公路绿化植物油松(Pinus tabulaeformis)和小叶杨(Populus simonii)对重金属元素的吸收与积累

对内蒙古西部公路绿化植物油松（Pinus tabulaeformis）、小叶杨（Populus simonii）及其根际土壤中重金属元素（Cd、Hg、Pb、Cu、Zn、Ni、Cr）和类金属元素（As和Se）含量以及根际土壤重金属（Cu、Zn、Pb、Ni和Cr）形态、土壤pH值进行了测定。对比分析了公路沿线不同绿化植物及其不同器官对重金属元素的吸收与积累特征。结果表明：绿化植物根际土壤对重金属元素的吸附及污染程度以Cd为最高。随原子序数的递增,小叶杨和油松两种植物的根部和茎叶两种营养器官中重金属的含量均表现出“N”字形变动趋势。而且重金属元素在不同植物不同器官中的含量具有Zn〉Cu〉Ni,Cr,As,Pb〉Cd〉Hg的基本规律。小叶杨茎叶对重金属元素Cr、Ni和Pb的富集能力较根部为强,油松茎叶对重金属元素Cr、Ni、Cu和Pb的富集能力较根部为强。绿化植物根际土壤重金属元素有效态占总量百分比的大小序列为Zn〉Pb〉Ni、Cr〉Cu,与重金属元素在不同植物不同器官中的含量大小序列Zn〉Cu〉Ni、Cr、As、Pb〉Cd〉Hg并非趋于一致。公路绿化植物对根际土壤中重金属元素的吸收和积累与重金属元素有效态所占的比例有关。     

鄂尔多斯地区公路沿线土壤重金属形态与生物有效性

采用TessierA连续提取法对鄂尔多斯地区公路沿线土壤重金属（Pb、Zn、Cu、Ni、Cr）化学形态进行了测定。同时对土壤pH值、重金属含量和公路绿化植物重金属（Cd、Hg、Pb、Cu、Zn、Ni、Cr、As和Se）含量进行了分析，对该区域重金属的生物有效性与潜在生态风险进行预测。结果表明：土壤重金属有效态占总量百分比的大小序列为Zn〉Pb〉Ni、Cr〉Cu，与重金属元素在绿化植物中含量大小序列Zn〉Cu〉Ni、Cr、As、Pb〉Cd〉Hg并非完全趋于一致。不同公路段土壤重金属与其不同形态存在较大的变幅。公路沿线表层土壤中重金属的有效态占其总量为G109（东胜-准格尔段）15．7％～46．1％，G210（达拉特-东胜段）8．0％-40．9％，G109（东胜-鄂托克段）9．1％～33．9％，而且以有机态和Fe—Mn氧化结合态的比例较大，为各元素有效态的主要形态特征。Cu在不同植物不同器官中的含量较高，可能在鄂尔多斯地区特定环境条件下随植物的蒸腾拉力、水分和营养盐运移的生理生态作用下使其在植物体中富集。土壤重金属Zn的有效态含量较高，而残渣态含量低，须特别注意其对区域生态系统的潜在影响。     

模拟酸雨对污染土壤中Cd、Cu和Zn释放及其形态转化的影响

研究了模拟酸雨连续浸泡下污染红壤和黄红壤中重金属释放及形态转化．结果表明。随着模拟酸雨pH值下降,污染土壤中重金属释放强度明显增大;Cd、Zn释放量与酸雨pH值呈线性极显著负相关．Cu与酸雨pH值呈线性显著负相关．模拟酸雨作用下,污染红壤和黄红壤中Cd均以交换态为主;Cu则以有机结合态和氧化锰结合态为主;Zn在污染红壤中以残留态和交换态为主．在污染黄红壤中以残留态和有机结合态为主．土壤有机质含量和阳离子交换量对Cd、Cu、Zn的释放产生一定的影响并影响Cd、Zn的形态转化,但对Cu形态转化影响不明显,随着模拟酸雨酸度增大,污染红壤和黄红壤中重金属Cd、Cu的生物可利用态明显增多,但难解吸态Zn向生物有效态转化效应不明显．     

