我国城市土壤重金属的污染格局分析

收集了国内43个大中城市的3688个城区土壤重金属数据,通过描述性分析、评价分析、聚类分析等,初步确定了我国城市土壤重金属的污染格局.结果表明,我国城市土壤As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的平均赋存量分别为13.39、0.68、63.04、38.17、0.31、26.18、47.34、137.72 mg·kg-1.Nemerrow指数、地质累积指数和潜在生态危害指数评价表明,污染最严重的城市是太原、南京、开封,主要污染重金属是Hg、Cd、Pb.43个城市中,上海、武汉、淄博、昆明、抚顺、昌吉、郑州、贵阳、成都、攀枝花、天津、珠海、大庆、北京、南宁、广州、香港、长春、太原等19个城市属于Cd强度污染;徐州、长沙、开封、重庆、乌鲁木齐、沈阳、西安、杭州、南京、兰州、洛阳等11个城市属于Hg-Cd强度污染、Pb中度污染;其余13个城市属一般轻度污染.长江以南城市土壤重金属污染比长江以北城市严重,中小城市土壤重金属污染低于特大城市.     

改良剂对中国两种典型土壤铜锌有效性的影响及机理

研究了改良剂对土壤铜锌有效性的影响,以期对重金属复合污染土壤的修复有一定的指导意义。在红壤与黄泥土中施用石灰、重钙和沸石,观测土壤有效态铜锌含量及pH,并测定了不同pH值下土壤有效态铜锌含量,以阐明改良剂影响土壤重金属有效性的机理。向供试土壤中外源加入一定量的铜锌溶液,制成铜、锌污染土壤,稳定平衡30d,采用CaCl2浸提法测定土壤有效态铜锌的含量。结果表明,施用改良剂能显著降低土壤铜锌的有效性,其中石灰的效果最佳,沸石次之,重钙最差。两种土壤中,复合污染下铜锌有效态含量均高于单一污染,其中铜单一污染有效态含量与复合污染差异显著(P<0.05),而锌单一污染与复合污染差异不显著(P>0.05)。可能是因为锌比铜竞争力更强,更易于被土壤吸附固定。随着土壤pH升高,两种土壤的有效态铜锌含量均显著下降,且复合污染高于单一污染;而在相同pH值下,两种土壤中有效态铜锌含量的差异不显著。可见,pH值是影响土壤重金属有效性的关键因素。改良剂影响土壤重金属有效性的主要机理在于其能显著提高土壤pH值,致使有效态重金属含量明显下降。     

中国城市土壤重金属污染研究现状及对策

中国城市土壤重金属污染的主要来源是工业“三废”排放，金属采矿和冶炼，家庭燃煤，生活垃圾，汽车尾气排放。重金属在城市土壤中的分布规律表现为城市土壤重金属含量高于郊区，人类活动密集区和交通拥挤区重金属含量较高；人类活动的干扰导致土壤剖面重金属污染特征不明显。应采取预防与治理相结合的措施综合控制土壤重金属污染，并加紧制定我国的城市土壤健康评价标准。     

