Physiological and Biochemical Responses of Perennial Ryegrass Mixed Planting with Legumes under Heavy Metal Pollution

In artificially controlled pot experiments,perennial ryegrass was mixed with other leguminous plants(white clo-ver and alfalfa)and treated with lead,zinc and cadmium(337 mg·kg^(-1),648 mg·kg^(-1),and 9 mg·kg^(-1),respectively)to simulate compound pollution conditions.The results showed that the concentrations of heavy metals,trans-port factors,and bioconcentration factors in mixed planting of ryegrass decreased compared with those in mono-culture.Regardless of whether heavy metal pollution was introduced,mixed planting increased the aboveground and underground biomasses of ryegrass.The different mixed planting treatments had no significant impact on the chlorophyll concentration of ryegrass.The mowing time,mixed planting treatment,and heavy metal treatment had impacts on antioxidant and osmotic adjustment substances,and there were some interactions.The mixed planting treatment did not significantly affect glutathione concentration,cysteine concentration,or nonprotein thiol.Mixed planting generally increased the nitrogen and phosphorus concentrations of ryegrass while reducing the stoichiometric ratio of carbon,nitrogen,and phosphorus.These results suggest that the mixed planting of ryegrass with legumes promotes the growth of ryegrass in the presence of high concentrations of heavy metal pollution.However,it does not enhance the ability of ryegrass to remediate heavy metal pollution in the soil.

Effects of Combined Pollution of Pb and Cd on Growth and Yield of Rice

[Objective] The aim was to study the damage and the mechanism of combined pollution of Pb and Cd on rice growth,yield and quality of rice. [Method]Effects of combined pollution of Pb and Cd on the growth and yield of rice were studied by pot experiment with cultivating rice. [Result] Pb and Cd could promote rice growth at low concentration while inhibit plant height at high concentration; Pb and Cd stress reduced the number of rice tillers significantly,with the increasing of stress concentration,the decrease amplitude of the number of tillers was greater; the panicle per pot,seed setting rate,1 000-grain weight and yield of rice were reduced significantly by Pb and Cd stress,the grain number per panicle decreased significantly under low concentration of Pb and Cd but increased significantly under high concentration; the brown rice rate and milled rice rate increased significantly under low concentration of Pb and Cd while at high concentration of Pb and Cd,the both two reduced significantly,the head milled rice rate reduced significantly with the decreasing of concentration; The Pb and Cd content of grains were significantly positively related to the concentrations of Pb and Cd content in soil,it had excessively exceeded hygienic standard when the concentrations of Pb and Cd in soil were medium-high and the unqualified rate reached 333% and 122%. [Conclusion]The study had provided basis for the establishment of rice cultivation system in pollution areas.

Effects of Cadmium Pollution in Soil on Physiological and Biochemical Index of Allium sativum L.

[Objective] The experiment aimed to study the effects of cadmium pollution in soil on physiological and biochemical index of Allium sativum L. and provided reference for the recovery of cadmium pollution in soil. [Method]By setting eleven Cd concentrations from 0.21 to 500 mg/kg in soil and the pot test, ecological corresponding mechanism of plant height, chlorophyll (Chl) content, catalase (CAT) activity and malondialdehyde (MDA) of Allium sativum L. was analyzed. [Result] The plant height had a strong tolerance to cadmium pollution in soil, while the total chlorophyll content and chlorophyll a content had no significant difference compared with control treatment, except Cd concentration was 500 mg/kg. The high Cd concentration would increase the damage to membrane of Allium sativum L. however with the regulation of physiological mechanism, the damage was gradually decreased.[Conclusion] Allium sativum L. had strong eco-physiological adaptability to Cd contaminated soil and it had potential for recovering Cd contaminated soil.

