• ISSN 1008-505X
  • CN 11-3996/S

留言板

尊敬的读者、作者、审稿人, 关于本刊的投稿、审稿、编辑和出版的任何问题, 您可以本页添加留言。我们将尽快给您答复。谢谢您的支持!

姓名
邮箱
手机号码
标题
留言内容
验证码

复合污染土壤上几种叶类蔬菜对Cd和As的富集效应

孟媛 张亮 王林权 上官宇先 杨阳 李雪芳 李娜

引用本文:
Citation:

复合污染土壤上几种叶类蔬菜对Cd和As的富集效应

    作者简介: 孟媛 E-mail:15191419886@163.com;
    通讯作者: 王林权, E-mail:linquanw@nwsuaf.edu.cn
  • 基金项目: 国家重点研发计划(2017YFD0200105)。

Cd and As accumulation of several leafy vegetables in soils contaminated by combined heavy metal

    Corresponding author: WANG Lin-quan, E-mail:linquanw@nwsuaf.edu.cn ;
  • 摘要: 【目的】不同蔬菜镉、砷富集系数各异,对镉和砷污染土壤的响应也不同。研究复合污染土壤上不同叶类蔬菜对Cd和As的积累效应,为轻度–中度Cd和As污染土壤的合理与安全利用提供适宜的蔬菜种类。【方法】采集了西安市12个污染程度不同的菜地耕层土壤,于2015年3月6日—5月26日在西北农林科技大学资源环境学院遮雨大棚内进行了盆栽试验。供试7种叶菜,包括菠菜、油菜、生菜、油麦菜、苋菜、空心菜和茼蒿。蔬菜收获后,测量了蔬菜产量、Cd和As含量与吸收累积量,计算了蔬菜对Cd和As的富集系数等,并用线性回归模型研究了不同蔬菜栽培的土壤Cd和As安全临界值。【结果】镉污染土壤 (0.6~2.4 mg/kg) 对大多数蔬菜生物量有抑制效应,中、低浓度镉砷复合污染 (Cd 1.0~2.4 mg/kg,As 24.9~26.8 mg/kg) 对供试蔬菜生长没有叠加效应。镉污染土壤上,菠菜、油菜、苋菜叶、生菜可食部Cd含量均超出食品安全限量标准(0.2 mg/kg),其中菠菜和油菜Cd最高超标4倍以上;而茼蒿和空心菜茎秆Cd未超标。虽然供试蔬菜砷含量随着土壤砷含量增加有升高趋势,但叶菜As含量没有超标。7种蔬菜Cd富集系数为0.083~0.491,高低顺序为油菜、菠菜、生菜和苋菜叶 > 油麦菜、苋菜茎和空心菜叶 > 空心菜茎和茼蒿。菠菜、油菜、生菜、油麦菜、苋菜、空心菜和茼蒿土壤Cd安全临界值分别为0.33、0.38、0.46、1.15、0.59~1.79、1.49~8.16和8.98~17.11 mg/kg,其中菠菜、油菜和生菜阈值与现行标准 (0.3~0.6 mg/kg) 相当,而油麦菜、苋菜、空心菜和茼蒿均大于土壤重金属污染限量值。As富集系数为0.002~0.006,空心菜叶和茼蒿叶片As富集系数显著高于其他蔬菜。7种蔬菜的土壤As临界阈值分别为62.31、70.35、70.21、67.41、67.86~90.43、57.21~75.70和72.43~105.06 mg/kg,均高于现行标准 (25 mg/kg)。【结论】中等程度的Cd和As复合污染土壤上,Cd对蔬菜的生长有显著的抑制,As与Cd没有叠加作用。不同蔬菜的产量、污染程度和安全阈值等有显著差异,因此选择低富集、抗污染蔬菜品种是利用中低重金属污染土壤的一条可行途径。空心菜和茼蒿对Cd富集系数低,可推荐在中、低污染土壤上种植。
  • 图 1  7种叶菜可食部Cd、As富集系数 (n = 36)

    Figure 1.  The bioconcentration factor of Cd and As in the edible parts of seven leafy vegetables

    表 1  西安市城郊菜地土壤基本理化性质

    Table 1.  The basic physicochemical properties of vegetable soils in the suburbs of Xi’an

    处理
    Treatment
    土壤Cd
    Soil total Cd
    (mg/kg)
    土壤As
    Soil total As
    (mg/kg)
    pH有机质
    Organic matter
    (g/kg)
    速效氮
    Available N
    (mg/kg)
    速效磷
    Available P
    (mg/kg)
    速效钾
    Available K
    (mg/kg)
    CK-10.315.67.411.115.234.5178.5
    CK-20.312.67.810.120.011.1116.1
    CK-30.319.27.510.813.420.6524.9
    CK-40.420.77.611.117.913.7526.4
    As-10.224.77.714.015.616.6218.4
    As-20.325.47.413.111.813.6283.1
    As-30.327.07.711.017.7 6.2232.0
    As-40.228.37.812.625.4 7.2220.3
    Cd-10.620.87.811.017.623.5452.7
    Cd+As-11.025.67.5 9.810.016.8345.2
    Cd+As-21.226.87.7 8.723.3 6.8249.4
    Cd+As-32.424.97.510.016.312.9478.5
    下载: 导出CSV

    表 6  土壤重金属Cd和As安全阈值 (n = 36)

    Table 6.  Safety thresholds for Cd and As in soil

    蔬菜
    Vegetable
    CdAs
    回归方程
    Regression
    equation
    拟合优度
    Coefficient of
    determination
    阈值
    Threshold
    value
    回归方程
    Regression
    equation
    拟合优度
    Coefficient of
    determination
    阈值
    Threshold
    value
    菠菜 Spinachy = 0.2658x + 0.11200.95**0.33y = 0.0104x – 0.14800.73**62.31
    油菜 Coley = 0.2939x + 0.08760.92**0.38y = 0.0086x – 0.10500.84**70.35
    生菜 Cos lettucey = 0.1847x + 0.11470.88**0.46y = 0.0089x – 0.12490.66**70.21
    油麦菜 RLy = 0.1073x + 0.07640.86**1.15y = 0.0095x – 0.14040.62**67.41
    苋菜叶 EALy = 0.1492x + 0.11130.91**0.59y = 0.0093x – 0.13110.73**67.86
    苋菜茎 EASy = 0.0808x + 0.05550.93**1.79y = 0.0063x – 0.06970.62**90.43
    空心菜叶 WSLy = 0.0863x + 0.07130.81**1.49y = 0.0103x – 0.08930.59* 57.21
    空心菜茎 WSSy = 0.0209x + 0.02950.87**8.16y = 0.0077x – 0.08290.51* 75.70
    茼蒿叶 GCLy = 0.0200x + 0.02040.85**8.98y = 0.0074x – 0.03600.62**72.43
    茼蒿茎 GCSy = 0.0101x + 0.02720.73**17.11 y = 0.0052x – 0.04630.54* 105.06
    注(Note):RL—Romaine lettuce;EAL—Edible amaranth leaf;EAS—Edible amaranth stem;WSL—Water spinach leaf;WSS—Water spinach stem;GCL—Garland chrysanthemum leaf;GCS—Garland chrysanthemum stem. y—蔬菜含量 Vegetable content;x—土壤全量 Soil total content;*—P<0.05;**—P<0.01.
    下载: 导出CSV