施用污泥对油菜根际养分和不同种类重金属的影响

根际是控制植物养分动态的重要因素,养分动态也影响着根际土壤环境。当土壤被污水污泥改良后,根际土壤中的养分和重金属性质也会发生变化。目前很少有人研究施用污泥的土壤中植物根系对根际重金属有效性和分布的影响。采用根垫—冰冻薄层切片法对施用污泥后土壤中油菜根际的养分和重金属分布情况进行研究,以期探明污泥改良土壤中根际重金属的活化特征。当土壤施用污泥后,根际土壤中DTPA提取态Zn,Cd,Ni,Mn,有效磷,有效钾和铵态氮被显著消耗,而根际土壤中DTPA提取态Cu没有明显的消耗或积累。当土壤中施用大量污泥时,根际土壤的pH值随着离根表面距离的增加而增加。无论土壤是否用污泥处理,油菜根际土壤中可交换态Cu都显著减少。当土壤被50%污泥改良时,在距离根表面0—2 mm处的油菜根际土壤中碳酸盐结合态,铁锰氧化物结合态,有机物结合态,残渣态的Cu和Zn都被消耗较多。污泥的施用对油菜的生长有促进作用。随着污泥施用量的增加,油菜地上部分Cu和Zn的含量没有显著变化。施用污泥量小于25%的土壤中,污泥没有增加重金属的可利用性和移动性。除了Cu,油菜根际土壤中DTPA提取态Zn,Cd,Ni的减少表明施用污泥的土壤中重金属的活化是非常有限的。     

模拟酸雨对红树林底泥中营养元素及Cu、Zn分布的影响

采用柱状试验,研究不同pH值酸雨对红树林底泥中营养元素(N、P及有机碳)和重金属(Cu、Zn)空间分布的影响。结果表明,不同pH值的酸雨对底泥化学性状指标Eh、pH及盐度影响不显著(P0.05),对底泥不同层次TN、TOC及Cu的分布具有极显著影响(P0.01)。酸雨对底泥上层的氮及有机碳的淋溶具有显著促进作用(P0.05)。在酸雨作用下,营养元素及Cu、Zn含量分布具有随底泥深度增加而减小的趋势。TN、TOC与Cu、Zn的分布均呈极显著正相关关系(P0.01),TP与Cu、Zn的分布均呈正相关关系(P0.05),表明营养元素N、P和有机碳对重金属的淋溶、沉积具有显著促进作用。底泥中的TN是影响营养元素及重金属特别是Cu分布最重要因子。     

嵩山景区旅游活动对土壤组成性质和重金属污染的影响

沿嵩山景区登山路线,在嵩阳书院(455m)、老母(715m)、石船(930m)和天爷庙(1490m)采集混合土壤样品,在离景点200 m以外的受旅游活动影响微弱的地方采集对照土壤样品.根据我国土壤常规分析方法或国家标准分析方法开展土壤组成、性质和重金属(Cu、Zn、Pb、Ni、Cd和Cr)含量分析.与对照样相比,景点土壤具有以下特征:①黏粒含量高,质地偏细,相对紧实、干燥,根系分布少,颜色浅.②CEC小,盐基饱和度大,pH高.③有机质含量下降,速效养分减少,肥力衰退.④黏粒部分CaO含量高,SiO2含量相对下降,Saf减小,出现"假淋溶风化现象".⑤土壤重金属含量高于对照样,大部分超过我国棕壤和褐土背景值.土壤Cu和Ni没有发生污染,其它重金属污染程度的次序为:Zn＞Pb＞Cd＞Cr;不同景点重金属污染程度的次序为:嵩阳书院＞老母洞＞天爷庙＞石船.     

污泥与园林废弃物混合堆肥对波斯菊生长及重金属积累的影响

随着城镇人口增加和城市化的快速发展,每天产生大量的污泥和园林废弃物,而厌氧消化的污泥与园林废弃物的混合堆肥产品应用于林地土壤改良,是城市废弃物循环利用的一种经济有效的方式。本研究在北京平原造林区开展试验,探讨混合堆肥对波斯菊的生长及对重金属元素吸收的影响。结果表明:施用堆肥对土壤全氮和有机质含量无显著影响; Cu、Zn、Cd三种重金属元素在土壤中主要以残渣态的形态存在;施用堆肥提高了土壤Cu、Zn含量,但Zn总量未超过土壤环境质量标准(GB 15618—2018)中的土壤污染风险筛选值300 mg·kg-1,Cu在施肥量较高时超过土壤污染风险筛选值100 mg·kg-1;土壤背景值中Cd含量已经高于土壤污染风险管制值4.0 mg·kg-1,施用堆肥对Cd含量的影响无明显规律;波斯菊株高、生物量和花数均随着堆肥施用量的增加而增加;波斯菊对重金属元素的富集性表现为CuCdZn。本研究表明,北京平原造林区的人工林生态系统可以忍受一定浓度的污泥和园林废弃物混合堆肥,并利用其中的营养物质,提高土壤肥力,促进植物生长。     