生物炭配施氮素对Cd胁迫下泡桐幼苗生理生态的影响

【目的】探究生物配施氮素对Cd胁迫下泡桐幼苗形态特征、根系形态、抗氧化性、光合特性及Cd积累、富集及转运的影响。【方法】以‘泡桐1201’幼苗为试验材料,设置组培和水培结合试验,通过生物炭和氮素单一处理,生物炭配施氮素处理,测定幼苗的生长指标、根系参数、光合气体参数、抗氧氧化酶活性、MDA含量及Cd积累量、富集系数与转运系数。【结果】①Cd胁迫下,施加生物炭和氮素可以显著增加泡桐‘幼苗株高、生物量及根系参数,两者交互处理效果最佳;②泡桐幼苗叶片和根系SOD、CAT活性增加,MDA活性降低。POD活性在两者单施处理下随浓度的升高而降低,在两者交互处理下随浓度的增大略有回升;③生物炭和氮素单施或配施,泡桐幼苗叶片Chla、Chlb、Chl(a+b)显著增加,Chl(a/b)无显著变化;泡桐幼苗叶片光合气体参数(P_(n)、T_(r)、C_(i)、G_(s))升高,单一生物炭处理下WUE最高,Ls值显著降低,叶片光合作用增强;④泡桐幼苗Cd含量减小,富集系数降低,转运系数及Cd积累量增大;⑤对泡桐幼苗叶片幼苗各指标进行相关性及PCA分析,发现各指标之间存在相关性,整体促进效果为生物炭配施氮素>生物炭>氮素。【结论】施加生物炭和氮素可提高泡桐幼苗光合能力,减少对Cd的吸收,缓解Cd毒害,进而增大生物量,促进各器官Cd积累量,以生物炭配施氮素处理效果最佳。

甜玉米自交系重金属Pb、Cd积累差异及分子检测

【目的】筛选获得在重金属Pb、Cd单一污染及复合污染下Pb、Cd低积累的优良甜玉米自交系,以及可用于甜玉米重金属Pb、Cd积累早代鉴定的分子技术。【方法】以10个甜玉米自交系为供试材料,通过盆栽试验研究重金属Pb、Cd单一污染及Pb、Cd复合污染下,玉米根系、茎叶和籽粒中Pb、Cd含量的积累差异;同时对供试材料ZmHMA2 InDel位点进行Pb、Cd积累差异分子检测,综合分子标记检测与重金属Pb、Cd在不同材料间的积累结果,筛选甜玉米重金属低积累自交系。【结果】无论是单一污染还是复合污染,重金属Pb、Cd的积累规律均表现为根系>茎叶>籽粒;在复合污染下,玉米不同组织对重金属Pb、Cd的积累无明显竞争与协同效应,表明玉米Pb、Cd的积累机制存在一定差异。通过鉴定,获得籽粒Pb低积累玉米自交系2份,籽粒Cd低积累玉米自交系3份,仅有一份材料闽甜系X901表现出籽粒Pb、Cd均低积累。利用InDel位点(InDel2307)对供试材料进行分子检测,结果发现供试材料中有4份存在该位点,含有该位点的材料中根系、茎叶和籽粒Cd含量平均值较其他材料平均值分别低1.801、0.64、0.131 mg·kg^(-1)。【结论】InDel2307位点能将不同玉米自交系按Cd累积量进行区分,对甜玉米Cd含量的区分具有特异性标记。综合分子标记检测与Pb、Cd含量积累结果,筛选出自交系闽甜系X901为Pb、Cd低积累材料。

