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1.
市政污泥直接施用对玉米生长和品质的影响   总被引:1,自引:0,他引:1  
[目的]研究市政污泥施用后对土壤和作物生长与品质的影响,为市政污泥的直接土地利用提供科学依据。[方法]以玉米为试验材料,利用田间试验研究了污泥不同的施用方式(沟施、撒施、表土下20 cm施用)和施用量(30,90,200 t/hm~2)对玉米生长和品质以及土壤重金属含量的影响。[结果]适量的污泥对玉米个体的生长有促进作用,施用量为30 t/hm~2时株高、单株生物量、叶片叶绿素含量、籽粒蛋白质含量均显著高于对照。表土下20 cm施用污泥在整体上较其他两种施用方式有更高的出苗率和籽粒产量,在施用量为30 t/hm~2时籽粒产量最高,为656.70 kg/667m~2,高出对照29.64%。3种施用方式下,土壤中的Cu,Zn,Pb含量及玉米籽粒中的Cu,Zn含量均随污泥施用量的增加而增加,而玉米籽粒中Pb含量与对照相比差异不显著,土壤和籽粒中重金属含量均未超过国家相关标准。以重金属浓度满足土壤环境质量标准为限制条件,推算出当地的市政污泥施用量为30 t/hm~2可以连续施用5 a。[结论]施用30 t/hm~2的污泥具有良好的效果和环境效应;为了降低污泥在土壤中的局部累积而导致的胁迫效应,表土下20 cm施用和地表撒施是相对较好的方式。  相似文献   

2.
兰州市城市污泥施用对小麦生长和重金属富集的影响   总被引:4,自引:0,他引:4  
戴亮  任珺  陶玲  未碧贵 《土壤通报》2012,(5):1257-1263
以兰州市安宁区污水处理厂污泥为研究对象,采用盆栽的方法研究污泥土地利用后对土壤中重金属含量以及对3种小麦生长和重金属富集的影响。结果表明,污泥施用后使污泥混合土壤中重金属Pb、Cu、Zn含量显著增加,但3种重金属含量均未超过我国土壤环境质量二级标准(GB15618-1995)中的限制性标准值。污泥土地施用后,小麦获得了良好的生长响应。污泥低施入量(污泥在混配土壤中的干重比为5%、10%、15%)时不同程度的促进了小麦的生长发育,使3种小麦出苗率提高,植株更高,生物量增加。污泥高施入量(污泥在混配土壤中的干重比为25%、35%)时,小麦的出苗率和根长受抑制明显。污泥的施用使小麦籽实中的Pb、Cu、Zn的含量显著升高,呈现递增趋势,污泥在混配土壤中的干重比超过25%时,籽实中Cu和Pb含量相对国家无公害食品标准有超标现象。综合考虑污泥对小麦生长和重金属富集的影响及土壤中重金属含量的变化,对小麦的耕种土壤中一次性施用污泥时,污泥在混配土壤中的干重比应限量在25%以下。  相似文献   

3.
污泥农用对土壤和作物重金属累积及作物产量的影响   总被引:20,自引:2,他引:20  
以3 a定位试验为基础,比较3种不同处理的污泥肥料(消化污泥、污泥堆肥及污泥复混肥)农田施用下土壤养分、土壤和作物籽粒中Mn、Cu、Zn、Pb、Cd 5种重金属的积累以及作物产量的变化情况,以阐明污泥农用对土壤及作物的影响。研究表明,3种污泥肥料提高了土壤中氮素和有机质的含量;与空白和普通化肥处理相比,3种污泥肥料增加了土壤中Mn和Cu的含量,而对土壤交换态重金属含量没有显著影响;3种污泥处理均增加了小麦籽粒中Zn的含量;相对普通化肥处理,3种污泥肥料处理对小麦和玉米产量均无显著影响。合理施用污泥肥料可以有效地提高作物产量;污泥肥料施用对土壤重金属有一定累积效应,但短期施用对土壤比较安全。  相似文献   

