几种多环芳烃的植物吸收作用及其对根系分泌物的影响

采用水培试验方法,以多年生黑麦草(Lolium multiflorum Lam.)为供试植物,研究了芘、菲、苊和萘的植物吸收作用及其对根系分泌物的影响.结果表明,黑麦草能明显吸收富集多环芳烃(PAHs);随培养液中PAHs浓度的升高,其在黑麦草根和茎叶中的含量增大,且根的PAHs含量、富集系数要远大于茎叶.芘、菲、苊、萘污染胁迫下,黑麦草根系分泌物中可溶性有机碳、草酸和可溶性总糖的含量均高于无污染对照.供试污染浓度范围内,随着培养液中菲、苊、萘浓度提高,可溶性有机碳、草酸及可溶性总糖的分泌量增大;但在芘胁迫下,与污染对照相比,分泌量的增加幅度随着芘浓度的升高则呈先增大后减小的趋势.在较低污染强度下,供试PAHs对根系分泌物的促分泌效应由强到弱依次为芘、菲、苊和萘.4种PAHs对可溶性糖类的促分泌作用最强,其分泌量的增加幅度明显大于可溶性有机碳和草酸.     

植物多酚改性膨润土吸附重金属镉实验研究

对钙基膨润土、酸活化膨润土、自制单宁酸改性膨润土,通过表征测试研究了膨润土改性后的形态结构变化。结果表明:单宁酸改性膨润土较钙基膨润土结构未发生较大变化;并分别探讨了不同投加量、反应pH及不同初始浓度对单宁酸改性膨润土吸附镉的影响。实验表明:单宁酸改性膨润土对Cd2+的吸附性能优于钙基膨润土及酸活化膨润土,在材料用量越小及反应pH越低时,单宁酸对膨润土吸附Cd2+的促进作用越明显。单宁酸改性膨润土对Cd2+的吸附能用Langmuir吸附方程进行描述,其最大吸附量约为31.25mg/g,比钙基膨润土提高了20.6%。本研究将为非金属矿物在水体及土壤重金属污染修复方面的应用提供理论基础和科学依据。     

生物除磷机理与数学模型的探讨

概述了生物除磷在厌氧、缺氧和好氧条件下的反应机理，并基于对反硝化聚磷力的认识将现有除磷数学模型发展划分为两个阶段。基于除磷数学模拟所包含的涉磷组分、计量学参数、动力学参数以及生物衰减理论等对两阶段模型进行了较为详细的介绍和比较，认为Delft模型是现有模型中比较完善的，并提出今后发展除磷数学模型应重点解决的问题。     

人工湿地中常用填料和植物对污染物去除效果的比较

人工湿地工艺作为一种优选技术应用于流域规模的污染水处理。在此,根据人工湿地中常用填料和植物的物理、化学属性,分析其优缺点及适用性,总结出对氮、磷和COD处理效果较好的填料和植物,并提出了一系列综合优化的措施和建议。     

伊乐藻和氮循环菌技术对太湖氮素吸收和反硝化的影响

从太湖梅梁湾采集无扰动泥芯样,分别添加固定化氮循环细菌、水生植物伊乐藻建立室内微宇宙,模拟生态修复,探讨不同修复处理下,硝氮的去除机制.采用15N标记结合同位素配对技术测定了各生态模拟柱中的反硝化速率和植物吸收速率.结果表明,不同处理的实验柱反硝化速率差异明显,同时添加了水生植物和固定化氮循环细菌的实验柱反硝化速率最高,为99.35μmol·(m2·h)-1,植物氮吸收速率为36.55μg·(m2·h)-1.沉水植物伊乐藻在自身吸收氮素的同时也提高了耦合硝化反硝化的作用.与植物吸收相比,反硝化过程是主要的氮去除途径.沉水植物与固定化氮循环菌组合生态修复技术促进了湖泊水体氮素的脱除,起到了净化作用.     

人为扰动背景下城郊溪流底质磷的生物-非生物吸收潜力分析

为揭示土地利用变化对城郊溪流底质磷吸收的影响,2016年6~11月在合肥市城市边缘某一源头溪流逐月采集溪流底质样,利用实验培养法分析人为扰动背景下溪流底质磷的生物与非生物吸收潜力及其变化特征.结果表明:底质磷的总吸收潜力和非生物吸收潜力都表现为夏季高于秋季;毗邻排污口的3号采样点沉积物磷的总吸收潜力和非生物吸收潜力明显高于其它各采样点;无论是夏季还是秋季,6个采样点位底质磷的生物吸收贡献率都低于相应的非生物吸收贡献率,而且彼此之间差异十分明显;各采样点底质磷的吸收潜力、吸收贡献率的逐月变化态势,表明土地利用变化引发的强烈人为扰动对溪流底质磷的生物吸收影响很大.     

