Pyroligneous Acids Enhance Phytoremediation of Heavy Metal-Contaminated Soils Using Mustard

Heavy metal (HM) pollution has long been a problem in crop production. However, soils contaminated at low concentration such as areas for food production may have a high risk of biomagnification and food chain contamination. Different methods were used for remediating these polluted environments, but pyroligneous acids (PAs) such as wood vinegar (WV) application are rarely studied. Thus, the effects of WV on metal availability in soils and on the growth of mustard were evaluated by measuring chlorophyll content, biomass, nutrient and metal uptake. Bioconcentration factor (BCF) and translocation factor (TF) were computed to determine suitable phytoremediation practices. Overall results revealed favorable growth of mustard due to the direct source of nutrients provided by WV. WV decreased the metal concentration in soil and inhibited uptake through phytostabilization. Organic substances associated with WV are naturally endowed with adsorption sites available for chelation, rendering metals less bioavailable. As a result, HM-contaminated soils can now be utilized for food production.     

植物修复镉污染土壤的差异性研究

以茶花凤仙和百日草为供试植物,对不同镉浓度条件下两种植物的生物量、镉含量及其对镉的吸收、富集状况进行了研究.结果表明,不同程度镉浓度处理的土壤中生长的茶花凤仙和百日草对镉的吸收和富集特性不同,生物量随土壤镉浓度的升高而升高,但达到一定浓度时,生物量又随土壤镉浓度的升高而降低.茶花凤仙在低浓度区域,富集镉的能力要强于百日草,但是在高浓度区域时,茶花凤仙富集镉的效果却低于百日草的富集效果.本试验中所选的两种植物,百日草和茶花凤仙均没有达到超积累植物要求的标准.     

土壤重金属污染背景下的任豆修复试验

为寻找适合矿业尾矿坝人工生态恢复的植物,以广西南丹长坡矿堆存 50 a之久的尾矿坝为背景,通过盆栽模拟,运用室内土培和水培两种试验方法,研究了不同矿土比例（尾矿样与泥土比例分别为5∶0、4∶1、3∶2、2∶3、1∶4、0∶5）以及不同浓度（0、2.5、5、10、25、50、100、150、200、250 mg·L^-1）Pb^2＋、Cu^2＋、Zn^2＋在任豆苗体内的吸收、积累和分布的动态变化规律。结果表明,任豆对Pb、Cu、Zn都具有一定的吸收能力,任豆幼苗可以在一定的重金属胁迫环境下存活,任豆对重金属Pb的耐性最大,在高浓度下依然可以存活。任豆对不同类型的重金属的吸收及转运能力存在较大差异,从任豆对Pb、Cu、Zn的转运能力来看,任豆并非这3种重金属的超累积植物。试验表明,任豆在矿业尾矿坝的人工生态恢复（植物修复）中有一定的应用价值,但能否大规模采用任豆作为尾矿坝的生态修复物种,尚需进一步研究验证。     

EDTA-Enhanced Phytoremediation of Lead-Contaminated Soil by Corn

EDTA-enhanced phytoremediation by corn (Zea mays L.) of soil supplemented with 500 mg L^?1 lead (Pb) was examined. The chelate EDTA was used in order to increase Pb bioavailability at four levels: 0 (control), 0.5 (low), 1.0 (medium), and 2.5 mmol kg^?1 (high). Plants were grown under controlled conditions in a growth-chamber with supplementary light. An EDTA concentration of 5.0 mmol kg^?1 was lethal to plants. At high and medium EDTA levels plants grew significantly less than control ones. Lead concentrations in corn leaves increased with increased EDTA levels. Plants subjected to medium EDTA level had the greatest root to shoot Pb translocation. Plants subjected to high EDTA level showed high phosphorus (P) uptake and translocation within plants. Therefore, possibly it was not only Pb that caused toxic effect on plants, but also the high internal concentration of P that in turn could have complexed active Fe.     

