimentary deposits occur at a rate where the rate of extraction is insignificant compared with the volume of the resource. The response of coastal sand mining companies and consent-granting authorities to the requirements of the Resource Management Act (1991) are examined with respect to recent applications to mine sand from a coastal sand body in the Hauraki Gulf, New Zealand. The assessments of environmental effects (AEE) submitted in support of these applications do not establish the sustainability of the sand mining operations. Specifically they do not define the dimensions of the active sediment system, quantify the volume of the related resource, or state the period within which sustainability is achievable. Further, the AEE do not consider the cumulative effects of the extractions, either in terms of the total volume of sand mined or the cumulative effects of different anthropogenic activities. The test of sustainability demands a quality of information and understanding of coastal systems that is well beyond that obtained in the past or accepted at present. There is a clear need for New Zealand's resource management legislation to be supplemented by technical guidelines that help ensure the test of sustainability is rigorously applied.