堆肥对土壤重金属垂直分布的影响与污染评价

对不同畜禽粪便堆肥与土壤重金属垂直分布的关系进行了研究．结果表明，在畜禽粪便堆肥过程中，粪堆下土壤pH值和有机质显著增加，其pH和有机质含量的垂直分布表现为从表层到底层逐渐降低．各种畜禽粪便粪堆下土壤Zn、Cd含量明显增高，且从表层到底层呈逐渐减小的趋势．鸡粪和猪粪堆下土壤Cu含量随土层深度增加而降低；牛粪堆下土壤Cu含量随土层深度增加没有明显的变化．自然条件下Cd和Zn在土壤系统中的迁移能力大于Cu．各粪堆下的部分土层Cu、Zn、Cd含量超过我国土壤环境质量一级标准．应用地质积累指数法对各土层污染评价的结果表明，只有肉鸡粪堆下0～10cm土壤和蛋鸡粪堆下0～40cm土壤受到轻度Zn污染，其它粪堆下各土层均未受到Cu、Zn、Pb和Cd污染．     

好氧高温猪粪堆肥中重金属砷、铜、锌的形态变化及钝化剂的影响

采用连续提取法研究了猪粪好氧堆肥处理中重金属浓度和形态的变化以及添加不同比例的重金属钝化剂对其浓度和形态的影响.结果表明:经过堆肥处理后,猪粪中重金属As、Cu和Zn的总浓度均有所增加.从重金属结合形态的变化来看,可交换态As和Zn含量降低,残渣态As和Zn含量升高,表明As和Zn存在着向有效性相对较低的形态转化的趋势;重金属Cu则表现出不同的变化趋势,即可交换态与残渣态Cu含量下降,而碳酸盐结合态、铁锰结合态及有机结合态Cu含量有所增加,在今后的堆肥利用中应注意其可能带来的环境风险;3种重金属钝化剂及不同添加比例的处理中,5.0%的海泡石和2.5%的膨润土分别对重金属As、Zn表现出较好的钝化效果,堆肥后残渣态As和Zn的增幅分别达到79.8%和158.6%,均高于不加钝化剂处理.与对照相比,堆肥后7.5%的海泡石对残渣态Cu的降低幅度最小,为39.3%.猪粪堆肥中添加适量的重金属钝化剂,可以在一定程度上降低重金属的有效性以及猪粪堆肥利用中重金属污染的风险.     

施用污泥对土壤重金属形态分布和生物有效性的影响

采用盆栽技术和BCR连续浸提法研究了污泥的添加对土壤Cd、Pb、Cu和Zn形态分布的影响及重金属在黑麦草-施污泥土壤中迁移转化规律.结果表明:污泥的添加使土壤中生物有效态的Cd和Zn含量显著增加,生物有效态Pb含量显著降低,残渣态Pb的比例较CK增加了33.3％～74.5％,而可交换态和可还原态Cu含量在污泥与土壤添加比为1∶1时,仅占总量的0.7％和0.2％.污泥的添加能促进黑麦草对Cd、Cu和Zn的吸收,抑制对Pb的吸收.多元线性回归分析结果表明,黑麦草体内Cd、Zn和Cu含量分别与土壤中可还原态Cd、Zn和可氧化态Cu含量存在正相关,草体中Pb的含量则受土壤中可交换态和可氧化态Pb含量共同影响.种植黑麦草后根际土中可氧化态Cd和Cu分别向可交换态Cd和残渣态Cu转化,可交换态和可还原态Zn向可氧化态Zn转化,Pb的生物有效性基本未受影响.     

