Assessment of the Phytoremediation Potential of Salvinia minima Baker Compared to Spirodela polyrrhiza in High-strength Organic Wastewater

Salvinia minima combines several advantages for being used in aquatic phytoremediation. The objectives of this work were to compare the growth kinetics and productivity of S. minima and Spirodela polyrrhiza in high-strength synthetic organic wastewater (HSWW) and to evaluate the growth characteristics of S. minima in various culture media, including anaerobic effluents from pig wastewater (PWAE). It was found that the Relative Growth Rate (RGR) of S. minima was significantly higher (p?<?0.05) compared to the RGR of S. polyrrhiza in Hutner Medium (HM) and in HSWW. Also, S. minima showed a 1.5 fold productivity and a 2.3 fold productivity, compared to S. polyrrhiza in HM and HSWW, respectively. Diauxic growth of S. minima was observed preferentially under pH control and there was a simultaneous consumption of two nitrogen sources. Productivity of S. minima was similar in pig waste anaerobic effluents (PWAE) and in HM without ammonium nitrate and amended with ammonium sulphate (MHM?+?AS), at an initial NH₄ concentration of 35 mg l^?1. Above this level, the productivity was found to decrease as the initial ammonium concentration increased, in both media. Growth was completely inhibited at 140 mg l^?1 in the PWAE. In summary, S. minima is a better option than S. polyrrhiza for treating high-strength organic wastewater and lagoons should be operated at a maximum initial ammonium–nitrogen concentration of 70 mg l^?1 and at a pH of 5.0 or 6.0. Likewise, the initial density should be maintained in the range of 7 to 15 g dw m^?2.     

紫云英还田对水稻镉和铅吸收积累的影响

通过水稻盆栽试验研究紫云英还田对污染水稻吸收积累镉(Cd)和铅(Pb)的影响.结果表明:(1)与对照(不施肥)相比,纯化肥处理对土壤pH及土壤有效Cd、Pb含量没有显著影响;而紫云英还田可以显著提高土壤pH,显著提高土壤有效Pb的含量,对Cd无显著影响;在紫云英还田的基础上添加石灰虽然可以进一步提高土壤pH,但对土壤有效Cd、Pb含量并没有产生显著影响.(2)施用紫云英可以提高水稻根系对Pb的吸收,地上部分则呈现为分蘖期促进、成熟期抑制的作用,最终可显著降低糙米中的Pb含量.(3)施用紫云英可显著抑制水稻植株地上和地下部分对Cd的积累,尤其是地上部分的Cd含量,无论是分蘖期和成熟期均显著低于对照和纯化肥处理,其中糙米中的Cd含量降幅可达80％.研究结果还表明,紫云英还田不仅可以增加肥力,还可以显著抑制糙米对土壤Cd、Pb的吸收;但紫云英还田量不能太高,以30 000kg/hm2较佳.     

不同马铃薯品种对Cd、Pb吸收累积的差异

采用田间试验法,以中南地区主要种植的11个马铃薯品种为研究对象,测定马铃薯植株各部位重金属Cd、Pb含量,探讨不同品种的马铃薯对Cd、Pb的吸收累积差异,为马铃薯的安全种植提供实践参考。结果表明:Cd—Pb复合污染下,马铃薯块茎鲜重、茎叶鲜重以及根、茎叶、块茎中Cd、Pb含量在品种间均表现出显著差异。11个马铃薯品种块茎Cd含量范围为0.39～0.67 mg/kg,超标率100%,块茎Pb含量为0.16～0.43 mg/kg,超标率81.8%。马铃薯各部位Cd、Pb含量均呈现根茎叶块茎的分布特点;马铃薯对Cd的富集系数为2.35～5.56,对Pb富集系数为0.11～0.22,马铃薯富集转运Cd的能力大于Pb。尽管复合重金属靶标危险系数(TTHQ)法评价显示,金湘等5种马铃薯的TTHQ值1,对人体健康风险较小,但结合块茎Cd、Pb含量,建议污染区种植的马铃薯作为工业原料使用更安全。     

重金属铅在河道及滩地中的积累规律

基于山西省汾河3个代表性断面处河道与滩地分层土壤中重金属铅含量的测定资料,分析了土壤铅含量沿河道与滩地横向及垂向的分布特征及其机理.结果表明:重金属铅在沿横断面的水平方向上,随着距离河道主槽水平距离增加,铅含量减小;与山西土壤背景值相比较,表层土壤、地下水位处土壤和深层土壤受污染河水的影响范围分别是距河道主槽100m,80 m和60 m;在河道垂向上,随着土层深度的增加,铅含量也呈下降的趋势,但在个别土层稍有起伏;在非饱和土壤中,其运移动力依次是对流作用,分子扩散作用,机械弥散;在饱和土壤中,运移动力依次是对流作用,机械弥散,分子扩散作用.     