Bioavailability of trace metals in brownfield soils in an urban area in the UK

Thirty-two brownfield sites from the city of Wolverhampton were selected from those with a former industrial use, wasteland or areas adjacent to industrial processes. Samples (<2 mm powdered soil fraction) were analysed, using inductively coupled plasma–atomic emission spectrometry (ICP–AES) for 20 elements. Loss on ignition and pH were also determined. A five-step chemical sequential extraction technique was carried out. Single leach extraction with 0.12 M hydrochloric acid of Pb, Cu and Zn in soil was determined as a first approximation of the bioavailability in the human stomach. Some of the sites were found to have high concentrations of the potentially toxic elements Pb, Zn, Cu and Ni. The partitioning of metals showed a high variability, however a number of trends were determined. The majority of Zn was partitioned into the least chemically stable phases (steps 1, 2 and 3). The majority of Cu was associated with the organic phase (step 4) and the majority of Ni was fractionated into the residue phase (step 5). The majority of Pb was associated with the residue fraction (step 5) followed by Fe–Mn oxide fraction (step 3). The variability reflects the heterogeneous and complex nature of metal speciation in urban soils with varied historic histories. There was a strong inverse linear relationship between the metals Ni, Zn and Pb in the readily exchangeable phase (step 1) and soil pH, significant at P < 0.01 level. There was a significant increase (P < 0.05) in the partitioning of Cu, Ni and Zn into step 4 (the organic phase) in soils with a higher organic carbon content (estimated by loss on ignition). Copper was highly partitioned into step 4 as it has a strong association with organics in soil but this phase was not important for the partitioning of Ni or Zn. The fractionation of Ni, Cu and Zn increased significantly in step 3 when the total metal concentration increases (P < 0.01). The Fe–Mn oxide fraction becomes more important in soils elevated in these metals, possibly due to the scavenging of metals by oxides. Cu and Pb extracted by HCl was statistically similar to the sum of the metals in steps 1 to 4 (P < 0.01) and HCl available Zn was statistically similar to the sum of Zn in steps 1 to 3 (P < 0.01). Step 4 (the organic phase) was not an important phase for Zn, so it was concluded that any Cu, Zn and Pb present in soil in a nonresidue phase would be potentially available for uptake into the human system once soil has been ingested.     

Response of roselle (Hibiscus sabdariffa) to heavy metals contamination in soils with different organic fertilisations

The response of green roselle (Hibiscus sabdariffa) to Cu/Pb contamination and manure application in soil was investigated using pot experiments. Subsamples of a mineral soil were treated with increasing doses (0–500 mg kg^?1) of Cu/Pb only and/or amended (at 10% w/w) with poultry or swine manure. Roselle plants were grown, monitored for changes in growth rate and post-harvest aboveground dry biomass and tissue Cu/Pb concentrations were determined. The plants were typically greenish with linear growth profiles at all metal doses, indicating some level of tolerance. Dry biomass yields decreased as metal dose increased. Poultry manure enhanced roselle biomass yields better than swine manure. Tissue Cu/Pb concentrations increased linearly as metal doses increased in unamended soils; whereas nonlinear responses were observed in manure-amended soils. Soil-to-plant transfer factors, T _f (%) indicated that Cu (13≤T _f (% )≤60) was more phytoavailable to roselle than Pb (11≤T _f (% )≤20). Tissue metal concentrations were modelled from soil pH, organic matter, plant available and pseudototal metal; but the models appeared more reliable with plant available metal as a covariate than with pseudototal metal content. These observations may become useful whenever phytoextraction is the remedial option for soils moderately contaminated by toxic metals.     

几种固定剂对镉污染土壤的原位化学固定修复效果

在野外现场条件下,开展了硅肥、钙镁磷肥、石灰和骨炭粉等多种材料对镉污染土壤的固定修复研究.结果表明,施用这几种固定剂后不同程度地抑制了玉米(Zea mays L.)对Cd的吸收,其中骨炭粉和石灰的效果最好,在0.5%的施用量下,这两种固定剂可使玉米可食部位Cd含量降低到安全限量标准水平.而其它处理在本研究条件下未能使作物Cd含量降低到安全范围.固定剂抑制植物吸收Cd的效果从大到小顺序依次为:骨炭粉≈石灰>硅肥≈钙镁磷肥>高炉渣≈钢渣.形态提取分析表明,施用固定剂处理使土壤Cd的水溶态、可交换态和碳酸盐结合态减少,而有机结合态和残渣态增加,说明促进Cd从有效态向缓效/迟效态转化是固定剂抑制植物吸收Cd的重要机制.     

南京城市土壤的特性与重金属污染的研究

研究了南京市城市土壤母质组成、剖面结构、pH值、土壤质地、土壤有机质、重金属元素全量及其不同形态含量等理化性质和分布规律。结果表明，城市土壤母质来源复杂，剖面层次混乱，土壤反应石灰性、粗粒化、有机质含量升高和表聚现象较明显。城市土壤重金属污染较为严重。不同功能区的污染元素和污染程度有显著差异。综合污染程度以老工业区含量最高。依次为老居民区、商业区、风景区、城市广场、开发区。但各功能区土壤重金属的形态分异不明显。城市土壤的随机空间变异十分突出，无论是土壤性质还是重金属污染积累都如此。城市中可能存在一些高度污染的岛状区域，这在城市环境质量上必须予以密切关注。     

