Phytoremediation of soil contaminated with cadmium, copper and polychlorinated biphenyls

A pot experiment and afield trial were conducted to study the remediation of an aged field soil contaminated with cadmium, copper and polychlorinated biphenyls (PCBs) (7.67 +/- 0.51 mg kg(-1) Cd, 369 +/- 1 mg kg(-1) Cu in pot experiment; 8.46 +/- 0.31 mg kg(-1) Cd, 468 +/- 7 mg kg(-1) Cu, 323 +/- 12 microg kg(-1) PCBs for field experiment) under different cropping patterns. In the pot experiment Sedum plumbizincicola showed pronounced Cd phytoextraction. After two periods (14 months) of cropping the Cd removal rates in these two treatments were 52.2 +/- 12.0 and 56.1 +/- 9.1%, respectively. Total soil PCBs in unplanted control pots decreased from 323 +/- 11 to 49.3 +/- 6.6 microg kg(-1), but with no significant difference between treatments. The field microcosm experiment intercropping of three plant species reduced the yield of S. plumbizincicola, with a consequent decrease in soil Cd removal. S. plumbizincicola intercropped with E. splendens had the highest shoot Cd uptake (18.5 +/- 1.8 mg pot(-1)) after 6 months planting followed by intercropping with M. sativa (15.9 +/- 1.9 mg pot(-1)). Liming with S. plumbizincicola intercropped with M. sativa significantly promoted soil PCB degradation by 25.2%. Thus, adjustment of soil pH to 5.56 combined with intercropping with S. plumbizincicola and M. sativagave high removal rates of Cd, Cu, and PCBs.     

Lead uptake and translocation by willows in pot and field experiments

Plant growth and lead (Pb) uptake by seven willow varieties were investigated in pot and field experiments to assess the suitability of willows for phytoremediation of Pb at heavily contaminated sites such as skeet ranges. Differences in uptake and translocation of Pb in Salix were observed between pot and field experiments. In the pot experiment, willows grown in Pb-contaminated field soil for 6 months showed tolerance to very high soil Pb concentration (21,360 mg kg(-1)), and with the addition of EDTA were able to take up and translocate more than 1000 mg kg(-1) Pb into above-ground tissues. In the field experiment, all willow varieties showed tolerance to heterogeneously high soil Pb concentrations. Plants were also able to take up and translocate Pb into above-ground tissues. However, after 4.5 months, the lead concentration in the above-ground tissues of willows grown in soil amended with EDTA was less than 200 mg kg(-1). The results from the pot experiment suggest that Salix varieties have the potential to take up and translocate significant amounts of Pb into above-ground tissues using EDTA. However, to verify the phytoextraction abilities of Salix in the field, additional research is needed.     

Bioavailability assessment and accumulation by five garden flower species grown in artificially cadmium-contaminated soils

Many studies have been conducted on phytoextraction; however, non-native hyperaccumulator species are not suitable for the natural environment of Taiwan in many cases. Drawing upon previous results, the growth and heavy metal accumulation in artificially cadmium-contaminated soils were compared for five local garden flower species. The treatments included a control (CK), 9.73 +/- 0.05 mg kg(-1) (Cd-10), and 17.6 +/- 0.8 mg kg(-1) (Cd-20). All plants were harvested at 35 days after transplanting and analyzed for Cd content. Cd accumulation in the shoot of French marigold (Tagetes patula L.) and Impatiens (Impatiens walleriana Hook. f.) grown in Cd-20 treatment were 66.3 +/- 6.5 and 100 +/- 11 mg kg(-1), which equated to a removal of 0.80 +/- 0.11 and 0.60 +/- 0.37 mg Cd plant(-1), respectively. The maximum Cd accumulation of Impatiens reached the threshold value (100 mg kg(-1)) characteristic of a Cd hyperaccumulator and its bioconcentration factor (BCF) and translocation factor (TF) were greater than one. Impatiens therefore has the potential to hyperaccumulate Cd from Cd-contaminated soils. With the exception of Garden verbena, significant relationships were found between Cd concentrations in soil extracted by 0.05 M EDTA, 0.005 M DTPA, and 0.01 M CaCl2 and the concentration of Cd in the shoots of the tested garden flowers.     

