Copper,Zinc, and Lead Fractions in Soils Long-Term Irrigated with Municipal Wastewater

Long-term irrigation with municipal wastewater may lead, even in spite of intense farming, to an accumulation of organic matter, nutrient elements, and trace metals in soils. Excessive increases of heavy metals may pose a potential risk to the food chain and provoke restrictions for the further cultivation of sensitive crops. Copper (Cu), zinc (Zn), and lead (Pb) forms in soils under long-term irrigation (for 100–120 years) with treated wastewater of Wroclaw were investigated by using selective seven-step sequential extraction (procedure of Zeien-Bruemmer) for partitioning the metals into operationally defined fractions, likely to be released in solution under various environmental conditions. The largest fraction of Cu, Pb, and particularly Zn in nonirrigated (control) soils was strongly bound in a residual form, while the percentage of exchangeable and the most labile fractions were negligible. Total concentration of metals in irrigated soils was elevated, and significant redistribution of metals among phases was observed. Percentages of residual fraction of Cu and Pb were no more than 25% (Zn < 40%), while significantly increased contribution of fractions occluded on iron (Fe) oxides and organically bound Cu. Exchangeable and readily mobile forms of Zn are predominant zinc fractions in soils irrigated with wastewater.     

添加外源耐砷菌与零价铁对土壤砷有效性和形态的影响

采用室内土壤培养试验,探讨了外源添加耐砷真菌棘孢木霉（TrichodermaasperellumL．）和零价铁对土壤砷的有效性和形态转化的影响。结果表明：向污染土壤中添加耐砷真菌棘孢木霉后,随着培养时间的延长,土壤中水溶态砷和NaHCO,提取态砷含量均呈稳定增加趋势,耐砷真菌促进了土壤中砷的溶出和释放;培养30d时,耐砷菌处理土壤有效砷含量比同期对照增幅达3．9％-10．7％,水溶态砷以As（V）为主,未检测到As（Ⅲ）、一甲基胂（MMA）、二甲基胂（DMA）等其他形态的砷;随着外源零价铁的加入,土壤中砷的活性大大降低,其有效砷含量降幅为76．5％-90．4％;在耐砷菌与零价铁联合作用下,相比于单纯的零价铁处理,土壤有效砷含量显著增加（p〈0．05）,因耐砷真菌棘孢木霉的加入导致零价铁对土壤砷的固定效率下降7．0％-11．1％。耐砷菌导致土壤砷活化可能主要与残渣态向非专性吸附态砷的转化等过程有关,外源零价铁对土壤砷的固定作用可能与非专性吸附态向无定形及弱晶质氧化物结合态、残渣态砷等转化过程相关;耐砷菌的加入抵消了零价铁对土壤砷的部分固定效果,但短期内（〈30d）不会构成大的影响。     

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.     

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.     

Redistribution and Availability of Iron,Manganese, Zinc,and Copper in Four Malian Agricultural Soils Amended with Solid Municipal Waste Compost

Abstract

Municipal waste compost can improve the fertility status of tropical soils. The redistribution of iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) in tropical soils after amendment with solid municipal waste compost was investigated. Four tropical agricultural soils from Mali characterized by poor trace‐element status were amended with compost and incubated for 32 weeks at 35°C. The soil were analyzed at the beginning and the end of the incubation experiment for readily available fractions, organic fractions, and residual fractions as operationally defined by sequential extraction. Readily available Fe increased significantly with compost application in most soils. Readily available Mn was mostly unaffected by compost application. After 32 weeks, readily available Zn had increased, and readily available Cu had decreased. Readily available levels of the elements remained greater than deficiency levels in the compost‐amended soils. Organic fractions of the elements increased after compost addition. The organic fractions and residual forms, depending on the element and the soil, remained constant or increased within the duration of the experiment.     

Effect of Water Quality on Heavy Metal Redistribution and Mobility in Polluted Agricultural Soils in a Semi-Arid Region

Mornag Plain is a coastal area of the Mediterranean basin, which has undergone an agricultural industrial boom. The aim of this study was to investigate the different water qualities used for irrigation on heavy metal mobility in these polluted agricultural soils. The geo-accumulation indices for heavy metals (Ni, Cr, Pb, Cd, Cu, and Zn) revealed that industrial activities and used treated wastewater (TWW) contributed to soil pollution, and water irrigation always decreased this contamination. After long-term use of different water types, high perturbation of heavy metal redistribution has occurred. Groundwater use altered all heavy metal redistributions in the irrigated soil among various soil-solid and soil-solution fractions, as compared to the unirrigated soil. Slight acid water use transferred some metals from different solid phase components into water-soluble and exchangeable fractions. However, TWW use transformed some Ni, Cr, Cd, Cu, and Zn from water-soluble and exchangeable fractions to less labile fractions, particularly into organically bound fractions. Reuse of conventional water within the same soil decreased the whole soil redistribution index values, indicating tendency to return to the pattern of distribution of groundwater-irrigated soil.     