Aqua regia extractable trace elements in surface soils of venezuela

Surface soils (0–15 cm) were sampled at 10–20 km intervals along two transects in Venezuela. One (1162 km, 70 samples) ran west to east parallel with the Caribbean coastline, the other (920 km, 92 samples) ran south to north from the frontier with Brazil to the Caribbean shore. Sampling took place in both a wet and a dry season. Trace metals were extracted from dried, sieved (<2 mm) soil with boiling aqua regia followed by analysis by ICP or flame AAS. Metal values did not differ significantly between the two seasons and dates were averaged. Geometric mean values for the west–east transect were: Cr=41.5, Cu 17.9, Cs 3.6, Li=13.9, Mn=294, Ni=21.3, Pb=17.4, Sr=39.4, V=60.4 and Zn = 83.7g g^–1, respectively. Similarly, for the south–north transect Cr=21.3, Cu=4.3, Cs=1.1, Li=2.0, Mn=55.7, Ni=4.4, Pb=6.1, Sr=13.3, V=28.2 and Zn=16.7g g^–1, respectively. A classification of samples by lithology showed surface soil composition to be related to rock composition. Metal values were low in the soils in the south of the country, in the Guyana highlands (Gran Sabana). Low Zn contents were prevalent. Lead contents were affected by roadside fallout from vehicles using leaded petrol except that high Pb contents of soils in the Gran Sabana were of more complex origin.     

Level,pattern, and risk assessment of the selected soil trace metals in the calcareous-cultivated Vertisols

Dynamics and distribution pattern of trace metals in agricultural lands are an increasing concern due to potential risks to the environment and human health. To ascertain more knowledge of this aspect, the fractions of total and available Fe, Mn, Zn, Cu, and Cd belonging to Vertisols under intensive cultivation and adjoining uncultivated soils were investigated. The order of abundance of metals in both cultivated and uncultivated soils was Fe?>?Mn?>?Cu?>?Zn?>?Cd and Fe?>?Mn?>?Zn?>?Cu?>?Cd for both available and total fraction, respectively. A relative enrichment was observed in the value of diethylene-triamine pentaacetic acid-extractable Fe (1.2–201%), Mn (2–31%), Cu (1–40%), and Cd (21–45%) as well as total fraction of Zn (3–17%), Cu (12–32%), and Cd (42–108%) after intensive cropping, which can be contributed to repeated application of agrochemical inputs and manure over long time. The values of RI (potential ecological risk) showed that cultivation caused a low potential ecological risk (33.3% of the soil samples) to moderate potential ecological risk (66.7% of the soil samples) in the study region and that cadmium made up 88%, on average, of the RI value.     

Seasonal variations in trace metal levels,speciation and physicochemical determinants of metal availability in dumpsite soils within Akwa Ibom State,Nigeria

Physicochemical properties, total metals and metal species were investigated in surface soil samples from six urban dumpsites within Akwa Ibom State, Nigeria. Results obtained indicated that Pb, Cd and Cr levels were higher in the dry season than in wet season, whereas Ni levels were higher during the wet season. Soil pH, organic matter and cation-exchange capacity (CEC) showed higher values in wet season than in dry season, whereas sand and clay levels were higher in the dry season. Speciation analysis showed the principal fraction of the metals to be Pb (reducible), Cd (acid extractable) and Ni (residual), whereas Cr existed in the residual fraction during the dry season and in the acid-extractable fraction during the wet season. Soil pH was positively correlated at p<0.1 with all metals in both seasons, sand was negatively correlated with the metals in both seasons, and CEC was negatively correlated with all metals in both seasons, except Pb in the wet season. Organic matter showed variable relationships with metals in both seasons. Seasonal variations affected metal availability and physicochemical properties of the soil. Total metal concentrations followed the order Pb>Ni>Cd>Cr, whereas their bioavailability followed the trend Cd>Pb>Cr>Ni.     

