Highest Translocation Factor Research Articles

Soil as levels and bioaccumulation in Suaeda salsa and Phragmites australis wetlands of the Yellow River Estuary, China.

Little information is available on As contamination dynamics in the soil-plant systems of wetlands. Total arsenic (As) in soil and plant samples from Suaeda salsa and Phragmites australis wetlands was measured in the Yellow River Estuary (YRE) in summer and autumn of 2007 to investigate the seasonal changes in As concentrations in different wetlands. The results showed that soil As levels greatly exceeded the global and regional background values. As levels in soil and the roots and stems of both types of plants were much higher in summer than in autumn, whereas leaf As showed higher level in autumn. Soil sulfur was the main factor influencing As levels in Suaeda salsa wetlands, whereas soil porosity was the most important factor for Phragmites australis wetlands. The contamination factor (CF) showed moderately to considerably polluted levels of As in both wetland soils. Plant roots and leaves of Suaeda salsa had higher As concentrations and biological concentration factors (BCFs) than stems, while the leaves and stems of Phragmites australis showed higher As levels and BCFs than roots. Compared to Phragmites australis, Suaeda salsa generally showed higher translocation factor (TF), while TF values for both plant species were higher in summer than in autumn.

Effects of Indole-3-Acetic Acid (IAA), a Plant Hormone, on the Ryegrass Yield and the Removal of Fluoranthene from Soil

A soil culture experiment was conducted to determine whether a plant hormone, indole-3-acetic acid (IAA), could influence fluoranthene (Flu) removal from soil. Four treatments were utilized: (i) unplanted soil (CK), (ii) soil planted with ryegrass (P), (iii) soil planted with ryegrass and treated with 0.24 mg kg−1 IAA (P+0.24), (iv) soil planted with ryegrass and treated with 2.4 mg kg−1 IAA (P+2.4). The Flu initial concentration was 200 mg kg−1. After 3 months, the percentage of Flu removal and plant root biomass were significantly increased under the P+2.4 and the removal rate was 35.68%. The total Flu content in plants was higher than that in the other treatments. The Flu concentration was significantly increased in the shoots, but not significantly altered in the roots. The highest translocation factor was observed in the P+2.4. Increase in number of bacteria, actinomycetes and fungi were observed in the planted treatments, and the amount of fungi was significantly increased in P+2.4. Flu removal was related to the Flu in ryegrass, and was insignificantly correlated with the stimulation of soil microflora, which suggesting that IAA may work mainly on improving plant growth, the Flu uptake, and eventually leading to enhanced remediation of Flu polluted soil.

Monthly variations of trace elements accumulation and distribution in above- and below-ground biomass of Phragmites australis (Cav.) Trin. ex Steudel in Lake Burullus (Egypt): A biomonitoring application

This study was carried out in some natural stands of Phragmites australis (Cav.) Trin. ex Steudel grown in Lake Burullus, a Mediterranean lake in north Egypt, to investigate: (1) the concentration of trace elements in the organs of P. australis, (2) the extent of trace elements mobility from sediment to below-ground organs and within the plant, (3) the organs of P. australis as potential bioindicators for the contamination of the water and sediment by the trace elements, and (4) the amount of trace elements that released back into the surrounding water after decomposition of dead tissues. Above- and below-ground biomass of P. australis, water and sediment were sampled monthly for one year at six sites of Lake Burullus (three sites represent each of the northern and southern parts of the lake) using six randomly distributed quadrats (each of 0.5×0.5m) at each sampling site. The above- and below-ground biomasses of southern sites are significantly higher than that of the northern sites. Above-ground biomass is >2.5 folds of the below-ground biomass in the northern and southern sites. The highest concentration in the below-ground organs is Cu, Fe and Zn; and in the leaf is Cd. The monthly highest values of trace elements are Cu and Fe in February at the beginning of the growing season; and Cd and Zn in January at the end of the growing season. The annual mean of trace element concentrations (inmgkg−1) in P. australis organs ranged from 11.0 to 23.8 for Cd, from 31.0 to 65.6 for Cu, from 34.4 to 97.3 for Zn, and from 505.0 to 2833.0 for Fe. The mean bioaccumulation factor of all trace elements from the sediment to the below-ground organs is greater than unity for all elements with the following sequence: Cd>Fe>Zn>Cu. Cd has the highest translocation factor from the below-ground to the above-ground organs, while Fe has the lowest. Positive linear correlations are detected between the concentrations of all elements (except Cu) in plant organs, water and sediment. The higher translocation factor of Cd in the above-ground organs of P. australis makes it suitable for the phytoextraction of this element from the water and sediment, while the lower translocation factor for Cu, Fe and Zn makes it suitable for their phytostabilization. In conclusion, all the organs of P. australis could act as bioindicators and biomonitors of the examined trace elements.

