Abbauverhalten von triadimefon und seinem metaboliten triadimenol in einer weizenmonokultur

Summary

In a 4‐year study, the behaviour of the residues of triadimefon and its metabolite triadimenol in different plant parts of winter wheat and in soil was investigated. The fungicide Bayleton DF (triadimefon + captafol) was applied at the beginning of earing. Triadimefon residues were quickly degraded in the great majority of the examined samples (more than 90% within the first 2 weeks after application in all aerial parts of the plant). Triadimenol residues were considerably more persistent. No residues either of triadimefon or triadimenol were found in grain at harvest time (detection limit 0.01 mg/kg).     

Behavior of triadimefon in two Lebanese soils.

The retention and fate of triadimefon fungicide were studied under two environmental conditions. Field studies were conducted on two soils, a sandy loam soil (Fanar) and a clay soil (Raouda). Fanar is a wet coastal area while Raouda is a dry agricultural area of the Bekaa plain located at an elevation of 870 m above sea level. Triadimefon was applied with a jet sprayer at 267 g a.i.ha(-1) and 200 g a.i.ha(-1) at Fanar and Raouda, respectively. Reconstituted soil columns (600 x 30 mm) glasses, were used to study the fungicide movement and metabolism in the two soils. Analyses of triadimefon and its metabolites were carried out using gas chromatography (GC) and high performance liquid chromatography (HPLC). The results indicated a weak reversibility of the adsorbed fraction in the clay soil. Clay is considered an important factor in triadimefon adsorption. Triadimefon mobility in the sandy-loam soil was relatively high in comparison with behavior in the clay soil where about half of the applied fungicide was detected in the upper 25 cm of soil, six days after treatment. Rapid degradation of triadimefon to triadimenol was observed in the two soils. The observed half-life was 8 days in sandy-loam and 13 days in clay soils.     

Behavior of captafol residues after prolonged application in a wheat monoculture

In a 4-year study, the behaviour of the residues of the fungicide captafol in different plant parts of winter wheat and in the soil was investigated. The fungicide Bayleton DF (captafol + triadimefon) was applied at the beginning of earing. Captafol residues clearly showed a high dependence on weather conditions in all examined aerial parts of the plant. After a 9-year application of captafol, there was no evidence of an enrichment of residues in the soil. At harvest, captafol residues in grains always were below the maximum residue limits of 0.5 mg/kg established in West Germany.     

Effects of fungicides triadimefon and propiconazole on soil bacterial communities

The impact of fungicides triadimefon and propiconazole on soil bacterial populations from a strawberry field was investigated. Two fungicides were applied to the soil at concentrations of 10 mg/kg or 100 mg/kg with soil water contents 20.2% (fresh soil water content) or 26.0% (field capacity). Changes in bacterial communities were assessed using DNA extraction, polymerase chain reaction (PCR) amplification of the 16S rDNA and denaturing gradient gel electrophoresis (DGGE). High performance liquid chromatography (HPLC) was utilized to detect the residue of fungicides in soils. The results showed that propiconazole was more persistent than triadimefon in soils, and the two soil water contents did not cause significant differences in dissipation rates between the two fungicides. A high concentration of propiconazole could inhibit the existence of soil microbes while one of triadimefon might induce the microbial population in the first stage. From unweighted pair-group method using arithmetic averages (UPGMA) dendrograms, the effect of triadimefon and propiconazole at the two applied concentrations on a soil bacterial community could be long term. After triadimefon was applied for 60 days and propiconazole for 75 days, the compositions of microbial communities were not recovered. From the viewpoint of environmental protection, it was of significant importance to pay more attention not only to the residues of pesticide but also to the change in soil microbial communities.     

