Contamination of highly weathered urban soils in Uberlândia,Brazil

We determined heavy metal, polycyclic aromatic hydrocarbon (PAH), and polychlorinated biphenyl (PCB) concentrations in 18 topsoils of Uberlândia (420,000 inhabitants, Brazil) and in 3 rural topsoils. Concentrations of Al (11—124 g kg^—1) and Fe (13—109 g kg^—1) are large because of desilification. Concentrations of Cd (0.1—0.5 mg kg^—1), Cr (13—72), Cu (6—154), Mn (28—974), Ni (4—29), Pb (3—26), Zn (4—107), the sum of 20 PAHs (=Σ20PAHs:7—390 μg kg^—1), and the sum of 14 PCBs (=Σ14PCBs:0.05—1.25) are comparable to or below background concentrations in temperate soils except for Cu at two sites. More than 67% of the metals are strongly bound in Fe oxides and silicates; metals are more bioavailable in the urban than in the rural soils. The most abundant PAHs in the urban soils, on average, are naphthalene (19.0 ± 13.4% of Σ20PAHs) and the benzo(b+j+k)fluoranthenes (11.4 ± 6.7%); the most abundant PCBs are nos. 138 (23.3 ± 11.0% of Σ14PCBs) and 153 (14.3 ± 6.4%). The rural soils contain larger percentages of low molecular PAHs and up to tetra‒chlorinated PCBs than the urban soils. The different pollutant concentrations and patterns in the studied tropical compared with many temperate soils indicate different sources and fate.     

Selected persistent organic pollutants (POPs) in the rhizosphere of sewage sludge-treated soil: implications for the biodegradability of POPs

The impact of regular application of sewage sludge or farmyard manure on the organic contaminant loads in soil was assessed in a model rhizobox experiment. Two soils originating from a long-term field crop rotation and fertilizer experiment running since 1996 were used. The total polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), organochlorinated pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) contents were determined in the rhizosphere and bulk soil. The results showed low but still detectable contents of PCBs and OCPs in the soil, substances which were banned a few decades ago. Among the OCPs, dichlorodiphenyltrichloroethane (DDT) and its metabolites reaching up to 18.2 µg kg^?1 of the soil even exceeded the preventive levels for these compounds in agricultural soils, i.e. 7.5 µg kg^?1 of soil. For PBDEs, PFOA, and PFOS, their contents in the soil significantly increased with sewage sludge application. The enhancement of the potential biodegradability of the POPs in the rhizosphere was confirmed only for hexachlorocyclohexane (γ-HCH), where, the level of γ-HCH increased significantly in the rhizosphere soil compared to bulk soil. Thus, natural attenuation of POPs in the soil-plant system seems to be insufficient for most of the investigated compounds.     

Single-laboratory evaluation of EPA method 8080 for determination of chlorinated pesticides and polychlorinated biphenyls in hazardous wastes

Method 8080, as published in the Second Edition of "Test Methods for Evaluating Solid Waste," EPA Manual SW-846, has been evaluated in a single-laboratory study. The Florisil procedure recommended in Method 8080 for sample cleanup does not separate organochlorine pesticides (OCPs) from the polychlorinated biphenyls (PCBs). Consequently, gas chromatographic analysis of OCPs on the packed column recommended in the method may result in false identifications or in no identifications at all when PCBs are present. Therefore, silica gel was substituted for Florisil, a capillary column was substituted for the packed column, and a sulfur cleanup procedure was incorporated in the method. The revised method was evaluated with samples spiked at 3 concentrations. Precision and accuracy indicate that the revised method can be reliably applied to the determination of OCPs and PCBs in liquid and solid matrixes. Detection limits for liquid matrixes range from 0.02 to 0.09 micrograms/L for OCPs and from 0.5 to 0.9 micrograms/L for PCBs. Detection limits for solid matrixes range from 1 to 6 micrograms/kg for OCPs and from 60 to 70 micrograms/kg for PCBs.     

