Plant Availability and Uptake of Lead, Zinc, and Cadmium in Soils Contaminated with Anti-corrosion Paint from Pylons in Comparison to Heavy Metal Contaminated Urban Soils

Red lead (Pb₃O₄) has been used extensively in the past as an anti-corrosion paint for the protection of steel constructions. Prominent examples being some of the 200,000 high-voltage pylons in Germany which have been treated with red lead anti-corrosion paints until about 1970. Through weathering and maintenance work, paint compounds and particles are deposited on the soils beneath these constructions. In the present study, six such “pylon soils” were investigated in order to characterize the plant availability and plant uptake of Pb, Cd, and Zn. For comparison, three urban soils with similar levels of heavy metal contamination were included. One phase extractions with 1 M NH₄NO₃, sequential extractions (seven steps), and extractions at different soil pH were used to evaluate the heavy metal binding forms in the soil and availability to plants. Greenhouse experiments were conducted to determine heavy metal uptake by Lolium multiflorum and Lactuca sativa var. crispa in untreated and limed red lead paint contaminated soils. Concentrations of Pb and Zn in the pylon soils were elevated with maximum values of 783 mg Pb kg⁻¹ and 635 Zn mg kg⁻¹ while the soil Cd content was similar to nearby reference soils. The pylon soils were characterized by exceptionally high proportions of NH₄NO₃-extractable Pb reaching up to 17% of total Pb. Even if the relatively low pH of the soils is considered (pH 4.3–4.9), this appears to be a specific feature of the red lead contamination since similarly contaminated urban soils have to be acidified to pH 2.5 to achieve a similarly high Pb extractability. The Pb content in L. multiflorum shoots reached maximum values of 73 mg kg⁻¹ after a cultivation time of 4 weeks in pylon soil. Lime amendment reduced the plant uptake of Pb and Zn significantly by up to 91%. But L. sativa var. crispa cultivated on soils limed to neutral pH still contained critical Pb concentrations (up to 0.6 mg kg⁻¹ fresh weight). Possible mechanisms for the exceptionally high plant availability of soil Pb derived from red lead paint are discussed.     

Plant Availability of Cadmium in Soils: II. Factors Related to the Extractability and Plant Uptake of Cadmium in Cultivated Soils

Abstract

Eighty four soil samples collected from southeastern Norway were analyzed for Cd by extraction with NH₄OAc, DTPA, NH₄OAc-EDTA, NH₄NO₃, HCl and CaCl₂. The total Cd, pH, exchangeable K and Ca, dithionite-extractable Mn, available P and fine sand (0.2–0.02 mm) contents were the principal factors related to the extractable Cd, with some inter-extractant variations. Cadmium extracted by NH₄NO₃, NH₄OAc, HCl and CaCl₂ decreased with increasing soil pH, but the Cd extracted by all the extractants increased with increasing total Cd, exchangeable K and Ca, available P, and Mn-oxide contents in the soils. The Cd concentrations in plants were significantly related to the extractable Cd, exchangeable Ca and Mg, pH, Mn-oxides and organic matter content.     

Predicting Maize Yield,Nutrient Concentration,and Uptake in Phosphorus- and Potassium-Fertilized Soils: Pressurized Hot Water and Other Alternatives to Mehlich I Extraction in Guatemala Soils

Abstract

Poor accessibility and cost of soil testing reduce effectiveness of fertilizer use on small‐scale subsistence farms, and inadequate funding promotes adoption of soil tests in developing countries with minimal validation. For example, Mehlich I extraction of phosphorus (P) currently used extensively in Guatemala may not be suitable for Guatemala's broad range of soils. At least four alternatives are available but relatively untested [Bray 1, Mehlich III, Olsen, and pressurized hot water (PHW)]. Pressurized hot water is relatively simple and inexpensive but is not yet tested against other extraction methods under variable P or potassium (K) fertilization levels. To determine whether PHW‐extracted nutrients could be used to predict maize yield and nutrient concentration and uptake, soil, plant tissue and grain samples were obtained from a multiple‐site field study, and calibration studies were conducted using five rates of P and three rates of K on soils incubated without plants or cropped with maize in greenhouse and field conditions. In the multiple‐site field study, maize yield related significantly to PHW‐extractable P (r²=0.36) and to leaf P concentration (r²=0.23), but Mehlich I–extractable P did not. In the two soils used in the greenhouse study, maize yield, vegetative P concentration, and total P uptake by maize were predicted by PHW‐extractable P (R²=0.72, 0.75, and 0.90, respectively). In the field experiment, grain yield was not improved by P or K application, but P concentration of maize leaf tissue did relate significantly with PHW‐extracted P (R²=0.40). Mehlich I did not. There were no yield responses to K application in any experiment, but relationships defined between extractable K for all five K‐extraction procedures and soil‐applied K were similarly significant. In comparison, PHW was as good as or better than Olsen whereas Bray 1 and Mehlich III were less consistent. Mehlich I was overall the poorest P extractant. Mehlich I extraction of P should be replaced by one of the four alternatives tested. PHW is the least expensive and, therefore, most viable for use in Guatemala soils.     