Phytoremediation of Zn: Identify the Diverging Resistance, Uptake and Biomass Production Behaviours of Poplar Clones Under High Zinc Stress

A dose–response study was performed in four commercial clones, Baldo (Populus deltoides), Jean Pourtet (Populus nigra), I-214 (Populus x euramericana) and Villafranca (Populus alba), to investigate the best performing species in terms of metal content and high metal resistance (absence of symptoms) useful in biomass production on contaminated water/land by zinc. Zinc (1 μM as control and 1 mM) was applied for 4 weeks in a hydroponic system. Clone Villafranca was the least damaged, while the most sensitive was clone I-214. The highest zinc concentration in all different parts of plants analysed was recorded in Villafranca > I-214 > Baldo > Jean Pourtet. The higher translocation factor was seen in Baldo, the lowest in Villafranca. Analyses of leaf damage showed a reduction on Chl a in young leaves (96 %) in I-214 stressed plants, whereas in Villafranca, Chl a was about double compared to the control. Regarding other photosynthetic pigments, violaxanthin was significantly correlated to zinc concentration in old leaves. The responses of clones to zinc (Zn) stress were specific: Villafranca was the most resistant, while I-214 showed the highest biomass production under Zn excess. Since these two clones have useful and complementary traits for uptake and detoxification while maintaining high biomass production under Zn excess, they are interesting candidates for understanding the key resistance mechanisms.

Manganese-induced oxidative stress in two ontogenetic stages of chamomile and amelioration by nitric oxide

Impact of manganese (Mn2+) excess (100, 500 and 1000μM over 7 days) on two ontogenetic stages (7-week-old plants and 7-day-old seedlings) of Matricaria chamomilla was compared. Mn excess depressed growth of seedlings (but not germination) and stimulated oxidative stress (ROS and lipid peroxidation) in both plants and seedlings. Growth inhibition could be evoked by higher Mn uptake and higher translocation factor in seedlings than in plants. Total thiols staining revealed elevation in almost all treatments. In 7-week-old plants, activity of peroxidases increased slightly and rather decreased under high Mn doses. Superoxide rather than hydrogen peroxide contributed to visualized ROS presence. Fluorescence of nitric oxide (NO) showed stimulation in plants but decrease in seedlings. Impact of exogenous nitric oxide donor (sodium nitroprusside/SNP) was therefore tested and results showed amelioration of 1000μM Mn-induced oxidative stress in seedlings (decrease in H2O2 and increase in NO content while antioxidative enzyme activities were variably affected) concomitantly with depleted Mn accumulation. It is concluded that NO participates in tolerance to Mn excess but negative effects of the highest SNP dose were also observed. Extensive fluorescence microscopy is also explanatively discussed.

Evaluation of Copper Bioaccumulation and Translocation in Jatropha curcas Grown in a Contaminated Soil

Contamination of soils with copper (Cu) has become a serious problem in the environment. Phytoremediation is an emerging green technology that uses green plants to remediate heavy metal contaminated areas. This study was conducted to evaluate the potential of Jatropha curcas for remediation of soils contaminated with Cu. Seedlings were planted in soils spiked with Cu in amount of 0, 50, 100, 200, 300, and 400 mg kg–1 (Cu0, Cu50,Cu100,Cu200,Cu300, and Cu400) for a period of five months. The maximum height and number of leaves were recorded in control (Cu0) whereas the highest basal stem diameter was found in seedlings exposed to Cu50. Copper concentrations among plant parts were in the following trend: roots > stems > leaves. The highest total Cu concentration (665 ± 1 mg kg−1) and total Cu removal (1.2 ± 0.2%) based on total plant dry biomass were found in Cu400 and Cu50 treatments, respectively. J. curcas exhibited high root concentration factor (RCF > 1) and low translocation factor (TF < 1). Although Cu accumulation by the plant didn't reach the criteria of Cu hyperaccumulators, this species showed a potential to be used in phytostabilization of mildly Cu contaminated areas. However, the plant cannot be used for phytoextraction of Cu-contaminated soils.

