云南阳宗海砷污染水平、变化趋势及风险评估

云南阳宗海砷污染事件引起社会广泛关注.为了解事件发生后阳宗海砷污染水平及变化趋势,分别于2008年12月、2009年2月、5月及9月四次采样,研究了阳宗海湖水、底泥、周边井水、土壤、农作物及水生生物中的砷含量及其变化趋势.研究结果显示:湖水平均砷浓度分别为176.9、147.3、159.3和161.1μg/L(算术平均),底泥平均浓度分别为32.87、62.41、62.99和46.96μg/g(算术平均).阳宗海湖水砷浓度经历了先升后降再到平稳的变化过程,底泥砷含量迅速升高后缓慢下降,湖水和底泥间砷交换还在进行.阳宗海附近土壤中砷最高浓度为23.33μg/g,未超过国家土壤环境质量三级标准.大米、玉米、花椰菜、小油菜等农作物可食用部分中砷的最高值为0.35μg/g,均未超过国家无公害食品标准.水生植物中砷水平大多在100～200μg/g之间,最高为苦草,砷含量超过300μg/g,说明该植物对砷有一定的富集能力.虾、鱼类等可食用水生动物砷浓度范围为1.52～11.4μg/g.     

日本遗弃化学武器污染土壤中砷的形态分析方法研究

土壤中无机砷的污染比较普遍,有机砷的污染情况比较特殊,处理日本遗弃在华化学武器(JACW)过程中与化学武器接触的土壤往往有机砷的污染比较严重,有时总砷含量超过国家标准的数十倍.为了查明污染的来源,必须砷的形态进行分析研究.本文在总砷含量测定的基础上,使用气相色谱-质谱(GC/MS)法对污染土壤砷的形态分析进行了研究,查明了东北某地被JACW污染的土壤中砷化合物的形态,主要含砷化合物为2-氯乙烯胂酸、双(2-氯乙烯基)胂酸、三(2-氯乙烯基)胂、三苯胂、笨胂酸和二苯胂酸等,为这些污染土壤的修复提供了技术数据.     

微波三步提取–高效液相色谱–原子荧光法测定土壤中砷形态

采用高效液相色谱–原子荧光法对土壤中的砷形态进行分析,以了解其对土壤的污染程度。用1 mol/L磷酸–0.5 mol/L抗坏血酸混合提取剂对污染土壤样品进行三步微波提取,用高效液相色谱–原子荧光联用仪测定砷形态含量。As(Ⅲ)和As(V)标准工作曲线的线性范围均为8～100μg/L,线性相关系数(r~2)分别为0.999,0.996,检出限分别为0.11,0.72μg/L。As(Ⅲ),As(V)测定结果的相对标准偏差分别7.6%和9.1%(n=11),加标回收回收率在82.2%～98.3%之间。多数土壤中砷形态以As(V)为主,As(Ⅲ)含量较低。该方法对土壤中的砷提取效果好,测定结果可靠,可为土壤砷污染的修复提供技术支撑。     

砷对植物生长的影响及植物耐砷机理研究进展

砷污染问题是全球面临的重大环境污染问题之一。综述了不同浓度砷及不同形态砷对植物生长的影响，耐砷植物及植物耐砷机理，指出了今后研究的主攻方向。     

原子荧光光谱法测定砷过程中还原反应条件的优化

自然界中砷和砷的化合物一般可通过水、大气和食物等途径进入人体,危害人体健康,原子荧光光谱法测定砷含量被广泛应用。为准确测定样品中砷的含量,以原子荧光光谱法(AFS)测定土壤中总砷含量为例,重点研究高价态砷(Ⅴ)还原为低价态砷(Ⅲ)的实验条件,采用正交实验进行条件优化,建立适合的实验方法。通过设计L9(34)正交实验,高价态砷的还原反应与四个因素有关,即与反应温度、反应时间、盐酸加入量和硫脲的用量呈一定的正相关,结果表明,四个因素中硫脲用量的影响最为显著,其次是盐酸加入量、反应时间和反应温度。通过对四个因素的多水平检验,优化后的实验条件为：硫脲用量2.0 mL、盐酸加入量10%、反应时间20 min、温度20～35 ℃(即普通室温)。采用土壤标准物质验证优化后条件的可行性,得出砷的测定值在标准值范围内,RSD在2.2%～4.2%,精密度和准确性均满足质控要求。优化后的实验条件使得操作简便易行,提高了工作效率。     