5种草本植物对土壤重金属铅的吸收、富集及转运

以临汾西山煤矿周边的5种优势种植物苍耳（Xanthium sibiricum）、夏至草（Lagopsis supina）、蒲公英（Taraxacum mongolicum）、灰绿藜（Chenopodium glaucum）、早熟禾（Poa annua）为试验材料,研究植物修复土壤重金属铅的污染,分析比较其对铅的吸收、转运和富集的能力。结果表明:在铅处理下早熟禾的生物量最大;5种植物地上部分对铅的吸收量在10 000 mg时均达到1 000 mg/kg以上,其中夏至草的吸收量最高,达5 447.25 mg/kg;地下部分对铅的吸收量在10 000 mg时也达到1 000 mg/kg以上,以苍耳最高,达13 448.5 mg/kg。夏至草的转运系数和富集系数最高,为铅超富集植物,其余4种植物对重金属铅也有很好的吸收富集作用。     

Silicon alleviates the toxicity of cadmium and zinc for maize (Zea mays L.) grown on a contaminated soil

Although silicon (Si) is not an essential element, it presents a close relationship with the alleviation of heavy‐metal toxicity to plants. This work was carried out to evaluate the effects of Si application to soil on the amelioration of metal stress to maize grown on a contaminated soil amended with Si (0, 50, 100, 150, and 200 mg kg^–1) as calcium silicate (CaSiO₃). Additionally, the cadmium (Cd) and zinc (Zn) bioavailability as well as their distribution into soil fractions was also studied. The results showed that adding Si to a Cd‐ and Zn‐contaminated soil effectively diminished the metal stress and resulted in biomass increase in comparison to metal‐contaminated soil not treated with Si. This relied on Cd and Zn immobilization in soil rather than on the increase of soil pH driven by calcium silicate application. Silicon altered the Cd and Zn distribution in soil fractions, decreasing the most bioavailable pools and increasing the allocation of metals into more stable fractions such as organic matter and crystalline iron oxides.     

某铅锌冶炼厂废弃地复垦整理区土壤重金属污染评价

对贵州省六盘水市某铅锌冶炼厂废弃地复垦整理区土壤中重金属Cu，Zn，Pb，Ni，Cd，Cr，Hg，As以及土壤部分理化性质进行了测定和分析，对土壤重金属污染状况进行了评价。结果表明：废弃地上堆放的铅锌冶炼矿渣中除Cu，Cr，Hg的含量较低、污染指数小于1之外，Zn，Pb，Ni，Cd，As的含量很高，其单项污染指数分别为2．95，45．14，1．00，10．67，50．41，综合污染指数高达36．98，属于剧烈污染源。项目区土壤综合污染指数在0．77～1．99之间；综合污染指数小于1的未受重金属污染的土壤占总样品数的50．00％，而综合污染指数〉1．00但没有超过2．00的样品数占总样品数的50．00％，说明项目区仅有部分土壤遭受重金属的轻度污染。采用适当的复垦整理、改良技术和合理的利用方式，可以促使该废弃地恢复农业生产能力。     

类芦植被对AMD污染土壤的生态修复效应及潜力

以贵阳市花溪区麦坪废弃煤矿区为研究区域,选择在受酸性矿山废水(AMD)污染的土壤上经类芦植被恢复的土壤为研究对象,研究自然恢复类芦植被后对AMD污染土壤的养分、酶活性及微生物数量的改善作用,探讨类芦植被对AMD污染土壤的生态修复效应及潜力。结果表明:AMD污染土壤呈养分极贫瘠、土壤酶活性和微生物活性极低的特征,污染土壤经自然恢复类芦植被后,污染土壤的理化性质及生物化学特性有显著改善,具体表现为:经类芦植被恢复的土壤的有机质、全氮、有效氮、有效磷、速效钾含量较对照(无类芦植被恢复)的污染土壤分别平均增加了48.95%,133.71%,46.23%,23.10%,29.83%,土壤过氧化氢酶、酸性磷酸酶、纤维素酶和脲酶活性得到极显著(p0.01)提高,土壤主要微生物类群(细菌、真菌、放线菌)数量和生物量极显著(p0.01)增加。相关性分析表明,土壤养分、酶活性和微生物数量之间呈正相关关系,表明土壤酶活性和微生物数量可作为评价AMD污染土壤修复前后质量改善状况的重要生物学指标。另外,主成分分析表明,在类芦植被对AMD污染土壤修复过程中土壤酶(脲酶)、土壤养分(全磷、全氮、有效磷、有效氮、有机质、速效钾)、土壤微生物(细菌)是主要控制因素。基于类芦植被能显著地提高AMD污染土壤有效养分含量、土壤酶活性和微生物数量,使AMD污染土壤朝着良性方向发展,并表现出对AMD污染土壤修复具有较大的潜力,因此类芦植被可作为AMD污染土壤植物修复和生态恢复的先锋物种或优势植物。     