ASSESSMENT OF HEAVY METALS UPTAKE AND TRANSLOCATION BY &lt;i&gt;AQUILARIA MALACCENSIS&lt;/i&gt; PLANTED IN SOILS CONTAINING SEWAGE SLUDGE

Increase in human population has resulted in an eno rmous growth in the volume of wastewater. The conventional methods of sewage sludge disposal, tha t is the by-product of wastewater treatment, are co stly and not environment-friendly. An ideal way for sewa ge sludge management is by using it as a soil amendment in agricultural land due to sewage sludge ’s high organic matter content. However, sewage sludge contains high levels of heavy metals that ca n be harmful to both plants and the environment. He nce, these metals need to be removed before the sewage s ludge is to be used as a soil amendment. The object ive of this study was to assess the potential of Aquilaria malaccensis to uptake and translocate heavy metals found in sewage sludge. A.malaccensis seedlings were planted on six different planting m edia: T0/Control (100% soil), T1 (80% soil and 20% sewage sludge), T2 (60% soil and 40% sewage sludge), T3 (40% soil and 60% sewage sludge), T4 (20% soil and 80% sewage sludge) and T5 (100% sewage sludge) for the duration of 16 weeks. The growth performance of height and basal diameter was measured using diameter tape and venier caliper every two weeks, respective ly. The average dry weight biomass of A.malaccensis was measured using destructive sampling at 16 weeks after planting. Plant samples were collected after harvest and soil samples were collected before plan ting and after harvesting. Atomic Absorbtion Spectrophotometer (AAS) was used to determine the concentration of heavy metals in the planting media and the plant parts (leaves, stem and roots). The h ighest growth of A.malaccensis was recorded for the T5 growth media. The highest concentration of Fe in th e roots of the A.malaccensis plant was in the T5 growth media (2770.75 ppm). The highest accumulation of Zn (95.62 ppm) was recorded in the roots of A.malaccensis in the T5 growth media, whereas the stem of the A.malaccensis in T5 recorded the highest Cd accumulation (3.75 ppm). The highest Pb uptake was recorded in the roots of A.malaccensis in T5 (39.79 ppm), while the lowest accumulation of Pb was noted in the leaves of the A.malaccensis in control (16.08 ppm). The highest Translocation Factor (TF) (2.00) for Cd was recorded in T5. The lowest Bioconcentration Factor (BCF) for Cu was recorded at T5 (0.18). The highest TF for Pb was recorded in control (1.50), while the lowest was in T5 (1.23). The BCF for Zn was lowest in T5 (0.64). The A.malaccensis plant was found to be suitable for taking up heavy metals from sewage sludge especially Cd and Cu. The roots of A.malaccensis are ideal in uptaking and storing Fe, while the ste m of the A.malaccensis plant is ideal for the uptake and accumulation of C d. More studies need to be conducted, especially in field conditions, to optimize the pot ential of the A.malaccensis plant as a phytoremediator.