双通道原子荧光光谱法同时测定土壤中的砷和汞

对现有国标检测方法(GB/T 22105.1-2008和GB/T 22105.2-2008)进行改进,采用王水水浴浸提-双通道原子荧光光谱法同时测定土壤样品中砷、汞的含量。采用土壤国家一级标准物质GSS-3,GSS-8,GSS-9与山西农田土壤样品为试验对象,筛选得到检测砷、汞元素含量最佳实验条件及仪器工作条件。砷、汞的质量浓度分别在0~150μg/L,0~2μg/L范围内与荧光强度成良好的线性关系,线性相关系数均大于0.999,砷、汞的检出限分别为0.021,0.0015 mg/kg。测定结果的相对标准偏差为1.81%~4.64%(n=8),砷、汞的样品加标回收率分别为92.7%~103.0%,82.0%~95.5%。经国家一级标准物质验证,该法检出限、准确度和精密度均满足检测要求。改良后的方法可以同时准确、快速地测定土壤中砷、汞,极大地提高了工作效率,可以更好地适应当前大量的土壤分析工作。     

砷从农业土壤向人类食物链的迁移

综述了砷在土壤．植物．人类系统中的迁移,包括：砷在环境中的行为,农业系统中砷迁移的动力学过程和粮食中砷的含量,影响砷对植物有效性的各种因子,以及砷在人体内的分布、对人体的营养作用及不同形态对人体的毒性。     

AB-DTPA浸提-原子荧光法测定土壤中有效砷和有效硒

硒和砷是土壤中重要元素,目前关于提取测定有效硒和有效砷的报道还比较缺乏。本文采用原子荧光光谱法,以AB-DTPA为浸提剂,建立了一种准确测定本地区土壤中有效硒和有效砷的分析方法。通过考察浸提剂加入量,即土液比（m/v）;浸提时的振荡时间和振荡频率的影响,确立了适用于本地区土壤有效硒和有效砷提取分析的有效方法,结果表明：随着浸提剂的不断加入,所测土壤中有效硒和有效砷含量逐渐增大,当土壤称样量和浸提剂使用体积比为1:5时,所测土壤有效硒和有效砷含量最高,继续加入浸提剂后形成稀释效应导致测量结果偏低,故将土液比（m/v）定位1:5;当振荡时间不断增大时,所测所测土壤中有效硒和有效砷含量逐渐增大,振荡时间在30min时,浸提效果最佳,继续增加振荡时间到50min时对浸提效果影响不大,故将30min确立为最佳振荡时间;随着振荡频率的增大,有效硒和有效砷提取量逐渐增加,振荡频率在90-130r/min之间时,浸提效果最好,继续增大振荡频率,所测土壤中有效硒和有效砷含量变化不大。通过上述条件探索,选取五种土壤标准物质（GBW07441,GBW07442,GBW07443,GBW07444,GBW07445）进行验证,结果表明五种不同的土壤标准物质中有效硒和有效砷含量测定值准确,测定误差在-2.84~1.03mg/Kg,相对标准偏差为5.32%~8.85%,精密度和准确度均满足国家相关标准要求。     

氢化物发生-原子荧光光谱法测定土壤中砷

采用氢化物发生-原子荧光光谱法测定土壤中砷的含量.样品经硝酸-盐酸(1+1)混合酸于沸水浴中加热1 h消解.对测定的影响因素:仪器的负高压、灯电流、载气和屏蔽气流量;硼氢化钾的浓度、酸的种类及其浓度、共存离子的干扰等试验条件作了研究并予以优化.荧光强度与砷的质量浓度在100 μg·L-1以内呈线性关系,方法的检出限(3s/b)为0.6 μg·L-1,方法的相对标准偏差(n=6)小于5%.应用此法对标准物质ESS-1和土壤样品进行分析,测得砷的回收率在93%～105%之间.     

HPLC-HG-AFS研究土壤-植物体系中As的形态

砷广泛存在于自然界中的有害元素之一.砷在土壤中的累积不仅影响植物、动物的生长和发育,而且通过食物链进入人体,直接危及人类健康~([1]).土壤中砷污染问题已经引起高度重视~([2]).     

镉污染土壤的植物修复

Cd在土壤中有稳定、积累和不易消除的特点,且可通过食物链富集使人体产生慢性中毒。我国农村镉污染尤其严重。植物修复技术是优秀的土壤镉污染治理技术,近两年来成为研究热点。本文阐述了土壤镉污染植物修复技术的机理、具体做法和技术进展。     

重金属有效态与土壤环境质量标准制订

制订合适的土壤环境质量标准是评价土壤健康质量及食品安全的核心问题,而土壤重金属有效态对制定土壤环境质量标准具有重要意义。土壤重金属有效态主要指植物有效态,它与重金属形态关系密切。影响土壤重金属有效态的因素很多,主要包括:土壤pH值、氧化还原电位、CEC、有机质含量、粒径组成(黏粒含量)、铁铝锰氧化物含量、植物种类、土壤微生物、土壤温度的高低、重金属来源等。化学试剂浸提法是测量重金属生物有效性的常用方法,所用化学试剂主要有三类:弱(稀)酸、络合剂和中性盐,中性盐由于对土壤pH值影响小而受到重视。我国现行土壤质量标准采用土壤重金属总量和pH两个因素为依据,但是不少学者认为,该标准仅适用于重金属有效态较高的土壤,而不能反映重金属有效态含量较低土壤的实际状况。     