Polychlorinated dibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxins,dibenzofurans, and biphenyls in soils of Moscow

The contents of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) in the soils of Moscow were estimated. The concentrations of PCDDs and PCDFs mainly vary in the range of 0.27–16.1 ng WHO-TEQ/kg with single points of very high contamination up to 57.3 ng WHO-TEQ/kg; the concentrations of PCBs are in the range of 2.1–50.8 ng/g with sites of high contamination up to 4020 ng/g. The contribution of dioxin-like PCBs to the total dioxin toxic equivalent is very high: from 16 to 85%. The high levels of PCDDs and PCDFs in the soils indicate the strong contamination of the atmospheric air. The main source of these compounds is apparently motor transport.     

Occurrence and distribution of organochlorine pesticides (OCPs) in tomato (Lycopersicon esculentum) crops from organic production

Organochlorine pesticides (OCPs) were quantified by GC-ECD in tomato (Lycopersicon esculentum) during a vegetation period. Plants were harvested at 15, 60, and 151 days after seed germination. Leaves, stem, roots, and fruit (peel and flesh) were analyzed separately. The results showed that tomato plants were able to accumulate OCPs from soils, and a trend to reach the equilibrium among tissues at mature stages was also observed. Endosulfans comprised the main OCP group, probably due to its spray during summer months in the surrounding areas. Banned pesticides such as DDTs, heptachlor, and dieldrin were found. OCPs levels in the fruit were below the maximum residues limits (MRL) considered by the Codex Alimentarius. DDE/DDT and alpha-/gamma-HCH ratios of <1 would indicate recent inputs of DDT and lindane in the environment. The occurrence of OCPs in the study farm, where agrochemicals have never been used, is a result of atmospheric deposition of those pesticides.     

Tillage effects on the accumulation of polychlorinated biphenyls in biosolid‐amended soils

Soil tillage along with the application of organic waste probably affects the concentrations of organic carbon and the enrichment of introduced polychlorinated biphenyls (PCBs). In a three‐year experiment the PCB status of soils from three different field sites (silty clay loam, silt loam, sandy loam) which were long‐term differently tilled (NT = no‐tillage, CT = conventional plough tillage) and amended with two different organic wastes such as sewage sludge and compost (biosolids) was examined. No significant alteration in soil‐PCB quality and quantity with biosolid application could be proven within the course of the experiments. This indicates soil‐air exchange of PCBs dominates their concentrations in soil. Organic carbon in soil was significantly tillage‐dependent and determined the fate of PCBs resulting in a generally elevated PCB‐level in the non tilled soils. Linear regression of PCB load and organic matter content of all investigated untreated soils was highly significant (R² = 0.73). Due to already elevated PCB levels in non tilled soils with a maximum of 65 μg kg^—1 in the superficial layer of the silt loam control plot, any additional potential input, i. e. through the amendment with organic wastes, should therefore be avoided.     

Organochlorinated compounds (PCBs and insecticides) in irrigated agrolandscapes of Russia and Uzbekistan

The spatial and temporal distribution of persistent chlororganic compounds in the form of insecticide residues—DDT, DDE, DDD, HCH and industrial pollutants—polychlorobiphenyls (PCBs) has been monitored in various components of irrigated agrolandscapes (soil, water, bottom sediments) in the Moscow region, the Kuban lowplain of the Krasnodar region (Russia) and in the Samarkand oasis (Uzbekistan) for the period 1989–1990. The widespread occurence of PCB compounds requires action for their hygienic control and monitoring. The main chlororganic pollutant found were DDT residues and their content in soils and bottom sediments in all regions under study exceeded in many cases the existing baselines (100 µg/kg). Special attention has been given to the ratios between various metabolites and isomers of chlororganic insecticides as well as between various homologs of PCBs among which tetrachlorobiphenyls were predominant in soils, bottom sediments and surface waters.     