Copper Accumulation and Availability in Sandy,Acid, Vineyard Soils

The use of copper (Cu)-based fungicides to control diseases in vineyards can cause excessive Cu accumulation in soils. Greater Cu availability is expected in acid sandy soils with low organic matter (OM), where the risk of toxicity to plants and environment contamination is high. This study aimed to study the evolution of Cu in acid, sandy soils planted with grapevines for a period of time between 2 and 32 years. Two studies were carried out in South Brazil: in the first study, soil samples, from 19 vineyards were collected and analyzed in the first 0.2 m depth-layer for the total and available Cu. In the second study, 3 soils were selected among the previous 19 according to the age of vineyard (5, 11, and 30 year-old), and their 0.60 m-depth profile was analyzed for 5 fractions of Cu (soluble, exchangeable, mineral, organic, and residual). All the soils were classified as Ultisols. The vineyards with more than 25 years under cultivation had a mean total Cu concentration of 90 mg kg^?1 in the 0–0.10 m layer. Approximately 80% of it was potentially available to plants. The greatest total and available Cu were found in the soil surface layers (0.2 m depth), where up to 75% of the total Cu is adsorbed in clay minerals and only 20% is complexed in the OM.     

高锰酸钾氧化修复污染土壤中菲和芘的研究

利用人工污染土壤,研究了高锰酸钾对4种不同土壤中菲和芘的氧化修复效果。结果表明,当高锰酸钾浓度为33.33mmol·L^-1时,土壤中菲和芘的氧化去除率达到最大。高锰酸钾氧化去除率不仅与高锰酸钾浓度有关,还与土壤性质和老化时间有关。土壤有机质含量的增加会降低高锰酸钾对土壤中菲和芘的氧化去除率;随着老化时间的增加,高锰酸钾的氧化去除率逐渐降低。老化40d后,4种土壤中菲和芘的氧化去除率显著降低,菲的氧化去除率在14%～67%之间,芘的氧化去除率在61%～84%之间。高锰酸钾氧化前后,4种土壤中有机质含量下降范围为0.77%～9.21%。从土壤有机质含量来看,高锰酸钾氧化修复多环芳烃污染土壤对土壤质量影响较小,具有较好的应用前景。     

多环芳烃芘对小白菜生长和元素吸收及营养品质的影响

通过土培试验测定了不同浓度芘处理下小白菜根和茎叶的生物量、芘及其它矿质元素的含量和一些营养品质指标。结果表明:芘对小白菜根干重的影响显著,对茎叶干重和株高的影响不显著,全株干重由于根干重的下降而呈下降趋势;根中的芘含量和土壤中残留的芘含量随土壤中芘浓度增加而显著增加,茎叶芘含量与对照无显著差异,土壤芘降解率随芘浓度增加表现为先上升再下降的趋势;茎叶有机碳和根粗灰分含量随土壤芘浓度的增加而下降,茎叶粗灰分和根有机碳含量施芘处理显著高于对照,芘促进了根对土壤中N、P、K和S的吸收同化,并加速其向茎叶的转移。茎叶粗蛋白含量较对照有所增加,粗纤维和可溶性糖含量则随芘浓度增加而下降,其中可溶性糖含量各个处理与对照之间的差异达显著水平。     

锯末对生物修复荧蒽和芘污染土壤的强化作用及影响因素

通过土壤微宇宙培养试验,研究了锯末尺寸、添加量和种类等因素对荧蒽特效降解菌MC(Mycobacterium flavescens)修复污染土壤(潮土、红壤、黑土、黄棕壤和水稻土)的效果.结果表明:锯末联合降解菌MC修复荧蒽污染的黄棕壤效果较好,优化条件下25 d荧蒽降解率为42.63％ ±1.05％;该联合修复对黑土和...     