水培条件下四种植物对Cd、Pb富集特征

利用水培方法测定了不同浓度下向日葵、蓖麻、紫花苜蓿及芥菜的生物量和植物体内重金属Cd、Pb含量,分析了植物对重金属的富集特征。结果表明:经过5周培养后,4种植物根部与地上部对重金属的富集量随着浓度的增加而增加,Cd浓度为20mg·L-1时,向日葵的根部Cd含量最高,达到237.86mg·kg-1,地上部Cd含量为89.48mg·kg-1;而Pb浓度为200mg·L-1时,芥菜根部对Pb的吸收量较高,达到597.22mg·kg-1,地上部Pb含量最高的则出现在向日葵处理Pb100mg·L-1中,为318.33mg·kg-1。4种植物对Cd、Pb的富集系数随重金属浓度的增加而减小;根部及地上部富集系数与生物量和重金属浓度呈现出一定的相关性;另外,在Cd、Pb复合处理中,一种重金属的存在会在不同程度上影响植物对另一种重金属的吸收。通过比较4种植物根部与地上部的生物量和对Cd、Pb富集特征,认为相对于其他3种植物向日葵对Cd、Pb具有较强的吸收潜力,并可以作为Cd、Pb污染土壤植物修复的备选植物。     

水葱对镉的超富集作用及其用于植物修复的潜力

野外观察与研究发现水葱(Scirpus tabernaemontani G.)可以耐受土壤中高浓度的重金属污染,并对镉有很高的生物富集量。实验室水培试验研究了两个主要因素,营养液pH值以及镉含量,对其生物量以及镉富集效果的影响。结果表明,水葱可耐受的高浓度Cd(30mg/L)和大范围pH值变化(3.7～7.7)。当营养液pH值为4.7,Cd含量为25mg/L时,水葱富集的Cd达到最大值:地上部分264.71mg/kg,地下部分234·39mg/kg,平均转运系数1.13。这显示了它用于植物修复镉污染土壤的巨大潜力。     

Response of Thlaspi caerulescens to nitrogen, phosphorus and sulfur fertilisation

The main limiting factor for cleaning-up contaminated soils with hyperaccumulator plants is the low production of aerial biomass and the number of successive crops needed to reach the objective of remediation. The aim of this study was to contribute to the determination of a fertilisation strategy to optimise soil metal phytoextraction by Thlaspi caerulescens. A pot experiment was conducted on an agricultural soil and on a contaminated soil from the vicinity of a former Pb/Zn smelter. The nitrogen (N) treatment consisted of 4 levels (0, 11, 21.5 and 31 mg N kg(-1) dry soil (DS)) added as NH4NO3. The highest N treatment was combined with 4 levels of phosphorus (P) (0, 20, 40 and 80 mg P kg(-1) DS as KH2PO4) and sulfur (S) additions (0, 10, 20 and 30 mg S kg(-1) DS as MgSO4). The highest N fertilisation contributed significantly to enhance biomass production of T. caerulescens and to decrease the concentration of Cd and Zn in the biomass. At constant N addition, P supply did not affect metal extraction by T. caerulescens but negatively affected plant health. Sulfur supply slightly increased phytoextraction of Cd. Our results show that N and S fertilisation might interact but further investigations on the effect of such interaction on Cd extraction efficiency are needed.     

改良剂对酸性土壤上伴矿景天铝毒缓解作用及镉锌吸收性的影响

为探究不同改良剂对酸性土壤铝(Al)胁迫条件下镉(Cd)锌(Zn)超积累植物伴矿景天Sedum plumbizincicola生长以及镉和锌吸取修复效率的影响,分别添加不同种类改良剂(钙镁磷肥(CMP)、MgCO3、KH2PO4)和不同浓度CMP进行温室盆栽试验。结果表明,CMP能够一定程度上提高土壤pH值并降低土壤交换性Al的浓度,MgCO3能够显著提高土壤pH值和降低土壤交换性Al的浓度,KH2PO4能够降低土壤中交换性Al浓度但未改变土壤pH值。施用适量的CMP(9.39 mg/kg)能够提高伴矿景天生物量和Cd、Zn吸取修复效率,用量过高会抑制伴矿景天生长和Cd、Zn修复效率;施用MgCO3可增大伴矿景天生物量和Cd、Zn修复效率,施用KH2PO4反而抑制了伴矿景天生长。酸性土壤上施用适量的CMP和MgCO3能够缓解伴矿景天的铝毒作用,维持较高的重金属吸收效率。     

Effect of fertilizers on Cd uptake of Amaranthus hypochondriacus, a high biomass, fast growing and easily cultivated potential Cd hyperaccumulator

