Flumequine Uptake and the Aquatic Duckweed,Lemna minor L.

Water, Air, & Soil Pollution - Phytotoxicity of Flumequine (F) on the aquatic duckweed, Lemna minor L., and plant drug uptake were evaluated by a simple ecotoxicological test. Flumequine, at...     

Cadmium accumulation and bioavailability in Coontail (Ceratophyllum demersum L.) plants

The aquatic vascular plant (Ceratophyllum demersum L.) was investigated as a potential biological filter for removal of Cd from wastewaters. Plants were grown in and harvested weekly from 0.10 M Hoagland nutrient solutions containing concentrations of Cd from 0.01 to 1.03 μg Cd mL^?1. Tissue Cd was positively correlated to increased concentrations of Cd in solution. Concentration factors (CFs) of Cd in plants after one week were 13.3 for the 0.01 μg Cd mL^?1 treatment; 451.4 for plants treated with 0.04 μg Cd mL^?1, and 506.5 for plants treated with 1.03 μg Cd mL^?1. Plants treated with 0.01 μg Cd mL^?1 sustained tissue Cd concentrations almost 9-fold over those at week 1. However, after 5 weeks tissue Cd concentration in plants exposed to 1.03 μg Cd mL^?1 had decreased 97% compared to the week 1 concentration. Growth measurements of dry weight, stem lengths, and lateral shoot growth were nagatively correlated to increased Cd treatments. Our results suggest that Coontail exposed to very low Cd concentrations (0.01 μg Cd mL^?1) can take up and accumulate Cd. However, plants exposed to Cd at 0.04 μg Cd mL^?1 or above did not accumulate Cd past one week.     

Chicory (Cichorium intybus L.) and dandelion (Taraxacum officinale Web.) as phytoindicators of cadmium contamination

Chicory (Cichorium intybus L.) and dandelion (Taraxacum officinale Web.) were demonstrated to be potential indicator plants for heavy metal contaminated sites. Chicory, grown with 0.5–50 μM cadmium (Cd) in nutrient solution, accumulated 10–300 μM Cd g^?1 in shoots and 10–890 μg Cd μg^?1 in roots and rhizomes. With dandelion, 20–410 μg Cd μg^?1 was found in shoots and 20–1360 μg Cd μg^?1 in roots and rhizomes. An inverse correlation existed between chlorophyll and Cd concentrations in shoots of both species. Accumulation of Cd from nutrient solution was similar with the counter-anions SO₄ ^2?, Cl^1? and NO₃ ^? in chicory. In chicory grown in Cd-amended (11.2 kg Cd ha^?1 applied five years previously) soils, Cd concentrations were substantially higher than in controls in all plant parts following the order: leaf > caudex > stem > root and rhizome. The above trend was the opposite of that observed in solution culture, where Cd accumulation was higher in roots and rhizomes than in shoots. Higher cadmium accumulation was found from a Cd-treated sand (Grossarenic Paleudult) than from a loamy sand (Typic Kandiudult) soil type. Chicory and dandelion are proposed indicator plants of cadmium contamination, and both have the potential to be an international standard heavy phytomonitor species of heavy metal contaminantion.     

Boron tolerance and accumulation in the duckweed,Lemna minor.

A sensitive measure of growth in the duckweed, Lernna minor, was used to demonstrate the tolerance of this higher plant to boron [B(OH)₃] at levels of 10 to 20 μg/mL in the growth medium at pH 5.0. Growth inhibition by B in concentrations up to 100 μg/mL in the external medium was reversible after transfer to control medium. At pH 4.0 and in the presence of 20 μg/mL B for 7 days, the plants accumulated 93 μg B/g fresh weight (148% of the control) and this increased with pH up to pH 7.0 where the plants accumulated 257 μg B/g fresh weight (525% of the control). Only at pH 7.0 in the presence of B was growth inhibited. Thus, plants which had accumulated more than 100 μg B/g fresh weight still grew normally. This corresponds to about 800 μg B/g dry weight accumulated by this monocot without effect upon growth rate.     