海南省瓜菜田土壤中有机氯农药残留及生态风险分析

采用气相色谱法检测了海南瓜菜田的33个表层土壤样品中18种有机氯(OCPs)农药残留,并对其进行污染来源分析和初步生态风险评价。结果表明:(1)土壤中的OCPs检出率为90.9%,最高残留量为17.37 ng·g-1,平均值为2.30 ng·g-1;(2)18种OCPs均有检出,六六六(HCHs)、滴滴涕(DDTs)、硫丹类农药的检出率较高,分别为63.6%、57.6%、54.5%;(3)DDTs是主要残留物质,占总OCPs残留量的54.6%,18.2%的土样可能有DDTs新的输入,土壤中HCHs主要来源于过去使用的林丹;(4)与国内其他地区土壤和国家《土壤环境质量标准》(GB 15618—1995)一级标准相比,海南省瓜菜田土壤DDTs和HCHs残留量处于较低水平,生态风险也较低。     

运用红边参数估算叶片叶绿素含量

Soil samples collected from several sites along an altitudinal transect on the eastern slope of the Tibetan Plateau were analyzed for hexachlorobenzenes(HCHs) and dichlorodiphenyltrichloroethanes(DDTs).The results showed that HCHs and DDTs were found in the soil samples from the remote high altitude areas away from source regions,which confirmed the long-range atmospheric transport phenomenon of these organochlorine pesticides(OCPs) insecticides.The OCP concentrations in the soils had a significant negative correlation with altitude;they showed a trend to increase with decreasing altitude,but the increase was not continuous,being interrupted at some moderate-altitude sites on the transect.The distances from the source region,landforms,soil properties,and physical-chemical properties of OCPs were more important than total organic carbon content to the distribution of OCPs in soils disturbed by human activities.An analysis of the compositions of HCH isomers and DDTs revealed predominantly low ratios of α-HCH to γ-HCH,ranging from 0.06 to 4.79,which suggested current lindane inputs.On the other hand,low p,p-DDT/p,p-DDE and o,p-DDT/p,p-DDT ratios were observed,indicating mainly aged historical DDT residues in the study area.     

Residues of currently and never used organochlorine pesticides in agricultural soils from Zhejiang Province, China

Studies on residues of currently and never used organochlorine pesticides (OCPs) facilitate the assessment of the contamination level, distribution, sources, transportation, and trend of these selected OCPs in China. In this work we investigated the concentration levels of endosulfans and chlordane, which are currently used, and the never used aldrin and dieldrin in the province of Zhejiang, a rainy, and hilly tea-growing province in eastern China. The average/mean residue levels of OCPs was in the order ∑endosulfan > ∑chlordane > aldrin > dieldrin. The residue level was in good agreement with the usage of OCPs in Zhejiang. The spatial distribution showed that the residues of OCPs in soils from the mountain area were always higher than those in soils from the plains. The distribution characteristics were related to usage for current-use OCPs and temperature for never used OCPs. The isomeric ratios and enantiomeric fractions are useful tools to identify the degradation preference of contaminants. The wide range of ratios between trans-chlordane (TC) and cis-chlordane (CC) indicated that the degradation of the two isomers of chlordane was different at different sites. Nonracemic residues of TC and CC were observed in most soils; this is significant since the enantiomers have different toxicities.     

污染土壤中六六六和DDT在温室中的分布特征及动态变化研究

应用PUF材料空气被动采样技术,研究了密闭温室条件下污染土壤中有机氯农药[DDT和六六六（HCH）]含量的动态变化及其向空气中扩散的规律。结果表明：土壤中∑HCHs和∑DDTs总量随着培养时间的延长而降低;空气中HCH和DDT浓度在20d时达到峰值,20d以后浓度逐渐降低。培养60d后,土壤中∑HCHs的浓度随土层深度增加而增加,0~2cm土层中∑HCHs的浓度（9.4±0.69）mg·kg-1显著低于6~8cm土层中的浓度（12.11±0.83）mg·kg-1;∑DDTs在土壤中浓度随土壤层次呈现先升高后降低的变化趋势。在温室条件下有机氯农药的异构体和降解产物的组成也发生一定变化,土壤中HCHs和DDTs在一定程度上被激活,温室条件也可能促进HCHs和DDTs的土-气交换过程;温室环境促进了p,p′-DDT和o,p′-DDT向p,p′-DDD和p,p′-DDE转化,从而增大DDT和HCH的环境风险。     