Zinc and Lead Accumulation by Two Contrasting Ecotypes of Sedum alfredii Hance at Different Zinc/Lead Complex Levels

The old mined ecotype (OME) was more tolerant to high zinc (Zn) and lead (Pb) levels than the nonmined ecotype (NME) of Sedum alfredii H. The greatest stem values of Zn and Pb of the OME at Zn/Pb of 2.0/0.1 mM reached 19.9 and 0.460 g kg^?1 respectively, which was 15 times greater for Zn but similar for Pb as compared with the MNE. The greatest leaf values of Zn and Pb for the OME were about 67 and 400 times more than for the NME. At Zn/Pb level of 1.0/0.2 mM, the OME shoots achieved the maximum Zn and Pb accumulation. No antagonistic effect of Zn and Pb was noted in the OME grown below tolerable metal levels, and Zn addition could enhance Pb uptake by the roots. The extraordinary ability to tolerate and accumulate both Zn and Pb by the mined ecotype of Sedum alfredii H. could be valuable for phytoremediation of multimetal‐contaminated soils.     

不同氮形态对铅胁迫下苏丹草根系形态及铅吸收富集特征的影响

为进一步研究富营养化水体中不同氮形态和重金属对修复植物的交互作用,通过水培试验研究了水体中不同形态氮培养对铅胁迫下苏丹草根系形态及其对铅吸收富集的影响。结果表明,水体Pb(0.5mmol/L)污染时,不同氮形态培养虽然对苏丹草根系形态有一定的影响,但没达到显著性差异,然而对苏丹草根系中丙二醛(MDA)含量及其各器官生物量的影响达显著差异(p<0.05),NH4—N营养液培养的苏丹草根系MDA含量比NO3—N,NO2—N营养液培养的分别高出了4.6和1.6倍;NO3—N营养液培养的苏丹草根、茎、叶生物量比NH4—N营养液培养的分别高出了28.7%,19.6%和23.9%,比NO2—N营养液培养的高出37.6%,30.9%和36.7%。水体Pb(0.5 mmol/L)污染时,NO3—N营养液培养的苏丹草根中Pb浓度明显比NH4—N营养液培养的高出2倍多,且其地下富集系数最大;NO2—N营养液培养的苏丹草茎中Pb浓度明显比NH4—N营养液培养的高出近8倍,且其对铅的转运能力影响作用最强。这表明受重金属污染的富营养化水体中如存在不同形态氮,在一定程度上还有利于削弱重金属对修复植物的毒性作用,增大水体对某些重金属的环境容量。     

Accumulation of Lead and Arsenic by Carrots Grown on Lead-Arsenate Contaminated Orchard Soils

Concerns have been raised of possible human food chain transfer of lead and arsenic from crops grown on orchard soils with histories of lead arsenate use. The objective of this study was to determine arsenic and lead uptake by three cultivars of carrots grown on four orchard soils with histories of lead arsenate use. Total concentrations of arsenic and lead in these soils ranged from 93 to 291 and from 350 to 961 mg kg^?1 for arsenic and lead, respectively. Arsenic in peeled carrot ranged from 0.38 to 1.64 mg kg^?1, while lead ranged from 2.67 to 7.3 mg kg^?1 dry weight. This study demonstrated that carrots will accumulate arsenic and lead in the root, which may become a human health risk when consumed. However, further studies are needed to determine what fraction of arsenic and lead in these carrots are bioavailable to humans when consumed.     