Copper uptake studies on Erica andevalensis,a metal‐tolerant plant from southwestern Spain

Abstract

Pot trials and chemical analyses were carried out on wild specimens of Erica andevalensis Cabezudo et Rivera (Ericaceae) and their associated soils. Natural soils hosting E. andevalensis all had elevated copper concentrations. Pot trials showed that the Erica would grow in sulphide‐ore substrates containing up to 12,500 μg g^‐1 (1.25%) copper, with or without amendment with EDTA. The addition of EDTA to these substrates increased the solubility of the copper to levels that killed other metal‐tolerant species (Biscutella laevigata and Brassica juncea), but not E. andevalensis. The copper concentrations in wild plants were only 1 to 24 μg g^‐1 (dry weight) despite the high levels of copper (up to 3,676 μg g^‐1) in the supporting soils. In the pot trials, the plant was able partially to exclude total copper up to 1,000 μg g^‐1 in the soil. Thereafter, there was an exponential increase of copper in plant until the limit of tolerance was reached. Conclusions of the study were: (a) tolerance to copper by the Erica is much higher compared with other metal‐tolerant plants tested, (b) the plant does not have hyperaccumulator status (> 1,000 μg g^‐1 dry weight) for copper, (c) copper uptake by the plant is governed by the extractable and not total copper content of the soil, hence limiting its use in biogeochemical prospecting, (d) uptake of copper by the plant follows the typical pattern of a metal‐excluding plant, (e) Erica andevalensis is a good geobotanical indicator of copper because of its faithful association with sulphide mineralization in the Huelva area of Spain.     

Effect of the herbicide fluazifop-butyl on fungal populations and activity in soil

The side effects of fluazifop-butyl on soil fungal populations and oxygen uptake were studied by incubating soil samples with a range of fluazifop-butyl concentrations (0, 0.6, 3 and 6 μg g^?1) over 8 weeks. Cellulose decomposition in soil was also studied in laboratory experiments with the herbicide which was either incorporated in soil or sprayed onto calico squares which were buried in soil. The mycelial dry weight of six fungal species under the effect of the herbicide was also examined. Fluazifop-butyl had no significant effect on total fungal propagule populations at 0.6 μg g^?1. At 3 and 6 μg g^?1, it caused temporary reduction in fungal populations observed after 1 and 2-wk of incubation. The herbicide had no significant effect on OZ uptake. The decay of calico buried in herbicide-treated soil was generally stimulated, while the decomposition of herbicide-treated calico, buried in untreated soil, was temporary delayed. The mycelial dry weight yields of Aspergillus favus (at 2 and 12 μg mL^?1 of fluazifop-butyl) and Cunninghamella echinulata (at 12 μg mL^?1) were significantly increased. At 24 μg mL^?1 the mycelial dry weight of A. flavus and Alternaria alternata was significantly reduced.     

Effect of elevated concentrations of Cd and Zn in soil on spring wheat yield and the metal contents of the plants

The effect of increasing concentrations of Cd and Zn in a sandy soil on spring wheat (Triticum vulgare L.) yields and the metal contents of the plants was examined in a pot experiment to establish critical levels of these metals in soil. The metals were added (individually and jointly) to the soil as sulfates in the following doses (in μg g^?1, dry wt.): Cd — 2, 3, 5,10, 15, 25, and 50; Zn ?200, 300, 500, 1000, 1500, 2500, and 5000. Cadmium added to soil did not affect yields of wheat. The Zn dose of 1000 μg g^?1 strongly reduced crop yields; at 1500 μg g^? Zn dose wheat did not produce grain. The metal contents of wheat increased with increasing concentrations of Cd and Zn in soil up to 10.3 and 1587 μ g^? of Cd and Zn in straw, respectively. The concentrations of both metals were higher in straw than in grain by factors of 3–7 and 1.5–2 for Zn and Cd, respectively. The relationships between Cd and Zn contents of the plants and soils were best expressed by exponential equations. High concentrations of Zn in soils (1042 and 1542 μg g^?1) enhanced uptake of Cd by plants. The tested threshold concentrations of the metals in soils (3 μg g^?1 for Cd and 200–300 μg g^?1 for Zn) are safe for Zn but are too high for Cd in terms of protecting plants from excessive metal uptake. The critical Cd content of sandy soil should not exceed 1.5 μg g^?.     