    表 2  不同Cd、As含量土壤上7种叶菜的产量 (g/plant,FW)

    Table 2.  Yields of seven leafy vegetables in soils containing different Cd and As contents

    处理
    Treatment
    菠菜
    Spinach
    油菜
    Cole
    生菜
    Cos lettuce
    油麦菜
    Romaine lettuce
    苋菜
    Edible amaranth
    空心菜
    Water spinach
    茼蒿
    Garland chrysanthemum
    叶Leaf茎Stem叶Leaf茎Stem叶Leaf茎Stem
    CK-18.7 cd5.8 ab8.1 bc5.3 de5.3 de 4.2 bcd4.5 ef 4.5 bcde7.3 a 6.4 abc
    CK-28.0 d 5.9 ab6.3 ef 6.2 bcd4.5 ef 4.0 bcd4.1 f 5.2 abc6.2 c 7.2 ab
    CK-39.5 bc4.8 c 7.4 bcde6.6 bc6.9 ab 4.2 bcd5.6 bc 4.2 def 6.9 abc3.8 e
    CK-48.6 cd4.6 c 7.6 bcd 6.2 bcd7.4 a 3.9 cd5.5 cd 3.8 def6.3 bc7.2 ab
    平均Mean8.7 5.2 7.3 6.1 6.0 4.1 4.9 4.4 6.7 6.2
    As-110.8 ab 5.9 ab9.8 a 5.9 cde5.1 de5.0 a 6.4 ab5.3 ab7.2 ab7.3 ab
    As-211.2 a 5.7 ab 6.8 def7.6 a 7.0 ab4.6 ab 4.7 def 4.7 bcd6.1 c 7.2 ab
    As-38.3 cd5.4 b 8.5 b 5.8 cde4.1 f 3.8 d 3.9 f 4.4 cdef6.2 c 7.8 a
    As-48.2 cd6.1 a 6.8 def5.0 ef4.0 f 4.5 abc4.4 ef 4.6 bcd 6.6 abc4.6 de
    平均Mean9.6 5.8 8.0 6.1 5.1 4.5 4.9 4.8 6.5 6.7
    Cd-18.3 cd4.5 c 5.8 f 6.1 cd7.1 a 5.0 a 3.9 f 3.7 ef 6.9 abc 7.1 abc
    Cd+As-18.7 cd5.7 ab 7.2 cde6.5 bc7.3 a 3.8 d 6.8 a 5.7 a 6.2 c 5.5 cd
    Cd+As-28.0 d 5.6 ab 6.9 cdef7.1 ab6.2 bc3.8 d 5.6 cde 4.3 def6.1 c 5.9 bcd
    Cd+As-38.2 cd4.7 c 4.3 g 4.1 f 5.6 cd3.7 d 4.4 ef3.6 f 7.2 ab 6.3 abc
    平均Mean8.3 5.3 6.1 5.9 6.4 3.8 5.6 4.5 6.5 5.9
    注(Note):产量数据为每个蔬菜 3 次重复平均值;同列数据后不同小写字母表示同种蔬菜的产量在不同处理间差异达 5% 水平显著。The yields are the average of triplicates of each vegetable;values followed by different lowercase letters in same column indicate significant difference in yield for the same vegetable among treatments at 0.05 level.
    下载: 导出CSV

    表 3  7种叶菜生物量对Cd和As胁迫的响应BRS值 (%)

    Table 3.  BRS values (%) of biomass responses to Cd As stress of seven leafy vegetables

    处理
    Treatment
    菠菜
    Spinach
    油菜
    Cole
    生菜
    Cos lettuce
    油麦菜
    Romaine lettuce
    苋菜
    Edible amaranth
    空心菜
    Water spinach
    茼蒿
    Garland chrysanthemum
    叶Leaf茎Stem叶Leaf茎Stem叶Leaf茎Stem
    As-123.8*11.2 33.1*–2.9–15.5 23.8*30.1*20.2* 7.618.1
    As-228.5* 7.3–7.9 25.4*15.812.8–4.0 5.4–8.616.3
    As-3–5.3 1.616.1–4.2–32.0*–7.6–19.9 –1.3 –7.4 27.3*
    As-4–5.8 15.5–7.6–18.5 –33.0* 9.8–9.9 4.1–1.8–20.9
    Cd-1–5.4 –15.5 –21.4*–0.217.6 22.2*–21.2* –16.5 3.014.6
    Cd+As-1–0.4 8.0–2.2 6.520.6–7.337.7*28.6*–7.6–10.4
    Cd+As-2–8.0 6.5–5.917.5 3.1–7.86.9–3.5 –8.2–4.8
    Cd+As-3–6.4 –11.6 –41.5*–32.4*–7.1–8.7–10.1 –18.8 7.0 2.1
    注(Note):*表示污染处理蔬菜生物量对镉和砷胁迫的响应显著 The vegetable biomass response to Cd or As treatments was significant.
    下载: 导出CSV

    表 4  7种叶菜可食部分Cd含量 (mg/kg)

    Table 4.  Cd content of edible parts of seven leafy vegetables

    处理
    Treatment
    菠菜
    Spinach
    油菜
    Cole
    生菜
    Cos lettuce
    油麦菜
    Romaine lettuce
    苋菜
    Edible amaranth
    空心菜
    Water spinach
    茼蒿
    Garland chrysanthemum
    叶Leaf茎Stem叶Leaf茎Stem叶Leaf茎Stem
    CK-10.1100.1320.050.1120.0990.1070.0870.0330.0230.030
    CK-20.1630.1450.1650.1120.1360.0740.1060.0390.0240.030
    CK-30.1890.1450.1220.0690.1340.0650.0740.0340.0250.025
    CK-40.1710.1830.1400.0930.1260.0640.0560.0330.0240.027
    As-10.1240.1200.1580.1320.1660.0810.1010.0320.0320.033
    As-20.1900.1540.1840.1180.1380.0610.0840.0330.0300.034
    As-30.1370.1710.1120.0860.1540.0840.1090.0390.0220.028
    As-40.1520.1590.1600.1180.1680.0870.1030.0330.0200.029
    Cd-1 0.268* 0.235* 0.205*0.155 0.214*0.1050.1620.0440.0370.036
    Cd+As-1 0.424* 0.484* 0.384*0.184 0.299*0.1460.1600.0590.0470.042
    Cd+As-2 0.420* 0.420* 0.370* 0.222* 0.255*0.154 0.203*0.0580.0450.040
    Cd+As-3 0.753* 0.784* 0.528* 0.332* 0.478* 0.250* 0.267*0.0760.0660.050
    注(Note):*表示蔬菜样品 Cd 含量超标 Cd content of vegetable samples exceeds the standard;蔬菜限量标准 Vegetable limited standard (Cd < 0.2 mg/kg,FW)[24].
    下载: 导出CSV

    表 5  7种叶菜可食部As含量 (mg/kg)

