氯唑磷在土壤中的降解性能与移动性研究

在实验室与野外田间状态下，研究了氯唑磷农药在砂土，砂壤土及粘壤土中的降解特性，降解速率依次为：砂壤土〉粘壤土〉矿土；其降解半衰期分别为４７．２、５９．８和６７．３ｄ。     

黑河中游边缘荒漠-绿洲非饱和带土壤质地对土壤氮积累与地下水氮污染的影响

在灌溉农田生态系统,土壤剖面中硝态氮(NO-3-N)的积累、分布、运移及地下水氮污染不仅受灌溉、施肥的影响,也与土壤质地有密切联系.本研究在黑河流域中游临泽平川绿洲设置了黑河河漫滩-老绿洲农田-新垦绿洲农田-绿洲外围固沙带一个监测断面10个观测井,对地下水NO-3-N含量进行连续监测,并对不同景观单元非饱和带土壤质地和NO-3-N含量进行了分析,对不同质地土壤NO-3-N在剖面的运移变化和氮淋溶损失进行监测.结果表明老绿洲农田,0~300 cm土层土壤质地的垂向分布为上层砂壤土,下层为壤土和黏壤土;而新垦沙地农田在土壤剖面中也有洪积黏土层出现,但0~300 cm不同土层砂粒含量均在80%以上;绿洲外围固沙带土壤在160 cm以下出现黏土层分布;土壤NO-3-N含量与黏粉粒含量呈显著相关,显著程度固沙带>新垦绿洲农田>老绿洲农田.土壤黏粉粒含量显著影响氮的淋溶.老绿洲农田区域,地下水NO-3-N含量变动在1.01~5.17 mg·L-1,平均2.65 mg·L-1;新垦沙地农田区域地下水NO-3-N含量变动在6.6~29.5 mg·L-1,平均20.8mg·L-1,2013年5~10月平均含量为26.5 mg·L-1,较2012年同期平均值上升了9.5 mg·L-1;绿洲外围固沙带地下水NO-3-N含量呈明显的增加趋势.地下水浅埋区非饱和带土壤质地是土壤NO-3-N淋溶损失和地下水NO-3-N污染的关键控制因子.边缘绿洲新垦沙地农田是地下水氮污染的脆弱带和高风险区域,实施有效降低地下水氮污染的种植模式及施肥和灌溉管理是区域生态农业需考虑的问题.     

TX100悬浮的多壁纳米碳管在土壤中运移及其对菲迁移的影响

采用柱淋溶实验研究了TX100悬浮的多壁纳米碳管在土柱中的淋溶行为及其对菲在土壤中迁移的影响,并用胶体运移的一级动力学对流-弥散模型对纳米碳管在土柱中的迁移能力进行了估算.实验结果表明,在砂土和粉砂壤土中分别有83.5%和73.4%的多壁纳米碳管能够穿透土柱,模型估算的最远迁移距离均大于200cm,说明多壁纳米碳管有向...     

Effects of phosphate on the adsorption of glyphosate on three different types of Chinese soils

Glyphosate （GPS） is a non-selective, post-mergence herbicide that is widely used throughout the world. Due to the similar molecular structures of glyphosate and phosphate, adsorption of glyphosate on soil is easily affected by coexisting phosphate, especially when phosphate is applied at a significant rate in farmland. This paper studied the effects of phosphate on the adsorption of glyphosate on three different types of Chinese soils including two variable charge soils and one permanent charge soil. The results indicated that Freundlich equations used to simulate glyphosate adsorption isotherms gave high correlation coefficients（0.990-0.998） with K values of 2751, 2451 and 166 for the zhuanhong soil（ZH soil, Laterite）, red soil（ RS, Udic Ferrisol） and Wushan paddy soil（WS soil, Anthrosol）, respectively. The more the soil iron and aluminum oxides and clay contained, the more glyphosate adsorbed. The presence of phosphate significantly decreased the adsorption of glyphosate to the soils by competing with glyphosate for adsorption sites of soils. Meanwhile, the effects of phosphate on adsorption of glyphosate on the two variable charge soils were more significant than that on the permanent charge soil. When phosphate and glyphosate were added in the soils in different orders, the adsorption quantities of glyphosate on the soils were different, which followed GPS-soil 〉 GPS-P-soil = GPS-Soil-P 〉 P-soil-GPS, meaning a complex interaction occurred among glyphosate, phosphate and the soils.     