4.
污泥施田后土壤和玉米植株中重金属分布特征   总被引:1,自引:0,他引:1  
对施污泥剂量分别为10、30和60thm-2的土壤,采用修正的BCR三步连续提取法分步提取并分析Pb、Cd、Cu、Zn的不同形态。利用高压密封消解技术和电感耦合等离子体质谱(ICP-MS)分析Pb、Cd、Cu、Zn在玉米器官中的分布及其转移富集特征。施污泥土壤中重金属主要以残渣态存在。施污泥量为常规用量的6倍时,即相当于连续6年施污泥的土壤中重金属Pb、Cd、Cu、Zn的含量基本未超过我国土壤环境质量标准。4种重金属在弱酸性土壤中残渣态含量比例的高低依次为CuZnCdPb。施污泥土壤上Pb、Cd在玉米各器官中的平均含量顺序为:茎叶根籽粒;Cu为:根茎叶籽粒;Zn为:根籽粒茎叶。玉米对于各元素的EC值按高低顺序依次为CuZnCdPb。  相似文献   

5.
  【目的】  明确长期化肥配施有机肥对重金属元素在土壤和农作物籽粒、秸秆中积累的影响及其环境效应,为安全高效施肥提供科学依据。  【方法】  在北京市农林科学院新型肥料长期定位试验站进行了为期10年的田间试验,其种植模式为冬小麦–夏玉米轮作,试验处理为不施肥 (CK)、单施化肥 (NPK)、氮磷钾 + 鸡粪堆肥的有机肥料 (NPKJF)、氮磷钾 + 污泥堆肥的有机肥料 (NPKWN)、氮磷钾 + 垃圾堆肥的有机肥料 (NPKLJ) 和氮磷钾 + 秸秆粉碎还田 (NPKJG) 共6个处理,施肥处理依据等氮量施肥原则,每季作物施 N 180 kg/hm2、P2O5 90.0 kg/hm2、K2O 90.0 kg/hm2。在玉米收获后测定了玉米秸秆、籽粒和0—20 cm耕层土壤中重金属全量。  【结果】  添加污泥处理显著提高了土壤中Cd、Hg、As、Cu、Zn的含量,单因子污染指数分别比对照提高了45.10%、150.00%、104.00%、44.60%、65.80%。不同施肥处理对土壤中全量Cd、Cr、Hg、Cu、Zn存在一定的富集效果。各处理重金属单项污染指数在0.02~0.46,远小于1,综合污染指数为0.23~0.36,均小于0.7,试验区土壤重金属均为无污染等级。施用有机废弃物堆肥的处理玉米籽粒Cd、Cu、Zn含量比对照显著增加,各处理间Hg、As、Cr、Pb、Ni含量差异不显著,连续10年定位施肥后试验站土壤以及玉米籽粒中重金属含量均未超标。同一作物不同部位对重金属的富集能力不同,玉米秸秆对重金属的富集能力大于籽粒。玉米籽粒中Pb、Cu、Zn含量与土壤Pb、Cu、Zn含量存在正相关性,玉米秸秆中Cd、Hg、Cr、Ni含量与土壤中Cd、Hg、Cr、Ni含量呈正相关或者显著负相关。  【结论】  在施氮总量不变的前提下,连续施用供试有机堆肥10年后,土壤重金属含量均未超标,土壤重金属单项污染指数在0.02~0.46,综合污染指数为0.23~0.36,无污染风险。只有污泥堆肥需要加强土壤Cd的监测。玉米秸秆对重金属的富集能力大于籽粒。玉米籽粒中Pb、Cu、Zn含量与土壤相应重金属含量存在正相关性,秸秆中Cd、Pb、Hg、Zn与Cr、Ni含量与土壤中相应重金属含量呈正相关,而秸秆中Cr、Ni含量与土壤中相应重金属含量呈负相关。  相似文献   