Effect of Anthracene and Pyrene on Dehydrogenases Activity in Soils Exposed and Unexposed to PAHs

The effect of anthracene and pyrene on dehydrogenases activitywas compared between freshly spiked soils and soils previouslyexposed to PAHs. Four different soils (two soils from anunpolluted rural area and two soils from highly pollutedindustrial areas) were spiked with anthracene and pyrene atthe levels of 1, 10, 100 and 400 mg Σ2PAH per kg of soil (laboratory experiments). The soil samples were moisted to60% of water holding capacity and incubated in the dark at 18-20 °C. Dehydrogenase activity was determined after 7 and30 days. The results indicate that long-term exposure of soilfrom an industrial area to high level of PAHs (Σ13PAH = 40 mg kg^-1) caused the acclimatisation of soilmicroorganisms and lowered their sensitivity to these compounds.After the longer incubation period (30 days vs. 7 days)the soil microorganisms in the uncontaminated rural samples showed an increase in their tolerance to the freshly introduced PAH compounds; in the industrial soils the effect was less pronounced. However, this apparent adaptation of soil microorganisms may be also partly explained by the dissipation and/or ageing processes of anthracene and pyrene during incubation.     

Soil Test to Predict the Copper Availability in Pasture Soils

Abstract

The proportion of copper (Cu) that can be extracted by soil test extractants varied with the soil matrix. The plant‐available forms of Cu and the efficiency of various soil test extractants [(0.01 M Ca(NO₃)₂, 0.1 M NaNO₃, 0.01 M CaCl₂, 1.0 M NH₄NO₃, 0.1 M HCl, 0.02 M SrCl₂, Mehlich‐1 (M1), Mehlich‐3 (M3), and TEA‐DTPA.)] to predict the availability of Cu for two contrasting pasture soils were treated with two sources of Cu fertilizers (CuSO₄ and CuO). The efficiency of various chemical reagents in extracting the Cu from the soil followed this order: TEA‐DTPA>Mehlich‐3>Mehlich‐1>0.02 M SrCl₂>0.1 M HCl>1.0 M NH₄NO₃>0.01 M CaCl₂>0.1 M NaNO₃>0.01 M Ca(NO₃)₂. The ratios of exchangeable: organic: oxide bound: residual forms of Cu in M1, M3, and TEA‐DTPA for the Manawatu soil are 1:20:25:4, 1:14:8:2, and 1:56:35:8, respectively, and for the Ngamoka soil are 1:14:6:4, 1:9:5:2, and 1:55:26:17, respectively. The ratios of different forms of Cu suggest that the Cu is residing mainly in the organic form, and it decreases in the order: organic>oxide>residual>exchangeable. There was a highly significant relationship between the concentrations of Cu extracted by the three soil test extractants. The determination of the coefficients obtained from the regression relationship between the amounts of Cu extracted by M1, M3, and TEA‐DTPA reagents suggests that the behavior of extractants was similar. But M3 demonstrated a greater increase of Cu from the exchangeable form and organic complexes due to the dual activity of EDTA and acids for the different fractions and is best suited for predicting the available Cu in pasture soils.     

Availability of Cd,Ni and Zn to Ryegrass in Sewage Sludge-Treated Soils at Different Temperatures

A pot experiment to compare the availability of Cd, Ni and Znto ryegrass (Lolium perenne L.) was conducted at 15 and 25 °C. For this purpose, three ratesof sewage sludge (0, 10 and 50 t ha^-1) were applied in aloamy sand (LS) and a clay loam (CL). Heavy metal availabilityassessed by soil extractions with 0.05 M CaCl₂ and the organic matter content were monitored during a period of twoyears, while uptake by ryegrass was monitored over one year after addition of the sludge. The concentrations of Cd and Ni in both the ryegrass and the soil extracts increased significantly, during the first year, especially at 50 t ha^-1. However, in the second year metal availability reached a plateau. During the first year, in the ryegrass Znconcentrations did not show an increase, but in the soil CaCl₂-extracted Zn increased. During the same period,the organic matter content decreased rapidly, especially at25 °C, in the first year and much more slowly in thesecond, giving a total decrease of 16%. Temperature had a marked effect on metal availability; both soil extracts andplant samples from the 25 °C treatment had greater concentrations of Cd, Ni and Zn than those at 15 °C. This may be attributed to the organic matter, which decomposedmore rapidly at 25 °C. Moreover, soil-plant transfercoefficients (Tc) of the metals were significantly higher at 25 °C than at 15 °C, with Cd showing the greatest difference, followed in decreasing order by Zn and Ni.     

