南宁市郊部分菜区土壤和蔬菜重金属污染评价

对南宁市郊 1 2个主要菜区土壤和蔬菜中重金属 ( Cu、Zn、Cd、Pb)含量调查和分析测定 ,采用重金属污染单因子评价方法对土壤重金属污染状况进行评价 ,以国家规定的蔬菜卫生标准评价蔬菜重金属污染状况 ,结果表明 :南宁市郊部分蔬菜区土壤不同程度地受到了 Cu、 Zn、 Cd、 Pb的污染 ,依次是 :Cd>Pb>Zn>Cu;蔬菜中 Cd、 Pb积累较 Cu、 Zn高 ,供试点中大部分蔬菜 Cd、 Pb含量超出了国家规定的蔬菜卫生标准     

重金属在矿区土壤——蔬菜系统的吸收与迁移特性研究

重金属污染土壤的农产品安全倍受大家的关注。研究选择某铅锌矿区周边的蔬菜地,采集叶菜类蔬菜及土壤样品,研究Cd、Pb、Cu、Zn在土壤中的赋存形态及其在土壤-蔬菜系统中的迁移特性。结果表明,污染土壤中Cd、Pb、Zn超标,分别为国家标准限值的1.44～6.44倍、2.97～3.88倍和1.30～2.30倍。BCR连续提取结果显示,Cd、Pb以可还原态为主,Cu、Zn以可还原态和残渣态为主,可还原态Cd、Pb、Cu、Zn分别占总量的70.6%、79.0%、34.4%和38.1%;残渣态Cu、Zn分别占总量的34.6%和30.2%。酸可提取态Zn、Cd分别达13.2%和6.3%。供试蔬菜茎叶中Pb含量超标,为国家标准限值的1.50～5.83倍。蔬菜茎叶中Cd、Pb含量与其土壤中可还原态含量显著正相关,Cd含量与土壤酸可提取态Cd含量显著正相关。蔬菜Cd的富集系数(BCF)相对较高(0.61～3.34),其中水芹和香芹Cd、Pb、Zn的BCF值显著高于其他蔬菜。蔬菜中Zn的迁移系数(TF)较高(0.54～2.07)。叶用芥菜中Cd、Pb、Zn的TF值较高,分别为1.02、2.25、1.62。因此,在污染土壤蔬菜风险评价中需要考虑不同蔬菜品种对重金属吸的吸收迁移特性的差异。     

海南省农产品重金属污染评价与特征分析

采用单项与综合污染指数法,以海南省农产品为研究对象,开展了农产品中重金属Cu、Zn、Pb、Cd、Ni、As、Cr和Hg含量的抽样调查分析与评价。结果表明,全省农产品中重金属的平均含量均低于食品中规定的限值,各重金属的单项与综合污染指数均≤1,综合污染指数为0.57;全省农产品未受重金属污染,属于安全水平,适宜发展无公害农产品。同时发现,个别监测点的农产品中重金属含量有超标现象,新鲜水果中个别样品Pb、Cd、Hg超标,超标率在2.17%～10.87%之间;豆类蔬菜中个别样品Ni超标,超标率为9.09%;瓜果类蔬菜中个别样品Pb、Cd超标,超标率为12.24%～24.49%;叶菜蔬菜中个别样品Pb超标,超标率为6.67%;谷物中个别样品Pb、Cd、As超标,超标率在2.11%～7.37%之间。农产品中重金属含量间多呈正相关,其中Zn与Ni、As与Hg之间差异达到极显著水平,Cu与Zn、Cu与As、Cu与Hg、Zn与As、Zn与Hg、Cd与As、Cd与Cr、Cd与Hg、Ni与As、Ni与Hg、As与Cr之间差异达到显著水平。结合主成分分析结果,推测Cu、Zn、Ni、As、Hg含量主要受农业生产和人类活动的影响,而Cr、Pb和Cd含量受土壤母质的影响比较大。     

郑州农区土壤重金属污染与蔬菜质量相关性探析

以单因子污染指数和综合污染指数为评价方法,对郑州市郊区3种不同灌溉方式农田土壤进行重金属(Hg、Cr、Cd、Pb、As、Cu、Zn)污染监测和蔬菜质量调查。结果发现,郑州市郊区的土壤均未超过GB15618—1995《土壤环境质量标准》二级标准限值;部分蔬菜已受到重金属的污染,含量超过国家食品卫生蔬菜类标准;土壤中的Zn、Cu、Cd、Cr污染与多数蔬菜的污染呈显著的正相关,而Pb、Hg污染在多数蔬菜中均表现为与土壤污染无相关性。     