6.
2013—2014年以苏州市相城区望亭镇某河道污泥为研究对象,以农田施用污泥20 kg?m~(-2)和不施用污泥为主处理,以施氮肥120 kg(N)?hm~(-2)(LN)和240 kg(N)?hm~(-2)(NN)为副处理,连续两季种植粳稻品种‘武运粳24’,研究河道污泥农田施用对水稻和土壤重金属含量及水稻氮素利用的影响。结果表明:1)河道污泥农田施用,显著提高了稻田土壤有机质含量、速效氮含量和重金属Cu、Zn、Pb含量,水稻产量平均增加7.05%,水稻籽粒中重金属Cu、Zn、Pb含量分别增加53.66%、18.71%和802.29%,水稻吸氮量显著增加,氮素利用效率显著降低。2)河道污泥施用后,较高施氮量(NN)增加了稻田土壤有机质含量和速效氮含量,对稻田土壤重金属含量和水稻籽粒中重金属含量影响不大,水稻产量、水稻吸氮量显著增加,但氮素利用效率显著降低。3)污泥处理条件下,与第1季相比较,第2季稻田土壤重金属Cu、Zn、Pb含量平均下降5.0%左右、籽粒中重金属Cu、Zn、Pb含量下降7.27%~12.65%,但均显著大于不施河道污泥的对照处理。4)污泥×氮肥、污泥×年度、氮肥×年度和污泥×氮肥×年度的互作效应对稻田土壤养分含量、重金属含量,水稻产量、籽粒重金属含量和水稻氮素吸收利用的影响均未达显著水平。  相似文献   

7.
为了探究不同用量污泥长期施用后对土壤-萝卜系统中重金属及土壤养分含量的影响,采用长期定位试验,研究连续10年单施化肥(CK)以及施用不同用量(4.5、9、13.5、18 t·hm~(-2))污泥对土壤、萝卜叶(地上部)和萝卜(地下部)中重金属(Pb、Cd、Cr、Ni、Cu、Zn)累积情况及土壤pH、有机质及氮磷钾含量的影响。结果表明:连续施用10年后,单施化肥和不同用量污泥处理对萝卜产量影响不大,土壤、萝卜叶和萝卜中的Pb、Cd、Cr、Ni、Cu和Zn含量均随污泥施用量的增加而增加,且中高量和高量污泥处理中重金属的累积量较大,显著或极显著高于对照、低量和中量处理。中量以上污泥处理土壤的Pb、Cr、Ni和Cu超出了土壤环境质量国家标准;除高量污泥处理Pb超标外,其他处理萝卜的各重金属含量均未超过食品安全国家标准。与CK处理相比,长期施用不同用量污泥能提高土壤pH 0.58~0.71个单位,并显著或极显著地提高有机质、全量氮磷以及速效氮磷含量。研究表明,连续10年施用不同用量污泥,土壤和萝卜中Pb、Cd、Cr、Ni、Cu、Zn的含量随污泥用量的增加而增加,其中Pb、Ni、Cr和Cu出现超标现象,萝卜中的重金属含量除高量污泥处理中Pb超标外,其他处理均未超过食品安全国家标准。随着作物产地土壤中污泥施用年限增长或用量增加,食品安全应得到更多的重视。  相似文献   

