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目前国内对于联苯菊酯在土壤中降解的相关因子的研究甚少,为了进一步加强联苯菊酯自然降解机制的研究,设置不同施药浓度,研究了联苯菊酯土壤中的动态残留以及微生物的生物降解,建立了一套适用于测定联苯菊酯在土壤中的残留量的气相色谱分析方法。研究结果表明,联苯菊酯在土壤中的降解动态规律符合一级动力学模型,且联苯菊酯是在土壤中残效期比较长的一类农药,易造成环境污染。微生物参与的生物降解有利于联苯菊酯在土壤中的降解,随着施药浓度增加,生物降解作用越明显。土壤中联苯菊酯浓度与降解半衰期的数值呈明显正相关,浓度越高,降解时间越长,建议科学使用农药,减少环境污染。 相似文献
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尽管我国从1983年就开始禁用有机氯农药，但环境中仍有大量残留存在。土壤中污染物的残留是吸附、降解和迁移等各种理化作用和生物作用的综合结果，其中降解是制约其残留量的关键过程。大量研究表明，影响土壤中农药降解的主要环境因素包括土壤有机质、土壤温度、土壤pH和土壤含水量等，因为这些因素显著影响着土壤微生物的数量和活性。微生物代谢所需的营养物质有一部分来自农药和土壤有机质，土壤中微生物对其降解起着重要作用。胡敏酸（HA）是土壤有机质的主要组分，因此以HA代表土壤有机质对农药降解的影响是合理的，也有很多关于HA对农药在土壤中吸附等环境行为影响的研究报道。 相似文献
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<正> 土壤对农药及一些有关的有机物质都有一定程度的保留作用。这种保留作用是影响农药的挥发、淋溶、降解及其在环境中的最终归宿的主要过程。因此,认识土壤保留农药的机制以及影响保留的各种因素,对于评价农药对环境的影响是非常重要的。然而,土壤对农药的保留过程中实际发生的键合机制很少有人进行阐明或证明。目前尚缺乏能够用来描述和区别土壤对有机残留物的各种保留机制或每种保留机制所起作用的程度的试验研究方法。 相似文献
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两种环境激素类农药及其混合剂在土壤中的降解研究 总被引：1，自引：0，他引：1
为了深入了解环境激素类农药在与其它多种农药同时存在条件下在土壤中的降解过程、阐释其机理,用室内培养的方法,研究氯氰菊酯、毒死蜱两种农药及其混合剂在灭菌和未灭菌土壤中的降解特征。结果表明,两种农药及其混合剂在土壤中的降解是微生物主导的过程;灭菌土壤中,混合剂中各农药组分与其单独存在降解过程基本一致,均符合单室模型C=C0e-kt,降解半衰期也与其单独存在相近;但在未灭菌土壤中,混合剂中各农药组分降解特点与其单独存在有所不同。两种农药单独存在时,氯氰菊酯、毒死蜱在未灭菌土壤中的降解方程均符合单室模型,降解半衰期分别为31.5 d和57.8 d;混合剂中各组分农药在未灭菌土壤中的降解过程符合双室模型C=C1e-αt+C2e-βt,不同阶段降解半衰期不同,氯氰菊酯前期和后期半衰期分别为33.0 d和53.3;而毒死蜱前期和后期的半衰期则分别为63.0 d和86.6 d。在未灭菌土壤中多种农药存在时各种农药降解均呈现先快后慢的特点。 相似文献
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有机磷农药污染土壤的微生物降解研究进展 总被引：3，自引：1，他引：3
有机磷农药是目前我国使用量最大的农药之一,严重污染环境和生态系统,并通过食物链在生物体内富集,进而危害人类健康。微生物降解技术具有降解效率高、代谢途径多、无二次污染的优势,是目前清除环境中有机磷农药的主要手段,能有效降低有机磷农药的危害。目前有机磷农药的降解微生物主要是通过实验室纯培养方法获得,与自然生态环境中存在的降解功能性微生物信息差异较大,而利用不可培养方法识别功能性微生物的技术具有广阔的应用前景。本文从有机磷农药的使用情况及引发的环境问题出发,概述了有机磷农药在土壤中的迁移转化途径,稳定同位素探测技术和磁性纳米材料等不可培养方法对有机磷农药降解功能性微生物的识别,微生物降解有机磷农药污染土壤的功能基因、降解途径及降解机理;探讨了植物–微生物联合修复在有机磷农药污染土壤修复中的作用,并分析了环境因子及农药自身性质对有机磷农药降解的影响;最后,讨论了微生物降解技术存在的问题及今后研究方向。 相似文献
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《土壤与作物》2012,(2)
土壤-植物系统是地球陆地表层生态系统中非常重要的亚系统,对保障粮食安全与人体健康发挥着关键作用。持久性有机污染物是土壤环境中难降解、长残留的毒害污染物。这类有机污染物在土壤组分、土壤微生物和植物的共同作用下,发生着一系列的物理化学与生物学的界面过程,导致其或者生物有效性的降低和毒性的下降,或者快速降解,进而减少在食物链中传递的风险,达到自然条件下土壤污染净化,实现自修复。以多氯联苯为例,综述了农田土壤-植物系统中持久性有机污染物的土壤组分界面过程、根际界面过程和植物体微界面过程研究进展,提出了发挥土壤-植物系统降解净化作用,实现持久性有机污染物自修复的新思路。参30。 相似文献
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数学模式在农业环境保护中的应用——土壤中农药降解的定量预测 总被引：2，自引：0，他引：2
本文综述了影响土壤中农药降解的因素及土壤中农药降解的定量预测方法,并对各种影响因素的作用机制及定量化作了简要说明。同时阐述了几种常见的用于预测农药在土壤中降解的数学模型及其适用性。 相似文献
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采用室内模拟实验方法,以太湖水稻土、江西红壤和东北黑土为代表性土壤,研究了噻虫啉等3种烟碱类杀虫剂在土壤中的降解、吸附特性,并利用GUS（Ground Ubiquity Score）指数分析了其对地下水污染的影响。结果表明,3种烟碱类杀虫剂在3种土壤中均较易降解,降解半衰期在5～31d之间,属于易降解农药,降解特性与土壤理化性质及农药本身性质有关。3种烟碱类杀虫剂在江西红壤、太湖水稻土与东北黑土中的吸附较好地符合Freundlich方程,Kd值在0.30～14.70之间,KOC在42.8～1750.9之间,属难吸附农药。吸附性强弱与农药本身溶解性和土壤有机质含量有关,水溶性越强吸附越弱,有机质含量越高,吸附性越强。3种烟碱类杀虫剂在太湖水稻土中的GUS值均小于1.8,而在江西红壤中,其GUS值均大于1.8,这3种杀虫剂在江西红壤中均有一定的淋溶性,对地下水均有一定的污染风险。 相似文献
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Factors influencing degradation of pesticides in soil 总被引：3，自引：0，他引：3
