铜污染土壤修复的有机调控研究Ⅲ.EDTA和低分子量有机酸的效应

通过盆栽试验研究了EDTA和低分子量有机酸对土壤溶液性质、土壤铜形态变化和印度芥菜生长及铜吸收的影响。结果表明 ,施用pH6.3的EDTA溶液 ( 3mmolkg- 1 )显著地增加了土壤溶液铜 ,特别是难解离态铜的含量 ,其消长规律与土壤溶液TOC的变化相一致 ,也显著地增加土壤NH4NO3提取态和NH4OAc提取态铜量 ,但对芥菜生长没有显著影响。EDTA的加入显著地增加芥菜各组织铜浓度和铜吸收量 ,从而增加了芥菜的铜总吸收量 ,提高了植物修复效率。施用 3mmolkg- 1 pH6.3的草酸、柠檬酸或苹果酸对土壤铜含量及其形态分配和芥菜生长及铜吸收均无明显影响     

氮磷钾肥料对茶园土壤溶液中氟含量的影响

在室内模拟条件下,设置茶园土壤单施不同水平及形态的氮肥以及配施不同水平氮、磷、钾肥料处理,根据各处理施肥后土壤中的肥料浓度向土壤中添加相应肥料溶液,测定不同时间段后土壤溶液的pH值和氟含量,分析氮肥水平和形态,氮、磷、钾配施对茶园土壤溶液中氟含量的影响。结果表明:(1)单施氮肥条件下,施用铵态氮和硝态氮增加了土壤溶液中氟含量,酰胺态氮则降低了土壤溶液中氟含量,且三者对氟含量的增加或降低作用均随施肥时间和氮肥水平的增加而增加;施肥后48 h土壤溶液中氟含量与土壤溶液pH值呈负相关(r=-0.658~(**)),氮肥形态通过影响土壤溶液pH进而影响土壤溶液氟含量。(2)氮、磷、钾配施时,随着施肥时间的增加,土壤溶液中氟含量增加,不同处理的差异显著性则降低;相同磷、钾水平下,土壤溶液中氟含量随氮肥(硫酸铵)水平的增加而显著增加;磷肥可显著降低土壤溶液中氟含量,钾肥可以增加土壤溶液中氟含量,同样施氮条件下,土壤溶液中氟含量的大小基本为N+KN+P+KNN+P;施肥后48 h土壤溶液中氟含量与氮水平高度正相关(P0.01),与土壤溶液pH值高度负相关(P0.01),氮、磷、钾配施茶园土壤溶液中氟含量主要受氮肥水平和土壤溶液pH的影响。可见,在茶园中施用适量的酰胺态氮,或者配施磷或磷钾,在一定时间内可以提升土壤pH值,进而降低土壤溶液氟含量,为合理施肥,降低茶园土壤有效氟提供了理论依据。     

淹水还原条件下红壤中葡萄糖及腐殖酸对铁锰形态的影响

通过设置不同的葡萄糖/腐殖酸配比模拟还原性土壤体系,考察长期(约74 d)淹水培养过程中铁锰元素在土壤溶液/矿物相中的分布形态演变。结果表明:在淹水培养初期,葡萄糖的添加可以促进铁锰离子的还原溶出,同时土壤中可交换态和酸可提取态铁、以及可交换态锰的含量也会随之增加;而腐殖酸的添加则会促进土壤中可氧化态铁/锰含量的升高。随着培养时间的增加,铁锰离子浓度及各个土壤提取形态的铁锰含量大多呈现降低趋势,铁锰元素逐渐转化成提取性更低的矿物形态。因此,淹水环境中铁锰还原溶出-分布形态演变受到土壤中有机物质种类和含量的显著影响,呈现出不同的金属移动性和生物有效性。     