工程堆积体入渗特性及持水能力对降雨条件的响应

为探讨降雨对工程堆积体入渗特性及持水能力的影响,采用室内土壤基本物理性质分析及野外双环入渗方法,对不同降雨条件下工程堆积体入渗特性及持水能力的变化及影响因素进行研究。结果表明:工程堆积体土壤基本物理性质在不同降雨条件和坡位有较大差异,不同降雨条件下工程堆积体坡下的土壤容重大小表现为干旱(Ⅰ)小雨(Ⅱ)中雨(Ⅲ)大雨(Ⅳ);不同坡位工程堆积体的总孔隙度、毛管孔隙度、非毛管孔隙度大小表现为坡下坡中坡上。不同降雨条件下,初始入渗速率大小表现为干旱(Ⅰ)小雨(Ⅱ)大雨(Ⅳ)中雨(Ⅲ),其大小依次为8.91,5.52,3.96,3.25mm/min;稳定入渗率大小表现为干旱(Ⅰ)中雨(Ⅲ)小雨(Ⅱ)大雨(Ⅳ),其大小依次为4.40,1.45,1.32,0.53mm/min。不同降雨条件下工程堆积体坡下的最大有效库容大小表现为大雨(Ⅳ)小雨(Ⅱ)干旱(Ⅰ)中雨(Ⅲ),其大小依次为469.03,402.48,378.11,321.88t/hm2,中雨(Ⅲ)条件下工程堆积体在各坡位的田间持水量最大。工程堆积体的持水能力与总孔隙度、毛管孔隙度、入渗性能呈显著正相关关系,而与容重呈显著负相关关系。研究结果可为工程堆积体边坡水土流失防治提供重要科学依据。     

蔬菜硝酸盐累积及其影响因素的研究

本文综述了蔬菜硝酸盐的含量其体内硝酸盐的累积情况,探讨了影响其累积的内外因素,并提出了硝酸盐累积的防治对策以及一些新的建议。     

铅胁迫对向日葵幼苗矿质元素吸收和积累的影响

以不同浓度铅胁迫的向日葵整株幼苗为试验材料,用火焰原子吸收光谱法测定3个不同基因型向日葵中大量元素(K、Ca、Na、Mg)和微量元素(Fe、Mn、Cu、Zn)的含量。结果表明:不同浓度铅胁迫下3个基因型植株中的矿质元素累积量有明显的不同。首先,相同浓度铅胁迫下不同基因型向日葵幼苗对矿质元素吸收和积累的表现不同;其次,不同浓度铅胁迫下相同基因型向日葵幼苗对矿质元素的吸收和积累存在显著的差异(Cu、Zn元素除外)。     

印度芥菜对土壤Cd,Pb的吸收富集效应及修复潜力研究

通过盆栽试验对比研究了印度芥菜(Brassica juncea)和油菜对复合污染土壤Cd,Pb的吸收富集效应及修复效率.初步探讨印度芥菜品种Wild Garden Pungent Mix净化重金属污染土壤的应用潜力.结果表明:Cd,Pb复合污染条件下,与油菜相比,印度芥菜对重金属Cd,Pb的抗耐性较强,地上部生物量较大,是同处理油菜的1.1～2.0倍.印度芥菜和油菜对重金属Cd,Pb的吸收富集表现出较为一致的特点,并且对土壤中重金属的吸收能力顺序均为Cd＞Pb,对土壤中Cd的吸收达到了100 mg/kg以上.表现出了超富集植物的特性.但相比之下,印度芥菜对土壤中Cd,Pb的吸收富集能力强于油菜.同时通过多元回归分析表明,两种植物对Cd,Pb的吸收不存在复合效应.本研究中,印度芥菜对Cd的净化率为0.35%～9.22%,是同处理下油菜的2.1～3.5倍;印度芥菜对Pb的净化率只有0.015%～0.356%,虽然是同处理下油菜的1.4～5.5倍,但远小于对Cd的净化率.研究表明,该品种印度芥菜具备应用于修复Cd污染土壤的潜力.     

土壤-小麦体系的镉积累特征及影响因素

选取我国主要农作区的33个典型土壤，开展了两个常规小麦品种(蓉麦4号(RM4)和山农22号(SN22))的盆栽试验，研究了土壤–小麦体系内Cd的积累特征，并探究了相关土壤主控因子。结果表明：RM4和SN22两个品种小麦籽粒Cd含量分别为0.21(0.040～0.99)mg/kg和0.18(0.037～0.70)mg/kg，据GB 2762—2017,Cd超标率分别为75.6%和69.7%；小麦籽粒Cd的生物富集系数(BCF)分别为0.92(0.24～2.55)和0.81(0.16～1.67)，均表现出较强的Cd富集能力。多元逐步回归和广义Boosted模型分析发现，土壤全Cd和pH是影响小麦籽粒Cd吸收的主控因子，分别解释33个土壤中变量的81.3%和80.5%。     