Degradation and sorption of six acidic pesticides (2,4-D, dicamba, fluroxypyr, fluazifop-P, metsulfuron-methyl, and flupyrsulfuron-methyl) and four basic pesticides (metribuzin, terbutryn, pirimicarb, and fenpropimorph) were determined in nine temperate soils. Results were submitted to statistical analyses against a wide range of soil and pesticide properties to (i) identify any commonalities in factors influencing rate of degradation and (ii) determine whether there was any link between sorption and degradation processes for the compounds and soils studied. There were some marked differences between the soils in their ability to degrade the different pesticides. The parameters selected to explain variations in degradation rates depended on the soil-pesticide combination. The lack of consistent behavior renders a global approach to prediction of degradation unrealistic. The soil organic carbon content generally had a positive influence on degradation. The relationship between pH and degradation rates depended on the dominant mode of degradation for each pesticide. There were positive relationships between sorption and rate of degradation for metsulfuron-methyl, pirimicarb, and all acidic pesticides considered together (all P < 0.001) and for dicamba and all bases considered together (P < 0.05). No relationship between these processes was observed for the remaining seven individual pesticides. 相似文献
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An environmental fate study was performed analyzing the effects of soil composition on the soil photolysis of a chemical. The study was conducted in two phases in which both moist and air-dried soils were fortified with either the common fertilizer sodium nitrate or the natural soil components iron or humic acid and dosed with niclosamide. The soils were photolyzed under a xenon lamp for 7 days. Increasing concentration of sodium nitrate did not affect the degradation pattern but did produce a lower concentration of aminoniclosamide. Soils fortified with iron displayed an unknown, which was not observed in other experiments, and the degradation of niclosamide from these soils was slower than from the sodium nitrate-fortified soils. There were no extractable degradates from any of the soils fortified with humic acid. In irradiated moist soils, the half-life of niclosamide increased when sodium nitrate was present at 20 ppm, and the half-lives of niclosamide in iron- and humic acid-fortified soil were increased slightly over that in unfortified soil. The effect of the nitrate and iron on the half-lives in dark control moist soils was minimal, but humic acid increased the dark control half-life from 420 to 611 h. No transformation of niclosamide was observed in the dark control air-dried soils. Soils with higher organic or iron contents or exposed to fertilizers do not affect as dramatically the half-life of pesticides as does the presence of moisture in the soil. Soil photolysis samples that were not maintained with moisture exhibited differences in half-life and degradation pattern. The maintenance of moisture was found to be more crucial to the reliability of soil photolysis studies than soil composition. 相似文献
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Previously isolated bacterial strains for chlorpyrifos and fenamiphos degradation were used to examine their potential as bioremedial agents in soils and water containing pesticide residues. Both, chlorpyrifos-degrading Enterobacter sp and fenamiphos-degrading consortium rapidly degraded pesticides when inoculated into natural and sterile water and soils. Degradation rate was slower in lower pH soils in comparison with natural and alkaline soils. Soil organic matter had no impact on pesticide degrading ability of isolates. Soil moisture <40% of maximum water-holding capacity slowed down degradation rate. The bacterial isolates