Atmospheric Transport and Air-Surface Exchange of Pesticides

Atmospheric transport and exchange of pesticides with soil, vegetation, water and atmospheric particles are discussed, with an emphasis on applying physicochemical properties of the compound to describe environmental partitioning. The octanol-air partition coefficient is promoted as a unifying property for describing volatilization of pesticides from soil and sorption to aerosols. Present-day sources of organochlorine (OC) pesticides to the atmosphere are continued usage in certain countries and volatilization from contaminated soils where they were used in the past. Models are available to predict volatilization from soil; however, their implementation is hampered by lack of soil residue data on a regional scale. The need to differentiate "new" and "old" sources is increasing, as countries negotiate international controls on persistent organic pollutants (POPs). A new technique, based on the analysis of individual pesticide enantiomers, is proposed to follow emission of chiral OC pesticides from soil and water. Air monitoring programs in the Arctic show the ubiquitous presence of OC pesticides, PCBs and other POPs, and recently a few "modern" pesticides have been identified in fog and surface seawater. Atmospheric loadings of POPs to oceans and large lakes take place mainly by air-water gas exchange. In the case of OC pesticides and PCBs, aquatic systems are often near air-water equilibrium or even oversaturated. Measurement of water/air fugacity ratios suggests revolatilization of PCBs and several OC pesticides in the Great Lakes and, for α-hexachloroacyclohexane (α-HCH), in the Arctic Ocean. Outgassing of α-HCH in large lakes and arctic waters has been confirmed by enantiomeric tracer studies. The potential for pesticides to be atmospherically transported depends on their ability to be mobilized into air and the removal processes that take place enroute: wet and dry deposition of gases and particles and chemical reactions in the atmosphere. Measurement of reaction rate constants for pesticides in the gas and particle phase at a range of environmental temperatures is a critical research need. The transport distance of a chemical is related to its overall environmental persistence, determined by the partitioning among different compartments (water, sediment, soil, air), degradation rates in each compartment and mode of emission (into water, soil, air). Several pesticides found in the arctic environment have predicted lifetimes in the gas phase of only a few days in temperate climates, pointing out the need for monitoring and evaluation of persistence in cold regions.     

滇池流域农田土壤有机氯农药残留特征

在滇池流域农田,重点是滇池滨湖区和入滇河流柴河流域,选择不同土地利用类型、不同种植年限大棚采集土壤样品进行气相色谱（ECD）分析。结果表明,试区土壤中有机氯农药（OCPS）检出率为95.9%,OCPS的残留量范围、平均值分别为nd-63.4 μg·kg-1、6.3 μg·kg-1,以p,p′-DDE为主要残留物,98.3%的样点达到国家《土壤环境质量标准》一级标准（〈50 μg·kg-1）。与国内同类报道相比,滇池周边土壤中OCPS的残留较低。不同土地利用类型有机氯残留量排序为：设施栽培〉水稻田〉露天菜地〉荒草地〉坡耕地;不同大棚种植年限土壤中,棚龄长于15 a的 OCPS残留量要明显高于棚龄短于15 a的,而棚龄短于15 a的,土壤中OCPS含量差异不明显。     

吉林省典型工农业地区多介质样品中有机氯农药和多氯联苯分布特征

采用气相色谱-电子捕获检测器分析了吉林省典型工农业地区表层土壤、水稻、玉米及稻田水样品中包括HCHs、DDTs在内的有机氯农药（OCPs）和7种多氯联苯（PCBs）指示性单体的含量。结果表明,表层土壤中OCPs（HCHs＋DDTs）平均含量排序为梅河口夏季（98.9ng·g-1）〉长春市（81.2ng·g-1）〉吉林市（72.6ng·g-1）〉梅河口秋季（25.2ng·g-1）,PCBs排序为梅河口夏季（98.7ng·g-1）〉长春市（平均61.0ng·g-1）〉吉林市（50.3ng·g-1）〉梅河口秋季（27.1ng·g-1）,梅河口土壤中PCBs异构体中以PCB28和PCB52为主;DDTs含量较高的地区为吉林市和长春市,其旱地土壤有利于DDTs的残留;所有水稻籽粒样品中均检出了HCHs和DDTs残留,水稻和玉米中HCH和DDTs的残留均低于国家食品卫生标准的限值,水稻秧苗和玉米秆茎样品中∑7PCBs含量都分别高于水稻和玉米籽粒样品中∑7PCBs含量;水稻田水中OCPs含量都低于国家地表水质标准限值。     