Availability and Toxic Level of Cadmium,Lead and Nickel in Contaminated Soils

ABSTRACT

The entry of Cd, Pb and Ni into the environment is a cause of concern due to potential toxicity of these metals to plants, animals, and humans. The present study evaluated the availability of Cd, Pb, and Ni to plants through soils. We examined three soil types (Typic Quartzipsamment (TQ), Xantic Hapludox (XH) and Rhodic Hapludox (RH)) with addition four rates of heavy metals: Cd (0, 2, 4 and 12 mg), Pb (0, 45, 90 and 270 mg) and Ni (0, 20, 40, 120 mg) per kg soil with reference to the corresponding rates defined in soil investigation values of the Brazilian environmental legislation. The availability of Cd, Pb and Ni was higher in the TQ than in XH and RH, and the roots and shoots of corn plants grown in TQ yielded the highest concentrations of toxic metals. Soil extraction with diethylene-triaminepentaacetic acid (DTPA) effectively assessed the bioavailability of Cd and Pb, while soil extractions with Mehlich-1 and aqua regia effectivety evaluated the bioavailability of Ni. The levels at which Cd, Pb, and Ni became toxic for plants were determined via extractioned by Mehlich-1, DTPA, Mehlich-3, and aqua regia. Plant growth was shown to influence heavy metal toxicity, with higher growth rates lowering the toxic effect of the metal. Cd, Ni, and Pb exhibited higher availiability in soils with low clay concentrations and were more easily absorbed by plants in those soils.     

湖南省主要茶园土壤锌的形态及其有效性

采用野外调查采样分析和田间试验方法研究了湖南省主要茶园生态系统中土壤Zn的形态及其有效性.结果显示:①成土母质明显影响土壤中各种形态Zn的含量,与母质本身的特性有关;②生物 秸秆和秸秆覆盖处理能明显提高茶园土中有效态Zn与有机态Zn的含量,而对其他形态Zn的含量影响不太明显;③土壤中对有效态Zn(AZn)含量影响最大的是交换态Zn(ExZn)与无定形氧化铁结合态Zn(AFeZn),其次为氧化锰结合态Zn(MnOZn)、有机态Zn(OMZn)及晶形氧化铁结合态Zn(CFeZn).     

土壤中硒含量、形态及有效性分析

近年来,硒(Se)对于植物以及人体的有效性逐渐得到重视,越来越多的富硒土壤被发现和利用,但目前人们对于土壤中硒的含量、形态、转化及其有效性还没有形成系统、全面和准确的认识。本文通过对国内外硒研究文献的整理和分析,认为当前对土壤中硒总量有较全面的数据,但对于硒的植物有效性与其他影响因素之间的关系认识不一,主要原因在于研究前提(土壤类型、气候等)的差异以及不同因素之间的掩盖。今后应在相对控制某一变量的前提下,采用定量模型技术,分析土壤硒有效性的真实影响因素和定量规律。在区域大气-土壤-水-植物系统的硒平衡方面,针对大气沉降、硒甲基化(挥发)、硒的淋失等途径的定量规律和影响因素,应开展大尺度范围的监测和分析。利用硒同位素技术(自然丰度和加富标记),更加准确地追踪硒在土壤、植物等子系统的转化规律,从而为提高硒的利用效率提供科学依据。     

Availability of Aged Toluene and Decane for Biodegradation in Soil

Toluene and decane which are common volatileorganic compounds (VOCs) found in natural gas spills, have beentested for their availability to biodegradation in soil aftervarious times of aging. For this purpose, single compounds wereadded to sterile soil in three concentrations of up to 1000 ppmand aged for 0, 35, and 70 days. After aging, soils were vented,inoculated and then incubated for 31 days. Both compounds wererapidly biodegraded reaching final soil concentrations below 1 ppm, regardless of the aging time. However, some sequestration ofsmall amounts of aged chemical in soil was evident for decane (up to 0.7 ppm), especially when the compound was added in largeramounts of 1000 ppm.     

