Heavy metal accumulation by panicled goldenrain tree （Koelreuteria paniculata） and common elaeocarpus （Elaeocarpus decipens） in abandoned mine soils in southern China

Phytoremediation can be used as a sustainable technology for mine spoil remediation to remove heavy metals. This study investigated the concentration of 7 heavy metal contamination in soil and plant samples at an abandoned mine site. We found that, after vegetation remediation at the abandoned mine site, the reduction rates for 7 heavy metals were in the range of 4.2%–86%, where reduction rates over 50% were achieved for four heavy metals (Zn, Mn, Cd, Ni). Transfer coe cients of the panicled goldenrain tree (Koelreuteria paniculata Laxm) and the common elaeocarpus (Elaeocarpus decipens) for Zn, Mn, Ni, and Co were more than 1. Enrichment coe cients of both trees for Mn were higher than 1. Our results suggest that the panicled goldenrain tree and the common elaeocarpus tree may act as accumulators in remediation. Moreover, the woody vegetation remediation in abandoned mining areas play an important role in improving scenery besides removing heavy metal from contaminated soil.     

Influence of Indian mustard （Brassicajuncea） on rhizosphere soil solution chemistry in long-term contaminated soils： A rhizobox study

This study investigated the influence of Indian mustard (Brassica juncea) root exudation on soil solution properties (pH, dissolved organic carbon (DOC), metal solubility) in the rhizosphere using a rhizobox. Measurement was conducted following the cultivation of Indian mustard in the rhizobox filled four di erent types of heavy metal contaminated soils (two alkaline soils and two acidic soils). The growth of Indian mustard resulted in a significant increase (by 0.6 pH units) in rhizosphere soil solution pH of acidic soils and only a slight increase (< 0.1 pH units) in alkaline soils. Furthermore, the DOC concentration increased by 17–156 mg/L in the rhizosphere regardless of soil type and the extent of contamination, demonstrating the exudation of DOC from root. Ion chromatographic determination showed a marked increase in the total dissolved organic acids (OAs) in rhizosphere. While root exudates were observed in all soils, the amount of DOC and OAs in soil solution varied considerably amongst di erent soils, resulting in significant changes to soil solution metals in the rhizosphere. For example, the soil solution Cd, Cu, Pb, and Zn concentrations increased in the rhizosphere of alkaline soils compared to bulk soil following plant cultivation. In contrast, the soluble concentrations of Cd, Pb, and Zn in acidic soils decreased in rhizosphere soil when compared to bulk soils. Besides the influence of pH and DOC on metal solubility, the increase of heavy metal concentration having high stability constant such as Cu and Pb resulted in a release of Cd and Zn from solid phase to liquid phase.     

Can phosphate compounds be used to reduce the plant uptake of Pb and resist the Pb stress in Pb-contaminated soils？

The effects of di erent phosphate-amendments on lead (Pb) uptake, the activities of superoxide dismutase (SOD) and the level of malondialdehyde (MDA) in cauliflower (Brassica oleracea L.) in contaminated soils with 2500, or 5000 mg P2O5/kg soil of hydroxyapatite (HA), phosphate rock (PR), single-superphosphate (SSP) and the mix of HA/SSP (HASSP) were evaluated in pot experiments. Results showed that the Pb concentrations in shoots and roots decreased by 18.3%–51.6% and 16.8%–57.3% among the treatments respectively compared to the control samples. The e ciency order of these phosphate-amendments in reducing Pb uptake was as follows: HASSPt HA > SSP t PR.With the addition of SSP, HA and the mix of HA/SSP, the SOD activity in shoot was reduced markedly (P < 0.05) compared with that in the control group. For example, the SOD activities in shoot by the treatments of HASSP, SSP, and HA in 5000 mg P2O5/kg were found to be only 51.3%, 56.2%, and 56.7%, respectively. Similar e ects were also observed on the level of MDA in the shoots with a decrease in 24.5%–56.3%. The results verified the inference that phosphate compounds could be used to reduce the plant uptake of Pb and resist the Pb stress in the plant vegetated in Pb-contaminated soils.     

