Phytoremediation of selenium by two helophyte species in subsurface flow constructed wetland

The phytoremediation of selenium by two different wetland species was investigated. Selenium (20.4 microg/l) was supplied continuously to subsurface flow constructed wetlands, one vegetated with Typha latifolia L. and the other with Phragmites australis (Cav.) Trin. ex Steud. The beds of both species had same hydraulic loading rate (0.079 m(3)/m(2)/d) and water retention time (24 h). However, the mass loading rate was 1.27 mg Se/m(2)/d for Phragmites and 1.35 mg Se/m(2)/d for Typha. In the Typha bed Se migrated faster than in the Phragmites bed. After 25 d of Se supplementation in the Typha bed about 54% of the Se inlet concentration remained in the outlet water. In the Phragmites bed Se was removed completely from the water after passing through 3/4 of the bed length. After 65 d of Se supplementation the highest amount of Se (2.8 microg/g dry matter) was determined in the organic material of the Typha bed. Roots and rhizomes accumulated 2.2 and 1.8 microg/g dry matter respectively. Phragmites accumulated Se in the leaves and stems, but not in the rhizomes. The accumulation in the leaves (1.8 microg Se/g dry matter) was three times higher than in the stems (0.6 microg Se/g dry matter).     

Phytoremediation of Cadmium-Contaminated Soils by Rorippa globosa Using Two-Phase Planting (5 pp)

Background Phytoextraction of contaminated soils by heavy metals can provide a great promise of commercial development. Although there are more than 400 species of hyperaccumulators found in the world, phytoremediation technology is rarely applied in field practice for remedying contaminated soils, partially due to low biomass and long growth duration for most of discovered hyperaccumulating plants. In order to enhance the metal-removing efficiency in a year, the two-phase planting countermeasure of phytoextraction by harvesting anthesis biomass was investigated on the basis of the newly found Cd-hyperaccumulator Rorippa globosa (Turcz.) Thell. with 107.0 and 150.1 mg/kg of the Cd accumulation in stems and leaves, respectively, when soil Cd added was concentrated to 25.0 mg/kg. Methods The field pot-culture experiment was used to observe the distribution property of R. globosa aboveground biomass and to examine characteristics of accumulating Cd by the plant at different growth stages. The concentration of Cd in plants and soils was determined using atomic absorption spectrophotometry (AAS). Results and Discussion The results indicated that the total dry stem and leaf biomass of R. globosa harvested at the flowering phase was up to 92.3% of that at its full maturity and the concentration of Cd in stems and leaves harvested at the flowering phase was up to 73.8% and 87.7% of that at the mature phase, respectively. The Cd-removing ratio by shoots of R. globosa harvested at the flowering phase was up to 71.4% of that at the mature phase. It was also found, by observing the growth duration of R. globosa, that the frostless period at the experiment site was twice as long as the growth time from the seedling-transplanted phase to the flowering phase of the hyperaccumulator. Conclusion R. globosa could be transplanted into contaminated soils twice in one year by harvesting the hyperaccumulator at its flowering phase based on climatic conditions of the site and traits of the plant growth. In this sense, the extraction efficiency of Cd in shoots of R. globosa increased 42.8% compared to that of at its single maturity when the plant was transplanted into contaminated soils after it had been harvested at its flowering phase and the plant accumulated Cd from soil at the same extraction ratio at its second flowering phase. Thus, the method of anthesis biomass regulation by the two-phase planting is very significant to increase the Cd-removing efficiency by phytoremediation used in practice over the course of a year. Recommendation and Outlook As for some hyperaccumulators that the growth duration from the seedling-transplanted phase to the flowering phase are short and the concentrations of heavy metals accumulated in their shoots at the flowering phase are high, the efficiency of phytoremediation can greatly be improved using the method of the two-phase planting.     