矿区Cd污染稻田生物炭生态原位钝化及Cd形态转化

为探究生物炭对矿区Cd污染稻田土壤原位钝化生态修复效果,进行稻田土壤Cd污染修复试验,设置海泡石(BC1)、生物炭(BC2)、空白对照(BC3)3种处理。采用梯度扩散薄膜(DGT)技术研究水稻根际土壤Cd生物有效性,明确其对水稻根际土壤Cd生物有效性和土壤Cd形态转化的影响。结果表明:生物炭影响矿区Cd污染稻田水稻根际土壤Cd形态比率。生物炭改变稻田土壤中Cd形态,明显提高土壤中残渣态Cd含量占比,提高幅度达27.84%,利于其他形态Cd向更稳定的残渣态转变。生物炭改变矿区Cd污染稻田水稻根际土壤Cd生物有效性。与空白对照相比,生物炭使水稻收获期的根际土壤Cd生物有效性降低了40.90%,土壤中有效态Cd含量降低了9.53%;海泡石处理的土壤Cd生物有效性比生物炭处理的土壤Cd生物有效性降低了83.90%,海泡石处理的土壤有效态Cd含量比生物炭处理的土壤有效态Cd含量降低了7.73%。生物炭可提升矿区Cd污染稻田土壤质量。生物炭改善了水稻土壤质量;与空白对照相比,生物炭处理的土壤有机质提高了6.75%,土壤阳离子交换量升高了8.44%,土壤pH值提升了7.44%;与海泡石对照相比,生物炭处理的土壤有机质提高了2.95%,土壤阳离子交换量升高了9.22%,土壤pH值降低了13.33%。研究表明,生物炭原位钝化能有效降低矿区Cd污染稻田土壤Cd生物有效性,提升生态修复水平。

Use of Atomic Absorption Spectrometry in Assessment of Biomonitor Plants for Lead,Cadmium and Copper Pollution

Eleven plant species were collected from the vicinity of lead-battery plant in the city of Gaziantep,Turkey.Lead,cadmium and copper concentrations in the soil and leaves of plants were determined by atomic absorption spectrometry.Lead,Cd and Cu concentrations in the soil samples taken from battery area were found to be in the ranges of 304～602,0.4～0.44 and 31～37 mg·kg-1,respectively.Significantly increased lead concentration up to 2 750 mg·kg-1 was found in the leaves of Eleagnus angustifolia L.plant.The lead concentrations in the other plant leaves taken from 50 m around battery factory followed the order Ailanthus altissima>Morus sp.>Juglans regia L.>Ficus carica L.>Cydonia oblonga Miller>Prunus x domestica L.The plants,Populus nigra L.,Eleagnus angustifolia L.and Salix sp.were found useful for Cd,and the plant,Eleagnus angustifolia L.for Pb,to be considered as potential biomonitor.Especially,leaves of trees and plants taken from the distance of 50 m from battery plant have relatively higher Pb concentrations.Therefore,people who and animals which live in this area and benefit from these soil and plants have vital risks.

Evaluation of genotoxicity of combined soil pollution by cadmium and phenanthrene on earthworm

The DNA-damaging effects of the combined pollution of heavy metal and organic contamination on earthworms were evaluated by single cell gel electrophoresis （SCGE） assay. Earthworms Eisenia andrei were exposed to single or combined test compounds in different doses of cadmium （Cd） 5, 10, 50 mg/kg and phenanthrene （Phe） 0.5, 2.5, 12.5 mg/kg with a treatment of 14 d. In SCGE assay, isolated coelomcytes and electrophoresis were employed to determine DNA damage degree after a 14-d treatment by test compounds. The results showed that there was a significant statistical difference between earthworms treated with Cd combined Phe with them treated alone with Cd or Phe. The Olive tail moment （OTM） of SCGE assay using earthworm coelomcytes appears to be a sensitive biomarker for evaluating exposure to genotoxic compounds. These tests also revealed that the interaction between Cd and Phe to DNA damaging effects was negative, and was strongly dependent on the concentration of pollution. This study corresponds to exploratory phase in order to reveal interaction effects of heavy metal and organic contamination on earthworms and then to set up more in-depth analysis to increase progressively the understanding of the genotoxicity mechanisms involved.