土壤中金属的生物可给性及其动态变化的研究

土壤中金属的生物可给性常应用于人体健康风险评价,如能准确地判定土壤中金属在胃肠阶段不同时间的溶出动态,研究者就可以更好地分析其对人体的健康风险。本文采集5种不同地区的重金属污染的土壤,利用改进的PBET方法,分别在胃阶段的20、40、60、80 min以及小肠阶段的1、2、3、4、5 h时取样并分析,探究土壤中8种金属元素（As、Al、Cd、Cr、Fe、Mn、Ni、Pb）的生物可给性和溶出动态,探讨造成金属溶出动态变化的影响因素,对其溶出机理进行初步探究。研究结果表明,Fe、Al的生物可给性较低,并且在胃肠阶段差异较小。与胃阶段相比,土壤中Pb、Cd的生物可给性在小肠阶段明显降低,而As、Mn、Cr、Ni的生物可给性在小肠阶段均升高。升幅最大的两个元素是Ni、Cr,其小肠阶段的平均生物可给性分别升高61.4%、29.9%。在溶出量随时间变化方面,在胃阶段,假定1 h时溶出率为100%。20 min时,土壤中Fe、Ni的平均溶出率较低,分别为59.3%、56.8%,其他6种金属元素的平均溶出率在71.2%~79.5%。As、Cd、Pb的溶出速率是先快后慢,Cr和Ni的溶出速率是先慢后快,而Fe、Mn、Al的溶出速率基本保持不变。在小肠阶段,假定4 h时溶出率为100%。Al、As、Cd、Mn的溶出率基本不变。1 h时,土壤中Cr（土壤A除外）、Ni的平均溶出率最低,分别为31.5%、32.7%,而5 h时,Fe、Cr、Ni的溶出率还在升高。由此可见,土壤中不同金属元素的生物可给性以及溶出动态是有明显差异的。     

Effect of zinc oxide nanoparticles on the trace element contents of soils

In the last few decades, metal oxide nanoparticles have shown impact in various areas, and such an impact causes an increased release in a different environment like soil, water, or air. A limited number of studies on soils showed that the biochemical parameters were affected by the metal oxide nanoparticles. However, the influence of metal oxide nanoparticles on soil elements has not been investigated. For this aim, zinc oxide nanoparticles were applied to two different soils; also, the effect of planting on soil elements was investigated via the cultivation of various plants roots (taproots, fibrous, bulb). Soils were treated with zinc oxide nanoparticles at 0, 1.0 and 20.0?mg during 4 weeks. Then, surface soil samples were collected and digested using an acid digestion procedure. Some biochemically important elements (Ca, Zn, Mg, Fe, Al, Cu, Co, Ni) were determined using a microwave plasma atomic emission spectrometer. The effect of time and dose-dependent zinc oxide nanoparticles on the element contents of different soils was investigated during planting, and the results were statistically evaluated.     

改良剂对土壤Sb赋存形态和生物可给性的影响

采用室内土壤培养法研究不同改良剂(骨炭、生物调理剂、沸石、石灰、油菜秸秆、生物炭、堆肥和赤泥)对土壤Sb化学形态转化和生物可给性的影响.结果表明,除堆肥处理外,添加5%的其他7种改良剂均显著地提高了土壤的p H值,其中石灰处理p H最为明显.BCR分级提取表明,土壤Sb主要以残渣态形式存在.添加生石灰、骨炭和生物调理剂显著地提高了土壤Sb的移动性,而添加赤泥、生物炭和堆肥却显著地降低了土壤Sb的移动性.添加不同的改良剂对土壤Sb的生物可给性也有影响,但是受不同培养时间影响较大.培养2个月后,添加5%的堆肥、5%赤泥和5%生物炭处理导致土壤Sb的生物可给性含量分别比对照降低38%、23%和20%;而添加5%的石灰、5%油菜秸秆和5%的生物调理剂处理导致土壤Sb的生物可给性含量分别比对照提高1.07倍、1.06倍和1.11倍.堆肥、赤泥和生物炭是钝化Sb污染土壤的潜力材料.     