Persistence of repeated triadimefon application and its impact on soil microbial functional diversity

The effects of repeated applications of the fungicide triadimefon in agricultural soil on the microbial functional diversity of the soil and on the persistence of the fungicide in the soil were investigated under laboratory conditions. The degradation half-lives of triadimefon at the recommended dosage, simulated by a first-order kinetic model, were 23.90, 22.95, and 21.52 days for the first, second, and third applications, respectively. Throughout this study, no significant inhibition of the Shannon-Wiener index (H') was observed. However, the Simpson index (1/D) and the McIntosh index (U) were obviously reduced (p ≤ 0.05) during the initial 3 days after the first triadimefon application and thereafter, gradually recovered to or exceeded the level of the control soil. A similar trend in variation but with a faster recovery in the 1/D and U was observed after the second and third triadimefon applications, respectively. Taken together, the above results indicate that the repeated application of triadimefon enhanced the degradation rate of the fungicide and the recovery rate of the soil microbial functional diversity. It is concluded that repeated triadimefon applications in soil have a transient or temporary inhibitory effect on soil microbial communities.     

Persistence of repeated triadimefon application and its impact on soil microbial functional diversity

The effects of repeated applications of the fungicide triadimefon in agricultural soil on the microbial functional diversity of the soil and on the persistence of the fungicide in the soil were investigated under laboratory conditions. The degradation half-lives of triadimefon at the recommended dosage, simulated by a first-order kinetic model, were 23.90, 22.95, and 21.52 days for the first, second, and third applications, respectively. Throughout this study, no significant inhibition of the Shannon-Wiener index (H′) was observed. However, the Simpson index (1/D) and the McIntosh index (U) were obviously reduced (p ≤ 0.05) during the initial 3 days after the first triadimefon application and thereafter, gradually recovered to or exceeded the level of the control soil. A similar trend in variation but with a faster recovery in the 1/D and U was observed after the second and third triadimefon applications, respectively. Taken together, the above results indicate that the repeated application of triadimefon enhanced the degradation rate of the fungicide and the recovery rate of the soil microbial functional diversity. It is concluded that repeated triadimefon applications in soil have a transient or temporary inhibitory effect on soil microbial communities.     

Agricultural reuse of reclaimed water and uptake of organic compounds: pilot study at Mutah University wastewater treatment plant, Jordan

The residues of polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated benzenes (CBs) and phenols were investigated for soil, wastewater, groundwater and plants. The uptake concentration of these compounds was comparatively determined using various plant types: Zea mays L., Helianthus annus L., Capsicum annum L., Abelmoschus esculentus L., Solanum melongena L. and Lycopersicon esculentum L. which were grown in a pilot site established at Mutah University wastewater treatment plant, Jordan. Soil, wastewater, groundwater and various plant parts (roots, leaves and fruits) samples were extracted in duplicate, cleaned up by open-column chromatography and analyzed by a multi-residue analytical methods using gas chromatography equipped with either mass selective detector (GC/MS), electron capture detector (GC/ECD), or flame ionization detector (FID). Environmentally relevant concentrations of targeted compounds were detected for wastewater much higher than for groundwater. The overall distribution profiles of PAHs and PCBs appeared similar for groundwater and wastewater indicating common potential pollution sources. The concentrations of PAHs, PCBs and phenols for different soils ranged from 169.34 to 673.20 microg kg(-1), 0.04 to 73.86 microg kg(-1) and 73.83 to 8724.42 microg kg(-1), respectively. However, much lower concentrations were detected for reference soil. CBs were detected in very low concentrations. Furthermore, it was found that different plants have different uptake and translocation behavior. As a consequence, there are some difficulties in evaluating the translocation of PAHs, CBs, PCBs and phenols from soil-roots-plant system. The uptake concentrations of various compounds from soil, in which plants grown, were dependent on plant variety and plant part, and they showed different uptake concentrations. Among the different plant parts, roots were found to be the most contaminated and fruits the least contaminated.     

Effects of municipal solid waste compost and mineral fertilizer amendments on soil properties and heavy metals distribution in maize plants (Zea mays L.)