Chemistry of Lowland Rice Soils and Nutrient Availability

Rice is the staple food crop for about 50% of the world's population. It is grown mainly under two ecosystems, known as upland and lowland. Lowland rice contributes about 76% of the global rice production. The anaerobic soil environment created by flood irrigation of lowland rice brings several chemical changes in the rice rhizosphere that may influence growth and development and consequently yield. The main changes that occur in flooded or waterlogged rice soils are decreases in oxidation–reduction or redox potential and increases in iron (Fe²⁺) and manganese (Mn²⁺) concentrations because of the reductions of Fe³⁺ to Fe²⁺ and Mn⁴⁺ to Mn²⁺. The pH of acidic soils increased and alkaline soils decreased because of flooding. Other results are the reduction of nitrate (NO₃ ^?) and nitrogen dioxide (NO₂ ^?) to dinitrogen (N₂) and nitrous oxide (N₂O); reduction of sulfate (SO₄ ^2?) to sulfide (S^2?); reduction of carbon dioxide (CO₂) to methane (CH₄); improvement in the concentration and availability of phosphorus (P), calcium (Ca), magnesium (Mg), Fe, Mn, molybdenum (Mo), and silicon (Si); and decrease in concentration and availability of zinc (Zn), copper (Cu), and sulfur (S). Uptake of nitrogen (N) may increase if properly managed or applied in the reduced soil layer. The chemical changes occur because of physical reactions between the soil and water and also because of biological activities of anaerobic microorganisms. The magnitude of these chemical changes is determined by soil type, soil organic-matter content, soil fertility, cultivars, and microbial activities. The exclusion of oxygen (O₂) from the flooded soils is accompanied by an increase of other gases (CO₂, CH₄, and H₂), produced largely through processes of microbial respiration. The knowledge of the chemistry of lowland rice soils is important for fertility management and maximizing rice yield. This review discusses physical, biological, and chemical changes in flooded or lowland rice soils.     

江苏省如皋市土壤中量元素含量有效性评价

为平衡施肥提供依据,本文应用GPS定位技术采集了江苏省如皋市290个代表性土样,并对土样中钙、镁、硫、硅4种中量元素有效态含量进行了检测和评价。结果显示,全市土壤交换性钙、交换性镁、有效硫和有效硅平均含量分别为4 570、403、26和144 mg/kg。如皋市土壤交换性钙、镁含量丰富,但在各土系土壤间分布不均。有效硫和有效硅同时存在缺乏和过高现象。整体来看,有近1%的土壤缺硅,约14%的土壤缺硫。土壤交换性镁和有效硅的含量为中等变异,交换性钙和有效硫的含量属于高度变异。相关分析显示,4种中量元素有效性与土壤pH、有机质、全氮、有效磷和速效钾含量存在不同程度的相关性。如皋市土壤中量元素有效性不仅与成土母质关系密切,同时受土壤理化性状以及肥料施用的重要影响。今后中量元素肥料的施用应考虑多种因素,以实现平衡施肥。     

Transformation and Availability of Various Forms of Zinc in Soils

The transformation and availability of various forms of Zn applied into a cinnamon soil and a carbonate meadow soil as well as the effects of fertillizer-P on them were studied by using the field experiment method and chemically sequential extraction procedure.Zn added into the soils was found to be rapidly transformed into the various forms. In the cinnamon soil,the amount of Zn transformed into the carbonate bound form was the highest,and the carbonate bound form was proven by the analyses of intensity factor and capacity factor to be the primary available Zn pool.But in the carbonate meadow soil,the Zn transformed was relatively homogeneously distributed in the various forms though the amount of Zn transformed into the Mn-oxide bound form was relatively high,and the organically bound,Mn-oxide bound and amorphous Fe-oxide,bound forms were found to be the main available Zn pool.Fertilizer-P took part in the regulation and control of available Zn in the soils to a certain degree.In the carbonate meadow soil,application of P fertilizer probably aggravated Zn deficiency at low Zn rate,while it was favorable to the storage of available Zn in the case of high Zn rate.     

