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1.

Purpose  

A contaminated soil was amended to reduce bioavailability of metals (As, Cd, Cu, Pb, and Zn) and to modify its potential environmental impacts. Reproduction toxicity tests using two different soil invertebrates, Enchytraeus crypticus and Folsomia candida, were used to evaluate efficiency of soil amendments to reduce metal availability.  相似文献   

2.
Background, Aim and Scope  The toxicity of contaminated sediments should be evaluated considering the direct exposure of laboratory organisms to whole sediments and the indirect exposure to elutriates or extracts (Tay et al. 1992, Byrne and Halloran 1999, Nendza 2002). The alga Dunaliella tertiolecta is indicated for the use in toxicity bioassays because it is highly sensitive to several xenobiotics. Harpacticoid copepods have been already used for toxicity testing and Tigriopus fulvus is a promising Mediterranean target-species in ecotoxicology (Todaro et al. 2001, Faraponova et al. 2003, Pane et al. 2005a). In this study, the toxicity of sediments collected in harbour sites of the Northeastern Adriatic Sea was evaluated by growth inhibition test with free living and alginate-immobilized Dunaliella tertiolecta and acute toxicity test with nauplii and adult Tigriopus fulvus with the aim of pointing out the importance to utilize model organisms from different trophic levels in sediment ecotoxicology. Methodology  Elutriates and whole sediments were tested on free living and immobilized (Pane et al. 1998) algal cells, and on laboratory reared copepods. Free-living D. tertiolecta were exposed to diluted elutriates in a static, multi-well plate system. Naalginate immobilized D. tertiolecta were placed in polystyrene inserts fitted with polyester mesh bottoms and exposed to a thin layer (2 mm) of whole sediments in multi-well plates (EPS 1992, Pane and Bertino 1999). Toxicity tests with copepods were carried out on Tigriopus fulvus nauplii (elutriates) and adults (whole sediments and elutriates). Same-aged nauplii useful for toxicity tests were obtained by egg sac detaching and consequent hatching stimulation (Pane et al. 2006). Newborn nauplii (I–II stage) were exposed to elutriates in multi-well plates provided with polystyrene inserts. Adult T. fulvus maintained in polystyrene inserts fitted with polyester mesh bottoms were placed in contact with a thin layer (2 mm) of whole sediment placed on multi-well plate bottoms. All end-points were evaluated after 96 h. Results  In general, the effects increased with the increasing of elutriate concentration up to 50%; the stimulation or inhibition of algal growth was statistically significant in comparison to the control. The inhibiting elutriates induced EC50 variations of algal growth ranging from 66.9% to 74.3%. The mortality of T. fulvus nauplii was always < 25% after treatment with 100% elutriates and < 10% after treatment with 50% dilution; no effect was shown up with 25% dilution; therefore LC50 was not calculable. The effect of elutriates was negligible on adult copepods and LC50 values were never calculable; percent mortality always resulted in < 10% after treatment with whole sediments. Discussion  Both experimental systems gave substantially similar results after exposition to whole sediments and elutriates. During the experiment with algal cells, the immobilization in Na-alginate and the employment of inserts which allowed the contact of organisms with sediments and their easy counting were particularly useful. Likewise, the employment of inserts of adequate mesh size in the tests with copepods allowed the contact of organisms with the sediment and made organism handling and counting easy, as well as the evaluation of mortality. The methodology here described and the utilization of the proposed test-species could have an importance also considering that the current trend in ecotoxicological research is towards finding the most appropriate organism for specific areas of concern by using indigenous species (Mariani et al. 2006) and towards the major significance of chronic and reproductive end-points. Conclusions  Based on the above results, it can be stated that the bioassay with Dunaliella tertiolecta could be a good estimation tool for the ecotoxicological assessment of marine sediments. The immobilization of algae in Na-alginate was seen to be useful to evaluate the toxicity of whole sediments; the employment of polystyrene inserts allowed an improvement of the procedures. T. fulvus nauplii and adults, as other harpacticoids such as Tigriopus japonicus (Yoon et al. 2006), satisfy the basic criteria for the employment of a standard species in marine bioassays. To date only pelagic Acartia tonsa are utilized in the standardized procedure to evaluate the risk assessment of chemicals or wastewaters (ISO 1999). As, on the contrary, the exposure of copepods to solid-phase contaminants it is not yet standardized, the employment of polystyrene inserts improved the procedures for T. fulvus too. So, the rapidity and the possibility to solve practical problems could be the main attractive features of this technique (Pane et al. 2005a) when applied to whole sediments. Recommendations and Perspectives  The methodology here developed being also applicable to long term and reproduction tests should be recommended because it provides relevant information in comparison with other frequently applied, standardized biotests with crustaceans (ISO 1999). The procedure has been shown to be easily applicable to selected marine organisms. ESS-Submission Editor: Prof. Dr. Henner Hollert (henner.hollert@bio5.rwth-aachen.de)  相似文献   