Soil amendments based on crop nutrient requirements are considered a beneficial management practice. A greenhouse experiment with maize seeds (Zea mays L.) was conducted to assess the inputs of metals to agricultural land from soil amendments. Maize seeds were exposed to a municipal solid waste (MSW) compost (50 Mg ha⁻¹) and NPK fertilizer (33 g plant⁻¹) amendments considering N plant requirement until the harvesting stage with the following objectives: (1) determine the accumulation of total and available metals in soil and (2) know the uptake and ability of translocation of metals from roots to different plant parts, and their effect on biomass production. The results showed that MSW compost increased Cu, Pb and Zn in soil, while NPK fertilizer increased Cd and Ni, but decreased Hg concentration in soil. The root system acted as a barrier for Cr, Ni, Pb and Hg, so metal uptake and translocation were lower in aerial plant parts. Biomass production was significantly enhanced in both MSW and NPK fertilizer-amended soils (17%), but also provoked slight increases of metals and their bioavailability in soil. The highest metal concentrations were observed in roots, but there were no significant differences between plants growing in amended soil and the control soil. Important differences were found for aerial plant parts as regards metal accumulation, whereas metal levels in grains were negligible in all the treatments.     

Evaluation of copper availability to plants in copper-contaminated vineyard soils

The repeated use of copper (Cu) fungicides to control vine downy mildew has led to long-term accumulation of Cu in vineyard soils which now raises the issue of the potential bioavailability of Cu for various living organisms including plant species. The bioavailable Cu can be defined as the portion of soil Cu that can be taken up by roots, for a given plant species. In order to evaluate the bioavailability of Cu to plants, a pot experiment was conducted in glasshouse conditions with a crop species (maize) and 12 soils sampled in the upper horizon of 10 vineyard plots (total Cu ranging from 38 to 251 mg kg-1) and two woodland plots (control soils that had not received any Cu application; total Cu amounting to 20-26 mg kg-1). These soils were selected for their diverse physical (large range of particle size distribution) and chemical (from acid to calcareous soils) properties. After 35 days of growth, plant shoots were harvested for analysis. The roots were separated from soil particles for further analysis. The concentrations of Cu in the roots and aerial parts of the maize were then compared with the amounts of Cu extracted from the soil by a range of conventional extractants. Observed Cu concentrations in maize roots which have grown in contaminated vineyard soils were very high (between 90 and 600 mg kg-1), whereas Cu concentrations in the aerial parts varied only slightly and remained low (< 18 mg kg-1). Root Cu concentrations observed for maize increased with increasing total Cu content in the soil and with decreasing soil CEC. Cu accumulation in maize roots may be as high in calcareous soils as in acid soils, suggesting that soil pH had little influence. In the case of the vineyard soils studied, the lack of correlation found for maize between Cu concentrations in roots and in the aerial parts, suggests that an analysis of the aerial parts would not be a good indicator of plant Cu uptake, as it provides no insight into the real amount of Cu transferred from the soil to the plant. For maize, our results show that extraction with organic complexing agents (EDTA, DTPA) and extraction with ammonium acetate seem to provide a reasonably good estimate of root Cu concentration.     

水葱修复土壤镉污染潜力的研究

野外观察与研究发现水葱(Scirpus tabernaemontani G.)可以耐受土壤中高浓度的重金属污染,并对镉(Cd)有很高的生物富集量.实验室水培试验研究了两个主要因素,营养液pH与Cd含量,对水葱生物量以及Cd富集效果的影响.结果表明,它可耐受高浓度Cd (30 mg/L)和大范围pH变化 (3.7～7.7).当营养液pH为4.7, Cd为25 mg/L时,水葱富集的Cd达到最大值:地上部分264.71 mg/kg,地下部分234.39 mg/kg,平均转运系数1.13.这显示了它用于植物修复Cd污染土壤的潜力.     