GC–MS–MS analysis of bacterial fatty acids in heavily creosote-contaminated soil samples

Phospholipid fatty acid profiles of soil samples enable rapid and reproducible measurement and characterization of the dominant soil microbial communities. When extensive polycyclic aromatic hydrocarbon (PAH) pollution is present in the soil it is very difficult, or even impossible, to distinguish specific fatty acids in GC–MS chromatograms in full-scan mode, because of the PAHs which, because of their lipophilic character, are co-extracted with the lipids. Selected ions in the samples were scanned in MS–MS mode to eliminate the aromatic hydrocarbon signals and obtain clear chromatograms of the fatty acids. By using this technique it was possible to clearly distinguish at least eleven fatty acids in heavily creosote-contaminated soil samples (PAH concentration approximately 15 g kg⁻¹ dry weight of soil).     

Cold ultrasonic acid extraction of copper, lead and zinc from soil samples

A cold ultrasonic acid method for extracting Pb, Cu and Zn from soil samples has been studied. This work focused on studying the experimental condition for extrating trace metals from soil samples at ambient temperature (≈25 °C) using Syrian soil samples; the same conditions were applied to reference soil samples(SL-1, Soil-7, SDM, and BCR-32). A short exposure time (4 h), and 2 ml of concentrated hydrochloric acid were found to be best. Under the applied conditions Pb, Cu and Zn were quantitavely extracted, while Sr, Mn, Fe, Al, Cr, Co, and Ni were partialy extracted. The advantages of the cold ultrasonic extraction method are as follows: it is selective, it is matrix free, the extraction time is short, the amounts of consumed chemicals are small, the by-products of the process are negligible and it is environmentally clean, since no fume emissions are emitted. The only disadvantage is that it is not a real total digestion method. Comparable results for the proposed ultrasound method and the hot-plate acid digestion method for Cu, Pb and Zn in certified refrence soil samples(SL-1, SDM, Soil-7, BCR-32, Soil-6) and some Syrian soil samples are obtained.     

Determination of Nicotine in the Soil Mixed With Tobacco Powder as Fertilizer

ABSTRACT

The nicotine content of the tobacco powder completely degrades in one week when it is added to a non manured soil. If some organic manure is added to the soil so as to sensibly increase the microbial flora, then nicotine degrades in less than twenty-four hours. In sterilized soil nicotine content is constant over the time because of the total absence of microorganism. In the determination of the nicotine in the soil, accurate analytical results can be obtained by adding methanol to the soil sample at the moment of the sampling. Methanol degrades the enzymatic systems causing a soil sterilization and avoids, therefore, the degradation of the alkaloid. The extracted nicotine is analyzed by means of high performance liquid chromatography in a rapid and accurate manner.     

Rapid analysis of 2,4-D in soil samples by modified Soxhlet apparatus using HPLC with UV detection

The 2,4-dichlorophenoxy acetic acid (2,4-D) is used as a systemic herbicide to control broadleaf weeds in wheat, corn, range land/pasture land, sorghum, and barley. In this study, a fast and efficient method is developed by selection of modified extraction apparatus and high-performance liquid chromatography (HPLC)-UV conditions for the determination of 2,4-D in soil samples. The method is applied to the study of soil samples collected from the agricultural field. The herbicide is extracted from soil samples by acetonitrile in a modified Soxhlet apparatus. The advantages of the apparatus are that it uses small volume of organic solvent, reduced time of extraction, and better recovery of the analyte. The extract is filtered using a very fine microfiber paper. The total extract is concentrated in a rotatory evaporator, dried under ultrahigh pure N2, and finally reconstituted in 1 mL of acetonitrile. HPLC-UV at 228 nm is used for analysis. The herbicide is identified and quantitated using the HPLC system. The method is validated by the analysis of spiked soil samples. Recoveries obtained varied from 85% to 100% for spiked soil samples. The limit of quantitation (LOQ) and the limit of detection (LOD) are 0.010 and 0.005 parts per million (ppm), respectively, for spiked soil samples. The LOQ and LOD are 0.006 and 0.003 ppm for unspiked soil samples. The measured concentrations of 2,4-D in spiked soil samples are between 0.010 and 0.020 ppm with an average of 0.016 +/- 0.003 ppm. For unspiked soil samples it is between 0.006 ppm and 0.012 ppm with an average of 0.009 +/- 0.002 ppm. The measured concentrations of 2,4-D in soil samples are generally low and do not exceed the regulatory agencies guidelines.     