Chromium accumulation by the hyperaccumulator plant Leersia hexandra Swartz

Leersia hexandra Swartz (Gramineae), which occurs in Southern China, has been found to be a new chromium hyperaccumulator by means of field survey and pot-culture experiment. The field survey showed that this species had an extraordinary accumulation capacity for chromium. The maximum Cr concentration in the dry leaf matter was 2978 mg kg(-1) on the side of a pond near an electroplating factory. The average concentration of chromium in the leaves was 18.86 times as that in the pond sediment, and 297.41 times as that in the pond water. Under conditions of the nutrient solution culture, it was found that L. hexandra had a high tolerance and accumulation capacity to Cr(III) and Cr(VI). Under 60 mg l(-1) Cr(III) and 10 mg l(-1) Cr(VI) treatment, there was no significant decrease of biomass in the leaves of L. hexandra (p>0.05). The highest bioaccumulation coefficients of the leaves for Cr(III) and Cr(VI) were 486.8 and 72.1, respectively. However, L. hexandra had a higher accumulation capacity for Cr(III) than for Cr(VI). At the Cr(III) concentration of 10 mg l(-1) in the culture solution, the concentration of chromium in leaves was 4868 mg kg(-1), while at the same Cr(VI) concentration, the concentration of chromium in leaves was only 597 mg kg(-1). These results confirmed that L. hexandra is a chromium hyperaccumulator which grows rapidly with a great tolerance to Cr and broad ecological amplitude. This species could provide a new plant resource that explores the mechanism of Cr hyperaccumulation, and has potential for usage in the phytoremediation of Cr-contaminated soil and water.     

Nickel and other metal uptake and accumulation by species of Alyssum (Brassicaceae) from the ultramafics of Iran

Some plants growing on serpentine (ultramafic) soils are able to hyperaccumulate nickel in their above-ground parts. The genus Alyssum L. contains the greatest number of Ni-hyperaccumulator plants so far reported. There are substantial areas of serpentine soils at many locations in Iran. This paper presents the analyses for Ni, Cr, Mn, Fe, Mg and Ca in soils and Alyssum species from the ultramafics of west and northwest Iran. Soil analysis for total elements in these areas indicates that typical concentrations of Ni, Cr, Mn, Fe, Mg and Ca are up to about 1240, 365, 800, 51,150, 152,390 and 11,790 microg g(-1), respectively. During this study, seven Alyssum species were collected. Analysis of leaf dry matter shows that Alyssum bracteatum can contain up to 2300 microg Nig(-1), while the other species contain much lower concentrations of Ni and other elements. A. bracteatum is endemic to Iran and the first Ni hyperaccumulator reported from this species.     

Uptake and accumulation of cadmium, lead and zinc by Siam weed [Chromolaena odorata (L.) King & Robinson

The Siam weed, Chromolaena odorata (L.) King & Robinson, Family Asteraceae, was found to be a new Pb hyperaccumulator by means of field surveys on Pb soil and hydroponic studies. Plants from field collection accumulated 1377 and 4236mgkg(-1) Pb in their shoots and roots, respectively, and could tolerate soil Pb concentrations up to 100000 mgkg(-1) with a translocation factor of 7.62. Very low concentrations of Cd and Zn were found in plants collected from the field. Under nutrient solution culture condition, C. odorata from the contaminated site (CS) and from non-contaminated site (NCS) grew normally with all three metals (Pb, Cd, Zn) supplied. However, the relative growth rates of all treated plants decreased with increased metal concentrations. The percentage uptakes of Pb, Cd, and Zn by C. odorata increased with increasing metal concentrations. Pb concentration in shoots and roots reached its highest values (1772.3 and 60655.7mgkg(-1), respectively) at a Pb supply level of 10mgl(-1). While the maximum concentrations of Cd (0.5mgl(-1)) in shoots and roots of C. odorata were 102.3 and 1440.9mgkg(-1), and the highest concentrations of Zn (20mgl(-1)) were 1876.0 and 7011.8mgkg(-1), respectively. The bioaccumulation coefficients of Pb and Cd were greater than 1000. These results confirm that C. odorata is a hyperaccumulator which grows rapidly, has substantial biomass, wide distribution and has a potential for the phytoremediation of metal contaminated soils.     

Genotypic differences in effects of cadmium exposure on plant growth and contents of cadmium and elements in 14 cultivars of bai cai