黄土丘陵沟壑区典型灌木林地枯落物的蓄积特征及持水性能

[目的]对黄土丘陵区不同植被枯落物层持水效能进行研究,为该区植被恢复和水土流失防治提供理论基础。[方法]以柠条、沙棘、狼牙刺、杠柳4种典型灌木林地枯落物层为研究对象,采用室内浸泡法对其水文效应特征进行分析。[结果]①沙棘林地地表枯落物蓄积量最大(1.048 kg/m~2);沙棘林地土壤中枯落物量最大(0.674 kg/m~2);土壤中枯落物占枯落物总蓄积量的20.15%～68.75%,其中柠条和狼牙刺土壤中枯落物高于地表枯落物。②地表枯落物和混入土壤枯落物的持水量均随浸泡时间呈极显著对数函数关系(R~2≥0.745,p0.01),地表枯落物5 min持水量可以达到最大持水量的40%,且与最大持水量存在显著的幂函数关系(R~2=0.38,p0.01),可以通过5 min持水量来拟合最大持水量,而混入土壤枯落物并没有呈现这一规律。混入土壤枯落物的持水量显著大于地表,其中地表枯落物有效持水量杠柳最大(2.13 g/g),土壤中枯落物有效持水量柠条最大(1.90 g/g)。③地表枯落物有效拦蓄量沙棘林地最大,为21.16 t/hm~2;土壤中枯落物有效拦蓄量柠条林地最大,为10.01 t/hm~2;土壤中枯落物拦蓄量的校正系数变化范围在0.18～0.42之间。[结论]土壤中枯落物不容忽视,其混入量占枯落物总蓄积量的1/5甚至2/3以上;柠条总有效持水量最大,而受枯落物类型和积累量的影响,沙棘总拦蓄能力最大,具有较强的水源涵养和水土保持功能。     

Interactive Effects of Copper, Cadmium and Lead on Zinc Accumulation in the Gastropod Mollusc Littorina Saxatilis

The effects of copper, cadmium and lead on the bioaccumulation of zinc were studied in populations of the gastropod mollusc Littorina saxatilis from sites in the Isle of Man subjected to varying degrees of mine-related metal contamination. Exposures to 2 mg/L Zn alone and in combinations with 0.01 mg/L, 0.1 mg/L and 1 mg/L of the respective metals were conducted at ～10 ^°C in semi-static assays. Copper had a significant antagonistic effect on Zn accumulation at 1 mg/L Cu, but was not antagonistic at 0.01 and 0.1 mg/L Cu. Prior exposure to metals in the field did not appear to affect the interactive effect of copper as all populations showed similar patterns. Combinations of Zn with Cd or Pb at the above concentrations did not show any significant effects on Zn accumulation. On the other hand, Zn had an antagonistic effect on Cd and Pb accumulation but showed inconsistent effects on Cu accumulation. Interactions of Cu and Zn in particular may have repercussions for interpretation of biomonitoring data in L. saxatilis.     

EDTA对铅污染土壤上芥菜生长及铅积累特性的影响

采用盆栽实验研究了EDTA对Pb污染土壤上芥菜生长及Pb积累特性的影响。结果表明,单独Pb处理对芥菜生物量没有明显的影响,但高Pb处理(2000mg kg-1 Pb)芥菜地上部含水量显著降低;Pb处理芥菜体内Pb含量随土壤Pb浓度的增加而明显增加,根系Pb含量高于地上部Pb含量;3mmol kg-1 EDTA处理能促进土壤Pb溶解,增加土壤有效Pb含量,影响芥菜的正常生长,芥菜地上部生物量下降,高Pb浓度处理比低Pb浓度处理更明显;EDTA处理14天芥菜地上部和根系Pb积累量都比不加EDTA的对照明显增加,地上部Pb总量增加到对照的13.1～80倍;EDTA处理芥菜地上部与根系Pb含量的比值上升,表明EDTA处理促进Pb向地上部运输,这种促进作用因土壤Pb浓度的不同而略有差异。     

设施土壤重金属污染物累积的影响因素分析

通过实地调查、采样分析,研究了云南主要设施栽培区土壤重金属污染的累积状况及其影响因素.结果表明,云南省设施土壤重金属综合污染指数均>1.00,设施土壤已经开始受到污染,并且随着栽培年限的延长有累积程度加重的趋势,其中以Cd的污染程度较严重;重金属Pb、Cu、Zn、Ni、As均在花-菜轮作方式下累积量最大,而Cd在花-花轮作方式下累积量最大:不同棚型对重金属元素含量没有显著影响;多元线性回归分析表明, 土壤理化性状对重金属元素的综合影响大小顺序为:Hg>Cr>Zn>Ni>As>Cu>Cd>Pb,且从不同的影响因素来看,有机质、DH和速效P的影响较大.     

