镉在南美蟛蜞菊、蟛蜞菊及其杂交种中的迁移和分布特征

为了解植物对镉的吸收和迁移特性,用200μmol/L镉处理蟛蜞菊(Sphagneticola calendulacea)、南美蟛蜞菊(S.trilobata)及其杂交种,研究了其对镉的吸收、迁移与分布的差异.结果表明,随着镉处理时间的延长,3种植物茎和叶中的镉含量逐渐上升,叶片的镉含量逐渐与茎相当,而根部的镉含量一直是...     

Effectiveness of Various Small‐Scale Constructed Wetland Designs for the Removal of Iron and Zinc from Acid Mine Drainage under Field Conditions

A system of planted and unplanted small‐scale subsurface flow (SSF) and surface flow (SF) constructed wetlands together with hydroponic systems (HP) were installed to compare the removal efficiencies of Fe and Zn from acid mine drainage (AMD) under long‐term field conditions. Maximum removal of 94–97 % (116–142 mg/m² d) for Fe and 69–77 % (6.2–7.9 mg/m² d) for Zn was calculated for the planted soil systems. The planted SSF was most sensitive to heavy rain fall. Short‐term increases of the metal concentration in the outflows, short‐term breakdowns of the Fe removal and continual long‐term breakdowns of the Zn removal were observed. In contrast to Zn removal, all wetland types are applicable for Fe removal with maximum removal in the range of 60–98 %. Most of the removed Fe and Zn was transformed and deposited inside the soil bed. The amount absorbed by the plants (0.03 to 0.3 %) and gravel‐associated soil beds (0.03 to 1.7 %) of the total input were low for both metals. The response of the planted SSF to rainfall suggests a remobilization of metals accumulated inside the rhizosphere and the importance of buffering effects of the surface water layers of SF systems. The importance of plants for metal removal was shown.     

Phytofiltration of arsenic from simulated contaminated water using Hydrilla verticillata in field conditions

The present study investigated arsenic (As) removal efficiency of Hydrilla verticillata from simulated As-contaminated water in field conditions. Plants (100 g fresh weight) were grown in simulated contaminated water (total 8 L) containing 1500 μg L⁻¹ As [in the form of arsenate (AsV)] for 45 d and As accumulation and biochemical changes were analyzed at 15 d intervals. As accumulation in plants increased progressively approaching 388 μg g⁻¹ dw at 45 d. Considering the total dry biomass, total As removed was 8546 μg (i.e. 72% of total As supplied). Despite significant As accumulation, no toxic effects were observed in terms of the level of hydrogen peroxide and lipid peroxidation, which could be attributed to the enhanced level of thiol metabolites (cysteine, glutathione) and enzymatic antioxidants (guaiacol peroxidase, catalase, ascorbate peroxidase). The study demonstrates that Hydrilla plants can find application in As remediation in field conditions.     

PHYTOREMEDIATION OF HEPTACHLOR AND HEPTACHLOR EPOXIDE IN SOIL BY CUCURBITACEAE

Plants in the family of Cucurbitaceae family are known to up take organochlorines. This study was designed to screen seven cultivars of the Lagenaria siceraria species of the Cucurbitaceae family to determine their capacity to remediate heptachlor- and heptachlor epoxide-contaminated soil. The seven Lagenaria cultivars were grown in contaminated and uncontaminated Molokai soil for 13 weeks. The results showed that all the plants tolerated heptachlor and heptachlor epoxide at levels of 0.169 and 0.376 μg/g, respectively, in the soil and were able to bear a limited number of immature fruits during the short study period. All seven Lagenaria cultivars showed some ability to up take heptachlor epoxide into their vines with bioaccumulation factors varying from 1.0 to 5.2. The two contaminants were not detected in the fruits and heptachlor itself was not detected in the vines. The mean concentrations of heptachlor in the soil of all the pots including the no-plant control were not significantly different from that in the initial soil, which might be due to the gradual release of the soil soil-bound heptachlor residues. In the soil, all pots showed a significant decrease for heptachlor epoxide as compared to the initial level, but there was no significant difference between the no-plant control pots and the planted pots of six of the seven cultivars. The local Hyotan cultivar showed the largest decrease, from 0.376 down to 0.050 μg/g dry soil, and was the only cultivar showing a significant difference in the soil heptachlor epoxide concentration with the no-plant control.     

Phytoremediation of potentially toxic elements in a polluted industrial soil using Poinsettia

Potentially toxic elements (PTEs) pollution has become a serious environmental threat, particularly in developing countries such as China. In response, there is a growing interest in phytoremediation studies to identify plant species as designated hyperaccumulators of PTEs in polluted soils. Poinsettia was selected as a candidate species for phytoremediation of six PTEs (Zn, Pb, Hg, Cr, As, Cu) in this study. A pot cultivation experiment (randomized incomplete block experimental design with 5 treatments and 4 blocks) was conducted using contaminated soils gathered from an industrial area in southcentral China. The bioaccumulation factor (BAF), translocation factor (TF), and bioconcentration factor were analyzed to determine the phytoremediation potential of poinsettia potted in different ratios of polluted soils. One-way ANOVA with post-hoc Tukey’s test showed that poinsettia had significant uptake of Zn, Pb, Cu (BAF < 1 and TF < 1, p < 0.05) and Hg (BAF < 1 and TF > 1, p < 0.05). Poinsettias can therefore effectively accumulate Zn, Pb, and Cu in their lateral roots while extracting and transferring Hg into their leaves. Moreover, poinsettia exhibited tolerance towards As and Cr. Interestingly, it was also observed that PTEs can inhibit the height of potted poinsettia at a certain concentration.     

PHYTOACCUMULATION OF ANTIMICROBIALS BY HYDROPONIC CUCURBITA PEPO

Consumer use of antimicrobial-containing products continuously introduces triclocarban and triclosan into the environment. Triclocarban and triclosan adversely affect plants and animals and have the potential to affect human health. Research examined the phytoaccumulation of triclocarban and triclosan by pumpkin (Cucurbita pepo cultivar Howden) and zucchini (Cucurbita pepo cultivar Gold Rush) grown hydroponically. Pumpkin and zucchini were grown in nutrient solution spiked with 0.315 μg/mL triclocarban and 0.289 μg/mL triclosan for two months. Concentrations of triclocarban and triclosan in nutrient solutions were monitored weekly. At the end of the trial, roots and shoots were analyzed for triclocarban and triclosan. Research demonstrated that pumpkin and zucchini accumulated triclocarban and triclosan. Root accumulation factors were 1.78 and 0.64 and translocation factors were 0.001 and 0.082 for triclocarban and triclosan, respectively. The results of this experiment were compared with a previous soil column study that represented environmentally relevant exposure of antimicrobials from biosolids and had similar root mass. Plants were not as efficient in removing triclocarban and triclosan in hydroponic systems as in soil systems. Shoot concentrations of antimicrobials were the same or lower in hydroponic systems than in soil columns, indicating that hydroponic system does not overpredict the concentrations of antimicrobials.