    Table 5.  As content of edible parts of seven leafy vegetables

    处理
    Treatment
    菠菜
    Spinach
    油菜
    Cole
    生菜
    Cos lettuce
    油麦菜
    Romaine lettuce
    苋菜
    Edible amaranth
    空心菜
    Water spinach
    茼蒿
    Garland chrysanthemum
    叶Leaf茎Stem叶Leaf茎Stem叶Leaf茎Stem
    CK-10.0250.0540.0120.0180.0060.0610.0860.0290.0850.027
    CK-20.0270.0270.0000.0200.0120.0120.0820.0510.0390.011
    CK-30.0270.0340.0080.0340.0270.0120.0690.0530.0830.048
    CK-40.0410.0310.0600.0070.0420.0700.1190.0700.1100.063
    As-10.0440.0670.0480.0350.0460.0480.0750.0220.1140.078
    As-20.0670.0940.0690.1000.0810.0440.1860.1010.1140.068
    As-30.1640.1280.1150.1290.1240.1150.1410.0870.1750.088
    As-40.1410.1490.1250.1740.1110.1140.2560.1390.1450.090
    Cd-10.0330.0550.0680.0420.0470.0490.1290.0630.12 0.065
    Cd+As-10.0750.0990.1300.0640.0970.06 0.1130.1000.1810.104
    Cd+As-20.1590.1210.0730.0770.1330.0960.1990.1790.1260.083
    Cd+As-30.0480.0610.0570.0210.0470.0830.0910.0570.1460.033
    注(Note):蔬菜限量标准 Vegetable limited standard (As < 0.5 mg/kg,FW)[24].
    下载: 导出CSV

    表 7  四个处理七种叶菜可食部位Cd、As的富集量 (μg/plant)

    Table 7.  Enrichment of Cd and As in edible parts of seven leafy vegetables in the four treatments