3.

Background

In arid and semiarid countries, grain yield of maize is increasingly impaired by soil salinity. Beside soil amelioration, the development of salt-resistant cultivars is a possibility to enhance crop yield on salt-affected soils.

Aims

This study aimed at testing yield performance in the field of salt-resistant maize hybrids on a salt-affected soil. In addition, planting density was optimized under the saline conditions.

Methods

Four salt-resistant maize hybrids (Zea mays L. SR-05, SR-12, SR-15, and SR-16) were grown under control (EC = 2.0–2.5 dS m−1) and saline (EC = 10.0–12.0 dS m−1) field conditions and compared to the salt-sensitive maize cv. Pioneer-3906. Planting density (5, 8, or 11 plants m−2) was optimized for saline soil conditions for SR-12 and the local hybrid EV-78.

Results

Yield of Pioneer-3906 was significantly reduced under salinity because of inhibited kernel setting, whereas the SR hybrids showed no decrease in grain yield. Based on grain yield, the optimum planting density was 8 plants m−2 with no further increase with 11 plants m−2. In contrast to SR-12, for cv. EV-78 no increase of harvest index with 8 relative to 5 plants m−2 was observed.

Conclusions

Vegetative growth of Pioneer-3906 and the SR hybrids was decreased due to Phase-I effects but neither due to water deficiency nor ion toxicity. The experiment corroborated the salt resistance of the SR hybrids under field conditions. Under saline conditions, optimum planting density of salt-resistant cultivars may be higher than under nonsaline conditions when sufficient water supply by artificial irrigation is guaranteed.  相似文献   

4.

Background

Agricultural soils often require organic amendments, which improve crop yield and ecosystem services. Biochar has been proven to increase nutrient availability and retention in fine-textured, tropical soils.

Aims

Here we determine how coarse-textured, temperate soils react to different biochar-application rates in different tillage systems.

Methods

We conducted a 6-month laboratory incubation experiment in microcosms filled with a coarse-textured, temperate agricultural soil to determine the effects of biochar-application rate (none, low, or high, i.e., 0, 20, or 40 t dw ha−1, respectively) and application method (mixed into the soil or applied to the soil surface) on microbial activity and biomass, and nutrient availability and leaching.

Results

Microbial activity and biomass and contents of carbon, nitrogen, and phosphorus in leachates were higher in biochar-addition treatments (by 134%, 37%, 372%, 28%, and 801%, respectively) than in the no-addition treatment. The effect was stronger with the low than with the high biochar-application rate. Biochar applied by both methods acted as a slow-release fertilizer, but this effect was stronger when biochar was mixed into the soil. Although available nutrient contents in the soil remained high, nutrient leaching decreased with incubation time. This effect was especially evident when biochar was mixed into the soil.

Conclusions

Biochar is an effective organic amendment in coarse-textured soils providing available nutrients. On the other hand, nutrient-retention mechanisms develop slowly after biochar application and may be greater when biochar is mixed into the soil than applied on the soil surface.  相似文献   

5.

Purpose  

Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons (PAHs) co-contaminated soil were reported in this study.  相似文献   

6.