Nitrification potentials of Chinese tea orchard soils and their adjacent wasteland and forest soils

To investigate the nitrifying activities of di erent soil types, soil samples collected from 8-, 50- and 90-year old tea orchards, the adjacent wasteland, and 90-year old forest were measured for their nitrification potentials using the conventional soil incubation and the liquid incubation method. Among di erent soil types, the nitrification potential of soil in tea orchards was higher than that of wasteland and forest soils. The slurry shaken liquid incubation method was confirmed to be more accurate and have reliable results than the soil incubation. Interestingly, experimental result revealed that the generally applied pH value of 7.2 for the liquid media was not the optimal pH for these acid soils with a strong bu er capacity. This suggested that tea orchard soils may have nitrifiers requiring pHneutral condition for the best activity. Our data also showed that treatment with the commonly used nitrogen fertilizer urea significantly improved nitrification potential of the soils; such enhancement e ect was stronger on all of three tea orchard soils than on wasteland and forest soils, and also stronger on the younger (8- and 50-year old) tea orchard soils than on the older one (90-year old).     

三环唑在稻-土-水体系中的持留、迁移变化

采用田间试验与模拟试验相结合,研究了二环唑在南方稻区稻-土-水体系中的残留与迁变。结果表明,三种土壤吸附性能,海涂土最差,小粉土与青紫泥相差不大。三环唑在海涂土和小粉土上渗漏性有明显差异,吸附性差的海涂土渗漏速率大;不同淋洗水量对海涂土渗漏性影响随淋洗量增加而增大,在田间实际用药水平下,三环唑能够纵向渗漏至地下水,渗漏特性为海涂土>小粉土>青紫泥;三环唑还能够通过地表水流失横向迁移到周围池塘水中,速度较纵向渗漏快。室内控制条件下,水稻秧苗能够吸收土-水体系中的农药,且吸收量与水中农药浓度呈正相关,达极显著水平(0.01水平)。三环唑残留量采用凝结法净化,GC-FPD(S-型)检测。     

模型模拟土壤性质和植被种类对再生水灌溉水盐运移的影响

为推动再生水安全灌溉,本研究运用ENVIRO-GRO模型模拟了不同土壤性质、植被条件下土壤盐分的分布规律及累积趋势,探讨了土壤性质和植被种类对再生水灌溉水盐运移的影响.研究发现,不同土壤初始含盐量下,经多年重复模拟后最终达到统一的平衡状态;而不同土壤质地下,随着灌溉年份的增加,壤土、黏壤土中的土壤ECe年均值逐渐增加直到平衡,砂壤土中的土壤ECe年均值逐渐减少直到平衡,平衡时土层中的ECe值砂壤土〈壤土〈黏壤土.3种植被下,大叶黄杨、油松的土壤ECe值增加量小于早熟禾;土壤盐分在土层中的空间、时间分布也均有所不同.此外,不同模拟情景下,土壤盐分累积都不会影响植被的生长（黏壤土除外）,但均出现轻度盐渍化（砂壤土除外）.     

氨氮在饱水粉砂土和亚砂土层中吸附过程及其模拟

为在土地处理中选择合适保护土层厚度,防止ＮＨ４对地下水污染,通过动态土柱试验,了ＮＨ４在饱和粉砂土层和亚砂土层中的吸附和Ｃａｍｅｒｏｎ平衡＝动态吸附模型模拟了ＮＨ４在土层中的迁移过程,求得了不同土层和不同浓度条件下模型的各参数值,并求解出不同时刻,不同氨氮浓度条件下的沿程ＮＨ４浓度分布曲线。研究表明,在条件下,粉砂土和砂土的从向弥散系数分别为０．１７５和０．００９３ｃｍ＾２／ｍｉｎ;当水中氨氮浓度     