Fourteen cultivars of bai cai (Brassica campestris L. ssp. chinensis var. communis) were grown in the nutrient solutions containing 0-0.5 microg mL(-1) of cadmium (Cd) to investigate genotypic differences in the effects of Cd exposure on the plant growth and uptake and distribution of Cd in bai cai plants. The Cd exposure significantly reduced the dry and fresh weights of roots and shoots, the dry weight ratio of shoot/root (S/R), total biomass, and chlorophyll content (SPAD value). Cd concentrations in bai cai ranged from 13.3 to 74.9 microg g(-1) DW in shoots and from 163.1 to 574.7 microg g(-1) DW in roots under Cd exposure, respectively. The considerable genotypic differences of Cd concentrations and accumulations in both shoots and roots were observed among 14 bai cai cultivars. Moreover, Cd mainly accumulated in the roots. Cd also caused the changes of uptake and distribution of nutrients in bai cai and under the influence of cadmium, the concentration of potassium (K) decreased in shoot and increased in root. However, the concentrations of magnesium (Mg), phosphorus (P), manganese (Mn), boron (B), and iron (Fe) increased in shoots and decreased in roots. In addition, Cd exposure resulted in an increase in calcium (Ca), sulphur (S), and zinc (Zn) concentrations in both shoots and roots but had no significant effects on the whole uptake of the examined mineral nutrients except for S.     

An engineered plant that accumulates higher levels of heavy metals than Thlaspi caerulescens, with yields of 100 times more biomass in mine soils

Nicotiana glauca transformed with TaPCS1 was tested for its application in phytoremediation. When plantlets were grown in mine soils containing Cu, Zn, and Pb (42, 2600, and 1500 mg kg(-1)) the plant showed high levels of accumulation especially of Zn and Pb. Adult plants growing in mine soils containing different heavy metal concentrations showed a greater accumulation as well as an extension to a wider range of elements, including Cd, Ni and B. The overexpressed gene confers up to 9 and 36 times more Cd and Pb accumulation in the shoots under hydroponic conditions, and a 3- and 6-fold increase in mining soils. When the hyperaccumulator Thlaspi caerulescens was compared, the results were higher values of heavy metal and Boron accumulation, with a yield of 100 times more biomass. Thlaspi was unable to survive in mining soils containing either a level higher than 11000 mg kg(-1) of Pb and 4500 mg kg(-1) of Zn, while engineered plants yielded an average of 0.5 kg per plant.     

Macro, minor and toxic elemental uptake and distribution in Hypoxis hemerocallidea, "the African Potato"--an edible medicinal plant

The elemental uptake and distribution, in various parts of the admired herbal plant, Hypoxis hemerocallidea, the 'African potato' and its ability to accumulate elements in response to the growth soil quality are investigated. The total and exchangeable concentrations of twelve elements in the growth soils and their distribution in the roots, potato bulb and leaves of the plants grown under four different settings were compared. The typical concentrations of the twelve selected elements, in the bulb and leaves of the plant grown in a nursery pot (site 2) were (in microg g(-1)dry weight) Ca (8430 and 27075), Mg (2113 and 1566), Fe (66 and 150), Al (10 and 368), Zn (105 and 6.1), Mn (42 and 51), Cu (7.2 and 20.8), Ba (0.23 and 4.44), Co (0.20 and 0.42), As (2.05 and 24.56), Hg (0.92 and 1.82) and Cr (0.13 and 0.33). Except for Ca, Mg, Zn and Mn, the exchangeable cation concentrations in all the growth soils were low. Ca, Mg, Mn, Zn and As had bioaccumulation factors >1. Fe, Al and Co concentrations were high in the roots with little in the rest of the plant. High concentration of arsenic (approximately 13 microg g(-1) dry weight) with bioaccumulation factors of 7 and 20 were observed in the roots and leaves of the plant respectively (site 2), but the concentration of mercury in bulb was very low (0.92 microg g(-1) dry weight).     

Phytoextraction of excess soil phosphorus

In the search for a suitable plant to be used in P phytoremediation, several species belonging to legume, vegetable and herb crops were grown in P-enriched soils, and screened for P accumulation potentials. A large variation in P concentrations of different plant species was observed. Some vegetable species such as cucumber (Cucumis sativus) and yellow squash (Cucurbita pepo var. melopepo) were identified as potential P accumulators with >1% (dry weight) P in their shoots. These plants also displayed a satisfactory biomass accumulation while growing on a high concentration of soil P. The elevated activities of phosphomonoesterase and phytase were observed when plants were grown in P-enriched soils, this possibly contributing to high P acquisition in these species. Sunflower plants also demonstrated an increased shoot P accumulation. This study shows that the phytoextraction of phosphorus can be effective using appropriate plant species.     