Chemical fractionations and bioavailability of cadmium and zinc to cole （Brassica campestris L.） grown in the multi-metals contaminated oasis soil, northwest of China

A pot experiment was conducted to study the relationship between distribution of cadmium (Cd) and zinc (Zn) and their availability to cole (Brassica campestris L.) grown in the multi-metal contaminated oasis soil in northwest of China. The results showed that Cd and Zn in the unpolluted oasis soil was mainly found in the residual fractionation, however, with increasing contents of Cd and Zn in the oasis soil, the distribution of Cd and Zn changed significantly. The growth of cole could be promoted by low Cd and Zn concentration, but significantly restrained by high concentrations. There was antagonistic e ect among Cd and Zn in the multi-metals contaminated oasis soil. Stepwise regression analysis between fractionations distribution coe cients of the two meals in the soil and their contents in cole showed that both Cd and Zn in the exchangeable fractionation in the oasis soil made the most contribution on the uptake of Cd and Zn in cole. The bio-concentration factor (BCF) of Cd was greater than Zn in cole, and BCFs of the two metals in leaves were greater than those in roots. The translocation factors of the two metals in cole were greater than 1, and the two metals mainly accumulated in the edible parts in cole. Therefore, cole is not a suitable vegetable for the oasis soil because of the plants notable contamination by heavy metals.     

绿洲土Pb-Zn复合胁迫下重金属形态特征和生物有效性

通过对Pb-Zn复合胁迫下干旱区绿洲土壤中油菜种植进行盆栽试验模拟,探讨了重金属复合污染对油菜生长的影响及其各形态之间的转化规律和生物有效性.结果表明,低浓度Pb、Zn处理下,油菜生长得到促进,茎叶生长优势大于根系.随着外源重金属的投加,土壤中Pb、Zn主要赋存形态较对照均由紧结合态向松结合态转化,重金属生物有效性提升;可交换态Pb、碳酸盐结合态Zn分别是油菜不同部位吸收Pb、Zn的主要贡献形态.油菜在低浓度胁迫水平对Pb、Zn的富集能力和转移能力强于高浓度胁迫水平,且油菜对Pb、Zn的富集、迁移系数均随土壤中对应元素或共存元素生物有效态含量的增大而减小.所有处理中,油菜茎叶中的Pb含量均超出了食品安全限量指标,建议在此类土壤种植叶菜类蔬菜前进行相关指标检测.     

速生树种竹柳对复合污染土壤中镉和锌的吸收、积累与生理响应特性

为探讨竹柳在重金属复合污染(镉、锌)土壤中生长的生理变化及重金属在植株内的转移情况,以竹柳(Salix sp.)三号及竹柳五号为试验材料,以重金属复合污染的水稻土为供试土壤,通过盆栽试验研究了重金属对竹柳生理指标、重金属吸收与积累量、富集系数(BCF)和转运系数(TF)的影响.结果表明:竹柳各器官重金属含量和转移情况不同,其中,叶片中Cd、Zn含量最高,分别达61.4和1940 mg·kg~(-1);竹柳三号对Zn的转运能力大于竹柳五号,而竹柳五号的净光合速率更高;生长100 d后,重金属在竹柳叶片中的积累量和转移系数均高于其他部位,竹柳吸收的重金属主要分布在叶片中,可通过集中处理叶片达到去除土壤中重金属污染的目的.     

广西刁江沿岸土壤As,Pb和Zn污染的分布规律差异

分析了刁江流域矿区尾砂和上、中、下游地区土壤剖面重金属的含量. 结果表明:刁江流域上、中、下游地区都不同程度受到As,Pb和Zn的污染. 上游(距污染源16 km)表层土壤中w(As),w(Pb)和w(Zn)与尾砂相当,分别高达2.4×104,5.6×103 和1.2×104 mg/kg,下游拉烈和百旺(分别距污染源154和192 km)2个采样点表层土壤中w(As),w(Pb)和w(Zn)的平均值分别是《土壤环境质量标准》(GB15618—1995)三级标准的47.05,1.81和5.48倍. 表层土壤中w(As)和w(Pb)随采样点距污染源的距离增加呈幂函数下降,w(Zn)呈线性下降,表明Zn在流域内的迁移能力大于Pb和As. 土壤剖面中3种重金属的质量分数均随土层深度的增加呈降低趋势,在土壤剖面的迁移能力表现为Zn>Pb>As. 总体上看,刁江流域土壤污染与尾砂中重金属的形态及其迁移特征密切相关,尾砂的排放控制和治理应该是刁江流域污染整治的关键.      