8.
以兰州市安宁区污水处理厂污泥为研究对象,采用盆栽方法研究污泥施用后对土壤pH值的影响,对土壤中重金属Cu、Zn、Pb含量的影响以及对小麦叶片叶绿素含量和脯氨酸含量特性的影响。结果表明,污泥施用后土壤的pH值显著下降,并呈递减趋势。不同污泥施加量土壤中3种重金属元素的含量均远低于我国土壤环境质量二级标准(GB15618—1995)中碱性土壤的限制性标准值。3种小麦叶片的叶绿素总含量随污泥浓度的增加而增加,污泥在混配土壤中的干重比为15%时3种小麦均达到最大值,随着污泥施加量的进一步加大出现下降。污泥施用后3种小麦叶绿素a/b值与对照相比无显著变化,小麦叶片中脯氨酸含量比对照有大幅的增加。低污泥施加量时(5%、10%和15%),3种小麦叶片中脯氨酸含量随施加量增加而增加,但高污泥施加量时(25%和35%)的脯氨酸含量无显著增加,污泥中污染物胁迫超过小麦耐受限值后,小麦生理代谢出现反常。土壤中3种重金属元素的含量与3种小麦体内脯氨酸含量均呈极显著正相关关系,土壤的pH值与3种小麦的叶绿素总含量和脯氨酸含量均呈负相关关系。综合考虑污泥施用对小麦生理特性的影响,对小麦的耕种土壤中一次性施用污泥时,污泥在混配土壤中的干重比应限量在15%以下。  相似文献   

9.
污泥堆肥对盐碱土土壤环境和作物生长的影响   总被引:1,自引:0,他引:1  
以城市污水处理厂污泥堆肥为研究对象,采用盆栽试验方法研究不同用量(0%,5%,10%,20%)污泥堆肥施入盐碱土后,对玉米、大豆生长情况及土壤环境的影响。结果表明,施用污泥堆肥可降低盐碱土pH值和总盐含量,提高土壤养分及酶活,增加土壤微生物量碳、微生物量氮,同时施用污泥堆肥土壤重金属Zn、Cu含量增加,当施用量为20%时,土壤Zn含量超标。另外,玉米和大豆在污泥堆肥施用比例分别为10%和5%时长势最佳,且作物籽粒中重金属含量在国家食品卫生标准范围内。  相似文献   

10.
通过田间试验方法,研究了在铅锌矿废水污染的土壤上施用石灰1 a后,继续施用石灰和石灰后效处理对后续第1、2季低累积玉米(Zea mays)的产量以及重金属Cd、Pb、Zn和Cu含量的影响,并分析了土壤pH、土壤DTPA提取态重金属含量和土壤重金属全量的变化。结果表明,连续施用石灰和石灰后效均显著提高玉米产量,其中连续施用石灰处理效果最佳,第1季籽粒产量是对照(无石灰)的6倍,第2季是对照的3.8倍。与对照相比,连续施用石灰处理显著降低了2季玉米籽粒Cd、Pb、Zn和Cu含量,石灰后效只能降低第2季玉米茎叶Cd、Pb和Cu含量,而籽粒Cd、Pb含量与对照相比略有升高,说明石灰后效能维持一年半左右。对照处理土壤Cd和Zn全量显著低于石灰处理,可能是土壤中Cd和Zn随着雨水的淋洗向下层迁移造成的。施用石灰可防止Cd和Zn对地下水的污染。  相似文献   