were able to rapidly degrade fenamiphos and chlorpyrifos between 15 and 35 °C but their degradation ability was sharply reduced at 5 and 50 °C. Both groups of bacterial systems were also able to remove a range of pesticide degradation. An inoculum density of 104 cells g−1 of soil was required for initiating rapid growth and degradation. Ageing of pesticide in soils prior to inoculation produced contrasting results. Ageing of fenamiphos had no impact on subsequent degradation by the inoculated consortium. However, degradation of chlorpyrifos by Enterobacter sp after aging resulted in persistence of ∼10% of pesticide in soil matrix. Higher Koc value of chlorpyrifos may have resulted in a lack of bioavailability of a smaller percentage of chlorpyrifos to degrading bacteria. Overall, this paper confirms bioremedial potential of a fenamiphos degrading consortium and a chlorpyrifos degrading bacterium under different soil and water characteristics. 相似文献
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树的年轮和土壤中元素含量的长期分布情况 总被引：19，自引：0，他引：19
Soil erosion accelerates soil degradation. Some natural soils and cultivated soils on sloping land in southern Jiangsu Province, China were chosen to study soil degradation associated with erosion. Soil erosion intensity was investigated using the ^137Cs tracer method. Soil particle-size distribution, soil organic matter (OM), total nitrogen (TN) and total phosphorus (TP) were measured, and the effects of erosion on soil physical and chemical properties were analyzed statistically using SYSTAT8.0. Results indicated that erosion intensity of cultivated soils was greater than that of the natural soils, suggesting that cultivation increased soil loss. Erosion also led to an increase of coarser soil particle proportion, especially in natural soils. In addition, silt was the primary soil particle lost due to erosion. However, in cultivated fields, coarser soil particles over time were attributed not only to soil erosion but also to mechanical eluviation as a result of farming activities. Moreover, erosion caused a decrease in soil OM, TN and TP as well as thinning of the soil layer. 相似文献
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D. Levanon J. J. Meisinger E. E. Codling J. L. Starr 《Water, air, and soil pollution》1994,72(1-4):179-189
The impact of two tillage systems, plow tillage (PT) and no-tillage (NT), on microbial activity and the fate of pesticides in the 0–5 cm soil layer were studied. The insecticides carbofuran and diazinon, and the herbicides atrazine and metolachlor were used in the study, which included the incubation and leaching of pesticides from untreated soils and soils in which microorganisms had been inhibited. The mineralization of ring14C labeled pesticides was studied. The study differentiated between biotic and abiotic processes that determine the fate of pesticides in the soil. Higher leaching rates of pesticides from PT soils are explaned by the relative importance of each of these processes. In NT soils, higher microbial populations and activity were associated with higher mineralization rates of atrazine, diazinon and carbofuran. Enhanced transformation rates played an important role in minimizing the leaching of metolachlor and carbofuran from NT soils. The role of abiotic adsorption/retention was important in minimizing the leaching of metolachlor, carbofuran and atrazine from NT soils. The role of fungi and bacteria in the biodegradation process was studied by selective inhibition techniques. Synergistic effects between fungi and bacteria in the degradation of atrazine and diazinon were observed. Carbofuran was also degraded in the soils where fungi were selectively inhibited. Possible mechanisms for enhanced biodegradation and decreased mobility of these pesticides in the upper layer of NT soils are discussed. 相似文献