Distribution and Availability of Zinc and Copper in Benchmark Soils of Pernambuco State,Brazil

Abstract

The benchmark soils collection of Pernambuco state contain 13 of the 14 soil orders of the Brazilian System of Soil Classification. Thus, information on zinc (Zn) and copper (Cu) status in such soils is useful as a reference of micronutrient distribution and availability in a representative set of Brazilian soils. The present work was performed to assess Zn and Cu distribution into operationally defined fractions of benchmark soils of Pernambuco state. In addition, chemical extractants, with contrasting chemical properties, were used to assess the availability of these micronutrients to relate such values with fertility guidelines concentrations and with the fractions defined by the sequential extraction. The results demonstrated that the organic matter was the most important fraction retaining Zn and Cu in the studied soils, as indicated by the sequential extraction. The Zn availability in the majority of the soils (90% of the samples) is sufficient to meet the requirement of the major field crops, although the available Cu concentrations are below the critical levels for plant growth in 46% of the analyzed samples. Mehlich‐1 extractant appeared to be the most efficient in predicting the availability of Zn in the soils because of its better correlation with exchangeable and organic fractions. DTPA and Mehlich‐3 were the most efficient extractants for the evaluation of Cu availability, as suggested by the better correlation with organic matter, which is the main pool of available Cu in the soils.     

Hyperspectral Visible and Near-Infrared Determination of Copper Concentration in Agricultural Polluted Soils

The objective of this research was to develop a hyperspectral imaging system for estimating copper concentration in soils as an alternative to standard chemical analyses and to evaluate the analytical accuracy of the system using the visible–near-infrared and near-infrared regions. Hyperspectral imaging is a complex technology providing elevated information content. This work was carried out on air-dried <2-mm soil fraction contaminated by adding 20 mL of copper sulfate at concentrations ranging from 0 to 1000 mg of copper per kg of soil. The samples were scanned in random order and with orientation using visible–near-infrared and near-infrared spectrophotometers. A range of partial least squares regression models derived from the spectral arrays were tested on their ability to predict copper concentration. Significant correlations between predicted and known chemical concentrations were achieved with a correlation coefficient of 0.93 for the visible–near-infrared and 0.77 for the near infrared.     

Modeling the Requirements of Agricultural Limestone in Acid Sulfate Soils of Brazil and Colombia

The aim of this study was to model the determination of the amount of agricultural limestone necessary to correct acidification in acid sulfate soils (ASS). This study used 14 equations and the chemical variables of the soils including pH, soil organic matter (SOM), potential acidity (H+ Al), sum of bases (BS), potential acidity (T), base saturation (V) and exchangeable Al with KCl. The results indicated that in the studied, the lowest requirements for doses of limestone (DL) were described by the equations DL = 2.906((H+ Al) (45-V)/100)°⁸⁰, DL = 0.08 + 1.22Al_KCl, DL = 0.6T – BS, and DL = 1.5Al_KCl, with mean values of 29.5, 30.5, 31.5 and 37.4 t ha^?1. In addition, the models with the best correlation for determining the limestone requirements to obtain 80% of the maximum production of sorghum (dry matter) were DL = ?1.43 + 0.9237 (SOM (6-pH)) and DL = ?0.022 + 2.7425 ((H+ Al) (45-V)/100).     