好氧堆肥对生物炭理化性质及吸附Cd^(2+)稳定性的影响

生物炭可作为畜禽粪污好氧堆肥中去除重金属的功能材料,但堆体内部复杂的环境变化会影响生物炭的理化性质,从而影响其对重金属吸附的稳定性。将普通秸秆生物炭(BC)和磁性秸秆生物炭(FBC)置于牛粪中进行30 d好氧堆肥试验,研究两种生物炭基本理化性质及对Cd^(2+)吸附稳定性的影响。结果表明:堆肥处理使BC和FBC的比表面积分别增加20.56%和76.64%,总孔容分别下降2.36%和3.70%,平均孔径分别下降19.17%和46.54%,表面官能团发生变化,FBC的饱和磁化强度下降43.67%。堆肥后,饱和吸附Cd^(2+)的两种生物炭BC和FBC的TCLP提取态Cd(TCLP-Cd)占比和TCLP提取液pH(TCLP-pH)均呈下降趋势,其中TCLP-Cd占比分别从28.31%和22.85%显著下降至26.76%和13.85%(P<0.05),TCLP-pH分别从3.66和3.29显著下降至3.51和3.14。综上,堆肥老化改变了两种生物炭的理化性质,降低了其酸可提取态Cd的含量,提高了其吸附Cd 2+的稳定性,且FBC中Cd^(2+)的稳定性更强。

Review: effect of environmental cadmium pollution on human health

Based on the available data obtained from the population investigating, the authors reviewed research articles of the study on analytical me- thods and exposure levels of cadmium (Cd) in population, the injury of target organ, the evol- vement of sensitive index for surveillance, the study on effects of human disease and death for environmental Cd exposure, and the study on priority surveillance of human health risk.

基于作物Cd富集系数的土壤有效态Cd化学浸提方法筛选

土壤中镉(Cd)被作物吸收的程度及其生态风险取决于土壤中Cd的赋存形态,基于Cd有效形态的污染土壤风险评价及在此基础上制订污染土壤修复安全阈值是Cd污染农田土壤风险评价和治理亟待解决的问题。目前针对土壤中重金属有效态的化学浸提方法较多,但缺乏针对不同性质土壤中有效态Cd的普适性浸提方法已成为Cd污染土壤风险评价技术瓶颈。本研究采集了全国9个不同性质农田土壤,以水稻、小白菜和玉米为测试作物,通过外源添加方法制备Cd污染土壤,结合土壤培养和盆栽实验,测定了5种常用化学浸提方法,包括中性无机盐浸提方法(CaCl_(2)浸提法)、弱酸浸提法(HCl浸提法)、络合螯合剂浸提方法(DTPA和ETPA浸提法)和组合浸提方法(Mehlich-3(M3)浸提法)对不同性质土壤中有效态Cd浸提效果及其与作物Cd吸收的量化关系,筛选适用于不同性质土壤中有效态Cd的通用浸提方法。结果表明,不同化学浸提法提取的土壤有效态Cd含量间具有显著差异,不同浸提方法对土壤中Cd的浸提率(%)为DTPA≈EDTA≈HCl>M3≈CaCl_(2)。不同化学浸提态Cd与作物Cd吸收的相关系数间具有显著差异,基于综合相关系数方法,得出5种不同浸提态Cd与作物Cd吸收的综合相关系数为I M3=0.765,I EDTA=0.641,I DTPA=0.627,I HCl=0.606,I CaCl_(2)=0.711,M3浸提态Cd含量与不同性质土壤中水稻、小白菜和玉米植株地上部Cd相关性最高,可作为不同性质土壤中有效态Cd通用浸提方法。相关研究结果可为农田土壤中Cd有效态评价及Cd污染农田的修复提供理论依据。