Polycyclic Aromatic Hydrocarbons Content in Shoots and Leaves of Willow (Salix viminalis) Cultivated on the Sewage Sludge-Amended Soil

The aim of the present study was to investigate the uptake of 16 PAHs by willow (Salix viminalis) from soil amended with contaminated sewage sludge. Uptake experiments were conducted on field plots using sludge applications of 0, 30, 75, 150, 300, and 600 Mg ha^?1. The total PAH content of control soil and sludge were 49.6 μg kg^?1 and 5713 μ g kg^?1, respectively. The concentrations for the 16 PAHs listed as priority pollutants were measured for soil and plant tissue samples obtained at 0.5, 1.5, 2.5, and 3.5 years. Soil total PAH content decreased significantly within the first half year, followed by minimal changes over the subsequent three years of treatment. PAH analysis was carried out on a HPLC-UV. Total PAH content in control plants was 3.6–7.3 μ g kg^?1 for shoots and 13–27 μ g kg^?1 for leaves. Treated plant tissue content was higher with shoots and leaves containing ～5.5–17.6 and 13.5–33.8 μg kg^?1, respectively. Plant total PAH content did not show a significant trend relative to controls with respect to time. However, uptake did increase in relation to an increased sludge application. Bioconcentration factors (BCF), adjusted by control values, were calculated for total PAH content. BCF values were highest for the initial sampling (6 months) and did not show a significant temporal relationship. BCF values did decrease with increasing sludge application. With respect to individual PAHs, elevated plant tissue concentrations were measured for “light” PAH (e.g. naphthalene, phenanthrene, acenaphthalene) with leaf BCF values correlated with solubility and organic partitioning coefficients.     

Hydroponic Study of Aluminum Accumulation by Aquatic Plants: Effects of Fluoride and pH

The potential of five common aquatic plant species (Typha latifolia, Myriophyllum exalbescens, Potamogeton epihydrus, Sparganium angustifolium and Sparganium multipedunculatum)to be used for Al phytoremediation was tested. The plants were exposed, for 14 days under hydroponic conditions, to synthetic effluents representing extreme conditions that could occur accidentally at an aluminum refinery site. Tested Al concentrationsranged between 0 and 400 μM, fluoride concentrations between 0 and 900 μM, and the pH varied from 4.5 to 7.5. The results indicate that all the plants tested accumulated aluminum, and as a result induced a decrease of Al in the ambient water. For individual species Al uptake (in mol g^-1 dw d^-1) decreased in the following order: Myriophyllum exalbescens > Sparganium sp. ≌Typha latifolia > Potamogeton epihydrus. M. exalbescens accumulated Al more rapidly in its leaves than in other tissues, whereas T. latifolia and Sparganium sp. accumulated Al essentially in their roots. For P. epihydrus the relative importance of the leaves and roots varied with exposure conditions. For all species, fluoro-Al complexes contributed to Al uptake, contrary to the predictions of the Free-Ion Model, according to which the bioavailability of aluminum should be best predicted by the concentration of the free ion, Al³⁺. The influence of pH on Al uptake varied among the different species and among the parts of the plant: competition between Al and the H⁺-ion was evident for the roots of T. latifolia and the leaves and stem of M. exalbescensand P. epihydrus, whereas the roots of M. exalbescens, P. epihydrus and Sparganium sp. showed an inverse trend (Al uptake increased at low pH). For the leaves of T. latifolia and Sparganium sp., no pH influence could be demonstrated. Overall, the results of this study indicate that aquatic plants have a potential for Al phytoremediation.     