Potential of different crop species for nickel and cadmium phytoremediation in peri-urban areas of Varanasi district (India) with more than twenty years of wastewater irrigation history

Heavy metals introduced into soil by indiscriminate dumping along with irrigating with sewage effluent often lead to toxic accumulation of heavy metal ions, which not only impair soil productivity but also cause health hazards by entering into food chain via soil-plant-animal-atmosphere continuum. To evaluate the potential of different crop species for nickel (Ni) and cadmium (Cd) phytoremediation, fifteen crop species comprising of cereals, vegetables and flowers were collected from differentially contaminated soils (DTPA-Cd 5.7-6.75 mg kg –1 , DTPA-Ni 16.50- 20.85 mg kg –1 ). The tissue metal concentration and relative efficiency of transfer of heavy metals from soil to plant (transfer factor) for various groups of crops were worked out. The uptake of Cd and Ni increased with contents in soils and the major part of taken up Cd and Ni is translocated to the floricultural crops with maximum accumulation occurred in roots. Values of translocation factor of Cd and Ni were ranged between 0.2 to 0.8 and 0.2 to 1.0 respectively for the different crops studied. The mean total root colonization by arbuscular mycorrhiza in these soils ranged from 15% for cauliflower to 76% for marigold, suggesting a certain adaptation of these indigenous to such environmental stress. Among the different crops studied marigold with highest translocation factor, mycorrhization and Cd and Ni content in root part holds considered as a potential economic crop for phytoremediation.

HEAVY METAL UPTAKE AND TRANSLOCATION BY &lt;i&gt;DIPTEROCARPUS VERRUCOSUS&lt;/i&gt; FROM SEWAGE SLUDGE CONTAMINATED SOIL

Sewage sludge or biosolids is the solid waste that has been left after wastewater is treated in a dome stic wastewater treatment facility. The most common way of sludge disposal is to dispose it on the land, se a or air (incineration). However, these methods are not envi ronment-friendly, costly and time consuming that re quires expertise and knowledge. An ideal way to manage sewage sludge is to use it as a soil amendment in agri cultural land due to it’s high organic matter and other base cations. Sewage sludge contains high levels of hea vy metals such as lead, cadmium and zinc that can be harmful to both plants and the environment. Hence, these me tals need to be removed before the sewage sludge is used as a soil amendment. The objective of this study was to assess the potential of Dipterocarpus verrucosus to uptake and translocate heavy metals from sewage sludge contaminated soil. The D.verrucosus seedlings were planted on six different planting me dia; Control (100% soil), T1 (80% soil and 20% sewage sludge), T2 (60% soil and 40% sewage sludge), T3 (40% soil and 60% sewage sludge), T4 (20% soil and 80% sewage sludge) and T5 (100% sewage sludge) for the duration of 16 weeks. The growth performance, of height of D.verrucosus was measured using diameter tape, while the basal d iameter was measured using a venier caliper for every two weeks for a period of 16 weeks. The plant biomass was de termined using a destructive sampling method. Plant samples were collected after harvest and soil samples were collected before and after planting. The Atomic Absorbtion Spectrophotometer (AAS) was used to determine the concentration of heavy metals in the planting media and the plant parts (leaves, stem and roots). The highest plant biomass was recorded in the T1 growth media of 20% sewage sludge and 80% soil. D.verrucosus plant was able to remove heavy metals of Cd, Cu, Pb, Fe and Zn effectively. The highest concentration of heavy metal in the roots of the D.verrucosus plant was Fe, recorded in the T5 growth media (1879.75 ppm). The highest accumulation of Zn (68.47 ppm) in D.verrucosus was recorded in the stem of D.verrucosus in the T5 growth media whereas the stem of the D.verrucosus in T3 recorded the highest Cd accumulation (2.85 pp m). The highest Pb uptake was recorded in the roots of D.verrucosus in T5 (37.3 ppm), while the lowest accumulation of Pb was noted in the stem of the D.verrucosus in Control (23.49 ppm). For Cd, the highest translo cation factor (TF) (4.01) was recorded in T1. The lowest Bioconcentrat ion Factor (BCF) for Cu was recorded at T5 (0.22). The highest TF for Lead was recorded in control (2. 22) while the lowest was in T1 (1.64). The BCF for Zn was lowest at T3 treatment (0.16). The D.verrucosus plant was found to be suitable for taking up heavy metals from sewage sludge especially Cd, Zn, Cu and Pb. The roots of D.verrucosus are ideal in removing and storing Fe, while the stem of the D.verrucosus plant is ideal for the uptake and accumulation of Z n. However, more studies need to be conducted, especially in field conditions, in order to optimize the potential of the D.verrucosus plant as a phytoremediator.