洋葱伯克霍尔德菌菌株JLS17对Cd^(2+)胁迫的生长及代谢响应机制

【目的】探究1株植物促生菌洋葱伯克霍尔德菌菌株JLS17对Cd^(2+)的耐受与去除能力以及在Cd^(2+)胁迫下的代谢响应,以期为菌株在土壤镉污染修复的应用提供基础理论依据,并为阐明具有抗镉功能分子与代谢途径的挖掘及微生物Cd^(2+)耐受机制提供数据支撑。【方法】通过测定含不同Cd^(2+)浓度培养液的吸光度(OD600)值评价菌株对Cd^(2+)的耐受性,利用电感耦合等离子体质谱仪(ICP-MS)测定菌株对LB培养基中Cd^(2+)的去除效果,采用非靶向代谢组学技术(LC-MS)分析菌株在Cd^(2+)胁迫下的差异代谢物与代谢途径。【结果】1)不同程度的Cd^(2+)胁迫(50~800 mg·L^(−1))均对菌株JLS17的生长速率及生物量增长(OD600)有明显的抑制作用,且抑制作用随Cd^(2+)浓度的升高而不断加剧。2)菌株JLS17对LB培养基中Cd^(2+)的去除量随Cd^(2+)浓度的提高(10~100 mg·L^(−1))而增加,最高去除量可达55.90 mg·L^(−1),但去除率受Cd^(2+)浓度影响相对较小,维持在41.9%~66.0%。3)LC-MS分析结果表明,菌株JLS17在50 mg·L^(−1)和300 mg·L^(−1)的Cd^(2+)浓度胁迫处理下,共有147种差异代谢物表达趋势一致,其中92种共性上调,55种共性下调,主要涉及氨基酸及其衍生物、核苷酸及其衍生物、脂质、有机酸及其衍生物、萜类、酮类、生物碱等。KEGG富集分析结果表明,菌株JLS17在50 mg·L^(−1)和300 mg·L^(−1)的Cd^(2+)浓度胁迫处理下显著富集的共有代谢通路为嘧啶代谢、氨基苯甲酸酯降解、半胱氨酸和蛋氨酸代谢、色氨酸代谢、β-丙氨酸代谢、叶酸的生物合成与磷酸戊糖途径,其中嘧啶代谢、色氨酸代谢、磷酸戊糖途径共性下调,叶酸的生物合成共性上调。【结论】1)菌株JLS17对Cd^(2+)胁迫具有极强的适应性,并能有效去除LB培养基中的Cd^(2+),在镉污染修复中具有良好的应用潜力。2)菌株JLS17在Cd^(2+)胁迫下可通过氨基酸及其衍生物、核苷酸及其衍生物、脂质等代谢物含量变化影响体内的代谢途径,其中色氨酸代谢、β-丙氨酸代谢、半胱氨酸和蛋氨酸代谢、嘧啶代谢、磷酸戊糖途径、叶酸的生物合成等代谢途径与JLS17的Cd^(2+)耐受性密切相关。

入侵植物三裂叶薯生物炭对Cd2+的吸附性能研究

以外来入侵植物三裂叶薯(Ipomoea triloba)制备生物炭(IBC),分别于300℃、500℃、700℃限氧条件下制备得到三裂叶薯生物炭(IBC300、IBC500和IBC700),结合FTIR和XRD等手段对IBC在水溶液中Cd^(2+)的吸附特性及机理进行研究。结果表明,IBC对Cd^(2+)的吸附过程符合拟二级动力学方程(R^(2)值为0.868~0.976),以化学吸附为主;Langmuir模型更加适合用于模拟IBC对Cd^(2+)的吸附(R^(2)值为0.982~0.984),说明主要以单分子层吸附为主,为有利吸附。IBC700对Cd^(2+)吸附效果最好。吸附机理以化学吸附为主,具体机理与碳酸盐离子发生络合沉淀反应和官能团的π-π相互作用。