11.
Abstract

A previous study indicated that agricultural biosolid applications increased the concentration of EPA3050‐digestible trace elements in soils on Pennsylvania production farms but could not indicate potential trace‐element environmental availability. This study was conducted to determine if biosolid application had altered the distribution of trace‐elements among operationally defined soil fractions and the relationship of trace element concentrations in soil and crop tissues. Biosolid‐amended and unamended soils from production farms in Pennsylvania were extracted using a modified Bureau Communautaire de Référence (BCR) sequential fractionation technique and analyzed for chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). Trace‐element concentrations in crop tissues (soybean silage, sudangrass, corn grain, alfalfa hay, and orchardgrass hay) from the same farms were also determined. Fractionation results indicated that the proportion of Cr, Cu, Ni, Pb, and Zn that is potentially bioavailable is quite small in unamended soils. Biosolid applications significantly (P≤0.1) increased concentrations of Cu in all soil fractions (average increase over unamended soil=1.14, 8.27, 6.04, and 5.84 mg kg?1 for the exchangeable, reducible, oxidizable, and residual fractions, respectively), Ni (0.41, 1.65 mg kg?1 for the reducible and residual fractions, respectively), Pb (5.12 and 1.49 mg kg?1 for the reducible and residual fractions, respectively), and Zn (8.28, 7.12, 4.44, and 8.98 mg kg?1 for the exchangeable, reducible, oxidizable, and residual fractions, respectively) but did not significantly increase Cr in any soil fraction. Concentrations of Cu in all soil fractions were significantly (P≤0.01) correlated with concentrations of Cu in orchardgrass tissue (r=0.70, 0.66, 0.76, and 0.69 for the exchangeable, reducible, oxidizable, and residual soil fractions, respectively). Concentrations of exchangeable and reducible Zn were significantly correlated with Zn in sudangrass tissue (r=0.81 and 0.67), and reducible Zn was significantly correlated with Zn concentrations in orchardgrass tissue (r=0.65). Application of biosolids had little effect on bioavailability of Cr, Ni, or Pb, whereas higher loadings of Cu and Zn led to a shift toward the more labile soil fractions. Loadings of Cu and Zn were much smaller than cumulative loadings permitted under U.S. Environmental Protection Agency (USEPA) Part 503 regulations. Chemical soil fractionation was able to detect increases in labile soil Cu and Zn that relate to increased phytoavailability.  相似文献   

12.
土壤有效锌含量低是制约西北旱地冬小麦籽粒锌营养品质的关键问题。采用连续两年的田间定位试验,设0、10、25、50、100、150kg·hm。6个锌肥(ZnSO4·7H2O)水平,研究了施锌对小麦产量、籽粒锌含量和土壤有效锌含量的影响,分析了西北旱地冬小麦土施锌肥的可行性。结果表明,随锌肥用量增加,土壤有效锌含量显著提高,但小麦产量无明显变化,小麦籽粒锌含量两季最高值分别为19.8、32.1mg·kg^-1,比不施锌提高32%和44%,却依然低于40-60mg·kg^-1的推荐含量,总锌利用率不到1%。因此,在西北旱地,不建议通过土施锌肥来提高小麦籽粒锌含量。  相似文献   

13.
为探讨城郊污灌土壤-小麦体系中重金属Cu、Cd、Cr、Pb和Zn的迁移富集特征及潜在健康风险,选取北京城郊污灌区24块代表性小麦(Triticumaestivum)样地,运用高分辨电感耦合等离子体质谱仪(HR-ICP-MS)测定了土壤及小麦籽粒中消解态Cu、Cd、Cr、Pb和Zn含量。结果表明,污灌土壤中Cu、Cd、Cr、Pb和Zn的均值含量分别为26.51、0.24、101.29、28.04mg.kg-1和85.59mg.kg-1,高于北京土壤元素背景值,已出现积累现象;小麦籽粒中5种重金属含量顺序为Zn(52.38mg.kg-1)〉Cu(6.09mg.kg-1)〉C(r4.62mg.kg-1)〉Pb(0.17mg.kg-1)〉Cd(0.04mg.kg-1),其中Cr、Zn含量超出国家标准限值,食品安全需引起关注。在以污灌区小麦粉为主要食源条件下,健康风险评价显示:北京城郊污灌区单一重金属风险系数(HQ)尚未达到显著水平,但是郊区成人和儿童的5种重金属综合健康风险均大于1,4种不同人群的风险系数(HQ)和风险指数(HI)有相同的影响顺序,即郊区儿童〉郊区成人〉城区儿童〉城区成人;5种重金属中,Cr所占风险比例最小,由Cu和Zn所引起的健康风险所占比例最高。表明对北京城郊污灌区小麦籽粒主要消费区域和流通渠道以及由此引发的居民(尤其郊区儿童和成人)重金属健康风险需要予以关注,预防食品安全危害的发生。  相似文献   

14.