In a greenhouse pot experiment, we assessed the phytoextraction potential for Cd of three amaranth cultivars (Amaranthus hypochondriacus L. Cvs. K112, R104, and K472) and the effect of application of N, NP, and NPK fertilizer on Cd uptake of the three cultivars from soil contaminated with 5 mg kg(-1) Cd. All three amaranth cultivars had high levels of Cd concentration in their tissues, which ranged from 95.1 to 179.1 mg kg(-1) in leaves, 58.9 to 95.4 mg kg(-1) in stems, and 62.4 to 107.2 mg kg(-1) in roots, resulting in average bioaccumulation factors ranging from 17.7 to 29.7. Application of N, NP, or NPK fertilizers usually increased Cd content in leaves but decreased Cd content in stem and root. Fertilizers of N or NP combined did not substantially increase dry biomass of the 3 cultivars, leading to a limited increment of Cd accumulation. NPK fertilizer greatly increased dry biomass, by a factor of 2.7-3.8, resulting in a large increment of Cd accumulation. Amaranth cultivars (K112, R104, and K472) have great potential in phytoextraction of Cd contaminated soil. They have the merits of high Cd content in tissues, high biomass, easy cultivation and little effect on Cd uptake by fertilization.     

Technical note monitoring native vegetation on a dumpsite of PCB-contaminated soil

Composition of native vegetation on a polychlorinated biphenyls (PCB)-contaminated soil dumpsite at Lhenice, South Bohemia (Czech Republic), was determined and species variability in the accumulation of PCBs in plant biomass was investigated. Soil stripping contaminated by PCBs originated at a factory producing electrical transformers that mostly used the commercial PCB mixture Delor 103 and 106. The PCB content of soil in the most contaminated part of the dumpsite reached 153 mg kg(-1) dry soil. Low diversity of plant species was found on the dumpsite. Results showed three grass species, Festuca arundinacea Schreb., Phalaroides arundinacea (L.) Rauschert., and Calamagrostis epigeios (L.) Roth., to be the major components of the vegetation and confirmed their high tolerance toward PCB contamination. The highest content of PCB in plant biomass--813.2 microg kg(-1) dry biomass--was determined in Festuca aboveground biomass. For phytoextraction purposes especially, Festuca can be recommended due to its high biomass yield, but its bioconcentration factor was very low (0.006). Tripleurospermum maritimum (L.) Sch. Bip. and Cirsium arvense (L.) Scop. grew mainly at the margins of the most contaminated part of the dumpsite. The PCB content determined in their aboveground biomass-278.7 and 289.5 microg kg(-1) dry biomass, respectively--was nonsignificantly lower compared to grass species Phalaroides and Calamagrostis. Salix (Salix viminalis L. and Salix caprea L.) was monitored among plant species composition at this site as a representative of woody species.     

Effects of soil amendments and EDTA on lead uptake by Chromolaena odorata: greenhouse and field trial experiments

Greenhouse and field trial experiments were performed to evaluate the use of Chromolaena odorata with various soil amendments for phytoextraction of Pb contaminated soil Pb mine soils contain low amount of nutrients, so the additions of organic (cow manure) and inorganic (Osmocote and NH4NO3 and KCl) fertilizers with EDTA were used to enhance plant growth and Pb accumulation. Greenhouse study showed that cow manure decreased available Pb concentrations and resulted in the highest Pb concentration in roots (4660 mg kg(-1)) and shoots (389.2 mg kg(-1)). EDTA increased Pb accumulation in shoots (17-fold) and roots (11-fold) in plants grown in soil with Osmocote with Pb uptake up to 203.5 mg plant(-1). Application of all fertilizers had no significant effects on relative growth rates of C. odorata. Field trial study showed that C. odorata grown in soil with 99545 mg kg(-1) total Pb accumulated up to 3730.2 and 6698.2 mg kg(-1) in shoots and roots, respectively, with the highest phytoextraction coefficient (1.25) and translocation factor (1.18). These results indicated that C. odorata could be used for phytoextraction of Pb contaminated soil. In addition, more effective Pb accumulation could be enhanced by Osmocote fertilizer. However, the use of EDTA in the field should be concerned with their leaching problems.     