Aim and Background  

In order to identify potential risks of sediments contaminated by pulp and paper mill effluents, two boreal lake areas were investigated from core samples. Resin acids (RA) and their aromatized derivative retene were measured, suggesting that these aquatic toxicants can be long-lasting sources to expose benthic biota. On the other hand, dredging or other human actions can liberate toxicants, even from deep sediments, to an aqueous phase with harmful consequences to aquatic species. Since no historical sediment profiles were available, we investigated the toxic potential of sediment-water elutriates by way of the bioluminescent bacteria Vibrio fischeri. In this investigation, we therefore analyzed both the concentrations of toxic chemicals and the toxicity as profiles in two contaminated lake sediments in Finland.  相似文献   

7.

Purpose  

Previous studies have shown that ivermectin, a widely used parasiticide, is very toxic to many non-target invertebrate species. In view of the strong binding of ivermectin to sediments and the scarcity of data on chronic toxicity to freshwater sediment invertebrates, chronic effects of the parasiticide on the midge Chironomus riparius and the oligochaete Lumbriculus variegatus were investigated.  相似文献   

8.
Appropriate management of P from slurry can increase crop production and decrease nutrient loss to water bodies. The present study examined how the application of different size fractions of dairy slurry influenced the quantity and composition of P leached from grassland in a temperate climate. Soil blocks were amended (day 0 = start of the experiment) with either whole slurry (WS), the > 425 μm fraction (coarse slurry fraction, CSF), the < 45 μm slurry fraction (fine liquid slurry fraction, FLF), or not amended, i.e., the control soil (CON). Deionized water was added to the soil blocks to simulate six sequential rainfall events, equivalent to 250 mm (day 0.2, 1.2, 4.2, 11.2) or 500 mm of rainfall (day 18.2 and 25.2), with leachates collected the following day. The results showed that total dissolved P (TDP), dissolved reactive P (DRP), dissolved unreactive P (DUP), orthophosphate, phosphomonoester, and pyrophosphate concentrations generally decreased with the increasing number of simulated rain events. Total dissolved P was leached in the following order WS > FLF ≈ CSF > CON. Dissolved organic C was correlated with TDP, DRP, and DUP in leachates of all treatments. The highest concentrations of dissolved phosphomonoesters and pyrophosphate (147 μg P L–1 and 57 μg P L–1, respectively) were detected using solution 31P‐NMR spectroscopy in the WS leachates. Overall, there were significant differences observed between slurry treatments (e.g., relative contributions of inorganic P vs. organic P of dissolved P in leachates). Differences were independent from the rate at which slurry P was applied, because the highest dissolved P losses per unit of slurry P applied were measured in the FLF, i.e., the treatment that received the smallest amount of P. We conclude that the specific particle‐size composition of applied slurry influences dissolved P losses from grassland systems. This information should be taken in account in farm‐management approaches which aim to minimizing dissolved slurry P losses from grassland systems.  相似文献   

9.

Background

In practical farming, there is often a need for short-term availability of information on the soil nutrient status.

Aims

To develop a new express method for the extraction of major plant-available nutrients and measurement of soil nutrients. In future, this method shall serve for in-field measurements of soil samples with an ion-sensitive field-effect transistor (ISFET).

Methods

Various extraction conditions such as type of extractant, soil-to-solution ratio, time, and intensity were investigated on a broad selection of dried soil samples in the laboratory. Based on 83 field-moist soil samples with varying clay contents, these conditions were compared to standard laboratory methods.

Results

With increasing extraction time, the nutrient concentrations increased. When the soil-to-solution ratio was reduced, a greater share of nutrients was extracted, independent of soil type. H2O and 0.01 M CaCl2 and standard calcium-acetate-lactate (CAL) solution proved to be too weak in the short period to reach the ISFET sensor measurement range. Higher concentrated CAL solutions performed much better. Finally, a 5-min CaCl2 extraction followed by the removal of an aliquot for the determination of soil pH and NO3 was found to be effective. The remaining solution was then mixed with 0.20 M CAL solution for the analysis of H2PO4 and K+ at 10 min of extra extraction time. This extraction method showed very good correlations with the values based on the German laboratory reference methods for pH (R2 = 0.91) and for nitrate (R2 = 0.95). For phosphorus and potassium, we obtained an R2 of 0.70 and 0.81, respectively, for all soils. When soils were grouped according to clay content higher correlations were found.

Conclusions

A new express method based on a wet-chemical approach with a soil preparation procedure was successfully developed and validated. This seems to be a valuable basis for future in-field measurements via ISFET.  相似文献   

10.