平衡时间及含水量对红壤有效态铅提取量的影响

比较了4种浸提剂在9种平衡时间和2种土壤含水量条件下对红壤铅的提取能力。结果表明,随着平衡时间延长和土壤含水量增加,铅提取量有逐渐增加的趋势。不同提取剂提取的有效态铅达到平衡的时间分别为HAc4小时;NH4NO32小时;HCl2小时;EDTA1.5小时。不同提取剂的提取能力不同,对于黄筋泥,其顺序为:1molL-1NH4NO3<2.5%HAc<0.05molL-1HCl<0.01molL-1EDTA;对于红砂土,其顺序为:2.5%HAc<1molL-1NH4NO3<0.05molL-1HCl<0.01molL-1EDTA。     

滨海盐土灌水脱盐动态的土壤质地和水质差异性研究

通过在天津滨海新区的野外灌水脱盐试验,对比分析了灌溉淡水、中水和微咸水的中壤质、重壤质土和粘土土壤含盐量及pH的动态变化。结果表明,粘质滨海盐土经灌淡水后的土壤全盐量降低是逐渐的;重壤质滨海盐土的土壤全盐变化趋势与粘质土相似,最初4次灌水使各层土壤全盐累积降幅较大;中壤质滨海盐土则第一次灌水后土壤含盐量降低较多,表层（0～20cm）由1.75%降到0.511%,以后灌溉土壤全盐量降低得较缓慢,20～40cm土层的含盐量始终降低得较缓慢。灌溉淡水、中水、微咸水均能使土壤全盐量降低,灌溉中水、微咸水后表层和土体下层土壤的含盐量均逐渐降低,而灌溉淡水的表层土壤全盐量以初次降低明显,土体下层的土壤全盐量始终变化幅度较小。同灌淡水的情况下,中壤质滨海盐土的土壤pH较为稳定,在7.5～8.5范围,而重壤质和粘土在最初表现下降,至约7.5后上升到8.5～9.0范围,质地越粘土壤pH越高。灌溉淡水、中水、微咸水均使土壤pH有升高的趋势,灌溉淡水后表层土壤pH能够上升到9.0,灌溉微咸水、中水后土壤pH能够升高至8.5左右。     

The Fate of Cryptosporidium Parvum Oocysts in Reclaimed Water Irrigation-history and Non-history Soils Irrigated with Various Effluent Qualities

The present study aimed to look at the fate of protozoan parasite Cryptosporidium parvum oocysts applied through surface drip irrigation on reclaimed water irrigation-history and non-history sandy-loam (Hamra) soil columns. A new and simple isolation method for recovery of oocysts from soil samples was developed and used along this study. The new soil isolation method of oocysts is based on the “two phase separation method” formerly used to recover Clostridium perfringens spores from sediments and soil samples with minor modifications. The range recovery achieved by this method was 64–95% (mean 61.2?±?17.4). The objectives of the second part of this study were to investigate several physical and chemical factors governing transport and survival of C. parvum oocysts in sandy-loam soil columns by breakthrough curves. Comparison of fresh water and reclaimed water irrigation revealed that reclaimed water irrigated-history soil was more hydrophobic allowing water flow through channels with poor oocysts retention and fast flow. Examination of the organic matter effect (originating from reclaimed water irrigation) on oocysts breakthrough revealed that their soil infiltration increased. Calculations of oocysts concentration at different columns depths showed that most of the oocysts were retained in the first 5 cm of soil column. In the present study, comparing the two soil types (history and non-history of effluents irrigation) beside the surface electrostatic charge, one of the main elements found to affect oocysts infiltration and transport in soil columns was soil hydrophobicity caused by soluble organic matter originating from reclaimed water irrigation. Therefore, prior to application in soil irrigation, reclaimed water should be treated to high quality (i.e. membrane technology as the best option) to prevent enhanced transport of various pathogens through those irrigated soils.     

Positive Effects of Biochar and Biochar-Compost on Maize Growth and Nutrient Availability in Two Agricultural Soils

Previous studies have reported positive, negative, or neutral effects on maize yield by the application of biochar and/or compost in the presence or absence of inorganic fertilization. This study investigated the influence of biochar, compost, and mixtures of the two, along with N fertilization, on maize (Zea mays L.) growth and nutrient status in two agricultural Mediterranean soils. Biochars (BC) were produced from grape pomace (GP) and rice husks (RH) by pyrolysis at 300°C (BC-GP; BC-RH). Maize was grown for 30 days after seedling emergence in a greenhouse pot trial in two Mediterranean soils (Sandy Loam-SL and Loam-L) amended with biochar or/and compost (BC-GP+compost; BC-RH+compost) at 2% (w/w) application rate with nitrogen (N) fertilization. The addition of BC-GP amendment resulted in the highest increase of aboveground dry weight (16 g/pot) compared to the control (6.27 g/pot) in SL soil, whereas in L soil the highest increase of aboveground dry weight resulted from BC-RH+compost (13.03 g/pot) compared to the control (2.43 g/pot). The addition of BC-GP+compost significantly increased phosphorus (P) concentration of the aboveground and belowground tissues only in L soil. Potassium (K) concentration of aboveground and belowground tissues significantly increased almost by all the amendments with the greatest increase being observed after the addition of BC-GP+compost in SL soil. To conclude, biochar addition could enhance plant growth, although soil conditions, type of biochar and additional fertilization should receive special attention in order to be used as a tool for sustainable agriculture.     