Hydrocarbon status of soils under atmospheric pollution from a local industrial source

Contents and compositions of bitumoids, polycyclic aromatic hydrocarbons (PAHs), and free and retained hydrocarbon gases in soils along a transect at different distances from the local industrial source of atmospheric pollution with soot emissions have been studied. The reserves of PAHs progressively decrease when the distance from the source increases. Among the individual PAHs, the most significant decrease is observed for benzo[a]pyrene, tetraphene, pyrene, chrysene, and anthracene. On plowlands, the share of heavy PAHs—benzo[ghi]perylene, benzo[a]pyrene, perylene, etc.—is lower than in the forest soils. In automorphic soils of the park zone adjacent to the industrial zone, the penetration depth of four-, five-, and sixring PAHs from the atmosphere is no more than 25 cm. In soils under natural forest vegetation, heavy PAHs do not penetrate deeper than 5 cm; in tilled soils, their penetration depth coincides with the lower boundary of plow horizons. Analysis of free gases in the soil air revealed hydrocarbons only under forest. From the quantitative and qualitative parameters of the content, reserves, and compositions of different hydrocarbons, the following modification types of hydrocarbon status in the studied soils were revealed: injection, atmosedimentation–injection, atmosedimentation–impact, atmosedimentation–distant, and biogeochemical types.     

环鄱阳湖区蔬菜地土壤中有机氯农药分布特征及生态风险评价

利用GC-ECD对环鄱阳湖区11个县市蔬菜地土壤中有机氯农药测定的数据,研究蔬菜地土壤中有机氯农药残留状况,并进行生态风险评价。结果显示,蔬菜地土壤中HCHs、DDTs、氯丹和六氯苯均有检出,且DDTs、HCHs的残留量较高,总有机氯农药含量范围为2.39～47.28μg·kg-1。从整体上分析,处于工业分布区域的土壤中有机氯农药含量高于其他区域。有机氯农药组成特征研究表明,该地区土壤中除个别采样点有机氯农药主要来自于早期残留外,大部分地区有新的污染源输入。与国内其他地区蔬菜地土壤相比,环鄱阳湖区蔬菜地土壤中有机氯农药含量较低。生态风险分析显示,环鄱阳湖区蔬菜地土壤中HCHs残留对于土壤生物的风险较低,而DDTs可能对鸟类和土壤生物具有一定的生态风险。     

Soils of northern spurs of the Cherskii Ridge in the area of the northern pole of cold: Morphology,properties, and classification

The soils in the area of the northern pole of cold located on the interfluve between the Yana and Adycha rivers within the spurs of Kisilyakh Ridge included in the mountain system of Cherskii Ridge have been studied for the first time. The profile-genetic approach has been applied to describe the soils and determine their classification position. It is found that the major soil types in this region are the soils of the postlithogenic trunk belonging to the orders of lithozems (Cryic Leptosols), gley soils (Gleyic Skeletic Cryosols), and Al–Fe-humus soils (Spodic Skeletic Cryosols). The ecological ranges of altitudinal zones— the taiga zone with various types of lithozems below 630–700 m a.s.l. and the tundra zone with combinations of gley and nongley cryogenic soils above these heights—have been established. The development of gley or nongley soils is specified by the local orogenic and lithological conditions and slope aspect, which, in turn, control the degree of drainage and the presence and character of permafrost. In the profile of mountainous gley soils (gleyzems) with shallow ice-rich permafrost, cryogenic processes and features typical of the analogues of these soils on plains—cryogenic cracking, cryoturbation, solifluction, thixotropy, oxiaquic features above permafrost, saturation of the soil profile with mobile humus, etc.—are typical.     