重金属在猪饲料-粪便-土壤-蔬菜中的分布特征研究

本文调查分析了江西省余江县39个大型养猪场的饲料、猪粪、以及长期施用这些猪粪的菜地土壤及蔬菜的Cu、Zn、Pb、Cd含量,并对饲料、猪粪、土壤和蔬菜重金属含量进行了相关分析。结果表明,大猪和小猪饲料Cu含量超标率分别达81.6%和30.8%,Zn含量超标率分别达89.5%和94.9%,而Pb、Cd未超标。猪粪Cu、Zn含量亦严重超标,且饲料和猪粪中Cu、Zn、Pb、Cd含量呈显著正相关关系。土壤总Zn和总Cd含量分别有7.8%和5.2%的样品超过三级标准,污染较为严重。所有蔬菜样品Cu、Zn、Pb含量均未超过我国食品卫生质量标准,空心菜和芋头Cd含量超标。土壤总Cu、Zn、Cd含量与提取态呈显著正相关。     

重金属Cd、Zn、Cu、Pb复合污染对土壤微生物和酶活性的影响

通过野外土样采集及室内测定,研究了云南东川铜矿区土壤酶和微生物特征,并采用盆栽试验研究了重金属Cd、Zn、Cu、Pb复合污染对土壤微生物和酶活性的影响。结果表明,距离矿口越近,土壤有机质、有效N、P、K的含量、土壤pH值亦越低,土壤酶活性和土壤微生物数量、微生物生物量C和N受到的抑制程度也增强,其中土壤酶中的酸性磷酸酶和过氧化氢酶,土壤微生物中的细菌对重金属污染较为敏感。盆栽试验中,Cd、Zn、Cu、Pb复合污染使白菜(Brassica rapapekinensis)生物量明显下降,且随复合污染程度的增加,白菜生物量下降幅度增加。Cd与Zn、Cu、Pb,Zn与Cd、Cu、Pb,Cu与Cd、Zn、Pb的复合效应机制为协同效应,而Pb与Cd、Zn、Cu的复合效应机制为拮抗效应。重金属Cu、Zn、Pb、Cd复合污染使土壤酶活性显著降低,但低量的Cd、Zn、Cu、Pb复合污染刺激了细菌、真菌、放线菌、微生物生物量C和N。重金属Cd、Zn、Cu、Pb对土壤酶活性和土壤微生物数量及微生物生物量C和N的复合效应机制表现出协同和拮抗效应。     

海口市蔬菜基地土壤和蔬菜中重金属的分布特征及污染评价

对海口市四大蔬菜基地土壤-蔬菜系统重金属积累及污染状况进行了评价。结果表明,四个蔬菜基地中,新坡基地土壤中Cd、Cr、Zn、As、Ni最高,桂林洋土壤中Cu的含量在各基地中最高,坡博土壤中的Pb和Hg含量最高。叶菜中Pb、Cd、Cr、Ni等元素含量明显高于果菜,说明叶菜较果菜更易吸收和富集重金属。土壤中的Cd全部超过国家土壤环境质量二级标准(GB15612-1995),其中新坡基地土壤Cd污染指数最大。新坡土壤中的Ni超标率为66.7%。各基地土壤中Hg、As、Cr、Ni、Cu、Zn和Pb的含量均未超标,符合蔬菜种植用地要求。单项污染指数的评价结果表明,青菜、油菜、小白菜、大白菜、生菜、芹菜、西红柿均受到Pb轻度污染。综合污染指数结果表明,芹菜重金属轻微超标;青菜、油菜、小白菜、大白菜、生菜、西红柿的重金属污染处于警戒级水平;芥菜、薯叶菜、空心菜、辣椒、苦瓜的重金属属于安全水平。整体来看,叶菜类蔬菜中重金属的污染指数大于果菜类。仅Cr含量在蔬菜与土壤中呈显著负相关关系,说明蔬菜中重金属含量的高低受到除土壤之外的众多因素的影响。     

不同肥料长期施用下稻田镉、铅、铜、锌元素总量及有效态的变化

以中国科学院桃源农业生态实验站的长期田间定位试验为基础,研究了16年长期定量施肥对土壤Cd、Pb、Cu和Zn积累及其有效性的影响。结果表明:单施化肥可使土壤Cd含量降低、Pb含量增加,对Cu和Zn的积累无显著影响,水稻收获时的移出效应可能是Cd含量降低的主要原因;与单施化肥相比,有机物料循环可提高土壤Cd和Pb的积累,但对Cu和Zn的积累无显著影响。试验期内单施化肥对土壤Cd、Pb、Cu和Zn的有效性无显著影响;有机物料循环可显著提高Cd和Zn的有效性,这与有机物料循环引起的土壤有机质含量增加和pH降低有关。     