Leaching Behavior of Heavy Metals and Transformation of Their Speciation in Polluted Soil Receiving Simulated Acid Rain

Heavy metals that leach from contaminated soils under acid rain are of increasing concern. In this study, simulated acid rain (SAR) was pumped through columns of artificially contaminated purple soil. Column leaching tests and sequential extraction were conducted for the heavy metals Cu, Pb, Cd, and Zn to determine the extent of their leaching as well as to examine the transformation of their speciation in the artificially contaminated soil columns. Results showed that the maximum leachate concentrations of Cu, Pb, Cd, and Zn were less than those specified in the Chinese Quality Standards for Groundwater (Grade IV), thereby suggesting that the heavy metals that leached from the polluted purple soil receiving acid rain may not pose as risks to water quality. Most of the Pb and Cd leachate concentrations were below their detection limits. By contrast, higher Cu and Zn leachate concentrations were found because they were released by the soil in larger amounts as compared with those of Pb and Cd. The differences in the Cu and Zn leachate concentrations between the controls (SAR at pH 5.6) and the treatments (SAR at pH 3.0 and 4.5) were significant. Similar trends were observed in the total leached amounts of Cu and Zn. The proportions of Cu, Pb, Cd, and Zn in the EXC and OX fractions were generally increased after the leaching experiment at three pH levels, whereas those of the RES, OM, and CAR fractions were slightly decreased. Acid rain favors the leaching of heavy metals from the contaminated purple soil and makes the heavy metal fractions become more labile. Moreover, a pH decrease from 5.6 to 3.0 significantly enhanced such effects.     

Heavy metal contents of vegetable crops treated with refuse compost and sewage sludge

Refuse compost and sewage sludge were mixed with a loamy sand at various rates in pots and sown withBrassica chinensis, Daucus carota andLycopersicon esculentum in a glasshouse. A commercial fertilizer was also applied to the same soil for comparison. Dry matter production of the three crops and contents of Cd, Cu, Mn, Pb and Zn in the harvested tissues were determined at the end of the experiment. In general, crop yield in refuse compost treatment was improved over that in sandy soil alone, but was less than that in the sludge and fertilizer treatments. Despite the relatively high heavy metal contents of refuse compost, crops grown on compost-treated soils accumulated lower levels of metal than those grown on sludge-treated soils. This is probably due to the high pH and organic matter content of the composted refuse. Higher levels of heavy metals were found in the roots than in the aerial parts ofB. chinensis andL. esculentum, but the reverse was found inD. carota. In the edible tissue of the three crops,L. esculentum accumulated metals to a lesser extent than the other two.     

Leaching Heavy Metals from Contaminated Soil by Using Thiobacillus ferrooxidans or Thiobacillus thiooxidans

Iron- and sulfur-oxidizing bacteria identified as Thiobacillus ferrooxidans and T. thiooxidans were successfully enriched from various soil samples contaminated with heavy metals and organic compounds. Depending on the growth medium, the soil sample, and the type of contaminant, the indigenous isolates solubilized > 50% of most of the heavy metals present in the solid sample (As, Cd, Co, Cr, Cu, Ni, V, Zn, B, Be). Leaching with T. ferrooxidans strains resulted in total extraction of Cd, Co, Cu, and Ni. With sulfur-oxidizing bacteria > 80% of Cd, Co, Cu, and Zn was mobilized from rainwater sludge. Pb and Ba were not detected in the leachate, given the insolubility of their sulfate compounds. An increase in pulp density up to 20%, indicating 6.6% total organic carbon in the soil and rubble leach experiment (sample 557), did not inhibit the growth of the indigenous T. ferrooxidans strain. In view of these results, bioleaching appears to have some potential for remediation of heavy metal contaminated soils.     

The influence of sewage sludge on the content of heavy metals in potatoes and on tuber yield

Summary A small plot field experiment with two types of sewage sludge, one poor and one rich in heavy metals, applied in moderate and heavy quantities, and compared with NPK-fertilizer, was carried out 1973 and 1974, in potatoes. The chemical composition of the NPK-fertilizer and the sludges, and the amounts applied are found in Tables 1 and 2.The sludge increased the content of total Cd, Ni and Pb and the content of readily soluble Cu and Zn in the soil. The increase was greatest for Cu and Zn, and was more pronounced the second than the first year (Table 3). The small quantities of heavy metals in NPK-fertilizer did not influence the soil analytical values.Digested sludge increased the yield of tubers significantly, but based on the amounts of nutrients applied, NPK-fertilizer was much more efficient than sludge (Table 4). It is suggested that low utilization of N, or lack of K, is mainly responsible for the lower efficiency of sludge. Toxicity in the plants due to sludge was not observed.Application of 40–80 tons/ha of sludge dry matter, rich in heavy metals, increased considerably the concentration of Cu and Zn in the tubers, whereas 10–20 tons/ha did not influence the concentration (Table 6). The content of Hg, Ni and Pb in the tubers was very little influenced by sludge application. The Cd-concentration was mostly below 0.05 mg/kg of fresh tubers, and the analytical technique was not accurate enough to detect possible influence of increasing amounts of Cd in sludge. Generally, less than 0.5% of the heavy metals applied was accumulated in the tubers. The concentration of heavy metals in fresh tubers was in all cases below suggested maximum tolerable values for food. re]19760203     