Estimating Trace Element Availability in Soils with a Seasonal Water Table using Commercially Available Protocols

The soil accumulation of metals and other elements as a result of human activities is a global concern. This investigation involves the use of commercially available extractions to estimate elemental abundance and availability. The need exists, especially in poor nations, to have cost-effective analytical capabilities to perform an initial screening of a soil resource to determine if a problem exists. Three extraction protocols are proposed: (i) an aqua regia digestion to estimate a baseline geochemistry, (ii) a pyrophosphate extraction to estimate elemental abundances associated with the soil organic fraction, and (iii) a water extraction to estimate the most available fraction. If the soil resource is impacted, then more refined and traditional methods are required to document the extent of impact for possible remediation. The three extraction protocols were applied to soils with little impact to illustrate the assessment potential for selected metals and p-block elements.     

Characterization of the Soil Organic Matter in Agricultural Mine Spoils and Reclaimed Soils Treated with Organic Amendments

Recycling organic waste in agricultural soils is a valid solution. We performed short‐term experiments to investigate the fate of urban sludge and composts, in mine spoils, cultivated or uncultivated, and reclaimed soils located in Florence and Milan, Italy. The samples, either treated or untreated, were fractionated by density into light (<1.63 Mg m^?3) and heavy (>1.63 Mg m^?3) fractions. The fractions were analyzed for total carbon (C) and nitrogen (N) contents and for δ ¹³C and δ ¹⁵N isotopes, and they were characterized by ¹³C NMR spectroscopy. Treatment increased the heavy fraction. The addition of sludge in the Florence area acts in synergy with the cultivation, increasing the light fraction (LF). In the Milan area, the LF tends to be decomposed and apparently transformed into HF. The addition of amendments or cultivation enhances the decomposition with release of carbon dioxide. For future research, we suggest lengthening the time of the experiments to integrate climatic variations.     

Distribution of Copper in Sediments from Fluvial Reservoirs Treated with Copper Triethanolamine Complex Algicide

The control of algal growth in water reservoirs with copper-based algicides leads to elevated sediment Cu concentration and thus could affect long-term water quality. To assess the potential mobility of sediment-associated Cu, a study was conducted using samples from three drinking water reservoirs treated with Cutrine®, a copper triethanolamine complex algicide. Total Cu (Cu_T) in treated reservoir sediment ranged from 13.3 to 139.9 mg Cu kg^?1 and was on average 1.5 times the level in streams (48 mg Cu kg^?1) flowing into the reservoirs. Sediment Cu_T and algicide application history indicated the retention of 82–93% of the algicide Cu applied. Sequential extraction showed that Cu primarily accumulated in the residual fraction (60%), whereas the potentially mobile pools (water extractable: Cu_H2O, exchangeable: Cu_EX, organic bound) accounted for <10% of Cu_T. The leachable Cu fraction (extracted with 1 M acetic acid) also amounted to <9% of Cu_T and was related negatively to C/N and positively to H/C ratios of organic matter. In addition, these potentially mobile fractions were found to be related, not to total organic C, but to sediment respiration suggesting that the potentially mobile Cu fractions were primarily associated with aliphatic and readily biodegradable C (more so than total organic C). During a 2-year period without algicide treatment (that followed 4 years of repeated algicide applications to one of the studied reservoirs), mean dissolved Cu (micrograms per liter) in the reservoir (39.2) was similar to levels measured at locations upstream (43.3) and downstream (47.2) from the reservoir. These results indicate that the bulk of sediment Cu is associated with geochemically stable solid phases and thus should alleviate concerns about Cu transfer into the water column.     