In-situ cadmium phytoremediation using Solanum nigrum L.: the bio-accumulation characteristics trail

In this study, Solanum nigrum L. was used in-situ for Cdphytoremediation in Cd polluted soil on Shenyang Zhangshi Irrigation area (SZIA) in 2008. The performance of the plant over the whole growth stage was assessed. Results showed, during the whole experimental stage, the aboveground biomass of single Solanum nigrum L. grew by a factor of 190, from 1.6 +/- 0.4 g to 300.3 +/- 30.2 g with 141.2 times extracted Cd increase from 0.025 +/- 0.001 to 3.53 +/- 0.16 mg. Both the distribution of biomass and amount of extracted Cd in the above-ground part of the plant changed according to the growth of the plant. Particularly, the percentage of biomass and extracted Cd in the stem increased from 20% to 80% and from 11% to 69%, respectively. The bioconcentration factor and transfer factor both varied significantly during the growth of the plant and the lowest values were measured at the flowering stage (0.94 +/- 0.31 and 3.48 +/- 1.14 respectively). The results in this paper provide reference values for the future research on the application of Solanum nigrum L. in phytoremediation and on chemical or/and agricultural strategies for phytoextraction efficiency enhancement.     

印度芥菜-苜蓿间作对镉胁迫的生态响应

采用温室盆栽试验,研究了重金属镉（Cd）胁迫对印度芥菜和苜蓿间作下的土壤-植物系统的影响,同时对苜蓿的Cd饲用安全进行了评估.结果表明：在土壤Cd含量为0.37～20.37 mg·kg^-1范围内,与单作印度芥菜和苜蓿相比,间作使印度芥菜生物量降低了0.4%～11.8%,而使苜蓿生物量提高了55.3%~70.0%.土壤有效Cd主要受土壤全量Cd和种植植物种类的影响,种植方式对其影响不大.在土壤Cd含量为5.37 mg·kg^-1时,间作印度芥菜地上部Cd含量较单作提高了14.5%,而间作苜蓿地上部Cd含量较单作降低了57.1%;此时,单作和间作苜蓿地上部Cd含量分别为0.21和0.09 mg·kg^-1,均未超过饲料卫生限定标准(0.5 mg·kg^-1).在土壤Cd含量为10.37～20.37 mg·kg^-1范围内,虽然单作和间作苜蓿Cd含量均超过饲料卫生限定标准,但间作种植方式仍然使苜蓿地上部Cd含量较单作降低了2.8%～48.3%,印度芥菜地上部Cd含量也较单作降低了1.1%～48.6%.不论单作还是间作印度芥菜的Cd转运系数都远高于苜蓿.     

Large-area experiment on uptake of metals by twelve plants growing in soils contaminated with multiple metals

A site in central Taiwan with an area of 1.3 ha and contaminated with Cr, Cu, Ni, and Zn was selected to examine the feasibility of phytoextraction. Based on the results of a preexperiment at this site, a total of approximately 20,000 plants of 12 species were selected from plants of 33 tested species to be used in a large-area phytoextraction experiment at this site. A comparison with the initial metal concentration of 12 plant species before planting demonstrated that most species accumulated significant amounts of Cr, Cu, Ni, and Zn in their shoots after growing in this contaminated site for 31 d. Among the 12 plant species, the following accumulated higher concentrations of metals in their shoots; Garden canna and Garden verbena (45-60 mg Cr kg(-1)), Chinese ixora and Kalanchoe (30 mg Cu kg(-1)), Rainbow pink and Sunflower (30 mg Ni kg(-1)), French marigold and Sunflower (300-470 mg Zn kg(-1)). The roots of the plants of most of the 12 plant species can accumulate higher concentrations of metals than the shoots and extending the growth period promotes accumulation in the shoots. Large-area experiments demonstrated that phytoextraction is a feasible method to enable metal-contaminated soil in central Taiwan to be reused.     

Plant uptake and the leaching of metals during the hot EDDS-enhanced phytoextraction process

Using pot experiments, the effect of the application of the biodegradable chelating agent S,S-ethylenediaminedisuccinic acid (EDDS) in hot solutions at 90 degrees C on the uptake of Cu, Pb, Zn, and Cd by corn (Zea mays L. cv. Nongda No. 108) and beans (P vulgaris L. white bean), and the potential leaching of metals from soil, were studied. When EDDS was applied as a hot solution at the rate of 1 mmol kg(-1), the concentrations and total phytoextraction of metals in plant shoots exceeded or approximated those in the shoots of plants treated with normal EDDS at the rate of 5 mmol kg(-1). On the other hand, the leaching of Cu, Pb, Zn, and Cd after the application of the hot EDDS solution at the rate of 1 mmol kg(-1) was reduced by 46%, 21%, 57%, and 35% in comparison with that from the application of normal EDDS at 5 mmol kg(-1), respectively. For treatment with 1 mmol kg(-1) of EDDS, the leached metals decreased to the levels of the control group (that without EDDS amendment) 14 d after the application of EDDS. The soil amendment with biodegradable EDDS in hot solutions may provide a good alternative to chelate-enhanced phytoextraction in enhancing metal uptake by plants and limiting metals from leaching out of the soil.     