Effect of incubation temperature and wet-dry cycle on the availabilities of Cd, Pb and Zn in soil

The effect of incubation temperature and wet-dry cycle on the availabilities of Cd, Pb and Zn was studied. Three soils with pH ranging from 3.8 to 7.3, organic carbon （OC） from 0.7% to 2.4%, and clay from 12.3% to 35.6% were selected. Soils were spiked with reagent grade Cd（NO3）2, Pb（NO3）2, and Zn（NO3）2 at concentrations of 30 mg Cd/kg soil, 300 mg Zn/kg soil and 2000 mg Pb/kg soil. The soils were incubated at 35, 60, 105℃, respectively and went through four wet-dry cycles. Metal availability in soils was estimated by soil extraction with 0.1 mol/L Ca（NO3）2. According to this study, the effect of the spiking temperature on the metal availabilities was different among the metals, soils and wet-dry cycles. Mostly, 35 ~C was the first recommended spiking temperature for Cd and Pb while no spiking temperature was obviously better than others for Zn. Three wet-dry cycles was recommended regardless of the type of metals and incubation temperature.     

生物炭对土壤中重金属铅和锌的吸附特性

利用固定床热解实验装置在不同热解温度(300~700℃)下制备了3种生物炭[杨树枝炭(PBC)、水葫芦炭(WHC)和玉米秸秆炭(CSC)],以南京市铅锌银矿区周边的菜园土为对象,研究了生物炭种类、热解温度和生物炭添加量对土壤重金属(Pb和Zn)吸附特性的影响,并结合生物炭的孔隙度、XRD和FTIR等分析,初步探讨了生物炭对土壤重金属的吸附机制.结果表明,生物炭的添加均不同程度地降低了土壤中Zn和Pb的浸出含量,水葫芦炭对土壤重金属的吸附效果最佳,在热解温度为500℃和生物炭添加量为5%的条件下,水葫芦炭对土壤中Zn和Pb的吸附率分别为21.83%和44.57%,相应的单位吸附量分别为227.65μg·g~(-1)和363.76μg·g~(-1).随着热解温度的升高,生物炭对土壤中Zn和Pb的吸附率逐渐增大,且在热解温度为500℃和700℃下制备的水葫芦炭对土壤中Zn和Pb的吸附能力相差不大,这表明中等温度热解有利于水葫芦炭形成较好的理化特性.随着生物炭添加量的增加,水葫芦炭对土壤中Zn和Pb的吸附率逐渐增大,但单位吸附量却逐渐减小,当水葫芦炭添加量为10%时,其对土壤中Pb的吸附率可达93.93%.结合生物炭的理化结构和土壤重金属吸附实验的结果,可以推测离子交换和络合作用是水葫芦炭修复重金属污染土壤的主要作用机制.     

株洲城郊农田土壤重金属污染特征与Pb同位素示踪

通过采集湖南株洲城郊农田区表层土壤（A层）,并分析其Cd、Hg、Pb、Zn等重金属元素含量,研究了土壤中重金属元素的污染特征.为示踪这些金属元素的来源,选择农田区典型土壤样品及湘江沉积物、污染源区土壤样品,进行重金属元素含量和Pb同位素组成测定.结果表明,农田区A层土壤受到不同程度的重金属污染,其中,Cd、Hg、Pb、Zn含量最高,分别为21.71、24.52、261.49、577.94 mg·kg^-1,且Cd、Pb、Zn元素之间显著相关,而研究区附近湘江水体和沉积物中这些元素含量没有增高,说明这些重金属不是来自湘江,而是可能主要来自冶炼厂;铅同位素显示,冶炼厂附近A层土壤²⁰⁶Pb/²⁰⁷Pb值（1.150~1.164）低于周边区域A层土壤（1.164~1.169）,²⁰⁸Pb/²⁰⁶Pb值（2.108~2.122）高于周边地区（2.106~2.119）,说明受到人为污染的影响.从污染区分布空间位置和铅同位素源解析的结果看,农田区土壤中Cd、Hg、Pb、Zn等重金属的主要污染源是冶炼厂的冶炼烟气粉尘及与农耕活动有关的其他人为污染.     