Life-cycle phases of a zinc- and cadmium-resistant ecotype of Silene vulgaris in risk assessment of polymetallic mine soils

Short-term exposure of plants to heavy metals is often used for risk assessment of metal-enriched soils (OECD guideline 208) without considering the reliability of the assessment for long-term exposure, i.e. for the completion of a plant's life-cycle. In the present study with 15 orogenic soils three phases of the life-cycle of a Zn-Cd-resistant ecotype of Silene vulgaris were studied to improve risk assessment of metal-enriched soils. The first phase, i.e. emergence of seedlings was not related to the water-soluble or total metal concentration of the soils. Seedling mortality was low as long as the water-soluble metal concentration did not surpass 0.15 micromol Zn and 0.04 micromol Cu g(-1) dry soil. Curtailment of the life-cycle prior to flowering, i.e. the vegetative growth as second phase, occurred on those soils where roots and shoots were heavily enriched by Zn already in the seedling phase. In the third phase, i.e. the generative phase, time to flowering and yield differences between orogenic soils were substantial, but soil metal concentrations could not be directly related to timing of reproduction or biomass. Ranking of data showed a high inconsistency of the responses to metal exposure during the first phases of the life-cycle. It is concluded that total plant mass and seed mass are the only realistic endpoints of life-cycle bioassays in risk assessment as long as ranks are inconsistent between two successive early phases of the life-cycle.     

Biomass and nutrient concentration of sweet corn roots and shoots under organic amendments application

Two field experiments were conducted at the Waimanalo research station on the island of O'ahu, Hawaii to study the effect of chicken (CM) and dairy (DM) manures on biomass and nutrient concentration in sweet corn roots and shoots. Sweet corn (super sweet 10, Zea Mays L. subsp. mays) was grown for two consecutive growing seasons under four rates of application (0, 168, 337, and 672 kg ha^{? 1} total N equivalent) and one time (OTA) or two time (TTA) applications of organic manure types and rates. There were significant effects of types, rates, and number of manure applications on dry biomass and macro- and micro-nutrient concentration in roots and shoots tissues. Results of root tissue indicated a significant accumulation of N and C under CM and DM treatments compared with the control treatment. Manure application rates significantly increased the accumulation of N and C in root tissue. Dry weight of roots and shoots and both macro- and micro-nutrient contents in the plant tissues significantly increased under TTA treatment compared with OTA treatment. There was a significant correlation (r² = 0.46 to 0.81) between root biomass, macro-, and micro-nutrient contents during both growing seasons. The results of the study indicates that amending soils with CM at the highest application rate provided the best crop performance in terms of root and shoot biomass, crop N, C, and other macro- and micro-nutrients.     

Response of submerged plant (Vallisneria spinulosa) clones to lead stress in the heterogenous soil

In order to evaluate risk spreading among clones and antioxidant defence response of clonal ramets, turions of Vallisneria spinulosa, the dominant clonal plant of the submerged plant community in most of the lakes in Middle and Lower Reaches of Yangtze Rive, China, were planted in the heterogeneous soils contaminated with 40 and 160 microg g(-1) Pb (dry weight) in a greenhouse. After 100 d, the ranking order of tissue Pb concentrations in organs of the ortets (parental plants) was root>turion>rhizome>leaf, but that of tissue Pb quantities was leaf>turion>rhizome>root, due to their different biomass. Some of Pb was transferred from the ortets exposed in the Pb-supplied soil to leaves of the offspring growing in the favorable patch through rhizome (connective organ). A high foliar Pb concentration induced a significant decrease in superoxide dismutases, peroxidase and catalase activities. Catalase was more sensitive to Pb than the other two antioxidant enzymes. However, a low foliar Pb concentration, in the ortets exposed to 40 microg g(-1) Pb and in all of the offspring, slightly increased the activities of superoxide dismutases and peroxidase. The biomass accumulation per ortet and the biomasses percentages allocation to the roots and the leaves in Pb treatments decreased markedly. Nevertheless, there was no significant difference in biomass accumulation of the offspring between the low Pb level treatment and the control. The biomass percentage allocated to the root of the offspring was found to be larger than that of the ortets.     