多环芳烃芘对小白菜生长和元素吸收及营养品质的影响

通过土培试验测定了不同浓度芘处理下小白菜根和茎叶的生物量、芘及其它矿质元素的含量和一些营养品质指标。结果表明:芘对小白菜根干重的影响显著,对茎叶干重和株高的影响不显著,全株干重由于根干重的下降而呈下降趋势;根中的芘含量和土壤中残留的芘含量随土壤中芘浓度增加而显著增加,茎叶芘含量与对照无显著差异,土壤芘降解率随芘浓度增加表现为先上升再下降的趋势;茎叶有机碳和根粗灰分含量随土壤芘浓度的增加而下降,茎叶粗灰分和根有机碳含量施芘处理显著高于对照,芘促进了根对土壤中N、P、K和S的吸收同化,并加速其向茎叶的转移。茎叶粗蛋白含量较对照有所增加,粗纤维和可溶性糖含量则随芘浓度增加而下降,其中可溶性糖含量各个处理与对照之间的差异达显著水平。     

四种改良剂对铜和镉复合污染土壤的田间原位修复研究

研究了石灰、磷灰石、蒙脱石和凹凸棒石对冶炼厂周边Cu、Cd污染土壤的原位修复效果。以黑麦草(Lolium perenne L.)作为田间修复植物,采用植物重金属吸收性、土壤重金属化学提取性及土壤溶液重金属浓度变化等作指标来评价修复效果,并研究了黑麦草对Cu、Cd的吸收与土壤、土壤溶液中Cu、Cd含量的相关性。结果表明,石灰高添加剂量(石灰占污染土壤耕作层质量的0.4%)处理黑麦草对重金属的富集效果最好,显著降低了重金属毒性,促进了黑麦草的生长及其对重金属的富集;石灰和磷灰石各添加剂量均显著降低了污染土壤交换态Cu含量;石灰、磷灰石和蒙脱石各添加剂量均显著提高了土壤溶液pH并显著降低了其Cu、Cd浓度。黑麦草地上部、根中Cu浓度与土壤交换态Cu及土壤溶液Cu浓度呈显著或极显著正相关关系。     

石灰性土壤团聚体中钙形态特征及其与有机碳含量的关系

本文选取5种碳酸钙含量(4.29、17.45、98.66、131.85、143.82 g/kg)差异显著的北方碱性旱地农田土壤(黑土、淡黑钙土、潮土、灰钙土和黄绵土)为研究对象,分析土壤及其各粒级团聚体中有机碳、碳酸钙和不同形态钙含量的分布特征及相关性,探讨碳酸钙对碱性旱地土壤有机碳的影响。结果表明:全土有机碳含量与碳酸钙含量之间无显著相关关系,但在0.002～0.053、0.002 mm团聚体中二者含量显著负相关(R~2分别为0.67、0.83),碳酸钙含量过高影响微团聚体有机碳积累。土壤钙形态中酸溶态和可氧化态是影响微团聚体有机碳积累的主要钙形态,全土中占全钙含量都在64.09%以上,团聚体中其含量随粒径减小而增加。钙离子是有机无机复合体的重要胶结物,但钙离子过多则可能会抢占土壤颗粒上有机碳结合点位,与黏粒和粉粒结合形成微团粒结构,影响有机碳积累。     

有机酸对酸性土壤中铝的溶出和铝离子形态分布的影响

五种低分子量的有机酸对酸性土壤中铝的溶出和铝离子形态分布的影响的研究结果表明，有机酸主要通过与铝形成络合物而促进铝的溶解，使土壤溶液中有机络合态铝浓度增加，有机酸对无机铝形态的影响较小。不同有机酸由于本身的性质和结构不同，它们对铝溶解的影响不同。     

天然蒙脱石和沸石改良对黑麦草在铜尾矿砂上生长的影响

通过温室盆栽试验,开展了天然蒙脱石和沸石处理对黑麦草在铜矿尾矿砂上生长影响的研究。结果表明:蒙脱石和沸石改良对黑麦草的地上部生物量没有显著影响,但改变了黑麦草的根重;而施用肥料促进了黑麦草生长。蒙脱石的加入使尾矿砂的有效态锌含量显著降低,但对有效态铜的含量影响不明显;而沸石的加入均显著降低了尾矿砂的有效态铜和锌的含量;另外,矿物的加入降低了尾矿砂的pH值,但其变化与尾矿砂重金属有效态含量变化之间无相关性。矿物的加入降低了黑麦草根中的铜锌吸收,但蒙脱石增加了第一茬黑麦草地上部铜锌吸收,对第二茬黑麦草地上部铜锌吸收无影响;而沸石对两茬黑麦草地上部铜锌含量均无显著影响。不同生长期黑麦草对铜锌吸收量有差异,第二茬黑麦草的地上部锌含量明显高于第一茬,而铜含量则变化不大。     