Purpose

This study assessed the effect of biosolid application on the bioavailable fraction of some trace elements (Cu, Cr, Ni, and Zn) using a bioassay with sunflower (Helianthus annuus) and a chemical assay, diffusion gradient in thin films (DGT).

Materials and methods

Five surface soil samples (0–20 cm) were collected from an agricultural zone in Central Chile where biosolids are likely to be applied. Municipal biosolids were mixed with the soil at concentrations of 0, 30, 90, and 200 Mg ha?1. The experiment to determine the bioavailability of metals in the soil using the bioassay was performed using sunflower. The DGT technique and Community Bureau of Reference (BCR) sequential extraction were used to determine the bioavailable fractions of the metals.

Results and discussion

The application of biosolids increased the phytoavailability of Zn, Ni, and Cr in most of the soils, as indicated by the increasing concentrations in sunflower plants as the biosolid application rate increased. In two of the soils, Codigua and Pelvín, this increase peaked at an application rate of 90 Mg ha?1. Decreases in the bioavailable fractions of Zn, Ni, and Cr were observed with higher biosolid application rates. The bioavailability of metals was estimated through multiple linear regression models between the metals in the sunflower plants and the different chemical fractions of metals in the soils treated with different biosolid rates, which displayed a positive contribution of the labile (water soluble, carbonate, and exchangeable), oxide, and organic metal forms in the soil, particularly with respect to Ni and Zn at application rates of 30 and 90 Mg ha?1. The bioavailable fraction of metals was determined in soils using the DGT technique. The effective concentration (C E) results were compared with those in sunflower plants. The DGT technique could effectively predict the bioavailable fractions of Cr, Ni, and Zn in the Taqueral soil but only that of Zn in the Polpaico soil.

Conclusions

The application of biosolids significantly increased the labile fraction of most of the metals in the studied soils, particularly at the highest biosolid application rate. C E increased as the concentration of biosolids increased for most of the metals. The effectiveness of the DGT technique for predicting the bioavailability of metals was dependent on the soil type and the metal. However, the C E for soil Cu was not related to plant Cu for all soils studied.  相似文献   

15.
长期污灌农田土壤重金属污染及潜在环境风险评价   总被引:1,自引:0,他引:1  
以西安市某典型污灌区农田土壤为研究对象,分析长期污水灌溉对表层土壤重金属含量及富集状况的影响,采用内梅罗指数法和Hakanson潜在生态危害指数法对其污染现状及潜在环境风险进行评价。结果表明:长期污灌已导致农田土壤Cd、Cr、Cu、Hg、Ni、Pb和Zn7种重金属相对自然背景有不同程度累积,其富集比例依次为100%、82.69%、100%、100%、80.77%、98.08%和100%,仅有土壤As平均含量低于其背景水平;以国家土壤环境质量标准二级限量值作为污染评价阈值,其中Cd和Hg污染表现突出,按其污染指数平均值排序为Cd〉Hg〉Ni〉Cu〉Zn〉As〉Cr〉Pb;土壤重金属综合潜在环境风险为"强"等级,Hg、Cd的环境影响占据主导;随污灌年限增长,离灌渠越近,农田土壤重金属的污染水平和环境风险越高。鉴于该区土壤重金属已呈现较强生态危害性,应及时采取必要防治措施,调整土地利用结构,确保农田环境及农产品安全生产。  相似文献   