华北地区有机种植和常规种植模式下土壤重金属含量及污染评价

为探讨有机种植与常规种植两种不同种植方式对土壤重金属含量和污染特性的影响,本文在华北5个地区选取典型的有机蔬菜和有机小麦种植基地及附近相似条件的常规种植地块,比较了土壤中Cu、Zn、Pb、Cr、Cd、As共6种重金属含量的差异,并采用不同评价方法对不同种植方式下土壤中重金属的污染程度进行了评价。结果表明:与常规种植相比,有机种植减轻了土壤酸化和盐渍化,提高了土壤有机质含量和阳离子交换量,在一定程度上有利于降低土壤中重金属的生物有效性。与土壤背景值相比,所有调查地区的土壤重金属均有不同程度的增加和积累。与常规种植相比,有机种植模式能有效降低土壤中Cd、Cr含量,有机小麦种植地块因长期施用大量有机肥导致土壤中Cu、Zn、As大量富集;而常规温室菜田同时施用大量的有机肥、化肥及农药,土壤中Cu、Zn、As富集的风险比有机种植模式高;露天蔬菜有机种植地块土壤中Cu、Zn、As含量与常规地块差异不明显。综合污染指数评价结果显示,调查地区土壤均属于轻污染程度,主要贡献因子为Cd、Cu、Zn,有机种植降低了土壤中重金属的综合污染水平;地累积指数法评价结果表明,调查地区处于无污染到中等污染水平,最明显的污染元素是Cd,有机种植降低了土壤中重金属污染的程度和风险;潜在生态危害指数评价结果表明,所调查地块存在轻微潜在生态风险,其中产生较大生态危害的是Cd,表现出轻微生态危害程度。本研究表明,有机种植减轻了土壤中重金属综合污染水平和污染风险,并减轻了土壤重金属的潜在生态危害。     

深圳市主要公园及道路绿地土壤重金属含量状况比较研究

对深圳城市主要公园和道路绿地土壤Cu、Zn、Pb、Cd含量状况进行取样调查分析。研究结果表明,绿地土壤重金属含量与土地利用类型有关,表现为道路绿地土壤Cu、Zn、Pb平均含量高于公园绿地土壤,而Cd平均含量则相反。采用不同土壤重金属污染评价方法对深圳城市绿地土壤进行的环境质量评价均表明深圳城市绿地土壤Cd污染现象显著。在考察的四种重金属元素中,Zn含量与土壤有机质、pH有关,其中pH对Zn含量的影响相对较大;土壤Cu与Pb、Zn呈直线相关,表现出相互依存的关系。     

Bioavailability of As,Cd, Co,Cr, Cu,Hg, Mo,Ni, Pb,Se, and Zn from Biosolids Amended Compost

Appropriate compost standards are being considered in Canada. Five aspects of compost safety and quality are being evaluated; probably the most controversial aspect is the standards for metals in compost. In order to assist in the development of appropriate standards, the authors began an extensive research project in October, 1993 to determine the bioavailability of metals from compost and compost-metal mixtures. Swiss chard was grown in compost-amended soils or compost in a growth room using five treatments of increasing percentages of compost in the media (0, 25 percent, 50 percent, 75 percent, 100 percent compost (v/v)). A Truro loamy sand and a race-track manure-biosolids compost (RTM-biosolids) supplemented with a high metal biosolids were used in a completely randomized design with five replicates. Dry matter yield, metal content in plant tissue, and total metal uptake were evaluated as well as the total and DTPA-extractable metal content in the compost-soil mixes. The results of this and five other experiments conducted by the authors will help determine whether the suggested limits for As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se and Zn in composts are appropriate.     

Variation of N,P, K,Ca, Mg,Mn, Zn,and al in slash pine foliage

Abstract

The seasonal patterns of foliage nutrient concentrations and contents were monitored for two growing seasons in an 11‐year—old Pinus el1iottii stand. In the first growing season after needle initiation, N, P, K, Mg, and Zn concentrations decreased, but this was followed by an increase in the fall and winter months. Another drop in concentration of all elements, except P, occurred in the second growing season. Decreases in total contents indicated that this drop was a result of translocation to other tissues. In contrast to the mobile elements, the concentration and fascicle contents of Ca, Mn, and Al increased with aging of the needles.