Cadmium accumulation in eurasian watermilfoil plants

The aquatic vascular plant Eurasian watermilfoil (Myriophyllum spicatum L.) was investigated for its potential to take up Cd from nutrient-rich water in a short-term growth and harvest regime. Eurasian watermilfoil plants were grown in and harvested weekly from 0.10M Hoagland nutrient solutions containing concentrations of Cd from 0.04 to 7.63μg Cd mL^?1. Dry weights of plants significantly decreas4ed when exposed to 7.63μg Cd mL^?1. For both 0.04 and 1.03μg Cd mL^?1 treatment the greatest concentration of Cd in plants occurred during the first two weeks. The greatest Cd concentration of Cd in plants for the 7.63μg Cd ML^?1 treatment occurred during week one and decreased through week 2. Tissue P concentration in control plants increased over time but did not increase significantly over time when plants were exposed to 0.04 and 1.03μg Cd mL^?1 levels. Tissue P concentration decreased over time when plants were exposed to 7.63μg Cd mL^?1. Stem length, root dry weights, and root number significantly increased over time in control plants and in those exposed to the 0.04 and 1.03μg Cd mL^?1 treatments. Plants treated with 7.63μg Cd mL^?1 did not grow. These results suggest that Eurasian watermilfoil would be useful for absorbing Cd from nutrient-rich water when the solution concentration was in the range of 0.04 to 7.63μg Cd mL^?1. However, in solutions having the highest concentration of Cd, the harvest regime would have to sustain plant vigor, avoid tissue Cd loss, and realize maximum uptake of Cd from solution.     

Influence of soil pH and application of zinc on the yield and uptake of selected nutrient elements by rice

Abstract

Rice grown on a recently water‐leveled Crowley silt loam that contained less than 1.8 μg g^‐1 of 0.1 N HCl‐extractable Zn with pH levels ranging from 6.8 to 7.7, responded to Zn application. Each kg ha of applied Zn as Zn chelate, 14.2 % Zn, resulted in increases of +673, +477, and +2026 kg rice ha^‐1 at pH 6.8, 7.3, and 7.7, respectively. There was a critically low concentration of Zn in rice plants at the midtillering, first joint, and panicle differentiation stages of plant development when no Zn was applied. A yield response to applied Zn was obtained when the concentration of Zn in rice tissue was less than 15 μg g^‐1.

Application of Zn resulted in a significant increase in the uptake of N by rice plants at each of the three stages of plant development. Application of Zn also resulted in relatively large and significant increases in the uptake of Zn from the soil irrespective of soil pH. The uptake of Zn by rice plants at each of the growth stages showed a two‐ to three‐fold increase following Zn application when soil pH was 6.8 and 7.3. Also, the uptake of Zn by rice plants following Zn application showed a four‐fold increase at midtillering, a five‐fold increase at first joint, and a six‐fold increase at panicle differentiation, respectively, when soil pH was 7.7.     

Forms of Cd,Cu, Pb,and Zn in soil and their uptake by cereal crops when applied jointly as carbonates

The cereal crops (barley -Hordeum vulgare L., maize -Zea mays L., wheat -Triticum vulgare L.) were grown in a greenhouse using a sandy soil type treated with various doses of cadmium carbonate (salt), copper carbonate (malachite), lead carbonate (cerussite), and zinc carbonate (smithsonite), added jointly. The following levels of these metals were used: Cd ? 5, 10, 50μg g^?1 soil; Cu and Pb - 50,100, 500 μg g^?1 soil; Zn-150, 300, 1500 μg g-1 soil. Sequential extraction was adopted to partition the metals into five operationally-defined fractions: exchangeable, carbonate, Fe-Mn oxides, organic, and residual. The residual was the most abundant fraction in the untreated (control) soil for all the metals studied (50 to 60% of the total metal content). The concentrations of exchangeable Cd, Cu, Pb, and Zn were relatively low in untreated soil but increased (over the three year period) in treated soils for Cd, Zn, and Cu, whereas only small changes were observed for Ph. This experiment showed a significant increase in Cd, Zn, and Cu in tissue of plants grown on the treated soil, but a non-significant change in plant tissue with respect to Pb concentration.     