典型矿区周边水田土壤Cd生物有效性研究

为遴选可有效表征农田土壤Cd生物有效性的指标,文章采集浙江某地20组稻米及其协同土壤,分析稻米Cd质量比、土壤的基本理化性质、Cd总质量比、不同浸提态Cd质量比及欧共体标准物质局(European Community Bureau of Reference,BCR)形态。结果表明:稻米Cd质量比为0.01~0.51 mg/kg,土壤Cd质量比为0.17~3.15 mg/kg,稻米Cd富集系数为0.04~1.42;土壤Cd主要以弱酸态(40.5%)和还原态(37.1%)存在,二乙烯三胺五乙酸(diethylenetriaminepentaacetic acid,DTPA)浸提土壤Cd能力最强(15.6%);基于w(CaCl_(2)-Cd)构建的三次函数建立的回归模型可解释稻米Cd 57.4%方差,w(CaCl_(2)-Cd)可以作为表征水稻土壤Cd生物有效性的指标,基于水稻土壤Cd生物有效性可提高污染风险评价的科学性。

Recovery time of macroinvertebrate community from Cd pollution in Longjiang River,Guangxi,China

Estimating recovery times from pollution incident is an important issue of targeted biomonitoring programs.In the present study,the impact and recovery of macroinvertebrate communities from a cadmium wastewater discharge in the Longjiang River,Guangxi,China,in early January 2012 were studied based on 83 samples collected in fi ve surveys within 20 months after the incident.The pollution aff ected seriously the local aquatic biota,and consequently,the invertebrate abundance and species richness were reduced considerably.Twelve months later,the taxonomic number of macroinvertebrates began to increase.However,sensitive taxa remained rare.Twenty months later,the taxon richness and abundance of macroinvertebrates increased signifi cantly compared to those in the previous four time points.To explore the possible time-scale over which pre-disturbance conditions might occur,we chose four diff erent typical metrics of taxa richness(total taxa number,cumulative taxa number,taxa number per samples,and the Shannon-Wiener diversity index)and extrapolated modeled recovery trajectories.Target values for the four metrics were set at average values for sites from the nearby Lijiang River,which were used as a reference.Assuming a continued linear trajectory,the recovery times were estimated to be 52,39,39,and 31 months,respectively,which was roughly 3-5 years.This is consistent with results from recovery times from other studies of acute pollution cases,but contrasted strongly to the much longer recovery times associated with chronic pollution from groundwater contamination and mine-tailing runoff.

Assessment of the Potential of Honeybees (<i>Apis mellifera</i>L.) in Biomonitoring of Air Pollution by Cadmium, Lead and Vanadium

The aim of our study was to explore whether honeybees (Apis mellifera L.) could be used as a reliable alternative to the standard mechanical devices for monitoring of air quality, in particular with respect to the concentration of the heavy metals cadmium (Cd), lead (Pb) and vanadium (V). We therefore tested whether the concentrations of these metals in adult honeybees and in ambient air were positively correlated, and whether differences in concentration between locations were similar for bees and air. On the basis of our measurements, conducted over a two-month period at three distinct locations in the Netherlands with each three replicate honeybee colonies placed next to mechanical monitoring devices, we concluded that a significant positive relationship between the concentrations in bees and in air could only be established for V. Also, only in the case of V, the differences between the three locations in mean concentration were similar for bees and air. Both outcomes were probably due to the relatively large range over which the concentrations of V varied, both in bees and in air, as compared to Cd and Pb. However, for V, as well as for Cd and Pb, the concentrations in ambient air were about two orders of magnitude below the established air quality standards. We therefore conclude that in the Netherlands, both variation and levels of the atmospheric concentrations of these metals are too low to establish a relationship between the concentration in bees and in air that is useful to present honeybees as an alternative to mechanical devices in monitoring of air pollution. However, in countries with larger variation and higher levels of the atmospheric concentrations of these metals, further exploration of the potential of honeybees in biomonitoring of air pollution may be worthwhile.