我国典型土壤对病毒等温静态吸附的数值模拟

通过室内等温静态批量平衡吸附实验,采用3种常见的等温线（Freundlich方程、Langmuir方程和Temkin方程）对2种病毒（MS2和X174）在2种处理（非灭菌和灭菌）条件下的6种土壤（红壤土、红粘土、乌栅土、黄泥土、沙质潮土和壤质潮土）中的吸附行为进行了回归拟合.实验结果和模拟结果均表明,土壤性质、病毒性质、土壤中的土著微生物对病毒在土壤中吸附行为均具有重要的影响.红粘土对MS2和X174的平均吸附比例几乎能达到100％,而2种潮土（沙质潮土和壤质潮土）相对较弱;总体来看土壤对X174的吸附能力高于MS2,但灭菌后的土壤对MS2的吸附能力却高于X174.在数值模拟中,Freundlich方程和Langmuir方程均具有理想的相关性.Freundlich方程能够表现出病毒浓度对其在土壤中吸附行为的影响;尽管Langmuir方程能够应用于土壤对病毒吸附能力的比较,但本研究中不能应用Langmuir方程来计算土壤对病毒的最大吸附量.     

沙土不同粒径微团聚体对磷的富集特征

流失的水土是污染物的重要载体,为估算沙土吸附态磷流失量,采用平衡吸附法研究了沙土不同粒径微团聚体对磷的富集特征.结果表明,不同粒径微团聚体对磷的富集系数为:黏粒(3.79)＞粉粒(2.98),沙土中微团聚体对磷的富集作用比较强,其原因有三:细粒级微团聚体中腐殖质含量显著高于粗粒级;细粒级微团聚体中有机质是通过可溶有机质与黏土矿物相互结合形成复合体而富集,在复合体结构中存在孔隙填充方式磷吸附;粘粒和粉粒中的铁铝键有机矿质复合体所占比例显著高于其它粒级,在对磷吸附中发挥重要作用,其吸附机制除孔隙填充方式外,还存在铁铝氧化物及水化氧化物对磷的配位吸附.不同粒径团聚体对磷的吸附分配系数和富集系数均与腐殖质总量呈显著正相关(p＜ 0.01,r分别为0.854和0.954);西辽河流域沙土在暴雨径流中黏粒级和粉粒级冲泻质泥沙所携载的吸附态磷质量分数可分别按1269.15 mg·kg-1和997.53 mg·kg-1估算,黏粒和粉粒级微团聚体对磷的富集系数(Er)可分别按3.79和2.98计算.     

Clomazone dissipation, adsorption and translocation in four paddy topsoils

IntroductionClomazone,(2 [(2 chlorophenyl)methyl ] 4 ,4 dimethyl 3 isoxazolidinone) ,isasoil appliedisoxazolidinoneherbicideproducedbyFMCCorp .Itisintroducedforannualgrassandbroad spectrumweedsinsoybeans(Rani,1998;Vyas,2 0 0 0 ) .Itisalsocurrentlyregis…     

加油站泄漏污染物的迁移分布规律

选择某废弃加油站场地为研究对象,通过采集分析土壤和地下水样品中的铅（Pb）、总石油烃（TPH）、多环芳烃（PAHs）、苯系物（BTEX）、甲基叔丁基醚（MTBE）,分析了污染物在该区域地下环境中的迁移和分布特征.测试结果表明：场地包气带和含水层介质岩性以砂质粉土、粘质粉土和粉质粘土为主,土壤样品中总石油烃（C < 16）和苯均存在超标现象;垂向污染物高浓度值多出现在地下水面附近,其中上层滞水区总石油烃和苯大面积超标,潜水中总石油烃（C < 16）、苯及MTBE超标,承压水尚未被污染.在分析目前石油类污染场地修复技术的基础上,结合场地的实际条件,建议土壤和地下水的修复主要采用异位修复技术.     

黑土不同粒径有机-矿质复合体对镉的吸附特性

采用振荡平衡法研究了黑土不同粒级有机-矿质复合体对Cd2+的吸附等温过程和吸附动力学过程,并采用常见数值模型进行了拟合. 结果表明,原土及各粒级复合体对Cd2+的吸附量随平衡液中ρ(Cd2+)的增加而增加. 各粒级组分对Cd2+的吸附量表现为黏粒＞粉粒＞原土＞粗砂＞细砂. Langmuir和Freundlich方程对Cd2+的等温吸附过程均有较好的拟合效果,线性方程拟合效果较差. 最大吸附量与吸附作用强度均呈随粒径增大而减小的趋势. 对影响最大吸附量和吸附作用强度的因子进行回归分析表明,w(有机质)、CEC(阳离子交换量)和比表面积的影响较大,其中w(有机质)是最主要因素,CEC和比表面积的影响次之. 各粒级复合体对土壤吸附Cd2+的贡献率为粉粒＞细砂＞黏粒＞粗砂,99%的Cd2+吸附在＜200 μm的组分上. 不同粒级组分对Cd2+的吸附动力学过程可分为0~20 min的快速反应阶段（吸附量均达到饱和吸附量的90%以上）和慢速反应阶段. 各组分对Cd2+的吸附符合二级动力学过程,表明吸附过程以化学吸附为主,并且吸附速率随颗粒粒径的增大而减小.      