Hormesis phenomena under Cd stress in a hyperaccumulator—Lonicera japonica Thunb

A hydroponic experiment was carried out to investigate possible hormetic response induced by cadmium (Cd) in a potential hyperaccumulator-Lonicera japonica Thunb. The results showed that Cd at low concentrations induced a significant increase in plant growth, leaf water content and content of photosynthetic pigments in L. japonica, but decreased them at high concentrations, displayed inverted U-shaped dose response curves, confirming a typical biphasic hormetic response. The U-shaped dose response curves were displayed in malondialdehyde (MDA) and electrolyte leakage in leaves at low doses of Cd, indicating reduce oxidative stress and toxic effect. The increase of superoxide dismutase (SOD) and catalase (CAT) activities was observed along with the increased Cd concentration, indicative of increase in anti-oxidative capacity that ensures redox homeostasis is maintained. After 28 days exposure to 10 mg L(-1) Cd, stem and leaf Cd concentrations reached 502.96 ± 28.90 and 103.22 ± 5.62 mg kg(-1) DW, respectively and the plant had high bioaccumulation coefficient (BC) and translocation factor (TF'). Moreover, the maximum TF value was found at 2.5 mg L(-1) Cd treatment, implying that low Cd treatment improved the ability to transfer Cd from medium via roots to aerial structures. Taking together, L. japonica could be considered as a new plant to investigate the underlying mechanisms of hormesis and Cd tolerance. Our results suggest that hormetic effects should be taken into consideration in phytoremediation of Cd-contaminated soil.

Depth-wise distribution, mobility and naturally occurring glutathione based phytoaccumulation of cadmium and zinc in sewage-irrigated soil profiles

Field experiments were conducted to determine the mobility, distribution and naturally occurring glutathione (GSH)-based phytoaccumulation of cadmium and zinc in the sewage-irrigated alluvial soils, Allahabad, India. Frequent sewage-irrigation (up to 100 mL kg−1 soil) at 5 days’ interval indicated enrichment of soil profiles with Cd and Zn more prominently in surface soils and sub-surface soils below to the depth of 0.6 m and augmented cadmium and zinc accumulation in shoot tissues of Brassica species up to 10.6 and 31.5 mg kg−1, respectively. Both cadmium and zinc were found significantly correlated with organic matter and cation exchange capacity of the soils indicating their dominant role in the sewage-irrigated soils. Raphanus sativus L. and Brassica napus L. accumulated significant quantity of cadmium and zinc, and higher concentration of GSH in their shoot tissues synergistically boosted translocation as well as accumulation of metals in plants, especially at plant maturity. However, cadmium showed higher translocation than zinc. Such evidence supports the conclusion that elevated natural GSH concentrations of Brassica species during their developed stage of plant growth are involved in metal hyperaccumulation, which ensure their potential for phytoremediation of cadmium and zinc in the sewage-irrigated soils. Thus, the use of the unused part (mostly leaves) of these species as an innovative technology for phytoremediation is suggested. Successive sewage applications (at 0, 20, 40, 60, 80 and 100 mL kg−1 soil) indicated Cd and Zn enrichment of soil profiles below up to 0.6-m depth. Higher translocation factor (2.64 for Cd; and 1.91 for Zn) in Raphanus sativus L. and Brassica napus L. indicates its phytoaccumulation potential while higher Glutathione content in shoot tissues of Brassica species synergistically induces the phytoaccumulation of Cd and Zn in soil-plant systems.

Cadmium tolerance and accumulation characteristics of mature flax, cv. Hermes: Contribution of the basal stem compared to the root

The potential of mature flax plants (cv. Hermes) to tolerate and accumulate cadmium (Cd) was studied to determine which part of the plant would be the key organ for phytoremediation purposes. After 4month-growth on sand substrate containing 0.1mM Cd in a greenhouse, the roots and stems were separated and the stems were divided into three parts. The effects of Cd were studied on growth parameters, histology and mineral nutrition. No visible toxic symptoms were observed. Tolerance-index values calculated from growth parameters and nutrients remained relatively high, allowing the development of the plant until maturity and formation of seeds. The roots and bottom stem accumulated the highest quantity of Cd (750 and 360mg/kg dry matter), values which largely exceeded the threshold defined for hyperaccumulators. On the other hand, basal stem had a high bioconcentration factor (BCF=32) and translocation factor TF′ (2.5) but a low TF (0.5), indicating that this basal part would play a major role in phytoremediation (phytostabilization rather than phytorextraction). Therefore, the high tolerance to Cd and accumulation capacity make possible to grow Hermes flax on Cd-polluted soils.

