湖南铝产业园周边农作物氟污染特征研究

通过对湖南某铝产业园周边地区农作物中氟化物的含量进行监测分析以及周边地区环境空气的氟化物质量浓度进行监测分析,研究该产业园废气中的氟化物排放对周边农作物的污染影响程度、规律及其特征,经调查研究显示,产业园周边不同的农作物对氟的累积能力不同;农作物的氟污染程度与方位距离有关,并呈逐年上升趋势;农作物氟污染与空气氟浓度呈显著正相关。     

环评中含氟废气对农作物影响评价及实例探讨

目前在环评中含氟废气对农作物的影响评价主要通过预测氟化物浓度,然后与标准浓度限值比较后进行定性判断,往往忽视了在低于标准浓度限值情况下氟化物对农作物的影响评价。本文探讨了环评中含氟废气对农作物的影响,分别从标准的选取、评价方法、预测和评价内容、评价步骤等方面进行研究,并以某新材料厂含氟废气为实例进行评价,根据气象资料、氟化物对农作物伤害浓度阈限值等数据,对农作物叶片在不同浓度下的伤害程度进行定量评价。     

温度和放置时间对氟化物测定结果影响的探讨

氟是最活跃的非金属元素,自然界分布较广泛,多以氟化物(金属氟化物、氟化氢、四氟化硅)形式存在。空气中氟化物浓度超过一定量,会对人群、牲畜及农作物等产生不良影响。通过测定温度、放置时间两个因素对氟化物浓度的影响,得出温度为25℃、样品放置4h时为氟化物测定的最佳测定条件。     

氟化氢熏气对蚕豆叶片伤害阈值的初步研究

前言为了制定地方性大气氟化物排放标准,保护农作物免遭氟化物的危害,有必要研究大气HF对农作物的伤害阈值。国外自六十年代以来即进行了许多试验以便确定大气氟化物对植物的伤害阈值。而我国采用开顶式熏气装置进行同类的工作尚属开始。本文采用开顶式熏气装置研究了HF熏气对蚕豆叶片的仿害阈值、蚕豆对氟化物的累积系数等,观将试验结果作一初步报道。     

电解铝厂周边土壤和农作物氟污染评价

通过对广西某电解铝厂周边大气、土壤和农作物氟化物污染进行监测评价,结果表明:铝厂周围大气氟污染与采样点到铝厂距离无明显相关,却与采样点的方位成显著相关;土壤中水溶氟的含量与采样点到铝厂距离呈负相关.农作物玉米叶片氟污染物主要来自于铝厂排放的氟化物.玉米果实样品中的氟含量除对照点属于中度污染外,其余样点样品均属重污染.     

AERMOD在高原山地城市大气预测中的应用——以某电厂为例

采用AERMOD对位于高原山地城市的某电厂点源及面源所排放的SO2及氟化物进行了预测,结果显示:SO2和氟化物对农作物的影响均很小,需在冬季时减小排放;AERMOD能较好地对高原山地城市污染物扩散进行预测模拟,模型预测的浓度分布能够反映出气象场变化以及项目所在地地形条件等对大气污染物迁移和扩散的影响;研究区域内氟化物小时平均浓度和日均浓度分别超过《GB3095-2012环境空气质量标准》中的二级标准值的3.40倍和1.41倍,出现在北部厂界处。     

砖厂氟污染对农作物、果树的影响分析

本通过对白云区人和镇两个砖厂周围大气环境氟污染的调查和农作物、果树氟化物含量的测定分析，发现两砖厂周围的农作物和果树已受到严重的氟污染危害。     

土壤氟污染对水稻的影响

由于磷肥、炼铝、炼钢、制砖、水泥、玻璃、搪瓷、电力等工业大量排出含氟废气和废水,来自废气和废水中的氟化物溶解度较大,对农作物有较大的影响,这方面国内外有较多的研究和报导。但外来氟进入土壤造成土壤氟污染后对农作物的危害以及土壤中     

大气污染对农业的影响

大气污染对农业的影响青岛市环保科研所敦婉如青岛市黄岛区监测站邱中华工业生产过程产生的废气，常见的有二氧化硫、氟化物、氯气、氮氧化物、乙烯、氨气、臭氧、重金属粉尘等，这些污染物质均能影响农作物的生长和发育，造成农业减产。有些大气污染物质如氟化物、重金属...     

对制定大气环境及污染源氟化物标准的一点看法

<正> “氟化物”指含氟元素的无机及有机化合物。工业废气排放的氟化物有气态的氟化氢,四氟化硅、四氟化碳等;也有固态微粒状的氟化钠,六氟硅二钠,三氟化铝、六氟铝钠、氟化钙、含氟树脂、含氟农药等。其中气态氟化氢及四氟化硅对环境危害最大;易溶于水或弱酸的无机氟化物次之;惰性的四氟化碳及在强酸中都难以溶解的氟化物对环境的危害较小。不少国家在对氟化物的标准中,明确指明氟化物的种类,这样有利于选择相应的监测方法和科学地进行环境质量管理。苏联的大气环境中氟化物标准如下:     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.