Between‐tree variability was least for N, P, and Zn and the N, K, Mg, Mn, and Zn in the current foliage had consistently lower variation than that in the 1‐year‐old foliage. Between‐tree variation for K was lower in the winter than the spring.

For pine foliage, recommended sampling period for N, P, Mg, and Zn is mid to late summer and for the other elements it is late fall to late winter.

There are several sources of variation that influence the level of nutrients in tree foliage. The most important of these, apart from the tree nutrient status, are seasonal fluctuations, variation between trees, and age of needles . Smaller sources of variation are associated with position of the needles within the crown, diurnal changes, year to year variation, and analytical errors^1,2. These variables must be studied in order to develop suitable sampling techniques and in Pinus this has been undertaken for P. banksiana ¹, P. taeda ³, P. strobus ⁴, P. resinosa ⁴, P. sylvestris ⁵, and P. radiata ^6,7. However, foliage sampling has not been studied in detail for slash pine (Pinus elliottii Englem var. elliottii) and earlier studies with other pines have been largely confined to temperate or cool climates.

This study reports the variation in elemental concentrations with season, age of foliage, and between slash pine trees growing in a subtropical climate in Florida.     

Phytotoxicity of cobalt,vanadium, titanium,silver, and chromium

Abstract

The phytotoxicity of five nonessential elements (Co, V, Ti, Ag, Cr) to higher plants was studied in solution culture experiments with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen). All, but in varying degrees, tended to concentrate in roots with a decreasing gradient to stems and leaves. Cobalt was one of the more mobile of the five trace metals. Its toxicity was expressed as severe chlorosis; 43 (with 10^‐5 M) and 142 (with 10^‐4 M) μg Co/g dry weight in leaves resulted in severe chlorosis. Vanadium as 10^‐4 M vanadate resulted in smaller plants but not in chlorosis. Leaf, stem, and root V, respectively, were 13, 8, and 881 μg/g dry weight. Titanium was somewhat mobile with considerable yield decrease at 10^‐4 M; leaf, stem, and root Ti concentrations, respectively, were 202, 48, and 2420 μg/g. Symptoms were chlorosis, necrotic spots on leaves, and stunting. Silver was very lethal at 10^‐4 M AgNO₃; at 10^‐5 M yields were greatly decreased, but plants were grown without symptoms. Leaf, stem, and root concentrations of Ag for this treatment, respectively, were 5.8, 5.1, and 1760 μg/g dry weight. Plants grown with 10^‐5 N Cr₂O₇ were decreased in yield by about 25% with or without EDTA (ethylenediamine tetraacetic acid) while the same level of Cr₂(SO₄)₃ was essentially without effect. For the two salts, the leaf, stem, root concentrations for Cr, respectively were 2.2 and 1.3, 0.7 and 0. 7, and 140 and 104 μg/g. Most of the trace metals studied here had interactions in the uptake and/or distribution of other elements.     

Thin layer chromatographic determination of aflatoxins, ochratoxins, sterigmatocystin, zearalenone, citrinin, T-2 toxin, diacetoxyscirpenol, penicillic acid, patulin, and penitrem A.

A general method is described for determining 16 mycotoxins in mixed feeds and other food products used in the manufacture of these feedstuffs. The mycotoxins are extracted and cleaned up by extracting with solvents of different pH. Thin layer chromatography is used to separate the toxins; toxins are then quantitated by the limit detection method. The minimum detectable concentration of mycotoxins in various products is: aflatoxin B1 or G1, 4--5 micrograms/kg; ochratoxin A or ethyl ester A 140--145 micrograms/kg; citrinin 600--750 micrograms/kg; zearalenone, 410--500 micrograms/kg; sterigmatocystin, 140--145 micrograms/kg; diacetoxyscirpenol, 2400--2600 micrograms/kg; T-2 toxin, 800--950 micrograms/kg; patulin, 750--800 micrograms/kg; penitrem A 14,000--14,500 micrograms/kg; penicillic acid 3400--3650 micrograms/kg.     

Evaluation of Decomposition Procedure to Determine Ba,Co, Cr,Cu, Ni,Mn, V,and Zn Total Content in Soil Samples

Different procedures have been proposed to decompose soil samples. Most of them regard determination with fertility aims. In this case, the contents available to the plants are considered. On the other hand, there are procedures to determine total content. The objective of this work was to propose a new decomposition procedure to determine barium (Ba), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), vanadium (V), and zinc (Zn) total content in tropical soils with high content of oxides and silicate. According to the results, the digestion procedure proposed in this study provided satisfactory results for the contents recovery for the elements Ba, Co, Cr, Cu, Mn, Ni, V, and Zn, above 90%, and the use of inverted aqua regia, hydrogen peroxide (H₂O₂), hydrofluoric acid (HF), pre-digestions and agitation was shown as a new alternative for the high silicate content soil sample total digestion, such as the oxisols.     