Heavy metal bioavailability in a soil affected by mineral sulphides contamination following the mine spillage at Aznalcóllar (Spain)

A field experiment, lasting 14 months, was carried out in order to assess the effect of organic amendment and lime addition on the bioavailability of heavy metals in contaminated soils. The experiment took place in a soil affected by acid, highly toxic pyritic waste from the Aznalcóllar mine (Seville, Spain) in April 1998. The following treatments were applied (3 plots per treatment): cow manure, a mature compost, lime (to plots having pH < 4), and control without amendment. During the study two crops of Brassica juncea were grown, with two additions of each organic amendment. Throughout the study, the evolution of soil pH, total and available (DTPA-extractable) heavy metals content (Zn, Cu, Mn, Fe, Pb and Cd), electrical conductivity (EC), soluble sulphates and plant growth and heavy metal uptake were followed. The study indicates that: (1) soil acidification, due to the oxidation of metallic sulphides in the soil, increased heavy metal bioavailability; (2) liming succeeded in controlling the soil acidification; and (3) the organic materials generally promoted fixation of heavy metals in non-available soil fractions, with Cu bioavailability being particularly affected by the organic treatments.     

北京东郊作物土壤系统中重金属的迁移、分布、积累

 本文研究了北京东郊污灌区重金属在作物—土壤中的迁移、分布、积累规律,证实本区蔬菜中汞含量比粮食作物约大3—15倍,比水果约大6—200倍。麦粒、糙米中的Cu、Hg、Cd、Pb、Ni的含量与土壤含量相关性不显著。架豆中重金属含量与土壤中重金属含量的相关性,只有Zn,Pb达显著水平。白菜土有机质含量与重金属含量相关性达显著水平,而白菜的重金属含量与土壤的重金属含量相关性却不显著。说明除了土壤中重金属的总量外,有效态含量的多少,是影响本区作物吸收积累重金属的主要因素。 本区施污泥的土壤和生长的作物Cd／Zn大部小于1%、盆栽试验证明：施用本区污泥污水对水稻生长发育的影响比施污泥灌清水的影响大些,因此,施用含重金属污泥时,最好不要超过5000斤／亩。大田和室内模拟试验证明：重金属从土壤中迁移到植物,由植物带走输出的量极少,其中以带走输出的Hg、Cd,As相对较多,带走输出的Pb、Cr相对的少些。     

Effects of Municipal Sewage Sludge Doses on the Chlorophyll Contents and Heavy Metal Concentration of Sugar Beet (Beta vulgaris var. saccharifera)

The present study was conducted to assess the suitability of sewage sludge amendment (SSA) in soil for Beta vulgaris var. saccharifera (sugar beet) by evaluating the heavy metal accumulation and physiological responses of plants grown at a 10%, 25%, and 50% sewage sludge amendment rate. The sewage sludge amendment was modified by the physicochemical properties of soil, thus increasing the availability of heavy metals in the soil and consequently increasing accumulation in plant parts. Cd, Pb, Ni, and Cu concentrations in roots were significantly higher in plants grown at 25% as compared to 50% SSA; however, Cr and Zn concentration was higher at 50% than 25% SSA. The concentrations of heavy metal showed a trend of Zn > Ni > Cu > Cr > Pb > Cd in roots and Zn > Cu > Ni > Cr > Pb > Cd in leaves. The only instance in which the chlorophyll content did not increase after the sewage sludge treatments was 50%. There were approximately 1.12-fold differences between the control and 50% sewage sludge application for chlorophyll content. The sewage sludge amendment led to a significant increase in Pb, Cr, Cd, Cu, Zn, and Ni concentrations of the soil. The heavy metal accumulation in the soil after the treatments did not exceed the limits for the land application of sewage sludge recommended by the US Environmental Protection Agency (US EPA). The increased concentration of heavy metals in the soil due to the sewage sludge amendment led to increases in heavy metal uptake and the leaf and root concentrations of Ni, Zn, Cd, Cu, Cr, Pb, and Zn in plants as compared to those grown on unamended soil. More accumulation occurred in roots and leaves than in shoots for most of the heavy metals. The concentrations of Cd, Cr, and Pb were more than the permissible limits of national standards in the edible portion of sugar beet grown on different sewage sludge amendment ratios. The study concludes that the sewage sludge amendment in the soil for growing sugar beet may not be a good option due to risk of contamination of Cr, Pb, and Cd.     