Persistent organic pollutant concentrations in air‐ and freeze‐dried compared to field‐fresh extracted soil samples of an eastern Slovak deposition gradient

Sample preparation affects the results of the determination of persistent organic pollutant (POP) concentrations in soils. We compared the extraction results of POPs from air‐ and freeze‐dried with field‐fresh samples. We determined the concentrations of 21 polycyclic aromatic hydrocarbons (PAHs) and 14 polychlorinated biphenyls (PCBs) in 35 horizons of forest soils (Lithosols and Cambisols) along a deposition gradient caused by a chemical factory in Strá?ske (eastern Slovakia). The organic C (C_org) concentrations of the studied samples ranged 14‐477 g kg^‐1, the sum of 21 PAH (Σ 21PAHs) concentrations 53‐6870 μg kg^‐1, and that of 14 PCBs (Σ 14PCBs) 0.12 96 μg kg^‐1. The benzofluoranthenes were the most abundant PAHs, and the hexa‐chlorinated PCBs 138 and 153 were the most abundant PCBs. The deposition gradient was reflected by decreasing PAH and PCB storages in the organic layer with increasing distance from the chemical factory (Σ 21PAHs: 82‐238, Σ 14PCBs: 0.34‐2.3 g ha^‐1). The PAH concentrations in air‐ and freeze‐dried samples were consistently lower than those in field‐fresh extracted samples. For naphthalene, this was mainly attributable to volatilization losses during drying. Naphthalene losses decreased with increasing C_org concentrations. For all other PAHs, drying reduced the extractability; the latter was correlated with the water content of the samples. The differences in most PCB concentrations among the sample preparation methods were small (within the determination error of ±15 %) and inconsistent. However, PCBs 8, 28, 52, and 209 had markedly higher concentrations in dried than in fieldfresh extracted samples. The increased recovery of low‐chlorinated PCBs in dried samples may be explained by redistribution of PCBs from higher to lower contaminated samples via the drying room atmosphere because there were no PCBs in analytical blanks. This assumption is supported by a close correlation between the octanol‐air distribution coefficient and the up to hexa‐chlorinated PCB concentrations (normalized to those in field‐fresh extracted samples) in air‐ (r = ‐0.90) and freeze‐dried (r = ‐0.86) samples. Our study shows that each sample preparation method has its specific advantages and disadvantages. Sample drying results in a standardization to a well‐defined water content and facilitates homogenization; therefore it increases the reproducibility of POP determinations. Extraction of field‐fresh samples reduces volatilization losses and contamination risks.     

Arbuscular Mycorrhizal Fungal Infectivity in Two Soils as Affected by Atmospheric Phenanthrene Pollution

Arbuscular mycorrhizal fungi (AMF) hold a crucial role in ecosystems because they are involved in nutrient cycling between soil and plants. This work aimed at evaluating the impacts that atmospheric pollution by polycyclic aromatic hydrocarbons may have on infectivity of indigenous AMF in soils. Two agricultural soils (Maconcourt, La Bouzule) were exposed for 2?weeks to ambient air (control, C) or to atmospheric phenanthrene (PHE) deposition (180???g?m^?3 air). After exposure, soils were divided into a top (0?C1?cm) and a bottom (1?C15?cm) layer fraction. AMF infectivities of soils were determined after 2?weeks of atmospheric exposition using leek (Allium porum) as bioassay plant. Atmospheric PHE was mainly recovered in the top layer of soil (500?C1,350???g?kg^?1) of both soils and did not readily diffuse into the depth. Atmospheric contamination led to decreases in AMF infectivities of the top layer in both soils and affected the growth of leeks. Our results not only report evidence that infectivity of indigenous AMF is sensitive to PHE in soils but also emphasize that AMF are primary affected by the soil layer regardless to the pollution level.