Organochlorine pesticide residues in different Indian cereals, pulses, spices, vegetables, fruits, milk, butter, Deshi ghee, and edible oils.

A total of 244 samples of cereals (wheat flour, rice, and maize), pulses (arhar, moong, gram, lentil, and black gram), spices (turmeric, chili, coriander, and black pepper), vegetables (potato, onion, spinach, cabbage, brinjal, and tomato), fruits (mango, guava, apple, and grape), milk, butter, Deshi ghee, and edible oils (vegetable, mustard, groundnut, and sesame) collected from different cities of Northern Province (Utter Pradesh) were analyzed by gas liquid chromatography for the presence of organochlorine pesticide residues. Residues of hexachlorocyclohexane (HCH) and 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) were detected in about 85% of the total samples of cereals, spices, milk, butter, Deshi ghee, and edible oils analyzed in the present study. However, the residue levels were either very small (less than 0.06 ppm) or not detected at all in pulses, vegetables, and fruits as compared with very high concentrations in wheat flour (4.42 and 0.12 ppm), butter (1.19 and 4.85 ppm), mustard oil (1.26 and 2.42 ppm), Deshi ghee (1.10 and 3.84 ppm), vegetable oil (1.02 and 0.59 ppm), groundnut oil (0.51 and 1.49 ppm), and chili (0.48 and 1.92 ppm). The levels of HCH and DDT residues detected in rice, maize, turmeric, corlander, black pepper, and all the vegetables and fruits were also lower than those found in wheat flour, oil, and fat samples analyzed in the present study. These findings suggest that a restricted and controlled use of such persistent pesticides may be useful for decreasing their contamination levels in different food items.     

Estimation of Reference Values for Cadmium,Cobalt, Chromium,Copper, Nickel,Lead, and Zinc in Brazilian Soils

Abstract

The objectives of this study were 1) to recommend reference values (RVs) and tolerance limits (TLs) for representative Brazilian soils and 2) to propose a model to calculate natural contents of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in a soil from the silt, clay, manganese (Mn), iron (Fe), and cation exchange capacity (CEC) values. A set of 256 soil samples was classified by similarity in seven groups, and the concentrations corresponding to the upper quarter of data collected were then calculated. These concentrations are proposed as RVs for Brazilian soils. Additionally, TLs were obtained for each group from the antilog expression (m+2s), where m=mean value and s=standard deviation of data transformed in log₁₀. The classification functions of discriminant analysis proved to be suitable to allocate new samples in the established groups. Thus, it is possible to evaluate soils under anthropic activity and, by comparison with reference values, to be aware of pollution risks in a given area.     

Caimans,Capybaras, otters,manatees, and man in amazonia

Amazonia, the world's largest tropical rain forest, is often assumed to be a virtually untouched wilderness. The region is often referred to as a demographic void; there is on average only about one person per sq. km. Yet in response to international market forces, the hand of man has penetrated deep into the imposing forests. Since colonial times, wildlife, particularly along rivers, has been exploited on a large-scale basis for commercial purposes. This paper focuses on the effects of the trade on some aquatic animals.     

Die Bindungsformen von Si,Mg, Fe,Al, Mn,Cr, Ni und Co in Saprolit und Laterit über Serpentinit,Insel Gebe,Indonesien

Fixation of Si, Mg, Fe, Al, Mn, Cr, Ni and Co in saprolite and laterite above serpentinite - Gebe Island, Indonesia The fixation of various major and trace elements has been studied in a saprolite/laterite profile above serpentinized peridotite. Sequential extraction of < 63 μm fraction shows different types of element fixation in soil: adsorption on mineral surfaces (1), fixation to Mn-oxides (2), bonding to poorly and better crystallized Fe-oxides (3). In the laterite, most of the extractable Si-, Al-, Cr- and Ni-contents are bound to goethitic Fe-hydroxide. The saprolite has considerable amounts of secondary quartz which has been formed during ageing of amorphous silica modifications. Their precipitation is favoured by high Si adsorption capacity of poorly crystallized Fe-hydroxide. In saprolite and laterite Co is bound to Mn-oxides. It can readily be extracted from pure Mn-oxides. In contrast, the intimate association of Mn-oxides to goethite reduces the rate of easily extractable Mn and Co in middle and upper zones of the laterite.