Predicting the Phytoextraction Duration to Remediate Heavy Metal Contaminated Soils

The applicability of phytoextraction to remediate soils contaminated with heavy metals (HMs) depends on, amongst others, the duration before remediation is completed. The impact of changes in the HM content in soil occurring during remediation on plant uptake has to be considered in order to obtain a reliable estimate of the phytoextraction duration. To simulate the decrease in the HM content in soil and to assess the resulting decrease in the uptake of HMs by plants, contaminated soil was mixed with uncontaminated, but otherwise similar soil. Uptake of Cd, Pb, and Zn by the indicator plant Lupinus hartwegii and the Zn hyperaccumulator Thlaspi caerulescens (La Calamine ecotype) was a log-linear function of the in-situ measured HM soil solution concentrations. Over a wide range in dissolved Cd and Zn concentrations, uptake of these HMs by T. caerulescens was (much) greater than by L. hartwegii. Experimentally derived regression models describing the relationships between soil, soil solution, and plant were implemented in a HM mass balance model used to obtain estimates of the phytoextraction duration. For our target soils, estimates of the Cd phytoextraction duration using L. hartwegii or T. caerulescens increased significantly by more than 100 or 50 years when experimental soil—soil solution—plant relationships were used instead of the assumption of constant plant uptake of Cd. The two approaches gave similar results for phytoextraction of Zn by T. caerulescens.     

Uptake, Deposition and Wash Off of Fluoride and Aluminium in Plant Foliage in the Vicinity of an Aluminium Smelter in Norway

Uptake, deposition and wash off of fluoride and aluminium in/on plant foliage were studied in two experiments near an Al smelter by growing different plant species under cover with free wind-flow underneath, and in the open, and by washing the leaves. With an average ambient air concentration of 2.2 μg F m³, the F and Al contents in leaves varied between species from 138 to 665 mg F kg^?1 and from 150 to 1025 mg Al kg^?1when grown under cover. An average of about 60% of the F and nearly 70% of the Al could be washed off covered plants. Uncovered plants had 33–51% lower F content, indicating a considerable precipitation wash off. Precipitation wash off varied with species, probably due to different leaf surface properties. The strong effect of precipitation on plant foliage F has to be taken into consideration when comparing differences in F content between years, localities and species. On average about 40–50% of the F and 55% of the Al could be washed off the leaves of uncovered plants. Washed leaves of plants exposed to precipitation had about 20% lower F content, compared to washed leaves of covered plants, thus indicating leaching of F from leaves exposed to rain. In contrast to fluoride, the Al contents in washed leaves of uncovered plants were about 50–80% higher than in covered washed leaves, thus indicating a significant uptake of Al solved in rainwater through the leaf cuticle.     

Effects of aluminium ions on uptake of calcium,magnesium and nitrogen in Betula pendula seedlings growing at high and low nutrient supply rates

The effects of aluminium on plant nutrition in small birch plants (Betula pendula Roth) were investigated. By using relative addition rate (r _A, g g^?1 d^?1) of nutrients as the growth-controlling variable, it was possible to grow the plants at very low external nutrient concentrations and to simulate plant requirements at two different fertility levels. Before aluminium addition the plants were at steady-state relative growth rate, (R _G, g g^?1 d^?1). The two addition rates were free access of nutrients with R _G ≈ 0.215 d^?1, or nutrient-limited, R _Aand R _G=0.10 d^?1. Internal concentrations of calcium and magnesium decreased with increasing Al³⁺ conncentration in the nutrient solution while nitrogen concentrations in the plants remained unchanged or increased. It was demonstrated in both nutrition treatments that calcium and magnesium decrease per se does not reduce plant growth and that uptake has to be considered in relation to plant requirement at different growth rates. The interpretation of the effects of aluminium on Ca and Mg uptake and plant biomass development suggested that processes other than disturbances in Ca and Mg uptake are the cause of the decrease in growth.     

Single and Combined Effects of Cadmium and Zinc on Carrots: Uptake and Bioaccumulation