    蔬菜
    Vegetable
    CdAs
    CKAsCdCd+AsCKAsCdCd+As
    菠菜Spinach1.39 c1.47 c2.21 b4.40 a0.26 b0.94 a0.28 b0.77 a
    油菜 Cole0.79 b0.87 b1.05 b2.92 a0.19 b0.63 a0.25 b0.51 a
    生菜Cos lettuce0.84 c1.21 b1.18 b2.52 a0.15 c0.69 a0.39 bc 0.56 ab
    油麦菜 RL0.58 c0.69 c0.94 b1.37 a0.12 c0.65 a 0.25 bc0.35 b
    苋菜EA0.75 c0.78 c1.52 b2.16 a0.15 c 0.44 ab0.33 b0.60 a
    空心菜WS0.39 d0.48 c0.63 b1.11 a0.44 b0.76 a0.50 b0.74 a
    茼蒿GC0.16 b0.17 b0.25 a0.35 a0.53 b0.89 a0.83 a0.98 a
    注(Note):各处理蔬菜重金属富集量为样本平均值;CK、Cd、As、Cd & As等处理的样本数分别为 12、3、13、9;同行数值后不同小写字母表示同种蔬菜不同处理的重金属富集量在 5% 水平上差异显著。RL—Romaine lettuce;EA—Edible amaranth;WS—Water spinach;GC—Garland chrysanthemum. The enrichment amount was the average of samples in each treatment,and the each vegetable sample number in CK,Cd,As and Cd+As treatment was 12,3,13 and 9 respectively;values followed by different lowercase letters in the same row indicate significant difference among treatments for the enrichment of the same vegetable at the 0.05 level.
    下载: 导出CSV
  • [1] Khan S, Cao Q, Zheng Y M, et al. Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in Beijing, China[J]. Environmental Pollution, 2008, 152(3): 686–692. doi: 10.1016/j.envpol.2007.06.056
    [2] Song B, Lei M, Chen T B, et al. Assessing the health risk of heavy metals in vegetables to the general population in Beijing, China[J]. Journal of Environmental Sciences, 2009, 21(12): 1702–1709. doi: 10.1016/S1001-0742(08)62476-6
    [3] Zhuang P, Mcbride M B, Xia H P, et al. Health risk from heavy metals via consumption of food crops in the vicinity of Dabaoshan mine, South China[J]. Science of the Total Environment, 2009, 407(5): 1551–1561. doi: 10.1016/j.scitotenv.2008.10.061
    [4] Yang Q W, Xu Y, Liu S J, et al. Concentration and potential health risk of heavy metals in market vegetables in Chongqing, China[J]. Ecotoxicology and Environmental Safety, 2011, 74(6): 1664–1669. doi: 10.1016/j.ecoenv.2011.05.006
    [5] Yang L Q, Huang B, Hu W Y, et al. Assessment and source identification of trace metals in the soils of greenhouse vegetable production in eastern China[J]. Ecotoxicology and Environmental Safety, 2013, 97: 204–209.
    [6] Xiao Q, Zong Y T, Lu S G. Assessment of heavy metal pollution and human health risk in urban soils of steel industrial city (Anshan), Liaoning, Northeast China[J]. Ecotoxicology and Environmental Safety, 2015, 120: 377–385.
    [7] Hu J L, Wu F Y, Wu S C, et al. Phytoavailability and phytovariety codetermine the bioaccumulation risk of heavy metal from soils, focusing on Cd-contaminated vegetable farms around the Pearl River Delta, China[J]. Ecotoxicology and Environmental Safety, 2013, 91: 18–24.
    [8] Alexander P D, Alloway B J, Dourado A M. Genotypic variations in the accumulation of Cd, Cu, Pb and Zn exhibited by six commonly grown vegetables[J]. Environmental Pollution, 2006, 144(3): 736–745. doi: 10.1016/j.envpol.2006.03.001
    [9] Li Q S, Cai S S, Mo C H, et al. Toxic effects of heavy metals and their accumulation in vegetables grown in a saline soil[J]. Ecotoxicology and Environmental Safety, 2010, 73(1): 84–88. doi: 10.1016/j.ecoenv.2009.09.002
    [10] Xu L, Lu X, Wang J H, et al. Accumulation status, sources and phytoavailability of metals in greenhouse vegetable production systems in Beijing, China[J]. Ecotoxicology and Environmental Safety, 2015, 122: 214–220.
    [11] Lu J H, Yang X P, Meng X C, et al. Predicting cadmium safety thresholds in soils based on cadmium uptake by Chinese cabbage[J]. Pedosphere, 2017, 27(3): 475–481. doi: 10.1016/S1002-0160(17)60343-6
    [12] Yang Y, Zhang F S, Li H F, et al. Accumulation of cadmium in the edible parts of six vegetable species grown in Cd-contaminated soils[J]. Journal of Environmental Management, 2009, 90(2): 1117–1122. doi: 10.1016/j.jenvman.2008.05.004
    [13] Li X H, Zhou Q X, Wei S H, et al. Identification of cadmium-excluding welsh onion (Allium fistulosum L.) cultivars and their mechanisms of low cadmium accumulation[J]. Environmental Science and Pollution Research, 2012, 19(5): 1773–1780. doi: 10.1007/s11356-011-0692-0
    [14] Shao T J, Pan L H, Chen Z Q, et al. Content of heavy metal in the dust of leisure squares and its health risk assessment—A case study of yanta district in Xi’an[J]. International Journal of Environmental Research & Public Health, 2018, (15): 394–417.
    [15] Chen X D, Lu X W, Li L Y, et al. Spatial distribution and contamination assessment of heavy metals in urban topsoil from inside the Xi’an second ringroad, NW China[J]. Microchemical Journal, 2013, (68): 1979–1988.
    [16] Chen H, Lu X W, Gao T N, et al. Identifying hot-spots of metal contamination in campus dust of Xi’an, China[J]. International Journal of Environmental Research and Public Health, 2016, (13): 1–16.
    [17] Lu X W, Zhang X L, Li L Y, et al. Assessment of metals pollution and health risk in dust from nursery schools in Xi’an, China[J]. Environmental Research, 2014, 128: 27–34.
    [18] Chen Y P, Zheng Y J, Liu Q, et al. Atmospheric deposition exposes Qinling pandas to toxic pollutants[J]. Ecological Applications, 2017, (2): 343–348.
    [19] Deng W B, Li X X, An Z S, et al. Identification of sources of metal in the agricultural soils of the Guanzhong plain, northwest china[J]. Environmental Toxicology and Chemistry, 2017, (6): 1510–1516.
    [20] 李雪芳, 王文岩, 上官宇先, 等. 西安市郊菜地土壤重金属污染及其与蔬菜重金属质量分数的相关性[J]. 西北农业学报, 2014, 23(8): 173–181. Li X F, Wang W Y, Shangguan Y X, et al. Relationship of heavy metal pollution in soil and their mass fraction in vegetables in Xi’An city suburb[J]. Acta Agriculturae Boreali-occidentalis Sinica, 2014, 23(8): 173–181.
    [21] 李雪芳, 王林权, 尚浩博, 等. 小白菜和小青菜对镉、汞、砷的富集效应及影响因素[J]. 北方园艺, 2014, (1): 16–21. Li X F, Wang L Q, Shang H B, et al. The enrichment effect of Cd, Hg and As on brassica chinensis and Brassica pekinensis and its influencing factors[J]. Northern Horticulture, 2014, (1): 16–21.
    [22] Li X P, Feng L N, et al. Spatial distribution of hazardous elements in urban topsoils surrounding Xi’an industrial areas, (NW, China): Controlling factors and contamination assessments[J]. Journal of Hazardous Materials, 2010, 174: 662–669.
    [23] Zhang H H, Chen J J, Zhu L, et al. Transfer of cadmium from soil to vegetable in the Pearl River Delta area, South China[J]. PLoS One, 2014, 9(9): 1–11.
    [24] GB2762-2017, 食品中污染物限量[S].
    GB2762-2017, Contaminant limit in food [S].
    [25] Yang Y, Chen W P, Wang M E, et al. Regional accumulation characteristics of cadmium in vegetables: influencing factors, transfer model and indication of soil threshold content[J]. Environmental Pollution, 2016, 219: 1036–1043.
    [26] Wang X P, Shan X Q, Zhang S Z, et al. A model for evaluation of the phytoavailability of trace elements to vegetables under the field conditions[J]. Chemosphere, 2004, 55(6): 811–822. doi: 10.1016/j.chemosphere.2003.12.003