施肥对黑土密度分组中碳、氮的影响

以中国科学院海伦农业生态实验站的长期定位施肥土壤为基础,研究长期施肥对黑土密度分组中碳和氮的影响。结果表明:氮肥能够增加土壤有机碳和全氮含量,但不如NPKOM效果明显。土壤中各组分有机碳含量的变化趋势为重组>游离态轻组>闭蓄态轻组,三者之间差异达极显著水平(p<0.01),重组有机碳的含量最大值为23.72 g/kg,而闭蓄态轻组有机碳的平均值仅为0.69 g/kg;全氮的含量的变化呈重组最大,且极显著大于闭蓄态轻组和游离态轻组,后两者之间无明显差异。不同组分中有机碳浓度和全氮浓度的变化规律一致,为游离态轻组>闭蓄态轻组>重组,且游离态轻组明显大于其它两个组分。NPKOM处理的闭蓄态轻组和重组组分中的有机碳浓度和全氮浓度大于其它施肥处理。碳氮比的变化趋势为游离态轻组>闭蓄态轻组>土壤>重组,重组和土壤中,NPKOM处理的碳氮比最低,CK处理的碳氮比最大,可见有机肥的施用加快了土壤碳的周转速度。     

不同植被恢复对侵蚀型红壤活性碳库的影响

为了解侵蚀型红壤不同植被恢复后,土壤有机碳的演变状况,采集了持续时间为17年和9年的2个定位试验点土壤样品,分析了土壤总有机碳、微生物量碳、水溶性碳和矿化态碳含量.结果表明侵蚀型红壤植被恢复后,土壤总有机碳和各类活性碳含量均明显增加,并随着恢复时间的延长,土壤各类碳含量显著上升.同样是杉木林,恢复17年的土壤(0～20 cm)总有机碳、微生物量碳、水溶性碳和矿化态碳的含量分别是恢复9年土壤的2.18倍、2.95倍、2.25倍和2.01倍.不同处理比较来看,木荷林土壤各类碳含量明显高于杉木林土壤,黑麦草处理矿化态碳含量明显高于恢复时间相同的杉木和胡柚处理.分析了各处理活性碳占总有机碳的比例发现,植被恢复17年的2个处理,土壤微生物量占总有机碳比例明显高于恢复9年的3个处理;恢复时间分别为17年和9年的2个杉木处理,土壤水溶性碳占总有机碳比例明显较高,而矿化态碳占总有机碳比例明显偏低;黑麦草处理矿化态碳占总有机碳比例明显高于恢复时间相同的杉木和胡柚处理.从相关分析来看,土壤总有机碳、微生物量碳、水溶性碳及矿化态碳两两之间相关性均达极显著水平(P＜0.01);土壤各类碳与土壤全氮、水解氮、有效磷含量之间也具有极显著相关性.     