Phosphorus Availability in Soils Amended with Different Phosphate Fertilizers

Abstract

Accurate measurement and characterization of phosphate rock dissolution are important for a better understanding of phosphorus (P) availability in soils. An incubation study was carried out on two New Zealand topsoils (0–15 cm; high P buffering capacity Craigieburn and low P buffering capacity Templeton) amended with North Carolina phosphate rock (NCPR) and water‐soluble phosphate (WSP) at 218 mg P kg^?1 (equivalent to 60 kg P ha^?1). Isotopic exchange kinetics was carried out after 12 h and 28 days of incubation to characterize P availability. This study showed that sensitivity of capacity factors (r₁/R, n) to explain changes in E_1min values was affected by the P buffering capacity of the soils. The recovery of applied P in the E pool (Rec_inE%) with extended incubation time was similar from the NCPR and WSP treatments (3.1–3.3%) in the Craigieburn soil compared with the Templeton soil in which Rec_inE% values were greater in WSP (9%) than NCPR (1.3%) treatment. The higher values of P derived from the applied P fertilizers in the E pool (Pdff_inE%>80%) suggested that the NCPR application in both soils would be efficient for increasing P availability to plants.     

污灌土壤中氟及硫的形态分布特征

以乌鲁木齐雅马里克山的石灰性土壤为研究对象,采用连续提取法和分步提取法对土壤氟和硫的化学形态进行了测定,研究了不同水质及外源对土壤氟和硫各形态的含量及其分布的影响.结果表明土壤氟主要以残渣态为主,占全氟含量99.5%以上.各形态氟呈残余态氟>有机束缚态氟>水溶态氟>可交换态氟>铁锰结合态氟的趋势.不同水质浇灌后,土壤硫主要以有机硫为主,占71.5%～81.2%.并且呈现有机硫>盐酸可溶性硫>水溶性硫>吸附性硫的趋势.外源物质对土壤理化性质及对土壤中氟和硫各形态有不同程度的影响.土壤氟和硫各形态之间以及各形态与土壤理化性质之间的相关性分析表明,全氟与残余态氟极显著相关.土壤全硫与有机硫之间具有十分密切的相关性.土壤pH值、有机质和CaCO₃含量是影响土壤中氟及硫赋存形态的主要土壤因子.     

Trace Metal Availability in Soils Amended with Metal-Fixing Inorganic Materials

Immobilization of metals by two materials (zeolite, AZ, and a synthetic, carbonate-rich material, “slovakite”, SL) was tested in a pot experiment with two soils from urban areas of Sevilla and two soils affected by a mine spill. Barley (Hordeum vulgare L. Hispanic) was grown in the pots, and metal contents were measured after 31 days in shoots and roots. Available metal was estimated by extraction with CaCl₂ (readily soluble), ethylenediaminetetraacetic acid (EDTA; plant available), a mixture of organic acids (soluble by root exudates), and glycine (bioaccessible by ingestion). Neither treatment caused significant differences on plant growth or metal contents of shoots, whereas roots contained more Cu in the SL treatments. Root Zn uptake was reduced in all cases, but reduction of Pb in roots was observed only in AZ treatments of the mine-spill soils. The effects on metal availability were often method-dependent. Decrease of CaCl₂ data were observed only in the mine-spill soils. EDTA-soluble metals were clearly decreased by both materials. Bioaccessible Zn were decreased by either material in several cases (but not in the most heavily polluted soil), whereas Cu or Pb data were less conclusive.     

Kinetics of Copper Desorption from Highly Calcareous Soils

Abstract

Desorption of copper (Cu) is an important factor in determining Cu availability in calcareous soils. Kinetics of native and added Cu desorption by DTPA (diethylene‐triaminepentaacetic‐acid) from 15 highly calcareous soils of southern Iran were studied in a laboratory experiment. Our results showed that two constant‐rate, Elovich, simple Elovich, and parabolic‐diffusion equations were the best‐fitted equations among eight kinetic models used. The copper desorption pattern based on the parabolic‐diffusion equation revealed that the rate of native Cu desorption was higher in the first 2 h followed by a slower release rate, which suggests that two different mechanisms are involved. The trend may describe why the DTPA soil test has been considerably successful in predicting Cu availability in calcareous soils. Stepwise multiple regression equations indicated that CCE (calcium carbonate equivalent), CEC (cation exchange capacity), and clay content are the most important soil characteristics that predict the rate constants of the kinetic models. Mean extractant recovery percentage (ERP) of the soils was only 20%, which indicated that after 20 days, DTPA extracted only one‐fifth of added Cu. Regression equations indicated that as soil OM (organic matter) content increased, the value of ERP decreased. From results reported herein it seems that CCE, CEC, and clay are the most important factors controlling Cu release from highly calcareous soils of southern Iran. However, the initial soil Cu desorption rate is probably controlled by CEC.