Permissible Concentrations of Arsenic and Lead in Soils Based on Risk Assessment

Establishing permissible concentrations for As and Pb in soils is of practical importance because of toxicity of these metals, their widespread contamination, and limited resources available for remediation of contaminated soils. The USEPA pathway approach to risk assessment was used to assess an environmental hazard related to As and Pb in soils and to evaluate safe concentrations of these metals in contaminated soil. The results from large-scale field experiments with soil fly ash-biosolids blends were used as input data to analyze pathways of the most intense transfer of the contaminants to a target organism. A direct soil ingestion by children (the soil-human pathway) was considered the most important exposure route to soil As and Pb. A conservative risk analysis shows that As concentrations in soil can reach 40 μg g^-1 without a hazard to exposed organisms. A Pb concentration in soil up to 300 μg g^-1 does not cause an excessive intake of Pb by humans as evaluated by a direct soil ingestion exposure model.     

滨海沙地不同人工林凋落物现存量及其持水特性

为了研究滨海沙地沿海防护林凋落物水源涵养功能,采用野外调查和室内浸泡相结合,对滨海沙地4种典型人工林(木麻黄林、湿地松林、尾巨桉林和纹荚相思林)不同分解阶段的凋落物现存量、持水率、持水量和吸水速率进行研究。结果表明:相同林龄的4种人工林凋落物现存量表现为木麻黄林(19.12 t/hm~2)湿地松林(17.51 t/hm~2)尾巨桉林(10.90 t/hm~2)纹荚相思林(10.13 t/hm~2),半分解层凋落物储量占比高于未分解层;4种人工林最大持水率在140.55%～206.47%,为尾巨桉林纹荚相思林木麻黄林湿地松林,最大持水量在20.75～30.85 t/hm~2,为木麻黄林湿地松林尾巨桉林纹荚相思林,4种人工林凋落物最大持水率和最大持水量均为半分解层大于未分解层,不同分解阶段凋落物持水率和持水量与浸水时间呈对数关系;4种人工林不同分解阶段凋落物平均吸水速率在前0.25 h内差异较大,未分解层中尾巨桉林最大为2.05 mm/h,半分解层中湿地松林最大为4.32 mm/h,不同分解阶段凋落物吸水速率与浸水时间均存在幂函数关系;凋落物有效拦蓄深为木麻黄林(2.45 mm)湿地松林(2.04 mm)尾巨桉林(1.87 mm)纹荚相思林(1.72 mm)。综合来看,木麻黄林凋落物的持水能力最强,湿地松林次之,之后是尾巨桉林和纹荚相思林,说明从凋落物水源涵养能力来看,木麻黄林和湿地松林更利于滨海沙地的水源涵养。     

Enhancement of Lead Uptake by Fenugreek Using EDTA and Glomus mosseae

The influence of Glomus mosseae supplemented with ethylenediaminetetraacetic acid (EDTA) on lead (Pb) uptake by Fenugreek (Trigonella foenum-graecum) was studied under pot conditions in a 2?×?2?×?5 factorial design with two AM treatments (G. mosseae inoculated and uninoculated), two EDTA concentrations (without and with 2.5 mmol EDTA kg^?1), and five lead concentrations (0, 50, 100, 400, and 800 mg kg^?1). A negative interaction was found between increasing lead concentration and G. mosseae. The plant dry matter and chlorophyll content was enhanced by G. mosseae whereas G. mosseae with EDTA showed the greatest root and shoot phosphorus (P) content. Ethylenediaminetetraacetic acid significantly enhanced lead concentration in the plant; however, at the same time it resulted in a slight decrease in the dry matter. However, when EDTA was applied along with G. mosseae, the deleterious effect of EDTA was overcome by the G. mosseae by promoting mineral uptake and plant growth, and hence metal accumulation also increased.