根迹土壤根诱导的化学变化对植物吸收重金属的影响

It is increasingly recognized that metal bioavailability is a better indicator of the potential for phytoremediation than the total metal concentration in soils; therefore, an understanding of the inffuence of phytoremediation plants on metal dynamics at the soil-root interface is increasingly vital for the successful implementation of this remediation technique. In this study, we investigated the heavy metal and soil solution chemical changes at field moisture, after growth of either Indian mustard (Brassica juncea) or sunffower (Helianthus annuus L.), in long-term contaminated soils and the subsequent metal uptake by the selected plants. In addition, the fractions of free metal ions in soil solution were determined using the Donnan membrane technique. After plant growth soil solution pH increased by 0.2-1.4 units and dissolved organic carbon (DOC) increased by 1-99 mg L^-1 in all soils examined. Soluble Cd and Zn decreased after Indian mustard growth in all soils examined, and this was attributed to increases in soil solution pH (by 0.9 units) after plant growth. Concentrations of soluble Cu and Pb decreased in acidic soils but increased in alkaline soils. This discrepancy was likely due to a competitive effect between plant-induced pH and DOC changes on the magnitude of metal solubility. The fractions of free Cd and Zn ranged from 7.2% to 32% and 6.4% to 73%, respectively, and they generally decreased as pH and DOC increased after plant growth. Metal uptake by plants was dependant on the soil solution metal concentration, which was governed by changes in pH and DOC induced by plant exudates, rather than on the total metal concentrations. Although plant uptake also varied with metal and soil types, overall soluble metal concentrations in the rhizosphere were mainly inffuenced by root-induced changes in pH and DOC which subsequently affected the metal uptake by plants.     

蚓粪对黑麦草吸收污染土壤重金属铜的影响

在长江冲积物形成的高沙土中加入CuSO4.5H2O模拟土壤污染,使Cu污染浓度分别为200、400、600 mg kg-1,并设置加蚓粪(15%)和加原土(15%)处理,二处理各设种植黑麦草(Lolium multiflorum)和不种黑麦草培养试验,研究蚓粪对黑麦草生长及对Cu吸收的影响,以揭示蚓粪在Cu污染土壤植物修复中的作用。结果表明:蚓粪显著增加了黑麦草的地上部和地下部的生物量(p<0.001**)以及根系的长度、表面积、体积和根尖数(p<0.05*),在Cu浓度为200 mg kg-1时促进作用最大;蚓粪还显著提高了黑麦草地上部Cu的浓度及累积量,但显著降低了地下部的Cu浓度(p<0.05*),而对地下部的铜累积量没有影响,显示蚓粪能促进Cu从根系向地上部的运移及在地上部的富集。通过对土壤的pH和Cu的形态特征分析,发现种植黑麦草处理降低了土壤的pH并增加了可交换态铜的含量,而且这种作用在加入蚓粪后更加明显。推测蚓粪主要通过促进黑麦草根系的生长和活性而影响根系周围环境,提高重金属铜的生物有效性进而增加植物对铜的吸收。     

有机物质对土壤溶液中铜形态的影响

Incubation of two soils,a red soil derived from granodiorte and a fluvo-aquic soil from alluvial deposit,with rice straw,Chinese milk vetch and pig manure under submerged condition were conducted to study the species of Cu in soil solutions as affected by the organic materials.The organic materials increased total soluble Cu by raising dissolved organic carbon(DOC) in soil solution when the solution pH values were below the range in which Cu deposited quickly.When the solution pH rose to this rage,the increase of DOC did not raise total soluble Cu.Total soluble Cu in all the treatments dropped with incubation time.After adding organic materials labile Cu dropped with incubation time and decreased sharply in the pH range of Cu precipitation.Addition of organic materials enhanced slowly labile Cu but depressed the ratio of labile Cu to total soluble Cu.Slowly labile Cu decreased with incubation time.Sepwise multiple linear regression analysis showed that total soluble Cu was positively correlated with Eh and DOC(P=0.0025),labile Cu was negatively correlated with pH(P=0.0118),and slowly labile Cu was positively correlated with Eh and DOC(P=0.0022).Both the labile and slowly labile Cu were correlated with total soluble Cu at extremely significant levels.     