Soil physical changes and plant availability of Zn and Pb in a treatability test of phytostabilization

A treatability test of phytostabilization was carried out on two soils sampled downstream a mining Italian area with Lolium italicum and Festuca arundinacea. Beside chemical content of Pb and Zn in aerial parts and in roots, also some physical parameters were determined at the end of the growth cycle of plants. Particle size distribution was analysed with a laser granulometer while cracking patterns and porosity were determined by means of image analysis. Compost, used at two rates (10%, and 30% v/v) in order to improve soil physical characteristics, always raised biomass with similar effects for both doses. The concentration of Pb and Zn in aerial parts and in roots of L. italicum and F. arundinacea decreased more than five times in presence of compost. A general lack of clear effects of both plants on soil physical parameters was noticed. Formation of more water stable aggregates, a rise of the area occupied by cracks, and new porosity formed by elongated and irregular pores were found in soil samples treated with compost.     

Effects of six selected antibiotics on plant growth and soil microbial and enzymatic activities

The potential impact of six antibiotics (chlortetracycline, tetracycline and tylosin; sulfamethoxazole, sulfamethazine and trimethoprim) on plant growth and soil quality was studied by using seed germination test on filter paper and plant growth test in soil, soil respiration and phosphatase activity tests. The phytotoxic effects varied between the antibiotics and between plant species (sweet oat, rice and cucumber). Rice was most sensitive to sulfamethoxazole with the EC10 value of 0.1 mg/L. The antibiotics tested inhibited soil phosphatase activity during the 22 days' incubation. Significant effects on soil respiration were found for the two sulfonamides (sulfamethoxazole and sulfamethazine) and trimethoprim, whereas little effects were observed for the two tetracyclines and tylosin. The effective concentrations (EC10 values) for soil respiration in the first 2 days were 7 mg/kg for sulfamethoxazole, 13 mg/kg for sulfamethazine and 20 mg/kg for trimethoprim. Antibiotic residues in manure and soils may affect soil microbial and enzyme activities.     

Toxicity of copper on rice growth and accumulation of copper in rice grain in copper contaminated soil

Pot soil experiments showed that copper (Cu) is highly toxic to rice. Rice grain yields decreased exponentially and significantly with the increase of soil Cu levels. Rice grain yield was reduced about 10% by soil Cu level of 100 mg kg(-1), about 50% by soil Cu level of 300-500 mg kg(-1) and about 90% by soil Cu concentration of 1,000 mg kg(-1). Root was more sensitive to soil Cu toxicity than other parts of rice plant at relatively lower soil Cu levels (less than 300-500 mg kg(-1)), but the growth of whole rice plant was severely inhibited at high soil Cu levels (300-500 mg kg(-1) or above). Cu concentrations in rice grain increased with soil Cu levels below 150-200 mg kg(-1), but decreased with soil Cu levels above 150-200 mg kg(-1), with peak Cu concentration at soil Cu level of 150-20 mg kg(-1). Cu was not distributed evenly in different parts of rice grain. Cu concentration in cortex (embryo) was more than 2-fold that in chaff and polished rice. More than 60% of the Cu in grain was accumulated in polished rice, about 24% in cortex (embryo), and about 12% in chaff. So, about 1/3 of the Cu in rice grain was eliminated after grain processing (chaff, cortex and embryo was removed).     