Background

Organic farmers frequently report sufficient yield levels despite low or even very low soil phosphorous (P) contents questioning the applicability of widely used laboratory methods for soil P testing for organic farming.

Aims

The aim of this study was to compare the validity of a broad range of different soil extraction methods on soils under organic management from South West Germany and to test the correlation of the measured soil P concentration with plant offtake.

Methods

Twenty-two soil samples of eight different organic farms were extracted with different solutions: (1) water, (2) CAL, (3) Olsen, (4) Mehlich 3, (5) Bray P1, (6) Bray P2, (7) NaOH+Na2EDTA, and (8) total P. The results were then correlated with above ground plant P.

Results

Spearman's rank correlation coefficient (rs) of correlations between above ground plant P and extractable soil P (Water-P, CAL-P, and Olsen-P [+active charcoal {+AC}]) determined with ICP-OES were strong (0.94, 0.90, and 0.93, respectively). Among the tested methods, above ground plant P showed a strong correlation with CAL-P as detected by ICP-OES (rs = 0.90) and colorimetry (rs = 0.91). The comparison of CAL-P data provided by farmers and CAL-P analyzed during this research showed discrepancies between the results.

Conclusions

The results of this study indicate that the CAL method can be used in organic farming despite a low extraction of organic P (Porg). Furthermore, it is recommended for farmers to take soil samples for analyses regularly and interpret changes in P in the long-term instead of interpreting individual samples.  相似文献   

11.

Purpose  

The use of only one or a few species—representing an entire taxon—in ecotoxicological standard tests poses risk of underestimating the impact of toxicants on the environment. In earthworm ecotoxicity tests, the species Eisenia fetida or Eisenia andrei are commonly used, and there is evidence that these species respond relatively insensitive towards environmental pollution. With the present study, we wanted to evaluate the risk of underestimating effects of the insecticide imidacloprid in soil organisms by comparing E. fetida with two other earthworm species (Aporrectodea caliginosa and Lumbricus terrestris) regarding their sensitivities towards soil contaminated with this widely used insecticide.  相似文献   

12.

Purpose  

Changes in the behavior of earthworms (for example avoidance of a particular substrate) can influence the soil ecosystem. Our aim was to determine whether the earthworms Eisenia fetida and Lumbricus terrestris are able to avoid ivermectin (a veterinary endectocide belonging to the avermectins). A standard avoidance test with earthworms was conducted using standardized Lufa 2.3 soil (Speyer, Germany) and sandy soil provided by Cinkarna Celje (Slovenia).  相似文献   

13.

Purpose  

The relationship between plant absorption and accumulation of heavy metals and the effect of iron plaque on roots of wetland plants are unknown, especially for plants grown in heavy metal-contaminated soil. This experiment was designed to study the effects of iron addition on the formation of iron plaque in the rhizosphere of the wetland plant species Iris pseudacorus L. in artificial Pb-contaminated soil and the effects of iron plaque on Pb accumulation by plants.  相似文献   

14.
In this study, the effects of 1 h aeration, nitrogen gas N2(g) sparging (15 and 30 min) and increasing ferric ions (Fe+3) as FeSO4 (10, 20 and 50 mg L−1) and Fe3O4 nanoparticles (1, 2 and 4 g L−1) concentrations on three less hydrophobic and three more hydrophobic polycyclic aromatic hydrocarbons (PAHs) and toxicity removals from a petrochemical industry in Izmir (Turkey) were investigated in a sonicator with a power of 650 W and an ultrasound frequency of 35 kHz; 1 h aeration increased the yields in benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene PAHs (less hydrophobic) from 62% to 67% to around 95–97% after 150 min sonication at 60°C. However, 1 h aeration did not contribute to the yields of more hydrophobic PAHs (indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene). The maximum yields were obtained at acidic and alkaline pH for more and less hydrophobic PAHs, respectively, after 60 and 120 min sonication at 30°C; 30 min N2(g) sparging, 50 mg L−1 Fe+3 increased the yields of less hydropobic PAHs after 150 min sonication at 60°C. Two milligrams per liter of Fe3O4 nanoparticles increased both less (87–88%) and more (96–98%) hydrophobic PAH yields. The Daphnia magna acute toxicity test showed that the toxicity decreased significantly with an hour aeration, 30 min N2(g) sparging, 50 mg L−1 Fe+3 and 2 g L−1 Fe3O4 nanoparticles at 60°C after 120 and 150 min sonications. Vibrio fischeri was found to be more resistant to the sonicated samples than D. magna. Significant correlations were found between the physicochemical properties of sonicated PAHs and acute toxicities both organisms.  相似文献   

15.