三唑磷在土壤中的降解与吸附特性

三唑磷农药在江西红壤，河南二合土和东北黑土中均具易降解性，其土壤降解半衰期分别为28．3，3．75、3．28d，降解速率次序为东北黑土〉河南二合土〉江西红壤。土壤对三唑磷的吸附性能强弱次序为：河南二合土〈江西红壤〈东北黑土。其Freundich吸附常数分别为2，17．6，70．100。尽管河南二合土对三唑磷农药的吸附性弱（koc〈300）．且三唑磷的水溶解度〉30mg／kg，但由于三唑磷农药的易土壤降解性，正常施用，其对地下水的实际污染风险较小。     

Changes in the sorption, desorption, distribution, and availability of copper, induced by application of sewage sludge on Chilean soils contaminated by mine tailings

The effect of mine tailings and sewage sludge was evaluated on sorption, desorption, availability and distribution of copper in two soils, one high (sandy soil) and one low in copper (clay soil). In both soils contaminated by mine tailings the copper sorption capacity and the affinity of the substrate for the metal decreased substantially compared to the uncontaminated soils, however, the sorption remained always high in the clay soil substrates. In the substrates with sandy soil, the high Cu content and lower clay content were determining factors in the lower magnitude of the sorption. Similarly, metal desorption was closely related to these two parameters, and it was higher in clay soil with lower pH. In general, the application of sewage sludge favored the sorption of Cu in soils contaminated and uncontaminated with mine tailings, and in all cases desorption decreased, an effect that remained for at least 30 days. Simple extraction of Cu with CaCl2 and diethylenetriaminepentaacetic acid gave contradictory results, so a careful choice of the procedure is required, depending on the level of metal in the soil and on the acting principle of the extracting agent. In that relation, more complete information on the changes in the metal forms was obtained by application of the sequential extraction procedure proposed by the European Community Bureau of Reference.     

电动力学-新型竹炭联合作用下土壤镉的迁移吸附及其机理

研究了土壤中镉在均匀电动力学作用下的迁移特征及其影响因素,以及电场双向切换并加有新型竹炭材料条件下电动力学对镉的去除特性,揭示了利用均匀电动力学-新型竹炭材料联合修复镉污染土壤的特征及其可行性.结果表明,竹炭是一种良好的吸附材料,对镉具有较强的吸附作用,可以用 Freundlich和Langmuir模型很好的模拟吸附过程（R²>0.96）;在电压梯度为1.0 V/cm的条件下,受试土壤中Cd²⁺在均匀电动力学下的迁移速率为0.678 6～0.687 5　cm/h,并且迁移速率大小与Cd²⁺浓度和场强分布有关,电动力场可以有效地迁移土壤中的重金属离子;使用竹炭作为吸附剂的新型工艺中,在与速率实验相同的电压梯度,电场48　h的切换周期下,土壤中镉能够在电场作用下高效迁移至处理区并被吸附去除（12　d去除79.6%）,过程中可以很好地维持土壤的pH和水分条件,过程的电流随切换呈周期性的变化.电动迁移-竹炭吸附作为一种新型工艺具有广泛的应用前景.     

新疆不同质地土壤对石油类污染物的吸附作用

石油类污染物的迁移转化研究对环境保护及人体健康均有重要意义。由于石油类污染物在不同质地土壤中的吸附行为不同,采用静态吸附实验方法,研究了新疆甘泉堡工业区3种质地土壤(粉土、粉砂、粉质黏土)对石油烃的吸附动力学及吸附热力学行为,进行了吸附动力学和等温吸附拟合,并分析了土壤粒径、有机质含量、pH值及以含盐量对石油烃吸附量的影响。结果表明:粉土、粉砂、粉质黏土对石油烃的吸附均能在240 min达到吸附平衡,平衡吸附量分别为0.7765,0.6763,0.7173 mg/g;吸附能力顺序为粉土>粉质黏土>粉砂,准二级动力学模型(R2=0.9967~0.9989)能够更加准确地描述石油烃在土壤中的吸附过程;等温线为Langmuir型,其吸附平衡常数(K_a)分别为0.6126(粉土)、3.1310(粉砂)和0.1180(粉质黏土),表明石油烃在不同质地土壤中的吸附为单分子层吸附;土壤对石油烃的吸附量随土壤粒径和pH值的减小、有机质含量和含盐量的增加而逐渐增大。     