    [27] Qiu Q, Wang Y T, Yang Z Y, et al. Responses of different Chinese flowering cabbage (Brassica parachinensis L.) cultivars to cadmium and lead exposure: screening for Cd+Pb pollution-safe cultivars[J]. CLEAN-Soil Air Water, 2011, 39(11): 925–932. doi: 10.1002/clen.v39.11
    [28] Chen Y, Li T Q, Han X, et al. Cadmium accumulation in different pakchoi cultivars and screening for pollution-safe cultivars[J]. Journal of Zhejiang University-Science B, 2012, 13(6): 494–502. doi: 10.1631/jzus.B1100356
    [29] Wang X, Shi Y, Chen X, et al. Screening of Cd-safe genotypes of Chinese cabbage in field condition and Cd accumulation in relation to organic acids in two typical genotypes under long-term Cd stress[J]. Environmental Science and Pollution Research, 2015, (22): 16590–16599.
    [30] Girish C, Saifullah, Nanthi B, et al. Cellular mechanisms in higher plants governing tolerance to cadmium toxicity[J]. Critical Reviews in Plant Sciences, 2014, 33(5): 374–391. doi: 10.1080/07352689.2014.903747
    [31] Verbruggen N, Hermans C, Schat H. Mechanisms to cope with arsenic or cadmium excess in plants[J]. Current Opinion in Plant Biology, 2009, (12): 364–372.
    [32] Meng Y, Zhang L, Wang L Q, et al. Antioxidative enzymes activity and thiol metabolism in three leafy vegetables under Cd stress[J]. Ecotoxicology and Environmental Safety, 2019, 173: 214–224.
    [33] Akhter F, McGarvey B, Macfie S M. Reduced translocation of cadmium from roots is associated with increased production of phytochelatins and their precursors[J]. Journal of Plant Physiology, 2012, 169(18): 1821–1829. doi: 10.1016/j.jplph.2012.07.011
    [34] Mendoza-Cózatl D, Loza-Tavera H, Hernández-Navarro A, et al. Sulfur assimilation and glutathione metabolism under cadmium stress in yeast, protists and plants[J]. FEMS Microbiology Reviews, 2005, 29(4): 653–671. doi: 10.1016/j.femsre.2004.09.004
    [35] Souhir S, Alessandro F, Clarissa L, et al. Analysis of cadmium translocation, partitioning and tolerance in six barley (Hordeum vulgare L.) cultivars as a function of thiol metabolism[J]. Biology and Fertility of Soils, 2015, 51(3): 311–320. doi: 10.1007/s00374-014-0977-9
    [36] Negrin V L, Teixeira B, Godinho R M, et al. Phytochelatins and monothiols in salt marsh plants and their relation with metal tolerance[J]. Marine Pollution Bulletin, 2017, 121(1–2): 78–84. doi: 10.1016/j.marpolbul.2017.05.045
    [37] 文典, 胡霓红, 赵凯, 等. 小白菜对土壤中5种重金属的富集特征及土壤安全临界值的研究[J]. 热带作物学报, 2012, (11): 1942–1948. Wen D, Hu N H, Zhao K, et al. Five kinds of heavy metals enrichment characteristics in Pakchoi (Brassica chinensis L.) and the critical values in the soil for Pakchoi production[J]. Chinese Journal of Tropical Crops, 2012, (11): 1942–1948. doi: 10.3969/j.issn.1000-2561.2012.11.005
    [38] 赵勇, 李红娟, 孙治强. 土壤、蔬菜Cd污染相关性分析与土壤污染阈限值研究[J]. 农业工程学报, 2006, (7): 149–153. Zhao Y, Li H J, Sun Z Q. Correlation analysis of Cd pollution in vegetables and soils and the soil pollution threshold[J]. Transactions of the CSAE, 2006, (7): 149–153. doi: 10.3321/j.issn:1002-6819.2006.07.031
    [39] Wang J L, Yuan J G, Yang Z Y, et al. Variation in cadmium accumulation among 30 cultivars and cadmium subcellular distribution in 2 selected cultivars of water spinach (Ipomoea aquatica Forsk.)[J]. Journal of Agricultural and Food Chemistry, 2009, 57(19): 8942–8949.
    [40] Cui Y J, Zhu Y G, Zhai R H, et al. Transfer of metals from soil to vegetables in an area near a smelter in Nanning, China[J]. Environment International, 2004, 30(6): 785–791. doi: 10.1016/j.envint.2004.01.003
    [41] Huang R Q, Gao S F, Wang W L, et al. Soil arsenic availability and the transfer of soil arsenic to crops in suburban areas in Fujian Province, southeast China[J]. Science of the Total Environment, 2006, 368(2–3): 531–541. doi: 10.1016/j.scitotenv.2006.03.013
    [42] Lin Y W, Liu T S, Guo H Y, et al. Relationships between Cd concentrations in different vegetables and those in arable soils, and food safety evaluation of vegetables in Taiwan[J]. Soil Science and Plant Nutrition, 2015, 61(6): 983–998. doi: 10.1080/00380768.2015.1078219
    [43] Liu W T, Zhou Q X, An J, et al. Variations in cadmium accumulation among Chinese cabbage cultivars and screening for Cd-safe cultivars[J]. Journal of Hazardous Materials, 2010, 173(1–3): 737–743. doi: 10.1016/j.jhazmat.2009.08.147
  • [1] 丁能飞周吉庆龟和田国彦傅庆林郭彬刘琛林义成 . 不同种类与浓度的阴离子对菠菜镉吸收的影响 . 植物营养与肥料学报, 2008, 14(6): 1137-1141. doi: 10.11674/zwyf.2008.0617
    [2] . 植物砷的生理和分子生物学研究进展—从土壤、根际到植物吸收、运输及耐性. 植物营养与肥料学报, 2010, 16(5): 1264-1275. doi: 10.11674/zwyf.2010.0530
    [3] 阮云泽孙桂芳唐树梅 . 土壤养分状况系统研究法在菠菜平衡施肥上的应用. 植物营养与肥料学报, 2005, 11(4): 530-535. doi: 10.11674/zwyf.2005.0417
    [4] 史雅静史雅娟王玉荣王慧敏秦礼凯 . 无机硒肥对土壤有效氮含量及菠菜品质的影响. 植物营养与肥料学报, 2019, 25(2): 274-283. doi: 10.11674/zwyf.18347
    [5] 陕红刘荣乐李书田 . 施用有机物料对土壤镉形态的影响. 植物营养与肥料学报, 2010, 16(1): 136-144. doi: 10.11674/zwyf.2010.0120
    [6] 黄化刚李廷强朱治强王凯杨肖娥 . 可溶性磷肥对重金属复合污染土壤东南景天提取锌/镉及其养分积累的影响. 植物营养与肥料学报, 2012, 18(2): 382-389. doi: 10.11674/zwyf.2012.11294
    [7] 万敏周卫林葆 . 不同镉积累类型小麦根际土壤低分子量有机酸与镉的生物积累. 植物营养与肥料学报, 2003, 9(3): 331-336. doi: 10.11674/zwyf.2003.0315
    [8] 廖晓勇谢华陈同斌肖细元阎秀兰翟丽梅武斌 . 蜈蚣草的超微结构和砷、钙的亚细胞分布. 植物营养与肥料学报, 2007, 13(2): 305-312. doi: 10.11674/zwyf.2007.0220
    [9] 张丽张传光柳勇谷林静张乃明岳献荣夏运生 . 接种丛枝菌根真菌(AMF)对施磷石膏云烟87的生长以及砷污染的影响. 植物营养与肥料学报, 2015, 21(2): 475-484. doi: 10.11674/zwyf.2015.0223
    [10] 谢正苗卡里德黄昌勇俞劲炎 . 镉铅锌污染对红壤中微生物生物量碳氮磷的影响. 植物营养与肥料学报, 2000, 6(1): 69-74. doi: 10.11674/zwyf.2000.0111
    [11] 张丽娟巨晓棠文宏达夏晓平刘慧 . 土壤剖面不同土层硝态氮植物利用及运移规律研究. 植物营养与肥料学报, 2010, 16(1): 82-91. doi: 10.11674/zwyf.2010.0112
    [12] 刘伟徐坤苏华王惠林 . 氮素对菠菜衰老生理指标的影响. 植物营养与肥料学报, 2007, 13(6): 1110-1115. doi: 10.11674/zwyf.2007.0620
    [13] 张英鹏徐旭军林咸永章永松都韶婷李刚 . 氮素形态对菠菜可食部分硝酸盐和草酸累积的影响. 植物营养与肥料学报, 2006, 12(2): 227-232. doi: 10.11674/zwyf.2006.0214
    [14] 董亮张玉凤王学君齐军山杨力魏建林李国生 . 牛蒡提取物对菠菜生长及品质的影响. 植物营养与肥料学报, 2009, 15(3): 729-732. doi: 10.11674/zwyf.2009.0336
    [15] . 菠菜硝酸盐含量符合安全生产的氮肥用量研究. 植物营养与肥料学报, 2010, 16(5): 1282-1287. doi: 10.11674/zwyf.2010.0532
    [16] 邢素芝汪建飞李孝良邹海明 . 氮肥形态及配比对菠菜生长和安全品质的影响. 植物营养与肥料学报, 2015, 21(2): 527-534. doi: 10.11674/zwyf.2015.0229
    [17] 陈雨海余松烈于振文 . 小麦间作菠菜的边际效应与基施氮肥利用率. 植物营养与肥料学报, 2004, 10(1): 29-33. doi: 10.11674/zwyf.2004.0106
    [18] 李俊良刘洪对张晓晟王秀峰陈清 . 灌溉方式对露地菠菜的生长及氮素利用的影响. 植物营养与肥料学报, 2004, 10(4): 398-402. doi: 10.11674/zwyf.2004.0411
    [19] 张英鹏李彦张明文孙明王学君董晓霞高弼模 . 不同氮钙营养对菠菜安全品质与抗氧化酶活性的影响 . 植物营养与肥料学报, 2008, 14(4): 754-760. doi: 10.11674/zwyf.2008.0421
    [20] 张英鹏徐旭军林咸永章永松张丽苏陈甜甜 . 供氮水平对菠菜产量、硝酸盐和草酸累积的影响. 植物营养与肥料学报, 2004, 10(5): 494-498. doi: 10.11674/zwyf.2004.0509
  • 加载中
图(1)表(7)
计量
  • 文章访问数:  384
  • HTML全文浏览量:  248
  • PDF下载量:  14
  • 被引次数: 0
出版历程
  • 收稿日期:  2018-07-10
  • 网络出版日期:  2019-06-29
  • 刊出日期:  2019-06-01