Availability of Organic and Inorganic Phosphorus Fractions to Wheat in Toposequences of Calcareous Soils

Abstract

Information on the availability of different soil phosphorus (P) forms is useful for crop production. Phosphorus contents of 12 Iranian calcareous soils from upper‐, mid‐, and lower‐slope positions of two arid and two semiarid toposequences were fractionated to various organic and inorganic pools, and correlations of the P fractions with wheat responses were investigated. Among the inorganic P (IP) fractions, apatite type (Ca₁₀‐P) and dicalcium phosphate equivalents (Ca₂‐P) possessed the highest and the lowest amounts of P reserve in the soils, respectively. On average, about 20% of the total P was found in organic form (OP), of which 32% was labile (LOP), 51% was moderately labile (MLOP), and 17% was nonlabile (NLOP). The amounts of the soil P fractions were considerably influenced by the positions of the soils on the landscapes. The maximum contents of soil IP, Ca₂‐P, Fe‐P (iron‐bound P), and Ca₁₀‐P were observed in the lower‐slope positions. The amount of soil available [0.5 M sodium bicarbonate (NaHCO₃) extractable] P was significantly correlated with Ca₂P (r=0.895), Fe‐P (r=0.760), and Occl‐P (iron‐occluded P) (r=0.897). Direct correlation studies, however, showed that wheat shoot dry‐matter yield (DMY) was significantly affected by the amounts of Ca₂‐P, Fe‐P, OP, LOP, and MLOP fractions both at early (4 weeks) and late (10 weeks) stages of growth. All organic and inorganic P fractions, except Al‐P (aluminum‐bound P), Ca₈‐P (octacalcium phosphate equivalents), and NLOP, also showed significant relations to the amount and/or concentration of P in wheat tissues at 4 and 10 weeks after sowing. Among the measured soil properties, the amount of organic carbon was the most affecting factor on the size of the P fractions.     

丛枝菌根对菲芘污染土壤中几种酶活性的影响

采用温室盆栽试验方法,研究了丛枝菌根真菌（AMF）Glomus mosseae和Glomus etunicatum对菲芘复合污染土壤中3种酶活性的影响。宿主植物为三叶草（Trifolium repens L.）和黑麦草（Lolium multiflorum Lam）。土样中菲和芘起始浓度分别为203.4mg·kg^-1和107.5mg·kg^-1。结果表明,植物增加了土壤多酚氧化酶、酸性磷酸酶和过氧化氢酶活性。接种Glomus mosseae和Glomus etunicatum使三叶草根际土壤多酚氧化酶活性20-60d分别增加19.6%-72.0%和29.7%-90.6%,过氧化氢酶活性分别增加3.3%-12.2%和7.8%-34.7%,酸性磷酸酶活性总体呈增加趋势;接种Glomus mosseae使黑麦草根际多酚氧化酶活性增加18.0%-43.1%,过氧化氢酶活性总体上呈降低趋势,酸性磷酸酶活性先升高后降低。供试的两种AMF对三叶草根际酸性磷酸酶和过氧化氢酶活性的影响30d前有显著差异。AM真菌作用的性质与宿主植物特性有关。     

蚯蚓黏液对黑麦草幼苗生长及其对菲吸收的影响

以50 mg/kg菲人工污染黄棕壤为供试土壤,设置添加蚯蚓黏液处理和不添加蚯蚓黏液对照（(CK）),研究蚯蚓黏液对黑麦草幼苗生长及吸收菲的影响,添加蚯蚓黏液处理根据蚯蚓黏液浓度设置4个水平,分别为蚯蚓黏液原液浓度的2/8,3/8,1/2和1倍。结果显示：①蚯蚓黏液促进了黑麦草幼苗的生长,根系鲜重比对照增加了33.6% ~ 146%,地上部和整株生物量鲜重比对照增加了12.4% ~ 35.8% 和34.5% ~ 59.6%;②显著降低了根部菲的浓度,约23.0% ~ 49.0%,促进了黑麦草对菲的吸收,使吸收量比对照增加了约62.8%;③降低了黑麦草根系对菲的富集系数,与对照相比降低约33.7% ~ 52.6%,提高了菲在黑麦草体内的传输系数,约54.0% ~ 102.0%。