Uptake of 14C-atropine and/or its transformation products from soil by wheat (Triticum aestivum var Kronjet) and their translocation to shoots

Plant uptake of toxins and their translocation to edible plant parts are important processes in the transfer of contaminants into the food chain. Atropine, a highly toxic muscarine receptor antagonist produced by Solanacea species, is found in all plant tissues and can enter the soil and hence be available for uptake by crops. The absorption of atropine and/or its transformation products from soil by wheat (Triticum aestivum var Kronjet) and its distribution to shoots was investigated by growing wheat in soil spiked with unlabeled or ¹⁴C-labeled atropine. Radioactivity attributable to ¹⁴C-atropine and its transformation products was measurable in plants sampled at 15 d after sowing (DAS) and thereafter until the end of experiment. The highest accumulation of ¹⁴C-atropine and/or its transformation products by plants was detected in leaves (between 73 and 90% of the total accumulated) with lower amounts in stems, roots, and seeds (approximately 14%, 9%, and 3%, respectively). ¹⁴C-Atropine and/or its transformation products were detected in soil leachate at 30, 60, and 90 DAS and were strongly adsorbed to soil, with 60% of the applied dose adsorbed at 30 DAS, plateauing at 70% from 60 DAS. Unlabeled atropine was detected in shoots 30 DAS at a concentration of 3.9 ± 0.1 μg kg^?1 (mean ± SD). The observed bioconcentration factor was 2.3 ± 0.04. The results suggest a potential risk of atropine toxicity to consumers.     

Dieldrin uptake by vegetable crops grown in contaminated soils

The aim of these trials was to study the distribution of dieldrin in soil and its translocation to roots and the aerial parts of vegetable crops grown in greenhouses and fields. The main objectives were to characterize dieldrin accumulation in plant tissues in relation to the levels of soil contamination; uptake capability among plants belonging to different species, varieties and cultivars. The presence of the contaminant was quantified by gas chromatography-electron capture detector (GC-ECD) and confirmed by gas chromatography-mass spectrometer (GC-MS). The results showed a translocation of residues in cucurbitaceous fruits and flowers confirming that zucchini, cucumber and melon are crops with high uptake capability. The maximum level of dieldrin residue at 0.01 mg/kg was found to be a threshold value to safeguard the quality production of cucurbits. Tomato, lettuce and celery were identified as substitute crops to grow in contaminated fields.     

The copper tolerance strategies and the role of antioxidative enzymes in three plant species grown on copper mine

This study was undertaken to identify the strategies and the status of antioxidant enzyme activities involved in three plant species tolerance against Cu-toxicity in copper mine. The following methods were used for evaluations in three wild type species; Datura stramonium, Malva sylvestris and Chenopodium ambrosioides. The level of chlorophyll and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) by spectrometry, malondialdehyde (MDA) and dityrosine by HPLC and the levels of Cu in tissues and soils by atomic absorption spectrometry (AAS).

Analysis showed that total and available copper were at toxic levels for plants growing on contaminated soil (zone 1). However, there were not any visual and conspicuous symptoms of Cu toxicity in plant species. Among three species, excess copper was transferred only into the D. stramonium and C. ambrosioides tissues. The C. ambrosioides accumulated Cu in roots and then in leaves, in which the leaves chloroplasts stored Cu around two times of vacuoles. In D. stramonium most of Cu was accumulated in leaves in which the storage rate in vacuoles and chloroplasts were 42% and 8%, respectively. In zone 1, the chlorophyll levels increased significantly in leaves of C. ambrosioides with respect to the same plant growing on uncontaminated soil (zone 2). There was insignificant decrease in chlorophyll content of D. stramonium leaves, collected from zone 1 with respect to zone 2. The D. stramonium and C. ambrosioides in zone 1, both revealed significant increase in their tissues antioxidant enzyme activities in comparison with the same samples of zone 2. There was significant elevation in oxidative damage biomarkers; MDA and dityrosine, when the aerial parts of D. stramonium in zone 1 were compared with the same parts of zone 2.

We concluded that there were different tolerance strategies in studied plant species that protected them against copper toxicity. In M. sylvestris, exclusion of Cu from the roots or its stabilization in the soil restricted Cu toxicity effects. On the other hand D. stramonium and C. ambrosioides, elevated their antioxidative enzyme activities in response to cu-toxicity. In addition, the species D. stramonium accumulated excess of Cu in leaves vacuoles.     