Co-cropping for phyto-separation of zinc and potassium from sewage sludge

The use of sewage sludge as a fertilizer and soil amendment has resulted in high concentrations of heavy metals in the soil limiting its use. The present study was carried out to find the possibility of phyto-separating toxic and beneficial elements from the sludge using suitable plants. Of the five plants tested the hyperaccumulator Sedum alfredii H achieved the greatest removal of Zn, while shoots of Alocasia marorrhiza accumulated high content of K. Co-cropping these two plants on the sludge verified the previous observations on A. marorrhiza and the shoots of this plant could accumulate more than 120 g K kg(-1) dry matter in the median growth stage. Zn hyperaccumulated in Sedum's shoots to an extent more than 10 g kg(-1) dry matter; K concentrated five to ten times in the Alocasia's shoots which could be used as a good organic-K-fertilizer. Hence, the two elements were simultaneously phytoseparated and could be recycled. Furthermore, cultivation of plants in the sludge resulted in significant decreases in total Zn but kept the favorable agronomic characteristics of the sludge material, such as pH, organic matter content, and NPK concentrations and ameliorated its biological stability. These results suggest that simultaneous phyto-separation of toxic and beneficial elements from sewage sludge are possible by co-cropping using specific plants without the input of any chemicals.     

Sensitivity of Mediterranean woody seedlings to copper, nickel and zinc

The restoration of heavy metal contaminated areas requires information on the response of native plant species to these contaminants. The sensitivity of most Mediterranean woody species to heavy metals has not been established, and little is known about phytotoxic thresholds and environmental risks. We have evaluated the response of four plant species commonly used in ecological restoration, Pinus halepensis, Pistacia lentiscus, Juniperus oxycedrus, and Rhamnus alaternus, grown in nutrient solutions containing a range of copper, nickel and zinc concentrations. Seedlings of these species were exposed to 0.048, 1 and 4 microM of Cu; 0, 25 and 50 microM of Ni; and 0.073, 25 and 100 microM of Zn in a hydroponic silica sand culture for 12 weeks. For all four species, the heavy metal concentration increased in plants as the solution concentration increased and was always higher in roots than in shoots. Pinus halepensis and P. lentiscus showed a higher capacity to accumulate metals in roots than J. oxycedrus and R. alaternus, while the allocation to shoots was considerably higher in the latter two. Intermediate heavy-metal doses enhanced biomass accumulation, whereas the highest doses resulted in reductions in biomass. Decreases in shoot biomass occurred at internal concentrations ranging from 25 to 128 microg g-1 of Zn, and 1.7 to 4.1 microg g( -1) of Cu. Nickel phytoxicity could not be established within the range of doses used. Rhamnus alaternus and J. oxycedrus showed higher sensitivity to Cu and Zn than P. halepensis and, especially, P. lentiscus. Contrasted responses to heavy metals must be taken into account when using Mediterranean woody species for the restoration of heavy metal contaminated sites.     

Effects of heavy metals on growth and arsenic accumulation in the arsenic hyperaccumulator Pteris vittata L

The effects of Cd, Ni, Pb, and Zn on arsenic accumulation by the arsenic hyperaccumulator Pteris vittata were investigated in a greenhouse study. P. vittata was grown for 8 weeks in an arsenic-contaminated soil (131 mg As kg(-1)), which was spiked with 50 or 200 mg kg(-1) Cd, Ni, Pb, or Zn (as nitrates). P. vittata was effective in taking up arsenic (up to 4100 mg kg(-1)) and transporting it to the fronds, but little of the metals. Arsenic bioconcentration factors ranged from 14 to 36 and transfer factors ranged from 16 to 56 in the presence of the metals, both of which were reduced with increasing metal concentration. Fern biomass increased as much as 12 times compared to the original dry weight after 8 weeks of growth (up to 19 g per plant). Greater concentrations of Cd, Ni, and Pb resulted in greater catalase activity in the plant. Most of the arsenic in the plant was present as arsenite, the reduced form, indicating little impact of the metals on plant arsenic reduction. This research demonstrates the capability of P. vittata in hyperaccumulating arsenic from soils in the presence of heavy metals.     

Uptake of selected PAHs from contaminated soils by rice seedlings (Oryza sativa) and influence of rhizosphere on PAH distribution

The uptake of selected polycyclic aromatic hydrocarbons (PAHs) by rice (Oryza sativa) seedlings from spiked aged soils was investigated. When applied to soils aged for 4 months, naphthalene, phenanthrene, and pyrene exhibited volatilization loss of 98, 95, and 30%, respectively, with the remaining fraction being fixed by soil organic matter and/or degraded by soil microbes. In general, concentrations of the three PAHs in rice roots were greater than those in the shoots. The concentrations of root associated PHN and PYR increased proportionally with both soil solution and rhizosphere concentrations. PAH concentrations in shoots were largely independent of those in soil solution, rice roots, or rhizosphere soil. The relative contributions of plant uptake and plant-promoted rhizosphere microbial biodegradation to the total mass balance were 0.24 and 14%, respectively, based on PYR concentrations in rhizosphere and non-rhizosphere soils, the biomass of rice roots, and the dry soil weight.     