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侵蚀引起的苏南坡地土壤退化 总被引：5，自引：0，他引：5
Soil erosion accelerates soil degradation. Some natural soils and cultivated soils on sloping land in southern Jiangsu Province, China were chosen to study soil degradation associated with erosion. Soil erosion intensity was investigated using the 137Cs tracer method. Soil particle-size distribution, soil organic matter (OM), total nitrogen (TN) and total phosphorus (TP) were measured, and the effects of erosion on soil physical and chemical properties were analyzed statistically using SYSTAT8.0. Results indicated that erosion intensity of cultivated soils was greater than that of the natural soils, suggesting that cultivation increased soil loss. Erosion also led to an increase of coarser soil particle proportion, especially in natural soils. In addition, silt was the primary soil particle lost due to erosion. However, in cultivated fields, coarser soil particles over time were attributed not only to soil erosion but also to mechanical eluviation as a result of farming activities. Moreover, erosion caused a decrease in soil OM, TN and TP as well as thinning of the soil layer. 相似文献
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Kate L. Baker Samantha Marshall Colin D. Campbell Gilles Nicollier Kenneth Killham 《Soil biology & biochemistry》2010,42(7):1123-1131
Rates of degradation of pesticides by soil microorganisms are believed to depend on both microbial community composition and underlying soil physicochemical characteristics. The aim of this study was to determine which of these factors was more important in determining the rate of degradation of the fungicide metalaxyl-M in two soils. Soils exhibiting highly contrasting metalaxyl-M degradation rates were sterilised by gamma-irradiation and inoculated with either non-sterilised soil from the same site or with the soil from the contrasting site. After re-establishment of microbial communities, soils were treated with metalaxyl-M and the degradation rate (measured by 14C-HPLC), pH and microbial community structure (multiplex terminal-restriction fragment length polymorphism (T-RFLP) analysis of small subunit rRNA gene sequences) were assessed. Community composition was altered by the sterilisation and re-inoculation strategy but degradation in re-inoculated soils was still most rapid in the soil with the original faster degradation rate. This was the case regardless of the source of the soil inoculum, and the rate of degradation in the soil exhibiting the low natural degradation rate remained low when inoculated with the faster-degrading soil. The results suggest that while the slower-degrading soil possessed a degradative capacity, the degradation rate in this soil was significantly reduced by some of its physicochemical characteristics, despite introduction of the microbial community of the faster-degrading soil. These results and this experimental strategy provide a basis for the assessment of relative importance of the factors limiting biodegradation and management strategies required to enhance degradation rates. 相似文献