湘西花垣矿区主要植物种类及优势植物重金属蓄积特征

矿区重金属污染严重,寻找和发现适合当地气候与土壤条件的重金属耐性植物是矿区植被恢复和污染土壤修复的前提.通过对湘西花垣县锰矿、铅锌矿区植被调查,共记录到高等植物76种,隶属69属,39科.对两矿区的主要优势植物及其土壤重金属含量进行了测定、分析,结果表明,两矿区土壤Pb、Zn、Cd含量均超过国家土壤环境质量二级标准阈值,对矿区土壤造成了污染.主要优势植物均能适应矿区土壤重金属元素较高的环境,对重金属具有一定的耐性,但不同植物对重金属的吸收和蓄积特征不同,油茶、芒萁吸收的重金属主要分布在地上部分,属于金属富集型植物,适于修复湘西矿区重金属污染中等且使用价值较高的污染土壤;灰白毛莓、山莓、毛萼莓、魁蒿、蕨吸收的重金属主要累积在根部,属于根部囤积型植物;芒草、白茅、箬竹、飞龙掌血根、茎、叶重金属含量均较低,属于重金属规避型植物.这2种类型的植物适合种植在湘西矿区重金属污染严重、使用价值相对较低、面积较大的矿山废弃地.     

Accumulation of Pb, Cu, and Zn in native plants growing on contaminated sites and their potential accumulation capacity in Heqing, Yunnan

Phytoremediation is one of the cost-effective and environmental friendly technologies used to remove contaminants from contaminated soils,which has been intensively studied during the last decade.Presently,few economical and effective remediation methods are available for the remediation of Pb contaminated sites.This study was conducted to assess the potential of 19 plants growing on contaminated sites in Pb mine area.Plants and associated soil samples were collected and analyzed for total metal concentrati...     

抗生素环丙沙星(CIP)在两种红树林湿地中的残留及迁移特征

沿海地区水产养殖废水直排导致滨海红树林内抗生素富集.本研究在广东省湛江市高桥红树林自然保护区展开,采用高效液相色谱法对两种优势红树植物群落—红海榄(Rhizophorastylosa)、白骨壤(Avicennia marina)根际沉积物及植物根、枝、叶中环丙沙星(Ciprofloxacin,CIP)的残留进行定量分析,同时分析红树植物根系含脂率(Lipid ratio,LR)与根系中CIP累积的相关性.结果表明,红海榄、白骨壤根际沉积物中CIP残留无显著差异(p0.05),含量分别为(69.0±5.9)、(63.0±6.2)μg·kg~(-1),高于国内外其它湿地沉积物中CIP残留水平;植物体内CIP累积表现为白骨壤((1306.3±234.8)μg·kg~(-1))红海榄((366.6±52.0)μg·kg~(-1))(p0.05),且均呈现地上部(枝、叶)根部的特征,转移因子(Transfer Factors,TF)分别为3.5±1.7、1.4±0.5.两种红树植物对环境中CIP均具有净化潜力,其中,以白骨壤净化能力更强.研究同时发现,含脂率不是影响根系吸收累积CIP的关键因子.本研究对抗生素在红树林湿地内的迁移和吸附特征研究具有借鉴意义.     

Assessment of Pb uptake, translocation and immobilization in kenaf (Hibiscus cannabinus L.) for phytoremediation of sand tailings

The potential of kenaf (Hibiscus cannabinus L.) for phytoremediation of lead (Pb) on sand tailings was investigated.A pot experiment employing factorial design with two main effects of fertilizer and lead was conducted in a nursery using sand tailings from an ex-tin mine as the growing medium.Results showed that Pb was found in the root,stem,and seed capsule of kenaf but not in the leaf.Application of organic fertilizer promoted greater biomass yield as well as higher accumulation capacity of Pb.In Pb-spike...