16.
施用污泥后石灰性土壤中铜、锌、镉的植物有效性   总被引:2,自引:0,他引:2  
The toxicity of trace elements (TEs), such as copper (Cu), zinc (Zn), and cadmium (Cd), often restrict land application of sewage sludge (SS) and there was little information about soil-plant transfer of TEs in SS from field experiments in China. In this study pot and field experiments were carried out for 2 years to investigate the phytoavailability of TEs in calcareous soils amended with SS. The results of the pot experiment showed that the phytoavailability of Zn and Cu in the SS was equal to 53.4%-80.9% and 54.8%-91.1% of corresponding water-soluble metal salts, respectively. The results from the field experiment showed that the contents of total Zn, Cu, and Cd in the soils increased linearly with SS application rates. With increasing SS application rates, the contents of Zn and Cu in the wheat grains initially increased and then reached a plateau, while there was no significant change of Cd content in the maize grains. The bioconcentration factors of the metals in the grains of wheat and maize were found to be in the order of Zn > Cu > Cd, but for the straw the order was Cd > Cu > Zn. It was also found that wheat grains could accumulate more metals compared with maize grains. The results will be helpful in developing the critical loads of sewage sludge applied to calcareous soils.  相似文献   

17.
To determine “normal” levels of trace elements in soils, soil samples taken all over Belgium were analysed. The selection of the sampling places was based on the geological substrata, from which the soils originate and on the texture class to which they belong. The elements As, B, Be, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Ti, V and Zn were determined using an extraction method with strong acids. The found concentrations were called “total acid extraction concentrations”, although this extraction does not extract all the elements which are incorporated into the minerals. This has been done, however, by arc emission spectrography which was applied to determine the elements Ag, B, Co, Cr, Ga, Mo, Ni, Sn, Sr and V. The greatest difference between the “overall total” concentrations and the “total extractable concentrations” were found for chromium. Based on the obtained results, an upper limit for normal levels of trace elements was fixed. For Ag, Cd, Hg, Pb and Sb, this upper limit value is almost the same for all the investigated soils irrelevant of their texture. The same conclusion could not be made for the other elements. For these elements, the soil texture and also the geological parent material, on which the soil was formed, have an influence on the upper limit value.  相似文献   

18.
在北京顺义区采集了412份土壤表层样品,分析了其中7种重金属元素(Cu、Zn、Cr、Pb、Cd、As和Hg)的全量,采用单因子指数和内梅罗指数对土壤环境质量进行评价。结果表明,土样中As、Cd、Cr、Hg、Cu、Pb和Zn含量平均值分别为7.85、0.136、61.47、0.073、22.43、20.38mg.kg-1和69.75mg.kg-1,As、Cd、Cr、Cu和Zn含量平均值超过了北京地区环境背景值,但所有元素含量的平均值均未超出土壤环境质量一级标准。土壤中各重金属元素含量Shapiro-Wilk检验和相关性检验结果表明,研究区土壤中重金属Cr呈正态分布,Cd、Cr、Cu、Pb元素与As元素相关性显著。土壤各元素单因子污染指数排序为Zn〉Cr〉Cd〉Cu〉Pb〉As〉Hg,内梅罗综合污染指数平均值为0.745,达到了土壤环境质量评价分级标准Ⅱ级,污染等级为"警戒线"级;菜地、果园、荒地、林地、苗圃、设施农业用地和水浇地的土壤内梅罗指数分别为0.809、0.765、0.720、0.669、0.781、0.786和0.729,表现为菜地〉设施农业〉苗圃〉果园〉水浇地〉荒地〉林地。土壤环境质量总体安全,部分地区土壤重金属污染处于警戒水平。  相似文献   

19.
Total content of Fe, Mn, Zn, Cu, Pb, Cd, Ni and Co in soils irrigated with sewage effluent increased with increasing years of using sewage effluent in irrigation. Iron and Co applied to the soil from sewage effluent were immobilized mainly in unavailable form; Pb, Cd, and Ni in moderately available form; and Mn, Zn, and Cu in highly available form. The concentrations of Fe, Mn, Zn and Cu in tops of alfalfa and leaves of corn grown on these soils increased substantially with increased levels of available metal content of the soil, while those of other metals were little affected. As for orange, continuous increase in leaves metal content with time was found for Fe, Mn, Zn, Co and Cd. The concentrations of Cd, Co, Ni and Pb in corn grains and orange fruits were several times higher than normal, and this reduces their suitability for human consumption.  相似文献   

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