复合污染土壤上几种叶类蔬菜对Cd和As的富集效应

    作者简介:孟媛 E-mail:15191419886@163.com
    通讯作者: 王林权, linquanw@nwsuaf.edu.cn
  • 1. 西北农林科技大学资源环境学院,陕西杨凌 712100
  • 2. 四川省农业科学院土壤肥料研究所,成都 610066
  • 3. 中国科学院合肥物质科学研究院技术生物与农业工程研究所,合肥 230031
  • 基金项目: 国家重点研发计划(2017YFD0200105)。
  • 摘要: 【目的】不同蔬菜镉、砷富集系数各异,对镉和砷污染土壤的响应也不同。研究复合污染土壤上不同叶类蔬菜对Cd和As的积累效应,为轻度–中度Cd和As污染土壤的合理与安全利用提供适宜的蔬菜种类。【方法】采集了西安市12个污染程度不同的菜地耕层土壤,于2015年3月6日—5月26日在西北农林科技大学资源环境学院遮雨大棚内进行了盆栽试验。供试7种叶菜,包括菠菜、油菜、生菜、油麦菜、苋菜、空心菜和茼蒿。蔬菜收获后,测量了蔬菜产量、Cd和As含量与吸收累积量,计算了蔬菜对Cd和As的富集系数等,并用线性回归模型研究了不同蔬菜栽培的土壤Cd和As安全临界值。【结果】镉污染土壤 (0.6~2.4 mg/kg) 对大多数蔬菜生物量有抑制效应,中、低浓度镉砷复合污染 (Cd 1.0~2.4 mg/kg,As 24.9~26.8 mg/kg) 对供试蔬菜生长没有叠加效应。镉污染土壤上,菠菜、油菜、苋菜叶、生菜可食部Cd含量均超出食品安全限量标准(0.2 mg/kg),其中菠菜和油菜Cd最高超标4倍以上;而茼蒿和空心菜茎秆Cd未超标。虽然供试蔬菜砷含量随着土壤砷含量增加有升高趋势,但叶菜As含量没有超标。7种蔬菜Cd富集系数为0.083~0.491,高低顺序为油菜、菠菜、生菜和苋菜叶 > 油麦菜、苋菜茎和空心菜叶 > 空心菜茎和茼蒿。菠菜、油菜、生菜、油麦菜、苋菜、空心菜和茼蒿土壤Cd安全临界值分别为0.33、0.38、0.46、1.15、0.59~1.79、1.49~8.16和8.98~17.11 mg/kg,其中菠菜、油菜和生菜阈值与现行标准 (0.3~0.6 mg/kg) 相当,而油麦菜、苋菜、空心菜和茼蒿均大于土壤重金属污染限量值。As富集系数为0.002~0.006,空心菜叶和茼蒿叶片As富集系数显著高于其他蔬菜。7种蔬菜的土壤As临界阈值分别为62.31、70.35、70.21、67.41、67.86~90.43、57.21~75.70和72.43~105.06 mg/kg,均高于现行标准 (25 mg/kg)。【结论】中等程度的Cd和As复合污染土壤上,Cd对蔬菜的生长有显著的抑制,As与Cd没有叠加作用。不同蔬菜的产量、污染程度和安全阈值等有显著差异,因此选择低富集、抗污染蔬菜品种是利用中低重金属污染土壤的一条可行途径。空心菜和茼蒿对Cd富集系数低,可推荐在中、低污染土壤上种植。

    English Abstract

    • 土壤污染状况调查公报 (2014) 的发表和土壤污染防治行动计划 (2016) 的出台表明土壤污染治理刻不容缓。北京污灌区土壤和农作物重金属含量超出中国环境保护部和世界卫生组织安全标准[1],其中蔬菜主要风险物是As[2]。中国南部大宝山矿区土壤和蔬菜Zn、Pb和Cd严重超标[3]。重庆居民每日从蔬菜摄入Pb、Mn和Cd量超出了国际安全标准,严重威胁身体健康[4]。有山东省寿光市蔬菜温室和江苏省南部蔬菜生产基地Cd和Hg污染报道[5]。中国东北部辽宁鞍山市土壤出现Cd、Pb、Zn和Cu污染,其中钢铁产区尤为重灾区[6]。珠江三角洲地区蔬菜Cd含量超限,其中71.4%是叶类或茎秆蔬菜[7]。叶类蔬菜是重金属Cd和As高富集种类,比其他农作物 (茄属类、甘蓝类、根菜类、葱类、豆科等) 更容易受到污染[3, 5-11]。重金属污染土壤修复难度大、费用高,种植对重金属低富集的粮食和蔬菜作物是一种污染土壤利用途径[12-13]。因此研究Cd和As轻度复合污染土壤上不同蔬菜重金属吸收累积特性、筛选低累积性蔬菜具有一定的理论与实践意义。

      西安是中国著名旅游城市,也是9个国家中心城市之一。西安市道路、休闲广场、加油站、校园等场地的粉尘重金属含量超标[14-17]。大气沉降导致秦岭大熊猫食区竹子中重金属含量升高,威胁大熊猫健康[18]。城郊农田土壤重金属污染严重[19-21],主要污染源是交通和工业排放[22]。本文采集西安城郊Cd和As污染程度不同的12个菜地土壤样本,采用大棚盆栽试验,研究了叶类蔬菜对土壤中重金属Cd和As的吸收累积特征,探讨其安全生产的土壤污染阈值,为无公害蔬菜生产及污染土壤合理利用提供基础资料和理论依据。

      • 在前期土壤和蔬菜重金属污染调查基础上,采集了西安市灞桥区、未央区和临潼区等不同污染程度的12个菜地耕层土壤 (0—20 cm),其基本理化性质见表1

        表 1  西安市城郊菜地土壤基本理化性质

        Table 1.  The basic physicochemical properties of vegetable soils in the suburbs of Xi’an

        处理
        Treatment
        土壤Cd
        Soil total Cd
        (mg/kg)
        土壤As
        Soil total As
        (mg/kg)
        pH有机质
        Organic matter
        (g/kg)
        速效氮
        Available N
        (mg/kg)
        速效磷
        Available P
        (mg/kg)
        速效钾
        Available K
        (mg/kg)
        CK-10.315.67.411.115.234.5178.5
        CK-20.312.67.810.120.011.1116.1
        CK-30.319.27.510.813.420.6524.9
        CK-40.420.77.611.117.913.7526.4
        As-10.224.77.714.015.616.6218.4
        As-20.325.47.413.111.813.6283.1
        As-30.327.07.711.017.7 6.2232.0
        As-40.228.37.812.625.4 7.2220.3
        Cd-10.620.87.811.017.623.5452.7
        Cd+As-11.025.67.5 9.810.016.8345.2
        Cd+As-21.226.87.7 8.723.3 6.8249.4
        Cd+As-32.424.97.510.016.312.9478.5

        2015年3月6日—5月26日,以12个土壤样本为栽培基质,通过盆栽试验研究了7种叶菜,分别为:华星春秋大圆叶菠菜 (Spinacia oleracea L.)、秦都黑油冬油菜 (Brassica rapacampestris L.)、香港玻璃脆生菜 (Lactuca sativa L.)、广东四季香油麦菜 (Lactuca sativa L. var. longifolia)、青丰青苋菜 (Amaranthus mangostanus L.)、利丰大叶空心菜 (Ipomoea aquatica forsk L.) 和华星小叶茼蒿 (Chrysanthemum coronarium L.) 等对不同污染土壤的响应,及其对镉和砷吸收累积效应。菠菜、油菜、生菜、油麦菜、茼蒿种植时间是2015年3月6日—4月25日,苋菜和空心菜在4月7日播种,5月26日收获。试验在西北农林科技大学资源环境学院大棚进行,供试蔬菜种子均购自陕西华星绿色种苗有限公司。

        将供试土壤样品经风干粉碎后过2 mm筛,装入上口径14 cm、下口径10 cm、高12 cm的黑色塑料盆,每盆土壤重1.8 kg;塑料盆底部配有垫纱网和托盘,防止浇水后水土流失。种植前每盆施用1.6 g复合肥 (15–15–15),与土壤充分混匀,浇水平衡一周后播种。每个土壤样本种植7种蔬菜,每种土壤每种蔬菜重复3次,共计252盆,随机排列。每盆播种15颗种子,待出齐苗后定植为7株蔬菜苗。种植大棚透光通风遮雨,光照与外界自然气候条件一致。浇水频率视天气状况而定,保持土壤湿润状态。