生物炭对铜矿区排土场污染土壤理化性质和重金属形态的影响

为了探讨在重金属胁迫下,不同用量(0,1%,2%,4%)生物炭对土壤pH、有机碳、全氮、全磷以及重金属形态的影响,以铜矿区排土场污染土壤为研究对象,开展室内盆钵试验。结果表明：与对照K相比,在不同剂量生物炭处理下,土壤pH、有机碳、全N和全P增幅分别为3.5%～23.0%,5.6%～13.2%,2.9%～6.8%和3.4%～9.5%,酸溶态Cd, Pb, Cu和Zn含量降幅分别为65.5%～71.2%,49.9%～71.5%,34.6%～50.6%和45.3%～52.1%,可还原态Cd, Pb, Cu和Zn含量降幅分别为71.5%～74.3%,44.4%～63.6%,38.5%～57.8%和29.1～39.1%,可氧化态Cd含量降幅为15.6%～36.9%,可氧化态Pb, Cu和Zn含量增幅分别为16.9%～20.5%、3.9%～26.0%和18.8%～55.9%,残渣态Cd, Pb, Cu和Zn含量增幅分别为42.4%～44.2%,11.0%～23.5%,15.0%～37.9%和20.0%～41.9%。添加生物炭可以提高土壤pH,增加土壤有机碳和全氮含量,对土壤全磷含量也略有增加,但...     

污染紫色土重金属的淋溶特征及释放动力学研究

通过室内土柱试验,探讨雨水作用下紫色土中Cu、Pb和Cd等重金属元素的淋溶和释放特征。结果表明,在淋溶量为6 000 ml的模拟降雨作用下,淋溶量2 000 ml内是紫色土中重金属快速释放时期,在这个期间,淋溶液内重金属浓度较高,释放速度不断减小,是快速释放过程,对环境及地下水威胁较大;2 000ml后,淋溶液内重金属浓度很低,累计释放量变化不大。整个淋溶过程中,3种重金属释放率的顺序为：Cd〉Cu〉Pb。模拟降雨条件下污染紫色土重金属的释放过程可用修正的Elovich方程和双常数方程进行拟合,且Elovich方程拟合的效果更好。     

陕北地区土壤重金属污染特征及生态风险评价

以陕西省靖边县表层土壤（0~20 cm）为研究对象,应用SPSS 19.0软件分析土壤样品中重金属Cr、Cu、Zn、As、Cd、Pb、Hg等7种重金属的含量及来源,运用Hakanson潜在生态危害指数法评价研究区土壤重金属潜在生态危害程度。结果表明,研究区土壤重金属平均含量均低于《土壤环境质量标准》二级标准,各重金属元素变异性较小;相关性分析表明,研究区土壤重金属元素中Cu、Zn、As、Pb两两之间呈极显著的正相关关系;因子分子显示,土壤中重金属的主要来源可能包括研究区附近石油开采活动、交通运输、无机农药和化肥的施用以及工业和居民燃煤等;生态危害评价显示,研究区土壤中仅有Cd元素存在潜在生态风险,其他Cr、Cu、Zn、As、Pb、Hg 6种元素的潜在生态风险均处于低危害水平。     

间作两个生态气候区的龙葵和少花龙葵促进茄子幼苗生长且降低镉吸收

Soil contamination by heavy metals is a serious environmental problem worldwide,and reduction of heavy metal accumulation in vegetables grown on contaminated land is a matter of urgency.A pot experiment was conducted to study the effects of intercropping with the Cd hyperaccumulators Solanum nigrum and Solanum photeinocarpum from two ecoclimatic regions,Ya'an and Chengdu,Sichuan Province,China,on the growth and cadmium (Cd) uptake of eggplant (Solanum melongena L.).The biomass,photosynthetic pigment contents,and activities of antioxidant enzymes of eggplant were enhanced by intercropping.The biomass of eggplant was the highest after intercropping with S.photeinocarpum from Ya'an,but did not differ significantly from that after intercropping with S.nigrum from Chengdu.The shoot Cd content of eggplant was significantly reduced by intercropping with the hyperaccumulators,which ranked as follows:S.nigrum from Chengdu ＞ S.nigrum from Ya'an ＞ S.photeinocarpum from Chengdu ＞ S.photeinocarpum from Ya'an,with the decreases being 19.60％,14.36％,9.66％,and 6.42％,respectively,as compared with the control.The lowest shoot Cd content and translocation factor of eggplant were attained after intercropping with S.nigrum from Chengdu.Therefore,it was feasible to intercrop eggplant with S.nigrum and S.photeinocarpum on Cd-contaminated soil.     