ABSTRACT

The present study was conducted to evaluate the effects of different concentrations of cadmium (Cd) and zinc (Zn), singly and in combination, on uptake and bioaccumulation of Cd and Zn in Daucus carota L. (carrot) grown under natural field conditions. Carrot plants were treated with two Cd concentrations (10 and 100 μg mL^?1), two Zn concentrations (100 and 300 μg mL^?1), and two combined concentrations of Cd and Zn (10 + 100 and 100 + 300 μg mL^?1) 15 d after seed germination. Treatments were repeated at 10 d intervals up to 90 d of plant age. A control was also kept without a Cd or Zn treatment. Uptake, total accumulation rate (TAR), bioconcentration factor (BCF), primary transport index (PTI), secondary transport index (STI), and accumulation of Cd and Zn in root, stem, and leaf were quantified. The results show that uptake, TAR, and accumulation of Cd and Zn are concentration-dependent phenomena. Highest accumulation of Cd and Zn was found in the root, followed by the stem and then leaves. The results also showed that bioaccumulation of Cd in root, stem, and leaf was greater at the low metal-application rates of Cd and Zn in combination than at the higher rate. This study further showed that interactions of Zn and Cd are dependent on the concentrations of those metals in the soil.     

Fluoride in bones of small rodents living in areas with different pollution levels

Bone fluoride concentration was measured in field voles (Microtus agrestis) trapped throughout a year at a moderately polluted site 1 km south of an Al reduction plant at Holyhead, Anglesey. Fluoride values ranged from 300 to 4800 μg g^?1, with a mean of 2074 μg g^?1 and increased with age as judged by dried eye-lens weight and body weight. At a heavily polluted site about 250 m from the pot-room of the reduction plant field voles had bone fluoride concentrations which ranged from 910 to 11000 μg g^?1 with a mean of 7148 μg g^?1. Wood mice (Apodemus sylvaticus) at this same location had a mean bone fluoride concentration of 8430 μg g^?1 and ranged from 1800 to 17 200 μg g^?1. The difference in mean bone fluoride concentration between these two species at this location was not significant (P > 0.1). A sample of field voles from presumed unpolluted sites in other parts of Britain had bone fluoride concentrations which ranged from 23 to 540 μg g^?1 with a mean of 168 jig g^?1. There was a high positive correlation (r > 0.97) between fluoride concentrations in different parts of field vole skeletons. There was no correlation between bone fluoride concentration in field voles and their femur diameters (r < 0.2).     

浮萍净化氮磷污水的蛋白质生产能力及耐寒能力比较研究

以3种国外优化浮萍为参照，通过对比试验，对5种长江三角洲地区本地浮萍在净化氮磷污水过程中的蛋白质生产能力及耐寒能力进行了比较研究。结果表明：本地少根紫萍和3种国外浮萍，无论在蛋白质生产能力上，还是在浮萍植物体(干基)蛋白质含量上，均具有相当高的水平。2种本地浮萍(稀脉浮萍和少根紫萍)和2种国外优质浮萍(Lemna minor 8627和Spirodella punctata 7776)能在低温条件下成活生长，具有良好的耐寒能力。     

浮萍吸收不同形态氮的动力学特性研究

吸收试验结果表明,浮萍(Spirodela oligorrhiza)吸收铵态氮和硝态氮的动力学特性可用M ichaelis-M enten方程来描述。浮萍对铵态氮的亲和力大于对硝态氮的亲和力,证实了浮萍“优先吸收净化铵态氮”的观点。研究还发现,浮萍吸收硝态氮的最大速率大于吸收铵态氮的最大速率,基于浮萍吸收不同形态氮的动力学特性,提出了构建物理作用(增氧工艺)—微生物(硝化作用)—植物(浮萍)复合污水净化体系的见解。     

Lead and Zinc Extraction Potential of Two Common Crop Plants, Helianthus Annuus and Brassica Napus

Phytoextraction is a remediation technology that uses plants to remove heavy metals from soil. The success of a phytoextraction process depends on adequate plant yield (aerial parts) and high metal concentrations in plant shoots. A pot experiment was conducted to investigate the combination effects of plants [sunflower (Helianthus annuus) and canola (Brassica napus)] with soil treatments (manure, sulfuric acid and DTPA). Treatments, including two plants and seven soil treatments, which applied according to completely randomized factorial design with three replications. The largest shoot dry weight biomass production occurred in manure treatments for both plants. The maximum shoot concentrations of Pb and Zn were 234.6 and 1364.4 mg kg^?1 respectively in three mmoles DTPA kg^?1 treatment of sunflower. Furthermore the results showed that sunflower had a higher extracting potential for removal of Pb and Zn from polluted soil.