      • 土壤基本理化性质测定[21]:速效氮 (NH4++NO3) 用1 mol/L KCl浸提,流动分析仪测定;速效磷用0.5 mol/L NaHCO3浸提,紫外可见分光光度计测定;速效钾用1 mol/L NH4AC浸提,火焰光度计法测定;pH用0.01 mol/LCaCl2水溶液浸提,pH计测定;有机质用重铬酸钾—外加热法测定。

        土壤和蔬菜样品的采集:参考《中华人民共和国环境保护行业标准HJ/T 166-2004土壤环境监测技术规范》采集土壤样品。将蔬菜植株从茎基部将根剪断,用去离子水冲洗4遍,将苋菜、空心菜、茼蒿分茎和叶两种器官,称取鲜重后,在105℃杀青30分钟,然后65℃烘干至恒重。

        土壤和蔬菜重金属Cd和As含量测定[21, 23]:土壤样品用王水–高氯酸消解,植物样品用10% HNO3消解,分别用ICP-MS系统测定Cd和As含量。测定时每批上机样品均使用“GBW10048(GSB-26) 生物成分分析标准物质芹菜”和“GBW07409 土壤成分分析标准物质”分别进行蔬菜和土壤样品质量控制。监测仪器及型号:ICP-MS 7500(美国安捷伦公司产)。

      • 蔬菜地上部重金属富集系数=蔬菜地上部重金属浓度 (mg/kg,FW)/土壤重金属浓度 (mg/kg)。各供试蔬菜重金属平均富集系数是12个土壤处理的富集系数平均值 (n = 36)。每株叶菜Cd或As富集量 (μg) = 蔬菜可食部Cd或As浓度 (mg/kg,FW) × 每株蔬菜可食部鲜重 (g,FW)。

        生物量对胁迫的响应 = (Cd或As处理下蔬菜可食部生物量–CK处理蔬菜可食部生物量)/CK处理蔬菜可食部生物量 × 100%,其中,CK处理蔬菜生物量是未污染土壤 (CK1~CK4) 上蔬菜生物量的平均值。

        安全阈值计算方法:用不同蔬菜可食部重金属含量y (mg/kg, FW) 与土壤重金属含量x (mg/kg) 拟合线性方程计算 (表6)。将《食品中污染物限量》 (GB2762-2017) 中对叶菜的限量指标 (Cd 0.2 mg/kg, FW和As 0.5 mg/kg, FW) 分别代入相应拟合方程,计算得到安全阈值x。

        表 6  土壤重金属Cd和As安全阈值 (n = 36)

        Table 6.  Safety thresholds for Cd and As in soil

        蔬菜
        Vegetable
        CdAs
        回归方程
        Regression
        equation
        拟合优度
        Coefficient of
        determination
        阈值
        Threshold
        value
        回归方程
        Regression
        equation
        拟合优度
        Coefficient of
        determination
        阈值
        Threshold
        value
        菠菜 Spinachy = 0.2658x + 0.11200.95**0.33y = 0.0104x – 0.14800.73**62.31
        油菜 Coley = 0.2939x + 0.08760.92**0.38y = 0.0086x – 0.10500.84**70.35
        生菜 Cos lettucey = 0.1847x + 0.11470.88**0.46y = 0.0089x – 0.12490.66**70.21
        油麦菜 RLy = 0.1073x + 0.07640.86**1.15y = 0.0095x – 0.14040.62**67.41
        苋菜叶 EALy = 0.1492x + 0.11130.91**0.59y = 0.0093x – 0.13110.73**67.86
        苋菜茎 EASy = 0.0808x + 0.05550.93**1.79y = 0.0063x – 0.06970.62**90.43
        空心菜叶 WSLy = 0.0863x + 0.07130.81**1.49y = 0.0103x – 0.08930.59* 57.21
        空心菜茎 WSSy = 0.0209x + 0.02950.87**8.16y = 0.0077x – 0.08290.51* 75.70
        茼蒿叶 GCLy = 0.0200x + 0.02040.85**8.98y = 0.0074x – 0.03600.62**72.43
        茼蒿茎 GCSy = 0.0101x + 0.02720.73**17.11 y = 0.0052x – 0.04630.54* 105.06
        注(Note):RL—Romaine lettuce;EAL—Edible amaranth leaf;EAS—Edible amaranth stem;WSL—Water spinach leaf;WSS—Water spinach stem;GCL—Garland chrysanthemum leaf;GCS—Garland chrysanthemum stem. y—蔬菜含量 Vegetable content;x—土壤全量 Soil total content;*—P<0.05;**—P<0.01.
      • 数据分析采用SAS V8软件 (North Carolina State University,USA),用TTEST process进行t检验,ANOVA process作方差分析,新复极差法作多重比较。用SAS系统CORR process作相关性分析,REG process作线性回归分析。作图软件是Graphpad Prism 6 (La Jolla,CA 92037 USA)。

      • 供试土壤基本理化性质及重金属含量见表1,其中Cd浓度为0.2~2.4 mg/kg,As浓度为12.6~28.3 mg/kg。根据土壤环境质量标准 (GB 15618-2018) 规定的“农用地土壤污染风险筛选值”(pH>7.5时,Cd 0.6 mg/kg、As 25 mg/kg),CK-1~CK-4处理属于非污染土壤;砷污染土壤 (As-1~As-4)As含量是国标限量值的1.0~1.1倍;镉污染土壤 (Cd1) 的Cd含量与国标限量值相当;复合污染土壤 (Cd+As-1、Cd+As-2、Cd+As-3) 的Cd含量是国标限量值的1.8~4.0倍,As含量与国标限量值相当。

      • 供试蔬菜生长过程中未出现重金属毒害症状,蔬菜产量见表2。其中未污染土壤上,菠菜、油菜、生菜、油麦菜、苋菜、空心菜、茼蒿产量分别为8.7、5.2、7.3、6.1、10.1、9.3、12.9 g/(plant,FW)。由多重比较结果可以看出,较高镉污染 (Cd+As-3) 土壤上,生菜和油麦菜鲜重显著低于CK-1~CK-4处理;菠菜、苋菜叶、空心菜叶鲜重显著低于CK-3处理;油菜和空心菜茎低于CK-1和CK-2处理。相对于无污染土壤,较高浓度镉污染对大部分蔬菜有减产效应 (茼蒿、苋菜茎除外)。As污染土壤对蔬菜生物量影响不大。镉砷复合污染并没有对蔬菜生物量的抑制产生叠加效应。

        表 2  不同Cd、As含量土壤上7种叶菜的产量 (g/plant,FW)

        Table 2.  Yields of seven leafy vegetables in soils containing different Cd and As contents