Potential of Indigenous Plant Species for the Phytoremediation of Arsenic Contaminated Land in Kurdistan (Iran)

To evaluate the potential of the indigenous plant species for Arsenic (As) phytoremediation, a total of 138 plant samples and 138 soil samples from rooting zones were collected from two As-contaminated areas in Kurdistan, western Iran. The areas were the Sari Gunay Gold Mine (SG) and Ali Abad Village (AA). The soil of both areas naturally contains As, with mining activities at SG. Soil and plant samples were collected at five sites in the SG (SG1 to SG5) and at two sites in the AA (AA1 and AA2). Soil samples were analyzed for total and water-soluble As concentration, as well as for the main soil physical and chemical properties such as electrical conductivity (Ec), pH, organic carbon (Corg.), available phosphorus (Pava.), and soil texture. Plant samples were analyzed for As concentration in their shoots and roots. The average total and water–soluble As concentrations in soil were 751.6 and 6.2 ppm at SG and 920.8 and 8.0 ppm at AA, respectively. The highest root and shoot As concentration was found in Juncus inflexus (751.5 ppm) at AA2 and in Astragalus gossypinus (158.7 ppm) at AA1, respectively. With regard to phytoremediation strategies, Acantholimon brachystachyum, Astragalus gossypinus, Stipa barbata, and Ephedra major with a high translocation factor (TF) can be potentially used for As phytoextraction. However, Juncus inflexus, Phragmites australis, Bromus tomentellus, and Elymus sp., which show high bioconcentration factor (BCF) and low TF, are suggested as good candidates for As phytostabilization. In general, the TF values of terrestrial plants were higher than those of amphibious plants; meanwhile, BCF values showed the opposite behavior.

Assessment of heavy metal uptake and translocation in Dyera costulata for phytoremediation of cadmium contaminated soil

Heavy metal pollution is a widespread global problem causing serious environmental concern. Cadmium, one of the heavy metals, is water soluble and can be transferred from soil to plants and enter into the food chain. It is detrimental to human health because it accumulates in the body and can cause renal tubular dysfunction, pulmonary emphysema and osteoporosis. This heavy metal needs to be cleaned up for a clean and safe environment. An experiment was conducted to evaluate the potential of Dyera costulata as a phytoremediator to absorb cadmium from contaminated soils. Dyera costulata seedlings were planted on six different growth media (soil + different levels of cadmium): Control, 25 ppm Cd, 50 ppm Cd, 75 ppm Cd, 100 ppm Cd and 150 ppm Cd. The highest growth performance mainly height, basal diameter and number of leaves were in the control, 50 ppm Cd and 25 ppm Cd treatments, respectively. The highest accumulation of cadmium (52.9 ppm) was in the 75 ppm Cd treatment. Among the plant parts, leaves showed the highest concentration of cadmium. Dyera costulata showed high translocation factor and low bioconcentration factor values in soil at high cadmium concentrations and was also able to tolerate and accumulate high concentrations of cadmium. The roots of Dyera costulata were found to be suitable for the absorption of cadmium in contaminated soils. This species can be an efficient phytoremediator for soils contaminated with cadmium.