Effects of the new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate and potassium leaching in two soils

In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate (NO3--N) and potassium (K) leaching in the sandy loam soil and clay loam soil. The results showed that DMPP with ammonium sulphate nitrate (ASN) ((NH4)2SO4 and NH4NO3) or urea could reduce NO3--N leaching significantly, whereas ammonium (NH4 -N) leaching increased slightly. In case of total N (NO3--N NH4 -N), losses by leaching during the experimental period (40 d) were 37.93 mg (urea), 31.61 mg (urea DMPP), 108.10 mg (ASN), 60.70 mg (ASN DMPP) in the sandy loam soil, and 30.54 mg (urea), 21.05 mg (urea DMPP), 37.86 mg (ASN), 31. 09 mg (ASN DMPP) in the clay loam soil, respectively. DMPP-amended soil led to the maintenance of relatively high levels of NH4 -N and low levels of NO3--N in soil, and nitrification was slower. DMPP supplementation also resulted in potassium leached less, but the difference was not significant except the treatment ASN and ASN DMPP in the sandy loam soil. Above results indicate that DMPP is a good nitrification inhibitor, the efficiency of DMPP seems better in the sandy loam soil than in the clay loam soil and lasts longer.     

Effects of a new nitrification inhibitor 3,4-dimethylpyrazole phosphate （DMPP） on nitrate and potassium leaching in two soils

In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate （DMPP） on nitrate （NO3^-- N） and potassium （K） leaching in the sandy loam soil and clay loam soil. The results showed that DMPP with ammonium sulphate nitrate （ASN） （（NH4）2SO4 and NHaNO3） or urea could reduce NO3^--N leaching significantly, whereas ammonium （NH4^＋-N） leaching increased slightly. In case of total N （NO3^--N＋NH4^＋-N）, losses by leaching during the experimental period （40 d） were 37.93 mg （urea）, 31.61 mg （urea＋DMPP）, 108.10 mg （ASN）, 60.70 mg （ASN＋DMPP） in the sandy loam soil, and 30.54 mg （urea）, 21.05 mg （urea＋DMPP）, 37.86 mg （ASN）, 31.09 mg （ASN＋DMPP） in the clay loam soil, respectively. DMPP-amended soil led to the maintenance of relatively high levels of NH4^＋ -N and low levels of NO3^--N in soil, and nitrification was slower. DMPP supplementation also resulted in less potassium leached, but the difference was not significant except the treatment of ASN and ASN＋DMPP in the sandy loam soil. Above results indicate that DMPP is a good nitrification inhibitor, the efficiency of DMPP seems better in the sandy loam soil than in the clay loam soil and lasts longer.     

Impact of Drip Irrigation Method,Soil, and Virus Type on Tomato and Cucumber Contamination

The goal of this study was to better quantify the degree of viral contamination of tomato and cucumber in relationship to virus type, soil type, and irrigation method. Tomatoes and cucumbers were grown in ten-gallon (37.8 L) buckets filled with Pima clay loam or Brazito sandy loam soils. Plants were irrigated with secondary wastewater effluent using surface drip irrigation or subsurface drip irrigation. At specified time intervals irrigation water was seeded with bacteriophages MS-2 and P22, poliovirus type 1 (PV1), enteric adenovirus 40 (Ead 40), and hepatitis A virus. Surface drip irrigation always resulted in viral contamination of both the above and below ground parts of both crops. The roots showed the greatest level of contamination, followed by leaves and fruits. In contrast, with subsurface drip irrigation no viruses were detected in any of the above ground plant surfaces. It was found that under similar soil type and irrigation method, risk of crop contamination was similar for all of the viruses studied. It can be concluded that method of irrigation is the single most critical factor in the contamination trend of different parts of crop plants. Plant parts can be categorized into three groups (root, stem, and leaf/fruit) based on the risk of viral contamination from irrigation water.