Mitigative Effect of La on Glycine max seedlings under Pb-Cd Compound Pollution

Mitigative effect of La on Glycine max seedlings under combined Pb and Cd pollution was studied through pot culture experiment. The results show that the growth and metabolism of Glycine max seedlings are inhibited by the solution with 500 mg.L-1 Pb + 100 mg.L-1 Cd. When 30 mg. L-1 LaCl3 is used to spray Glycine max seedlings once, the injury effect of combined Pb and Cd pollution is reduced. The experiment proves that the effect is related to La which can raise photosynthetic rate, chlorophyll content and activity of nitrate reductase, and reduce cell membrane permeability, content of Pb and Cd, and keep TTC reduction ability of Glycine max seedling.

Remediation Technology for Combined Pollution of Lead and Cadmium in Farmland Soil

At present,the problem of heavy metal pollution in farmland in southern China is serious. Especially,the cadmium and lead are two heavy metal elements with serious pollution and great harm to human body. This paper reviewed some common methods and materials used in the control of cadmium and lead pollution in farmland soil. Then,it discussed the problems in the repair of cadmium and lead pollution in farmland soil. It came up with the future research direction,to provide references for remediation of lead and cadmium pollution in farmland soil.

Tissue distribution of cadmium and its effect on reproduction in Spodoptera exigua

Vegetable fields are often contaminated by heavy metals,and Spodoptera exigua is a major vegetable pest which is stressed by heavy metals mainly by feeding.In this study,cadmium accumulation in the tissues of S.exigua exposed to cadmium and its effects on the growth and development of the parents and the offspring were investigated.Under the stress of different concentrations of cadmium(0.2,3.2,and 51.2 mg kg^(-1)),the cadmium content in each tissue of S.exigua increased in a dose-dependent manner.At the larval stage,the highest cadmium accumulation was found in midgut in all three cadmium treatments,but at the adult stage,the highest cadmium content was found in fat body.In addition,the cadmium content in ovaries was much higher than in testes.When F1S.exigua was stressed by cadmium and the F_(2)generation was not fed a cadmium-containing diet,the larval survival,pupation rate,emergence rate and fecundity of the F_(2)generation were significantly reduced in the 51.2 mg kg^(-1)treatment compared to the corresponding F1generation.Even in the F_(2)generation of the 3.2 mg kg^(-1)treatment,the fecundity was significantly lower than in the parental generation.The fecundity of the only-female stressed treatment was significantly lower than that of the only-male stressed treatment at the 3.2 and 51.2 mg kg^(-1)cadmium exposure levels.When only mothers were stressed at the larval stage,the fecundity of the F_(2)generation was significantly lower than that of the F1generation in the 51.2 mg kg^(-1)treatment,and it was also significantly lower than in the 3.2 and 0.2 mg kg^(-1)treatments.The results of our study can provide useful information for forecasting the population increase trends under different heavy metal stress conditions and for the reliable environmental risk assessment of heavy metal pollution.

Cd^(2+)浓度对好氧颗粒污泥EPS各组分形成的影响

为探究重金属Cd^(2+)对好氧颗粒污泥系统运行的影响,采用紫外分析法和三维荧光光谱分析法研究了SBR反应器中不同浓度的重金属Cd^(2+)对好氧颗粒污泥EPS总量以及各组分(LB-EPS、SB-EPS、TB-EPS)的产生与组成成分的影响。试验结果表明:低浓度Cd^(2+)(小于0.1mg/L)促进EPS的产生,高浓度Cd^(2+)(大于3mg/L)抑制EPS的产生;SB-EPS随着Cd^(2+)浓度的增加逐渐减少,其中蛋白质含量增加,多糖、腐殖酸明显减少;当Cd^(2+)浓度小于0.1mg/L时TB-EPS显著增加,其中主要增加的成分是蛋白质;当Cd^(2+)浓度大于3mg/L时,TB-EPS的分泌受到抑制,但蛋白质含量仍高于空白对照组,多糖、腐殖酸含量显著降低;LB-EPS受到的影响因素较多,其含量变化不规律。采用扩展DLVO理论剖析了EPS各组分含量的变化对好氧颗粒污泥沉降性能的影响,以期为好氧颗粒化技术在工业废水处理中的应用提供有力的支持。