Uptake and accumulation of lead by plants from the Bo Ngam lead mine area in Thailand

A field survey of terrestrial plants growing on Bo Ngam lead mine area, Thailand, was conducted to identify species accumulating exceptionally high concentrations of lead. Plant and soil samples were collected from five areas. Lead concentrations in surface soil ranged from 325 to 142,400 mg/kg. The highest lead concentration in soil was found at the ore dressing plant area and lowest at a natural pond area. In different areas, the concentrations of lead in plants were different when comparing various study sites. A total of 48 plant species belonging to 14 families were collected from five sampling sites. Twenty-six plant species had lead concentrations more than 1000 mg/kg in their shoots. Three species (Microstegium ciliatum, Polygala umbonata, Spermacoce mauritiana) showed extremely high lead concentrations in their shoots (12,200-28,370 mg/kg) and roots (14,580-128,830 mg/kg).     

Determination of disulfoton and permethrin residues in an organic soil and their translocation into lettuce, onion and carrot.

The residues of disulfoton and permethrin in an organic soil and in vegetables grown in soil treated with a granular formulation of the pesticides were determined by gas chromatography. The residues were removed from soil or plant samples by successive extractions with acetone and hexane. Permethrin persisted in the soil for the initial 28 days and declined slowly during the rest of the season but disulfoton after persisting for one week at the applied concentration was degraded in the next two weeks. The insecticides did not translocate into the edible parts of the vegetables but were present in the root system of onion and lettuce. Carrot and lettuce yields were not singificantly different from those of the controls but onion yields were substantially decreased by the use of permethrin.     

Copper bioavailability in the rhizosphere of maize (Zea mays L.) grown in two Italian soils

In this study, potentially bioavailable copper was estimated in two soils (a fungicide polluted and a natural soil) using a passive sampling technique, DGT. As plants can alter copper mobility and bioavailability in the soil, the rhizosphere properties of Zea mays L. were investigated using rhizoboxes.

Compared to the total concentration, the soluble and the potentially bioavailable copper concentration in the bulk soils were generally low (less than 0.20% and 0.06% respectively), with a sixfold increase in the rhizosphere of the polluted soil. Our results suggest that maize cultivation in a polluted vineyard soil could increase the potentially available fraction of copper. DGTs showed a good sensitivity to soil properties and to root-induced changes in the rhizosphere, but the potentially bioavailable copper could not be related to the copper concentration in the above ground parts of maize. The results suggest that DGT may be used to predict some effects of the cultivation of polluted soils, for example, metal mobility and increased availability, but they cannot mimic the uptake of a tolerant plant.

For both soils, dissolved organic carbon (DOC) concentrations were threefold higher in the rhizosphere than in the bulk soil, whilst bioaccumulation in leaves and roots was not significant. DOC production, usually effective in ion mobilization and assimilation, may help also in the reduction of Cu uptake at toxic concentrations. The sequestration of available Cu in soil and soil solution by DOC seems to contribute to maize tolerance.     

生活垃圾填埋场封场后种植植物中重金属迁移研究

在上海老港生活垃圾填埋场填埋单元封场的覆盖土中掺混了矿化垃圾种植植物,分析Cd、Pb、Cu、Zn 4种重金属在土壤和植物中的迁移变化,研究表明:(1)覆盖土土质从一般耕作土变成肥沃土壤;覆盖土和种植混合土重金属Cd、Pb、Cu、Zn中Cd、Pb含量相近,但种植土的Cu含量略大于覆盖原土,Zn含量远大于覆盖原土;(2)植物能富集土壤和垃圾中的重金属,木本植物的根部富集重金属的能力强于草本植物,但重金属在草本植物根、茎、叶中的迁移速度大于木本植物;(3)植物根、茎、叶的Cu、Zn含量均远大于未受污染土壤种植植物相应部位的Cu、Zn含量,种植的植物不能供家养动物食用,以免通过食物链作用危及人体安全.