Assessment of the interactions of metals and nitrilotriacetic acid in soil/sludge mixtures

The solution phase forms of Cu, Mn, Ni, and Zn in digested sewage sludge and a soil/sludge mixture were investigated. Gel filtration chromatographic analysis indicated that Cu and possibly Ni were maintained in solution by association with a soluble, high molecular weight organic fraction; Mn solubility was due to the presence of unbound inorganic species and soluble Zn was distributed equally between the two forms. Speciation of the metals in the solution phase of the soil/sludge mixture generally reflected that of the sludge. However, the total amount of soluble Mn in the soil/sludge mixture was approximately 25 times greater than in the sludge and was attributed to heavy metal induced release of indigenous soil Mn. Increases in the quantities of soluble Ni and Zn in both the sludge and the soil/sludge mixture following equilibration with 40 mg L^?1 NTA were due to conversion of solid phase forms to soluble metal-NTA complexes. The preferential complexation of NTA with Cu already present in soluble organic forms resulted in a change in speciation without a corresponding increase in solubility. The importance of changes in speciation with regard to potential metal mobility and bioavailability within sludge-amended soil is discussed.     

Treatment of an acid soil with bentonite used for wine fining: effects on soil properties and the growth of Lolium multiflorum

When used to fine wines, bentonite acquires a protein load that makes it a potentially useful fertilizer. Other properties of bentonite are also potentially useful for soil amendment. In the work described in this paper, waste bentonite from a winery was applied to an acid soil, and its effects on soil properties and on the growth of Lolium multiflorum were evaluated. Soil N, K, and P contents all increased, as did pH and cation exchange capacity. Biomass production increased as the dose of bentonite increased up to 5 g kg(-1), decreasing at larger doses (possibly as a result of falling potassium/magnesium ratio and increasing electrical conductivity). Environmental drawbacks of waste bentonite include its high soluble copper content, although its conversion in the soil to less soluble forms reduces its potential phytotoxicity. The copper, manganese, and zinc contents of the ryegrass crop were low.     

土壤中水溶性铜对西红柿的毒害影响因素及预测模型

该文选取17种具有代表性的中国土壤,研究了土壤孔隙水以及0.01mol/LCaCl2浸提态Cu对西红柿生长的毒害,结果发现对于土壤孔隙水中Cu对西红柿生物量10%抑制的毒性阈值(EC10)和50%抑制的毒性阈值(EC50),在17个非淋洗土壤中变化范围分别为0.06～1.47和0.17～3.42mg/L,淋洗土壤变化范围分别为0.05～2.24和0.13～4.37mg/L,最大值与最小值相差为23～41倍;0.01mol/LCaCl2提取态Cu的EC10和EC50,在非淋洗土壤变化范围分别为0.18～2.64和0.57～6.14mg/kg,淋洗土壤变化范围分别为0.18～1.28和0.61～7.11mg/kg,相差从6.9～14.4倍,表明土壤溶液性质影响水溶性Cu对西红柿的毒性阈值。同时,发现土壤孔隙水中Ca2+、溶解性有机碳是影响孔隙水中Cu对西红柿生长毒性的主要因子。当进一步考虑土壤溶液的重要因子(溶解性有机碳、土壤溶液pH值、电导率、全硫含量、Ca2+、Mg2+、K+、Na+),发现基于水溶性Cu的毒性阈值和土壤溶液性质的多元回归系数变化范围为0.75～0.99,说明利用土壤溶液性质能较好的预测土壤中水溶性Cu对西红柿的毒性阈值。该研究可为土壤水溶性Cu的风险评估提供参考。     

Effect of earthworms on the phytoremediation of zinc-polluted soil by ryegrass and Indian mustard

In this paper, the effects of earthworms on the growth and Zn uptake of ryegrass and Indian mustard in artificially Zn-contaminated soils were studied. Earthworm inoculation increased plant shoot biomass by 29–83% for ryegrass and by 11–42% for Indian mustard, respectively, as compared to the treatments without earthworms, while the roots’ biomass of both plants were increased much more than their corresponding shoots. Earthworms also increased shoot Zn concentrations in both ryegrass and Indian mustard, although the increases in ryegrass did not show significant difference. Except for soil without Zn contamination, the Zn contents of both ryegrass and Indian mustard roots were significantly increased by earthworm addition. Generally, Zn contents of roots were relatively higher than those of shoots for both plants, which were independent of earthworms inoculation. Earthworm increased soil bioavailable metal (diethylenetriamine-pentaacetic acid–Zn) (DTPA-Zn) concentrations, which resulted in a direct increase in Zn uptake by the plants, since a significant correlation was observed between the DTPA–Zn contents and plant Zn uptake. However, the main reason for the increase in plant Zn uptake under earthworm inoculation was probably the increase in dry matter production stimulated by earthworms.     