栗钙土不同土地利用方式下有机碳和无机碳剖面分布特征

栗钙土是半干旱地区典型的地带性土壤,主要分布在内蒙古自治区。文章以内蒙古自治区乌兰察布盟(简称乌盟)和锡林河流域为例,分析了栗钙土有机碳和无机碳含量及其密度的剖面分布特征,旨在了解不同土地利用方式下土壤碳库的储量和分布特点及其成因与机理。结果表明:土壤无机碳在剖面上的分布有两种类型:高—低—(高)—(低)型和低—高—(低)—(高)型,后者可能是由于土壤侵蚀引起的碳酸盐再分布所形成的。100cm深的土壤有机碳密度的平均值为8.48kg·m-2,退耕地>耕地>干旱半干旱草原>典型草原,主要分布在表层,0～30cm土壤有机碳密度为0～100cm的43%左右;而土壤无机碳密度的平均值为7.10kg·m-2,退耕地>典型草原>耕地>干旱半干旱草原,主要分布在下层土壤,50～100cm无机碳密度为0～100cm的58%左右。     

广州市蔬菜地重金属剂量对蔬菜富集重金属的影响--以菜心为例

调查并分析了广州市蔬菜地土壤和菜心中主要重金属元素质量分数，通过多元统计分析建立了菜心中某一重金属元素和土壤中元素的数学回归模型。结果表明，Cd更易在菜心体内造成累积；总体上菜心中重金属质量分数与其在土壤中的质量分数有一定的相关性，菜心中Pb、As的积累分别取决于土壤中Pb、As的质量分数，土壤中Pb和As还分别促进了菜心对Cr、Hg的吸收，Pb对菜心中Cd的累积表现为协同作用；土壤重金属质量分数临界值可为今后无污染蔬菜的生产提供参考依据。     

Stabilization of metals in acidic mine spoil with amendments and red fescue (<Emphasis Type="Italic">Festuca rubra</Emphasis> L.) growth

Stabilization of metals with amendments and red fescue (Festuca rubra, cv. Keszthelyi 2) growth was studied on an acidic and phytotoxic mine spoil (pH_KCl 3.20–3.26; Cd 7.1 mg kg^?1, Cu 120 mg kg^?1, Pb 2154 mg kg^?1 and Zn 605 mg kg^?1) from Gyöngyösoroszi, Hungary in a pot experiment. Raising the pH above 5.0 by lime (CaCO₃), and supplementing with 40 mg kg^?1nitrogen (NH₄NO₃) made this material suitable for plant growth. All cultures were limed with 0.5% (m/m) CaCO₃ (treatment 1), which was combined with 5% (m/m) municipal sewage sludge compost (treatment 2), 5% (m/m) peat (treatment 3), 7.5% (m/m) natural zeolite (clinoptilolite) (treatment 4), and 0.5 (m/m) KH₂PO₄ (treatment 5). Treatments 1–5 were combined with each other (treatment 6). After 60 days of red fescue growth, pH of the limed mine spoil decreased in all cultures units. Application of peat caused the highest pH decrease (1.15), while decrease of pH was less than 0.23 in treatments 2, 5 or 6. Application of lime significantly reduced concentrations of metals in the ‘plant available’ fraction of mine spoil compared to non-limed mine spoil. Amendments added to limed mine spoil changed variously the ratio of Cd, Cu, Pb and Zn in exchangeable or ‘plant available’ fractions, differently influencing the phytoavailability of these metals. Most of the metals were captured in the roots of test plants. Treatment 2 caused the appearance of less Cd in shoots (<0.1 μg g^?1) or roots (3.11 μg g^?1), while treatment 5 resulted in the highest Cd concentration (2.13 μg g^?1) in shoots. Treatments did not influence significantly the Cu accumulation in shoots. The Pb accumulation of roots (44.7 μg g^?1) was most effectively inhibited by combined treatment, while the highest value (136 μg g^?1) was found in the culture treated with potassium phosphate. Pb concentration in shoots was below the detection limit, except for treatments 5 and 6. Peat application resulted in higher Zn concentration (448 μg g^?1) in shoots than other amendments, where these values were around 100 μg g^?1. All amendments influenced positively the dry matter yield of red fescue grown in limed mine spoil, however the application of 0.5 phosphate was less favourable. Liming, application of amendments and growth of red fescue can stabilize metals in acidic and phytotoxic mine spoil, and by phytostabilization they can reduce the risk of metal contamination of the food chain.     