古莲河煤矿不同造林树种对土壤养分及重金属含量的影响与评价

以大兴安岭古莲河煤矿排土场为研究对象,分析不同造林树种对土壤养分及重金属元素污染的改良效果.结果表明:各造林地土壤养分含量均有所增加,沙棘、落叶松和樟子松造林地土壤养分含量平均值分别为对照地的1.61,1.37,1.15倍;并且各造林地重金属元素含量也均有所下降,沙棘、落叶松和樟子松造林地重金属元素含量分别为对照地的0.95,0.86,0.97倍,土壤内梅罗综合污染指数分别为1.24,1.29和1.28,与未造林排土场内梅罗综合污染指数1.50相比明显降低,但都属于轻度污染.试验说明植树造林不但能提高土壤养分含量,还能吸收、固定土壤中的重金属元素,从而降低土壤污染程度.     

Application of Organic Wastes in a Soil Polluted with Different Rates of Cr-Pb: Effects on Soil Biological Properties

An experiment was performed to determine the effects of adding municipal solid waste (MSW) and poultry manure (PM) to a soil polluted with chromium (Cr), lead (Pb), and Cr + Pb on the biological parameters of the soil. Soil was mixed with two solutions of Cr(NO₃)₃ and/or Pb(NO₃)₂ to give three concentrations (0, 100, and 250 mg Cr kg^?1 soil and 0, 100, and 250 mg Pb kg^?1 soil) and treated with MSW or PM. When the soil was contaminated with the metals without combining, the greatest adenosine triphosphate (ATP), urease, and phosphatase inhibition percentages occurred for 250 mg Pb kg^?1 soil. When the heavy metals were mixed, the inhibition of the biochemical parameters increased. The application of MSW and PM decreased the inhibition of the biochemical parameters and microbial population in the polluted soils. The inhibition percentage was greater for the soil amended with MSW than with PM, possibly due to the high humic acid concentration.     

复垦不同年限煤矸山土壤重金属污染状况评价

为研究复垦年限对煤矸山土壤重金属的影响,以山西省霍州市曹村煤矿煤矸山复垦3 a,5 a,7 a和9 a农田为研究对象,对复垦地土壤重金属Hg,Cd,Pb,As和Ni的质量分数及其污染状况进行了分析。结果表明:（1）煤矸山复垦农田0—20 cm和20—40 cm土层土壤重金属质量分数有随复垦年限增加而增加的趋势,其中Pb,Cd表现最明显,而Hg的增加趋势主要出现在20—40 cm土层;同时,煤矸山复垦农田土壤重金属质量分数均不同程度地高于当地普通农田,尤其在20—40 cm土层表现更明显;（2）单因子污染指数表明,Hg和As在0—20 cm和20—40 cm土层污染程度随年限没有变化,分别为重度污染和轻微污染,Pb和Cd在0—20 cm也没有变化,分别为轻微污染和轻度污染,但在20—40 cm土层随年限增长达到轻度污染和中度污染;综合污染指数表明,复垦农田在0—20 cm和20—40 cm土层污染指数均表现为随复垦年限增加而增加的趋势,4种复垦年限农田均达到重度污染。研究结果有助于指导煤矸山植被恢复和复垦地的合理利用。     

Effects of Wastewater Irrigation on Physicochemical Properties of Soil and Availability of Heavy Metals in Soil and Vegetables

The present study investigated the impact of irrigation with wastewater on nutritional property and heavy‐metal concentrations in the soil and consequent accumulation in vegetables at sites having long‐term uses of wastewater for irrigation. Samples of irrigation water, soil, and root and shoot parts of palak plants were analyzed to determine the concentration of heavy metals. Wastewater irrigation led to increases in the total and phytoavailable heavy‐metal concentrations in the soil at all the sites. Heavy‐metal concentrations in soil under wastewater irrigation were negatively and positively correlated with soil hydrogen potential (pH) and organic carbon (OC), respectively. The enrichment factor and metal pollution index were higher at wastewater‐irrigated sites as compared to the clean water–irrigated ones. The study concludes that wastewater irrigation modified the physicochemical properties of the soil, leading to more availability of heavy metals in the soil and consequently to the plant.     