Identifying the functional groups and the influence of synthetic chelators on Cd availability and microbial biomass carbon in Cd-contaminated soil

Synthetic chelators play an important role in boosting the microbial biomass carbon (MBC), dissolved organic carbon (DOC), and heavy metal solubility in a contaminated soil toward a sustainability of environment for agricultural crops. Castor plant was grown under different levels of Cd contaminated soil (?Cd and +Cd) following adding three chelating agents, ethylenediaminetetraacetic acid (H₄EDTA), nitriloacetic acid (H₃ NTA), and NH₄ citrate (ammonium citrate) to the soil at rates of 10, 15, and 25 mmol in 5 kg of soil per pot. The highest bioavailable Cd concentrations in soil and castor plant were obtained from NH₄ citrate and H₄EDTA treatments in the contaminated soil. Fourier transform infrared (FTIR) analysis showed that NH₄ citrate was the most effective chelator in Cd-contaminated soil. MBC and DOC contents were significantly increased and reached at 81.98–80.37 and 1.96–1.90 mg kg^?1 respectively, in the (H₃ NTA) and NH₄ citrate treatments in Cd-contaminated soil. Further research is needed to investigate the use of chelators in the phytoextraction of Cd-contaminated soils under field conditions and whether it may be beneficial in accelerating the phytoextraction of Cd through hyperaccumulating plants.     

可降解螯合剂对镉胁迫下籽粒苋根系形态及生理生化特征的影响

采用盆栽试验研究了可降解螯合剂EDDS和NTA对镉胁迫下籽粒苋(Amaranthus hybridus L.)根系形态及生理生化特征的影响。结果表明:当螯合剂施入10 mg/kg的镉污染土壤后,籽粒苋根系生物量和总长等根系形态指标与对照无显著差异,过氧化物酶(POD)、过氧化氢酶(CAT)活性、谷胱甘肽(GSH)和可溶性蛋白含量显著上升。当螯合剂施入100 mg/kg的镉污染土壤后,籽粒苋根系生物量、总长、表面积、体积及侧根数比对照显著减少了12.30%—23.98%、17.01%—24.90%、41.87%—57.93%、16.46%—32.94%和23.48%—53.35%;EDDS的施入使籽粒苋根系POD、CAT活性、GSH和可溶性蛋白含量显著升高;而NTA施入后,根系中的POD活性比对照降低了4.12%—35.95%,并且CAT活性和可溶性蛋白含量在2 mmol/kg NTA处理下分别显著降低了14.66%—15.79%和26.81%—30.48%;EDDS和NTA施入后,GSH含量比对照显著升高了14.73%—65.65%和28.05%—84.10%。当镉处理浓度分别为10 mg/kg和100 mg/kg时,螯合剂的施入显著增强了籽粒苋根系对镉的吸收,比对照分别增加了40.76%—103.10%和15.03%—49.49%。因此,EDDS和NTA施入镉污染土壤后,通过影响籽粒苋根系形态和生理生化过程以响应重金属镉的胁迫。     

Hyperaccumulation of metals by Thlaspi caerulescens as affected by root development and Cd-Zn/Ca-Mg interactions

The aim of this work was to study, in a rhizobox experiment, the phytoextraction of metals by the hyperaccumulator plant Thlaspi caerulescens in relation to the heterogeneity of metal pollution. Six treatments were designed with soils containing various levels of metals. Homogeneous soils and inclusions of soils in other soil matrices were prepared in order to vary metal concentration and localization. Growth parameters of the plant (rosette diameter and shoot biomass) and localization of roots and shoot uptake of Zn, Cd, Ca, and Mg were determined after 10 weeks of growth. The plants grown on the polluted industrial soils provided a larger biomass and had lower mortality rates than those grown on the agricultural soil. Moreover, these plants accumulated more Zn and Cd (up to 17,516 and 375 mg kg(-1) DM, respectively) than plants grown on the agricultural soil (up to 7300 mg Zn kg(-1) and 83 mg Cd kg(-1) DM). The roots preferentially explored metal-contaminated areas. The exploration of polluted soil inclusions by the roots was associated with a higher extraction of metals. Zinc and Cd in the shoots of Thlaspi caerulescens were negatively correlated with Ca and Mg concentrations; however, the soil supply for these two elements was identical. This suggests that there is competition for the uptake of these elements and that Zn is preferentially accumulated.     