Purpose  

Road runoff residues are often reused in road and civil works building. Although the physicochemical and ecotoxicological characteristics of these materials are known, no extensive ecotoxicological studies have been carried out on the leachates obtained from these residues once they have been spread and exposed to rainfall. This study was aimed at assessing the ecotoxicological risks for lentic aquatic ecosystems receiving the leachates of road runoff residues, either raw or treated, through granulometric sieving.  相似文献   

16.

Purpose

In France, contaminated seaport sediments cannot be discharged into the sea according to recent regulation. Hence, they must be managed on land. Among the solutions identified, that of filling terrestrial quarries located in the littoral zone is one of the most promising. However, this requires developing a methodology for ecological risk assessment; which was the aim of the SEDIGEST research program. In the present study, we report the results of toxicological impacts of three sediments on aquatic ecosystems close to a quarry. These results were used to formulate a risk assessment methodology.

Materials and methods

The ecotoxicological approach was based on laboratory microcosm assays applied to leachates obtained from the sediments. The microcosms contained synthetic water and sediment and five pelagic (micro-algae, duckweeds and daphnids) and benthic (chironomids and amphipods) freshwater species. The biota were exposed for 3 weeks to a range of leachate concentrations; metals were monitored in the water column and the effects (i.e. mortality, growth inhibition and midge emergence) were measured.

Results and discussion

The results showed an absence of acute toxicity at concentrations of <10% (v/v) but sublethal effects for concentrations between 1 and 10%. Given the complex nature of the leachates, it was difficult to determine the factors of toxicity. Metals, especially Cu, might have been responsible for some of the effects on the amphipods.

Conclusions

Future quarries filled with seaport sediments might emit pollutants to aquatic ecosystems in their vicinity, and risk assessors should ensure that predicted environmental concentrations of leachates are below the maximum leachate concentration acceptable for the whole ecosystem; for example, by multiplying the concentration safe for the microcosm organisms by a factor of 10.  相似文献   

17.

Purpose  

Commercial monoculture plantations of the native Australian Araucaria cunninghamii are common in subtropical and tropical Queensland and are generally established following clearing of native mixed forest. The consequences of such forest conversion for soil fungal communities, however, have not been assessed in detail.  相似文献   

18.

Purpose  

Two main pathways of phytoremediation of heavy metal-contaminated soils are phytostabilization and phytoextraction. Some soil amendments can strengthen phytostabilization or phytoextraction through either reducing heavy metal bioavailability in soil or increasing the heavy metal accumulation capacity of the hyperaccumulator (enhancing heavy metal concentration or shoot biomass of the hyperaccumulator). Urea and chicken manure are often used as fertilizers. This research will explore their effects on a newly found hyperaccumulator, Rorippa globosa (Turcz.) Thell., phytoremediating cadmium (Cd).  相似文献   

19.

Purpose  

Phyllostachys praecox is one of the bamboo species used for the production of fine edible bamboo shoots and is widely distributed in Southern China. To maintain or increase the productivity of bamboo shoots, P. praecox forests are intensively managed through heavy fertilization and surface mulch of organic residues such as rice husk to increase soil temperature in the winter. Such management techniques can markedly influence soil quality and the dynamics of soil carbon (C). The objectives of this study were to investigate the long-term impact of intensive management practices on carbon pools and forms in the soil of bamboo forests and explore relationships between different soil organic C fractions, as little such information is currently available.  相似文献   

20.

Purpose  

A 7-month field experiment was conducted to investigate the polycyclic aromatic hydrocarbon (PAH) remediation potential of two plant species and changes in counts of soil PAH-degrading bacteria and microbial activity.  相似文献   

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