酸性矿石废水短期污染对水稻土的影响

以受酸性矿石废水(ARD)污染1年的水稻田为研究对象,根据“ARD–土壤–水稻”体系中Cu、Cd、Pb和Zn等重金属含量,评价污染风险,分析ARD初期污染土壤中重金属的迁移特性;并分析土壤酸化潜力、理化性质和土壤脱氢酶含量,研究其与土壤重金属间的关系,探讨土壤污染特征,为酸性矿石废水(ARD)短期污染土壤的治理提供依据。结果表明:ARD的p H在2~3,其Cu和Cd分别超过国家V类水标准8.53倍和13倍。受ARD污染1年后,土壤中已有不同程度的Cu的富集,其中污染最严重的污1土壤中Cu(64.0 mg/kg)均超过国家二级标准(50.0 mg/kg),但污染土壤上水稻中的重金属大部分富集在根中,稻米中的重金属均远低于国家食品卫生标准。ARD污染也造成不同程度的土壤酸化和功能衰减,污1样地酸化和功能衰减最严重,其土壤p H和净产酸量(ANG)分别为3.5和H2SO4 12.4 kg/t,土壤脱氢酶活性已降为TBF 0.002 mg/(kg干土?24h)。此外,土壤中重金属含量和土壤酸化及土壤其他理化性质有一定关系,如土壤中总Cu和有效态Cu均和土壤中p H、NAGPH、Fe和SO42–极显著相关(P0.01),而土壤中Cu和Cd均和有效硅和电导率极显著相关(P0.01)。     

Bioavailability and Accumulation of Cadmium and Zinc by Sedum plumbizincicola after Liming of an Agricultural Soil Subjected to Acid Mine Drainage

A glasshouse pot experiment was conducted to study the effects of liming on plant growth and zinc (Zn) and cadmium (Cd) accumulation by Sedum plumbizincicola in a heavy-metal-contaminated acidified paddy soil. Lime application significantly increased the soil pH, which reached a maximum of 5.53 after addition of 4.0 g kg^?1 lime to soil, about 1.4 units more than that of the control. Sedum plumbizincicola grew larger after lime application but aboveground biomass did not increase significantly with increasing soil pH. Liming significantly reduced shoot Zn and Cd concentrations and uptake except at the lowest lime application rate (0.5 g kg^?1 lime to soil). This indicates that S. plumbizincicola can grow well in acidic soil at a soil pH of 4.15, and application of lime did not increase plant heavy-metal extraction. Consequently, it is promising to use this plant for Cd and Zn phytoextraction from agricultural soils polluted with acid and metals.     

沈哈高速公路两侧土壤重金属污染特征及评价

为探讨高速公路对农田土壤重金属污染的影响,对沈哈高速公路两侧农田60个土壤样品Ph、Cu、Zn、Cd分布状况进行了分析。结果表明,高速公路两侧在距路肩0—320m范围内,Cu、Pb和Zn全量和有效态含量总体上呈现随距离增加而降低的趋势,Cd的变化规律不明显。高速公路两侧的土壤已不同程度出现重金属富集现象,其中Pb属轻度污染且主要集中在东侧距路肩20m处,Cd属重度污染。受研究地点主导风向的影响,高速公路东侧农田土壤的Ph含量明显高于西侧。高速公路旁土壤重金属以Ph、Cd污染为主,污染物主要来源于汽车尾气。     

连续施用沼液对土壤性质的影响及重金属污染风险评价

为实现沼液资源化利用,采用3年田间定位试验研究施用猪粪沼液对土壤理化性质的影响,并评估其对土壤潜在的重金属污染风险。田间试验种植方式为水稻—油菜轮作,施肥方式分别以清水和常规化肥为对照,另设10个猪粪沼液施用量梯度。通过单因子污染、内梅罗综合污染和Hakanson潜在生态风险指数法,评价连续施用猪粪沼液对土壤潜在的重金属污染风险。结果表明:当3年沼液施用总量为(546.25～626.00)×103 kg/hm2时,能显著提高土壤肥力,改善土壤结构,防止土壤生态功能遭破坏,保障农业安全生产,但需合理配施氮肥,防止土壤养分失衡;单因子污染指数显示土壤重金属Cd、As、Cr、Hg为轻度污染,Pb较安全;内梅罗综合污染指数显示Cd、As、Pb、Cr、Hg总体为轻度污染;Hakanson潜在生态风险指数显示Pb、Cd、Cr、As存在轻微潜在生态污染风险,Hg存在中等潜在生态污染风险,综合潜在生态污染风险程度属轻度;沼液还田引起土壤环境重金属污染的风险较小,需合理管控Hg和As可能引起的土壤环境污染问题。