Uptake of heavy metals by native species growing in a mining area in Sardinia, Italy: discovering native flora for phytoremediation

This study assessed the distribution and availability of plant uptake of Zn, Pb, and Cd present in an abandoned mine at Ingurtosu, Sardinia (Italy). Geological matrix samples (sediments, tailings, and soil from a nearby pasture site) and samples of the predominant plant species growing on sediments and tailings were collected. Mean values of total Zn, Pb and Cd were respectively (mg kg(-1)) 7400, 1800, and 56 in tailings, 31000, 2900, and 100 in sediments, and 400, 200, and 8 in the pasture soil. The metal concentration values were high even in the mobile fractions evaluated by simplified sequential extraction (Zn 7485-103, Pb 1015-101, Cd 47-4 mg kg(-1)). Predominant native species were identified and analyzed for heavy metal content in various tissues. Among the plant species investigated Inula viscosa, Euphorbia dendroides, and Poa annua showed the highest metal concentration in aboveground biomass (mean average of Zn: 1680, 1020, 1400; Pb: 420, 240, 80; Cd: 28, 7, 19 mg kg(-1), respectively). The above mentioned species and A. donax could be good candidates for a phytoextraction procedure. Cistus salvifolius and Helichrysum italicus generally showed behavior more suitable for a phytostabilizer.     

Arbuscular mycorrhiza decreases cadmium phytoextraction by transgenic tobacco with inserted metallothionein

The effect of arbuscular mycorrhiza (AM) on the phytoextraction efficiency of transgenic tobacco with increased ability to tolerate and accumulate cadmium (Cd) was tested in a pot experiment. The tobacco plants bearing the yeast metallothionein CUP1 combined with a polyhistidine cluster were compared to non-transgenic tobacco of the same variety at four Cd concentrations in soil, non-inoculated or inoculated with two isolates of the AM fungus Glomus intraradices. Mycorrhizal inoculation improved the growth of both the transgenic and non-transgenic tobacco and decreased Cd concentrations in shoots and root to shoot translocation. Differences were found between the two AM fungal isolates: one isolate supported more efficient phosphorus uptake and plant growth in the soil without Cd addition, while the other isolate alleviated the inhibitory effect of cadmium on plant growth. The resulting effect of inoculation on Cd accumulation was dependent on Cd level in soil and differed between the more Cd tolerant transgenic plants and the less tolerant non-transgenic plants. Mycorrhiza mostly decreased the phytoextraction efficiency of transgenic plants while increased that of non-transgenic plants at Cd levels in soil inhibitory to tobacco growth. Mechanisms of the observed effects of inoculation on growth and Cd uptake are discussed as well as the possible implications of the results for the exploitation of AM in phytoextraction of heavy metals from contaminated soils.     

Effects of Soil Type and Genotype on Cadmium Accumulation by Rootstalk Crops: Implications for Phytomanagement

The variations of Cd accumulation in three rootstalk crop species (radish, carrot and potato) were investigated by using twelve cultivars grown in acidic Ferralsols and neutral Cambisols under two Cd treatments (0.3 and 0.6 mg kg^?1) in a pot experiment. The result showed that the total Cd uptake was significantly affected by genotype, soil type and interaction between them, suggesting the importance of selecting proper cultivars for phytoextraction in a given soil type. Among the cultivars tested, potato cultivar Luyin No.1 in Ferralsols and radish cultivar Zhedachang in Cambisols exhibited the highest Cd phytoextraction efficiency in aerial parts (4.45% and 0.59%, respectively) under 0.6 mg kg^?1Cd treatment. Furthermore, the Cd concentrations in their edible parts were below the National Food Hygiene Standard of China (0.1 mg kg^?1, fresh weight). Therefore, phytomanagement of slightly Cd-contaminated soils using rootstalk crops for safe food production combined with long-term phytoextraction was feasible, and potato cultivar Luyin No.1 for Ferralsols and radish cultivar Zhedachang for Cambisols were promising candidates for this approach.