Heavy metal uptake and translocation by Justicia gendarussa Burm F. from textile sludge contaminated soil

Heavy metals are dangerous environmental pollutants that can be transferred and accumulated in human and animal bodies causing deoxyribonucleic acid (DNA) damage and carcinogenic effects. A glass house experiment was conducted to evaluate the potential of Justicia gendarussa Burm F. to absorb heavy metals from textile industry sludge. Justicia gendarussa seedlings were planted on six different growth media (soil+sludge) comprising: 100% soil, 100% sludge, 80% sludge+20% soil, 60% sludge+40% soil, 40% sludge+60% soil and 20% sludge+80% soil. The maximum height increment and number of leaves were found in 20% sludge+80% soil while the highest basal diameter increment was recorded in the 100% sludge. Copper and iron were highly concentrated in the roots, zinc in the leaves, while aluminium was concentrated in both leaves and stems. Justicia gendarussa seems to have a high potential to absorb high amounts of Al and Fe in the leaves and roots. This species showed high translocation (TF) and low bioconcentration factor (BCF) in the contaminated soil. Justicia gendarussa was able to tolerate and accumulate a high concentration of heavy metals. Therefore, this species can be considered as a potential phytoremediator.

Metal concentrations in the soils and native plants surrounding the old flotation tailings pond of the Copper Mining and Smelting Complex Bor (Serbia)

In this study concentrations of metals in the native plants and soils surrounding the old flotation tailings pond of the copper mine were determined. It has been established that the soil is heavily contaminated with copper, iron and arsenic, the mean concentrations being 1585.6, 29,462.5 and 171.7 mg kg(-1) respectively. All the plants, except manganese, accumulated metallic elements in concentrations which were either in the range of critical and phytotoxic values (Pb and As) or higher (Zn), and even much higher (Cu and Fe) than these values. Otherwise, the accumulation of Mn, Pb and As was considerably lower than that of Cu, Fe and Zn. In most plants the accumulation of target metals was highest in the root. Several plant species showed high bioaccumulation and translocation factor values, which classify them into species for potential use in phytoextraction. The BCF and TF values determined in Prunus persica were 1.20 and 3.95 for Cu, 1.5 and 6.0 for Zn and 1.96 and 5.44 for Pb. In Saponaria officinalis these values were 2.53 and 1.27 for Zn, and in Juglans regia L. they were 8.76 and 17.75 for Zn. The translocation factor in most plants, for most metals, was higher than one, whereas the highest value was determined in Populus nigra for Zn, amounting to 17.8. Among several tolerant species, the most suitable ones for phytostabilization proved to be Robinia pseudoacacia L. for Zn and Verbascum phlomoides L., Saponaria officinalis and Centaurea jacea L. for Mn, Pb and As.

Accumulation of Cu, Pb, Ni and Zn in the halophyte plant Atriplex grown on polluted soil

Three annual Atriplex species-A. hortensis var. purpurea, A. hortensis var. rubra and A. rosea-growing on soil with various levels of the heavy metals copper, lead, nickel, and zinc, have been investigated. Metal accumulation by Atriplex plants differed among species, levels of polluted soil and tissues. Metals accumulated by Atriplex were mostly distributed in root tissues, suggesting that an exclusion strategy for metal tolerance widely exists in them. The increased concentration of heavy metals in soil led to increases in heavy metal shoot and root concentrations of Ni, Cu, Pb and Zn in plants as compared to those grown on unpolluted soil. Accumulation was higher in roots than shoots for all the heavy metals. None of the plants were suitable for phytoextraction because no hyperaccumulator was identified. However, plants with a high bioconcentration factor and low translocation factor have the potential for phytostabilization. Similarly, the correlation between metal concentrations and translocations in plants (BCFs and TFs) using a linear regression was also statistically significant. Among the plants studied, var. purpurea was the most efficient in accumulating Pb and Zn in its shoots, whereas var. rubra was most suitable for phytostabilization of sites contaminated with Cu and Ni.