大田条件下不同钝化剂对空心菜吸收镉的影响及机理

通过大田试验,研究4种钝化剂（赤泥、海泡石、钙镁磷肥和磷矿粉）对两茬空心菜（Ipomoea aquatica Forsk.）生长和镉吸收的影响。钝化剂施用量为：赤泥（0.5%和1.0%）、海泡石（0.3%和0.5%）、磷矿粉（450和900 kg.hm-2）、钙镁磷肥（450和900 kg.hm-2）。结果表明,各钝化剂均能显著降低土壤有效态镉质量分数,钝化能力大小表现为海泡石〉赤泥〉钙镁磷肥〉磷矿粉;钝化剂提高了空心菜地上部生物量,第1茬时（50 d）,施用高量赤泥、低量海泡石和高量钙镁磷肥处理生物量增加最为明显,地上部分别增加78.7%、75.2%和76.6%。第2茬（80 d）,高量赤泥与高量磷矿粉处理增加最高,地上部分别增加24.6%和34.5%。钝化剂对空心菜镉吸收影响不同,第1茬时对根系和地上部分别起促进和抑制作用,施用高量赤泥和高量海泡石最能抑制地上部镉累积,镉质量分数分别降低27.3%和23.2%。第2茬时,除海泡石外,钝化剂均显著抑制了根系和地上部的镉吸收,高量磷矿粉和赤泥效果最佳。总体来看,赤泥是保障农产品安全的最佳钝化材料,海泡石效果最差。     

Natural and anthropogenic metal inputs to soils in urban Uppsala, Sweden

Urban soils are complex systems due to human activities that disturb the natural development of the soil horizons and add hazardous elements. Remediation projects are common in urban areas and guideline values are set to represent a desired level of elements. However, the natural content of trace elements may not always equal the desired levels. In this study, an attempt is made to distinguish between metals that are present in the soil due to natural origins and to anthropogenic origins. Seventy-five soil samples of the 0–5, 5–10 and 10–20 cm layers were collected from 25 sites in urban areas of Uppsala City and analysed for aluminium (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), tungsten (W) and zinc (Zn) using aqua regia for digestion. In order to highlight elements of geological origin, the results were compared to a similar study carried out in Gothenburg City, which has about three times as many inhabitants as Uppsala and has a more industrial history. A cluster analysis was also performed to distinguish between elements of natural and anthropogenic origin. Contents of As, Al, Fe, Cr, Ni, Mn and W in Uppsala were concluded to be of mainly geological origin, while contents of Cd, Cu, Zn, Pb and Hg seemed to have been impacted upon by mainly urban activities.     

南京城郊零散菜地土壤与蔬菜重金属含量及健康风险分析

采集南京城郊零散菜地土壤和青菜配对样品各18个,用原子吸收光谱仪测定了铜、锌、铅、镉的质量分数。结果表明,南京城郊零散菜地土壤中Cu、Zn、Pb、Cd质量分数的变化范围分别为39.38±9.85、254.79±132.77、67.77±57.52、1.03±1.28 mg/kg;重金属质量分数在土样之间存在较大的变异性,反映了人为活动已对南京城郊土壤重金属污染产生了明显的影响。在城郊零散菜地土壤上种植的青菜,其叶中Cu、Zn、Pb、Cd质量分数的变化范围分别为5.00±1.57、62.21±16.05、5.90±3.09、0.73±0.39 mg/kg,其中Pb、Cd质量分数全都超过国家食品卫生标准。依据USEPA推荐的RfD值和我国居民平均食物消费结构进行计算,结果表明这些零散菜地的蔬菜重金属污染可能给食用者带来健康风险;食用其中一些污染严重的蔬菜而摄入Pb、Cd引起的健康风险分别高达90.66%和42.17%。     

攀枝花市土壤微量元素分布

以攀技花市为例，初步研究了该市土壤中微量元素分布的地球化学特征及城市环境污染特征。因子分析结果表明，各层土壤中的元素可分为两类：一类是引起城市土壤污染的重金属元素，另一类则是以稀土元素为代表的微量元素。城市土壤微量元素污染的分布特征表明，该市土壤微量元素的污染与该市的采矿冶炼等工业活动有直接联系。