Movement of water and heavy metals (Zn, Cu, Pb and Ni) through sand and sandy loam amended with biosolids under steady-state hydrological conditions

New guidelines for using biosolids in UK agriculture favour the use of enhanced treated biosolids, such as dried and composted cakes, due to concerns about the potential for transfer of pathogens into the food chain. However, there is a need to ensure that their use is environmentally acceptable and does not increase the risk to potable water supplies or the food chain from other contaminants such as heavy metals and xenobiotic organic chemicals. The objective of this study was to determine whether the use of composted and dried mesophilic anaerobically digested dewatered (MADD) biosolids would increase the risk of heavy metal leaching from cultivated horizons when compared to more conventionally used MADD cake. Three biosolids (MADD sewage sludge cake - fresh, dried and composted) were mixed with a sand (typic quartzipsamments, %OM = 3.0, pH = 6.5) or a sandy loam (typic hapludalf, %OM = 4.8, pH = 7.6) at an application rate equivalent to 250 kg N/ha/y resulting in loadings of approximately Zn: 6 microg, Cu: 2 microg, Pb: 5 microg and Ni: 0.2 microg/g of soil dry weight basis. These amended soils were repacked into columns (0.4 m by 0.1 m internal diameter) and leaching of Zn, Cu, Pb and Ni was investigated following application of two 24 h simulated rainfall events of 4.5 mm/h. Water balance data and the use of conservative tracers (Cl- and Br ) showed that the hydrological regimes of each core were comparable and, thus, unlikely to account for differences in metal leaching observed. Although no significant difference (P = 0.05) was observed between biosolid amended and control soils, those amended with composted sludge consistently gave higher loss of all metals than did the control soils. Total losses of metals from compost amended soil over the two rainfall events were in the ranges, Zn:20.5-58.2, Cu:9.0-30.5, Pb:24.2-51.2 and Ni:16.0-39.8 microg metal/kg amended soil, compared with Zn:16.4-41.1, Cu:6.2-25.3, Pb:16.9-41.7, and Ni:3.7-25.4 microg metal/kg soil from the control soils. Losses of Zn, Cu, Pb and Ni from fresh MADD cake amended soils (19.8-41.3, 3.2-25.8, 21.6-51.6 and 7.6-36.5 microg metal/kg amended soil, respectively) and from dry MADD cake amended soils (10.7-36.7, 1.8-23.8, 21.2-51.2 and 6.8-39.2 microg metal/kg amended soil, respectively) were similar to the controls. Generally, quantities of metals leached followed the order Zn = Pb > Cu > Ni, which was consistent with the levels of metals in the original sludge/soil mixtures. These results suggest that composting or drying MADD biosolids is unlikely to increase the risk of groundwater contamination when compared to the use of MADD cake; therefore, the changes in UK sludge use in agriculture guidelines are satisfactory in this respect.     

铜陵铜尾矿凤丹种植基地重金属污染初探

通过对安徽铜陵凤凰山铜尾矿凤丹种植基地土壤和凤丹中重金属污染状况进行采样分析.结果表明,在尾矿空白地和凤丹种植地土壤中Cu、Cd、Pb、Zn元素含量、存在形态差异明显,说明凤丹对尾矿土壤的修复效果明显; 尾矿土壤中的Cu、Cd元素总量分别是国家土壤环境质量二级标准的4.36～14.43倍和3.67～3.86倍,凤丹种植地重金属元素的CPI指数达到5.607,表明尾矿土壤中重金属元素污染仍相当严重.研究发现,4种元素在凤丹各部位含量明显不同: 叶和根心为Cu＞Zn＞Pb＞Cd,茎和根皮为Zn＞Cu＞Pb＞Cd,根皮中Zn含量最高;土壤中重金属元素各形态的变化与凤丹体内相应元素总量无显著相关; 丹皮内Cu、Cd、Pb元素含量与丹龄之间相关系数分别为0.842、0.993、0.992,Cu、Cd元素在凤丹体内含量约是出口药用植物绿色行业限量指标的1.43～2.53倍和1.17～3.17倍,可见缩短栽种时间可有效减少重金属元素对丹皮药效的影响.