English

&nbsp; High concentrations of heavy metals are harmful to plants, animals and humans and their potential accumulation in human tissues and bio-magnification through the food chain cause serious health hazards. An experiment was conducted in the glasshouse to evaluate the potential of&nbsp;Dyera costulata&nbsp;as a bioaccumulator to absorb heavy metals from sewage sludge contaminated soils.&nbsp;D. costulataseedlings were planted in the following growth media: T0&nbsp;(control soil), T1&nbsp;(100% sludge), T2&nbsp;(80% sludge + 20% soil), T3&nbsp;(60% sludge + 40% soil), T4&nbsp;(40% sludge + 60% soil) and T5&nbsp;(20% sludge + 80% soil). T4&nbsp;showed the best growth performance in terms of height, basal diameter and number of leaves. The maximum reduction of Cd, Cr and Pb was found in the 100% sludge treatment. Zn, Cd, Ni and Cr were highly concentrated in the leaves, while Pb accumulated mainly in the stems.&nbsp;D. costulata&nbsp;showed high potential to retain high amounts of Zn, Ni and Cr in the leaves and Pb in the stems. The species had high translocation factor (TF) and low bioconcentration factor (BCF) values in the soil at higher metal concentrations as well as it was able to tolerate and accumulate high concentrations of Zn, Cd, Ni, Cr and Pb. It means that, this species is a good accumulator of heavy metals and can be considered as a potential bioaccumulator species. &nbsp; Key words:&nbsp;Phytoremediation,&nbsp;Dyera costulata, heavy metals, sewage sludge.

English

Many organic and inorganic pollutants, including heavy metals are being transported and mixed with the cultivated soils and water. Heavy metals are the most dangerous pollutants as they are non-degradable and accumulate and become toxic to plants and animals. An experiment was conducted in the glasshouse to evaluate the potential of&nbsp;Acacia mangium&nbsp;as a phytoremediator to absorb heavy metals from contaminated soils.&nbsp;A. mangium&nbsp;seedlings were planted in the growth media (soil + different levels of copper). The different levels of Cu were: T0&nbsp;(control, soil), T1&nbsp;(50 ppm Cu), T2&nbsp;(100 ppm Cu), T3&nbsp;(200 ppm Cu), T4&nbsp;(300 ppm Cu) and T5(400 ppm Cu). The highest growth performance such as basal diameter, height and number of leaves was in T1. The highest biomass was recorded in T1. Highest accumulation of Cu (93.55 ppm) and Zn (79.13 ppm) were recorded in T5&nbsp;while Cd (8.88 ppm) in T3. Cu was highly concentrated in the roots, Cd was accumulated in the leaves and roots, whereas, Zn was in stems and leaves.&nbsp;A. mangium&nbsp;showed high translocation factor (TF) and low bioconcentration factor (BCF) values in soil at higher metal concentrations as well as it was able to tolerate and accumulate high concentrations of Cd, Cu and Zn. It may be concluded that this species can be a good efficient phtyoremediator for heavy metals (Cd, Cu and Zn) contaminated soils to mitigate soil pollution. &nbsp; Key words:&nbsp;Heavy metals, phytoremediation, bioaccumulation capacity.

Heavy Metal Accumulation in Plant Species Indigenous to a Contaminated Portuguese Site: Prospects for Phytoremediation

Phytoremediation is a promising alternative to conventional soil clean-up methods; however, up to date, there is still not enough information on plant species suitable for application in this field of science. Therefore, plant screening on contaminated sites can lead to the identification of further species of interest. In the present study, pedological and botanical characteristics of an industrialised area known for its metal contamination, in special with Zn—Esteiro de Estarreja, in Portugal—were examined in a 1-year screening. Twenty-seven species were found, with a higher occurrence and variability in the summer/spring season. Zinc levels in the tissues of the collected plant samples ranged from 34 mg kg−1 in shoots to 2,440 mg kg−1 in roots of different species. Species as Verbascum virgatum, Hypochoeris radicata, Phalaris arundinacea, Conyza bilbaoana, Paspalum urvillei and Aster squamatus have shown high Zn shoot accumulation and bioconcentration factors (BCFshoots > 1) and high metal translocation factors (TF > 1). Others, namely Spergularia capillacea, excluded Zn from the shoot tissues and stored the metal at the root zone (BCFroots > 1), behaving as tolerant plants. Plants were also screened for arbuscular mycorrhizal fungi colonisation, and only few species showed mycorrhizal presence, namely C. bilbaoana, Hirschfeldia incana, Epilobium tetragonum, Conyza sumatrensis, Pteridium aquilinum, P. urvillei and A. squamatus. The present work showed important indigenous species that can cope with installed harsh conditions and with potential for utilisation in phytoremediation strategies, either through metal removal to aerial parts or through its immobilisation in the root zone.