Pyrolysis of agricultural residues from rape and sunflowers: Production and characterization of bio-fuels and biochar soil management

This research explores the opportunities of combining energy production with a biochar soil management using a pyrolysis process. Real-world issues justify this approach: the need to provide sustainable production systems that minimize on- and off-site pollution and soil degradation; and the demand for solutions to global warming. The proposed technology is a pyrolysis process that yields gas, bio-oil and biochar. The composition and heating value of the gas makes it suitable for use as a fuel. The bio-oil obtained may be evaluated as an environmentally friendly green biofuel candidate. The biochar product is carbon-rich and a potential solid biofuel. Other ways it might be used as a C and N source in soil amendment. This is a key to securing environmental benefits: the production of a biochar which can be applied to soil.     

Surfactant-enhanced remediation of organic contaminated soil and water

Surfactant based remediation technologies for organic contaminated soil and water (groundwater or surface water) is of increasing importance recently. Surfactants are used to dramatically expedite the process, which in turn, may reduce the treatment time of a site compared to use of water alone. In fact, among the various available remediation technologies for organic contaminated sites, surfactant based process is one of the most innovative technologies. To enhance the application of surfactant based technologies for remediation of organic contaminated sites, it is very important to have a better understanding of the mechanisms involved in this process. This paper will provide an overview of the recent developments in the area of surfactant enhanced soil and groundwater remediation processes, focusing on (i) surfactant adsorption on soil, (ii) micellar solubilization of organic hydrocarbons, (iii) supersolubilization, (iv) density modified displacement, (v) degradation of organic hydrocarbon in presence surfactants, (vi) partitioning of surfactants onto soil and liquid organic phase, (vii) partitioning of contaminants onto soil, and (viii) removal of organics from soil in presence of surfactants. Surfactant adsorption on soil and/or sediment is an important step in this process as it results in surfactant loss reduced the availability of the surfactants for solubilization. At the same time, adsorbed surfactants will retained in the soil matrix, and may create other environmental problem. The biosurfactants are become promising in this application due to their environmentally friendly nature, nontoxic, low adsorption on to soil, and good solubilization efficiency. Effects of different parameters like the effect of electrolyte, pH, soil mineral and organic content, soil composition etc. on surfactant adsorption are discussed here. Micellar solubilization is also an important step for removal of organic contaminants from the soil matrix, especially for low aqueous solubility organic contaminants. Influences of different parameters such as single and mixed surfactant system, hydrophilic and hydrophobic chain length, HLB value, temperature, electrolyte, surfactant type that are very important in micellar solubilization are reviewed here. Microemulsion systems show higher capacity of organic hydrocarbons solubilization than the normal micellar system. In the case of biodegradation of organic hydrocarbons, the rate is very slow due to low water solubility and dissolution rate but the presence of surfactants may increase the bioavailability of hydrophobic compounds by solubilization and hence increases the degradation rate. In some cases the presence of it also reduces the rate. In addition to fundamental studies, some laboratory and field studies on removal of organics from contaminated soil are also reviewed to show the applicability of this technology.     

QSPR-based prediction of adsorption of halogenated aromatics on yellow-brown soil

Halogenated aromatic compounds exist widely in soil and aqueous environment. The study of their transport and distribution is quite important for pollution control and risk assessment. In the present work, the adsorption coefficients of 28 halogenated benzenes, anilines and phenols on yellow-brown soil were measured with batch equilibrium method, and a prediction model was developed through the quantitative structure–property relationship (QSPR) technique. Then the obtained model was tested with Monte Carlo simulation and Jacknife methods. The results indicated that it was robust enough to estimate soil adsorption behaviors for the tested compounds. Based on the obtained model, it could be deduced that the adsorption of halogenated aromatics on yellow-brown soil was not a simple partitioning process but involved complicated interactions.     

钙对氟污染酸性土壤的改良效应

对珠三角典型土壤（潮土和水稻土）加入一系列硝酸钙、氧化钙和碳酸钙进行室内培养,采用连续化学提取方法对原土及添加上述成分后各种形态氟进行提取,并采用极谱测定方法进行检测,研究各形态的转化行为。试验结果表明：加入氧化钙和碳酸钙可使两种土壤pH值明显上升,有利于改善土壤酸性;但使两种土壤有效态氟（水溶态氟、可交换态氟）含量上升,而铁锰结合态氟总体下降。故氧化钙不适用于该类高氟土的酸性改良,而碳酸钙的适用性则由土壤理化性质决定。硝酸钙的加入使各形态氟含量均呈下降趋势,在施用剂量大于20mg／25g时,对土壤中有效态氟有较好的抑制作用,但对土壤酸化没有改善。