养分(磷)吸收机理模型的应用研究──Ⅲ.定量评价适应机制对玉米与大豆幼苗P吸收的作用

采用Claassen的养分吸收机理模型定量评价了不同土壤条件下,机理模型中未考虑的其它适应机制对玉米与大豆幼苗P吸收的作用。结果表明：同样土壤养分胁迫条件下,供试玉米与大豆幼苗的其它适应机制对P吸收的贡献率分别为1/4与1/5;土壤养分胁迫、土壤水分胁迫、土壤供N形态、土壤性质及土壤供Ca水平或pH值对这一P吸收适应机制的作用程度均有一定的影响,土壤水分胁迫能明显加强这一适应机制对玉米幼苗P吸收的作用;粘质棕红壤上养分胁迫与水分胁迫同时作用时,这一适应机制对玉米幼苗P吸收的贡献率可达69％。     

Persistence and Distribution of Endosulfan under Field Condition

Rapid increase in industrialization and agricultural activities to meet the population need has led to environmental pollution. The major revolution in agricultural production is mainly due to increased use of pesticides and fertilizers. Soil act as a major sink for majority of pesticides applied on agricultural crops. Among the organochlorines, endosulfan is the most commonly used pesticide, hence this study concentrates on the persistence and distribution behaviour of endosulfan under field conditions. The result showed that the alpha endosulfan concentrations were very minimum (0.98 mg/kg of soil) in all the four fields under study (Nazarath, Othikadu, Ekkadu and Ekkadukandigai of Thiruvallur district, Tamil Nadu). Where as beta endosulfan concentration at the time of application was 6.39 mg/kg and declined to 0.8 mg/kg on soil at 150th day. The endosulfan sulfate concentration was 11.8 mg/kg in soil at 15th day and then concentration declined to 2.2 mg/kg at 150th day. Field run-off samples showed maximum residue levels (0.024 mg/l) at the early irrigation period. While plant foliar parts showed maximum concentrations of α-endosulfan (43.4 mg/kg), β-endosulfan (40.6 mg/kg) and endosulfan sulfate (20.1 mg/kg). At harvest stage, rice grain and husk also had lower concentrations of endosulfan sulfate (2.2 and 0.09 mg/kg), respectively.     

基于稻草还田的稻田生态系统N素吸收特性研究

采用田间试验研究了稻草还田环境下施N模式对稻田生态系统N素吸收量及N肥利用率的影响.结果表明:稻草还田配施N肥能显著提高水稻N素吸收转化功能,且高量常规N处理下尽管水稻N素吸收量增多,但只有一定量N素能转移到穗部,其余则仍然留存在营养器官中.所有处理N肥的吸收利用率为26.7%～30.7%、农学利用率为10.5～12.2 kg·kg-1,N肥利用率较低,且随着施N量增加呈下降趋势.随着与稻草配合施用,N肥利用率各指标中除吸收利用率略有下降外,其他各指标(包括农学利用率、生理利用率和偏生产力)均有一定程度提高.根据稻田作物N素吸收转化状况与N肥利用率,在全年稻草还田量为7 500 kg·hm-2的红壤稻田系统,建议全年适宜配施N量为185 kg·hm-2.     

Determination of lead, cadmium and copper in roadside soil and plants in Elazig, Turkey

The concentrations of lead, cadmium and copper in roadside soil and plants in Elazig, Turkey were investigated. Soil samples were collected at distances of 0, 25 and 50 m from the roadside. The concentrations of lead, cadmium and copper were measured by Flame Atomic Absorption Spectrophotometry (FAAS). A slotted tube atom trap (STAT) was used to increase the sensitivity of lead and cadmium in FAAS. Lead concentrations in soil samples varied from 1.3 to 45 mg kg⁻¹ while mean lead levels in plants ranged from120 ng g⁻¹ for grape in point-4 to 866 ng g⁻¹ for apple leaves in point-2. Lead analyses showed that there was a considerable contamination in both soil and plants affected from traffic intensity. Overall level of Cd in soil samples lies between 78 and 527 ng/g while cadmium concentration in different vegetations varied in the range of 0.8–98.0 ng g⁻¹. Concentrations of copper in soil and plant samples were found in the range of 11.1–27.9 mg kg⁻¹ for soil and 0.8–5.6 mg kg⁻¹ for plants. Standard reference material (SRM) was used to find the accuracy of the results of soil analyses.