Arbuscular mycorrhizal fungi can decrease the uptake of uranium by subterranean clover grown at high levels of uranium in soil

Subterranean clover inoculated or not with the arbuscular mycorrhizal (AM) fungus Glomus intraradices was grown on soil containing six levels of 238U in the range 0-87 mg kg(-1). Increasing U concentration in soil enhanced the U concentration in roots and shoots of both mycorrhizal and nonmycorrhizal plants but had no significant effects on plant dry matter production or root AM colonization. Mycorrhizas increased the shoot dry matter and P concentration in roots and shoots, while in most cases, it decreased the Ca, Mg and K concentrations in plants. The AM fungus influenced U concentration in plants only in the treatment receiving 87 mg U kg(-1) soil. In this case, U concentration in shoots of nonmycorrhizal plants was 1.7 times that of shoots of mycorrhizal plants. These results suggested that mycorrhizal fungi can limit U accumulation by plants exposed to high levels of U in soil.     

海泡石及其复配材料钝化修复镉污染土壤

选取湖北大冶Cd污染土壤,采用室外盆栽实验,研究了海泡石、酸改性海泡石以及二者与石灰、磷酸盐配合使用对油菜生物量、体内Cd含量以及土壤pH和有效态Cd含量的影响。结果表明,不同钝化剂处理均能有效提高油菜地上部和根部生物量,最大分别提高1.03和1.43倍,复合处理以及改性海泡石单一处理的增产效果优于海泡石单一处理。不同钝化剂处理均能显著降低油菜地上部和根部Cd含量,最大分别降低66.40%和22.68%。钝化剂复合处理比单一处理对降低油菜Cd吸收的效果显著,6%的钝化剂添加量较为合适。钝化剂复合处理以及海泡石单一处理均能显著提高土壤pH。不同钝化剂处理均能显著降低土壤有效态Cd含量,钝化剂复合处理对土壤Cd有效性的影响要比单一处理显著。综合实验结果,海泡石与磷酸盐复合处理对土壤Cd污染的钝化修复效果最佳。     

Chelate-induced phytoextraction of metal polluted soils with Brachiaria decumbens

Chelate-induced phytoextraction with high biomass plant species has been proposed for the clean-up of heavy metal polluted soils. In the current work, the effect of the application of two different chelating agents, i.e. EDTA and EDDS, on the metal phytoextraction capacity of Brachiaria decumbens was studied. Although EDTA was, in general, more effective in soil metal solubilization, EDDS, a chelate less harmful to the environment, was more efficient inducing metal accumulation in B. decumbens shoots than EDTA. Indeed, in a moderately heavy metal polluted soil, EDDS caused a 2.54, 2.74 and 4.30-fold increase in Cd, Zn, and Pb shoot metal concentration, respectively, as compared to control plants. In this same soil, EDTA caused a 1.77, 1.11 and 1.87-fold increase in Cd, Zn, and Pb shoot metal concentration, respectively, as compared to control plants. EDDS was also more effective than EDTA in stimulating the translocation of metals from roots to shoots. B. decumbens plants were able to grow in the metal polluted soils showing no visible symptoms of phytotoxicity, which suggests their metal tolerance. Finally, B. decumbens, a fast-growing, high biomass, aluminum tolerant plant species, that has a well-established agronomic system, fulfills most of the requirements for chemically-induced phytoextraction.     

Strategies for enhancing the phytoremediation of cadmium-contaminated agricultural soils by Solanum nigrum L

Field trials contribute practical information towards the development of phytoremediation strategies that cannot be provided by laboratory tests. We conducted field experiments utilizing the Cd hyperaccumulator plant Solanum nigrum L., on farmland contaminated with 1.91 mg kg⁻¹ Cd in the soil. Our study showed that S. nigrum has a relatively high biomass. Planting density had a significant effect on the plant biomass and thus on overall Cd accumulation. For double harvesting, an optimal cutting position influenced the amount of Cd extracted from soils. Double cropping was found to significantly increase the amount of Cd extracted by S. nigrum. Fertilizing had no significant effect on plant biomass or on the Cd remediation of the soil over the short-term period. Our study indicates that S. nigrum can accumulate Cd from soils where the concentrations are relatively low, and thus has application for use in decontamination of slightly to moderately Cd-contaminated soil.