秸秆炭化后还田对不同镉污染农田土壤中镉生物有效性和赋存形态的影响

通过土壤培养试验和生物盆栽试验,研究不同镉污染土壤上作物秸秆炭化后还田对不同镉污染土壤中镉的赋存形态和生物有效性影响,结果表明：在碱性的镉污染土壤上,秸秆炭化后还田降低了玉米地上部生物量,但对玉米地上部镉含量和镉吸收量无显著影响;在酸性的模拟镉污染土壤上秸秆炭化后还田对玉米生长无影响,但还田含镉的油菜秸秆黑炭显著增加了玉米地上部镉含量和镉吸收量;还田不含镉的玉米秸秆黑炭对镉污染土壤中DTPA提取态镉含量没有明显影响,但还田含镉的油菜秸秆黑炭显著增加了镉污染土壤中DTPA提取态镉含量;施用含镉的油菜秸秆黑炭增加了镉污染土壤中水溶和交换态镉含量;施用玉米和油菜秸秆黑炭均显著降低了模拟镉污染土壤中水溶和交换态镉含量;增加了松有机结合态、碳酸盐结合态和紧有机结合态镉含量;模拟镉污染土壤施用玉米和油菜秸秆黑炭6个月后土壤中水溶和交换态镉仍然是土壤镉的主要赋存形态,水溶和交换态镉占土壤全镉的70%以上。综合以上结果可知,秸秆黑炭不能降低污染土壤中镉的生物有效性和植物对土壤镉的吸收量。     

Phytoavailability of lead altered by two Pelargonium cultivars grown on contrasting lead-spiked soils

Purpose

This study assesses the potential of two contrasted fragrant Pelargonium cultivars to induce pH and dissolved organic carbon (DOC) changes in the soil solution, Pb speciation, and their subsequent effects on rhizosphere phytoavailable Pb.

Materials and methods

Rooted plantlets were grown in special devices, floating on aerated nutrient solution in PVC tanks. This setup allows roots to be physically separated, through a mesh, from a 3-mm soil matrix layer that can be considered as rhizosphere soil. Two contrasted soils, each spiked with Pb-rich particles, emitted from a battery recycling industry, were used at total burdens of 500 and 1500 mg Pb kg^?1 in addition to a control unspiked soil. Soil solution pH, phytoavailable Pb, DOC, Pb adsorption, precipitation on roots, and Pb phases in soil and plant were investigated.

Results and discussion

Attar of Roses (Attar) cultivar acidified its rhizosphere by 0.4 pH units in both spiked soils. Concolor Lace (Concolor) was unable to change soil solution pH on soil-1 and increased it by 0.7 units on soil 2. Concentrations of Pb in soil solution from Attar plants were always higher than those of Concolor ones. DOC contents of both unspiked soil-1 and soil-2 without plants were not significantly different. In the case of spiked samples, DOC contents in the rhizosphere soil were increased by three and two times for Attar and Concolor, respectively, compared to the unspiked soil without plant. Both cultivars were able to increase DOC contents, independent of soil type and level of contamination. Accumulation of Pb in shoots and roots was higher in Attar as compared to Concolor due to enhanced available Pb as a result of pH and DOC modifications of the rhizosphere soil. Significant amounts of Pb were adsorbed on roots of both cultivars. X-ray elemental analysis of precipitates on roots revealed the association of Pb with P in cylinder-like structures. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that Pb was present, to a major extent in the inorganic form, mainly as PbSO₄ in the soil, whereas it was complexed with organic species within plant tissues. The conversion of Pb into organic species could decrease toxicity, may enhance plant tolerance, and could increase translocation.

Conclusions

Plant-induced changes were responsible for the modification of lead phases within the soil. Immobile forms present in the source leaded particles as well as in the soils were converted into soluble species, ultimately improving the phytoavailable or soil solubilized Pb.