        处理
        Treatment
        菠菜
        Spinach
        油菜
        Cole
        生菜
        Cos lettuce
        油麦菜
        Romaine lettuce
        苋菜
        Edible amaranth
        空心菜
        Water spinach
        茼蒿
        Garland chrysanthemum
        叶Leaf茎Stem叶Leaf茎Stem叶Leaf茎Stem
        CK-18.7 cd5.8 ab8.1 bc5.3 de5.3 de 4.2 bcd4.5 ef 4.5 bcde7.3 a 6.4 abc
        CK-28.0 d 5.9 ab6.3 ef 6.2 bcd4.5 ef 4.0 bcd4.1 f 5.2 abc6.2 c 7.2 ab
        CK-39.5 bc4.8 c 7.4 bcde6.6 bc6.9 ab 4.2 bcd5.6 bc 4.2 def 6.9 abc3.8 e
        CK-48.6 cd4.6 c 7.6 bcd 6.2 bcd7.4 a 3.9 cd5.5 cd 3.8 def6.3 bc7.2 ab
        平均Mean8.7 5.2 7.3 6.1 6.0 4.1 4.9 4.4 6.7 6.2
        As-110.8 ab 5.9 ab9.8 a 5.9 cde5.1 de5.0 a 6.4 ab5.3 ab7.2 ab7.3 ab
        As-211.2 a 5.7 ab 6.8 def7.6 a 7.0 ab4.6 ab 4.7 def 4.7 bcd6.1 c 7.2 ab
        As-38.3 cd5.4 b 8.5 b 5.8 cde4.1 f 3.8 d 3.9 f 4.4 cdef6.2 c 7.8 a
        As-48.2 cd6.1 a 6.8 def5.0 ef4.0 f 4.5 abc4.4 ef 4.6 bcd 6.6 abc4.6 de
        平均Mean9.6 5.8 8.0 6.1 5.1 4.5 4.9 4.8 6.5 6.7
        Cd-18.3 cd4.5 c 5.8 f 6.1 cd7.1 a 5.0 a 3.9 f 3.7 ef 6.9 abc 7.1 abc
        Cd+As-18.7 cd5.7 ab 7.2 cde6.5 bc7.3 a 3.8 d 6.8 a 5.7 a 6.2 c 5.5 cd
        Cd+As-28.0 d 5.6 ab 6.9 cdef7.1 ab6.2 bc3.8 d 5.6 cde 4.3 def6.1 c 5.9 bcd
        Cd+As-38.2 cd4.7 c 4.3 g 4.1 f 5.6 cd3.7 d 4.4 ef3.6 f 7.2 ab 6.3 abc
        平均Mean8.3 5.3 6.1 5.9 6.4 3.8 5.6 4.5 6.5 5.9
        注(Note):产量数据为每个蔬菜 3 次重复平均值;同列数据后不同小写字母表示同种蔬菜的产量在不同处理间差异达 5% 水平显著。The yields are the average of triplicates of each vegetable;values followed by different lowercase letters in same column indicate significant difference in yield for the same vegetable among treatments at 0.05 level.

        蔬菜生物量对土壤重金属的胁迫响应 (BRS) 见表3。低As污染 (As-1、As-2) 土壤上,菠菜生物量增加了24%~29%;As-1处理苋菜茎的BRS为正值,叶子的为负值,即促进茎生长,抑制叶子生长;空心菜、茼蒿、生菜BRS都是正值,说明有促进作用。

        表 3  7种叶菜生物量对Cd和As胁迫的响应BRS值 (%)

        Table 3.  BRS values (%) of biomass responses to Cd As stress of seven leafy vegetables

        处理
        Treatment
        菠菜
        Spinach
        油菜
        Cole
        生菜
        Cos lettuce
        油麦菜
        Romaine lettuce
        苋菜
        Edible amaranth
        空心菜
        Water spinach
        茼蒿
        Garland chrysanthemum
        叶Leaf茎Stem叶Leaf茎Stem叶Leaf茎Stem
        As-123.8*11.2 33.1*–2.9–15.5 23.8*30.1*20.2* 7.618.1
        As-228.5* 7.3–7.9 25.4*15.812.8–4.0 5.4–8.616.3
        As-3–5.3 1.616.1–4.2–32.0*–7.6–19.9 –1.3 –7.4 27.3*
        As-4–5.8 15.5–7.6–18.5 –33.0* 9.8–9.9 4.1–1.8–20.9
        Cd-1–5.4 –15.5 –21.4*–0.217.6 22.2*–21.2* –16.5 3.014.6
        Cd+As-1–0.4 8.0–2.2 6.520.6–7.337.7*28.6*–7.6–10.4
        Cd+As-2–8.0 6.5–5.917.5 3.1–7.86.9–3.5 –8.2–4.8
        Cd+As-3–6.4 –11.6 –41.5*–32.4*–7.1–8.7–10.1 –18.8 7.0 2.1
        注(Note):*表示污染处理蔬菜生物量对镉和砷胁迫的响应显著 The vegetable biomass response to Cd or As treatments was significant.

        镉污染土壤 (Cd-1) 对大多数蔬菜生物量有抑制效应 (苋菜、茼蒿除外),其中对生菜、空心菜影响较大。低镉 (Cd+As-1) 对空心菜有促进作用。较高镉污染 (Cd+As-3) 土壤对蔬菜生物量有抑制作用 (茼蒿除外),其中生菜和油麦菜产量分别下降了42%和32%。

      • 蔬菜可食用部分Cd含量见表4。在无污染土壤 (CK-1~CK-4) 和砷污染土壤 (As-1~As-4) 上,蔬菜镉含量是0.020~0.190 mg/kg,均未超过食品安全限量值标准0.2 mg/kg。在砷污染土壤 (As-1~As-4) 上,土壤As对其他蔬菜Cd含量的影响并不显著 (t检验)。在镉污染土壤 (Cd-1) 上,菠菜、油菜、生菜和苋菜叶可食部分Cd含量是国标限量值的1~1.3倍,其余蔬菜未超标。在轻度复合污染土壤 (Cd+As-1) 上,菠菜、油菜、生菜和苋菜叶Cd含量超过国家限量值50%~142%。较高浓度镉砷复合污染土壤 (Cd+As-3) 上,除茼蒿和空心菜茎秆外,其余蔬菜均为Cd超标,其中菠菜和油菜Cd含量是国标值的4倍。

        表 4  7种叶菜可食部分Cd含量 (mg/kg)

        Table 4.  Cd content of edible parts of seven leafy vegetables

        处理
        Treatment
        菠菜
        Spinach
        油菜
        Cole
        生菜
        Cos lettuce
        油麦菜
        Romaine lettuce
        苋菜
        Edible amaranth
        空心菜
        Water spinach
        茼蒿
        Garland chrysanthemum
        叶Leaf茎Stem叶Leaf茎Stem叶Leaf茎Stem
        CK-10.1100.1320.050.1120.0990.1070.0870.0330.0230.030
        CK-20.1630.1450.1650.1120.1360.0740.1060.0390.0240.030
        CK-30.1890.1450.1220.0690.1340.0650.0740.0340.0250.025
        CK-40.1710.1830.1400.0930.1260.0640.0560.0330.0240.027
        As-10.1240.1200.1580.1320.1660.0810.1010.0320.0320.033
        As-20.1900.1540.1840.1180.1380.0610.0840.0330.0300.034
        As-30.1370.1710.1120.0860.1540.0840.1090.0390.0220.028
        As-40.1520.1590.1600.1180.1680.0870.1030.0330.0200.029
        Cd-1 0.268* 0.235* 0.205*0.155 0.214*0.1050.1620.0440.0370.036
        Cd+As-1 0.424* 0.484* 0.384*0.184 0.299*0.1460.1600.0590.0470.042
        Cd+As-2 0.420* 0.420* 0.370* 0.222* 0.255*0.154 0.203*0.0580.0450.040
        Cd+As-3 0.753* 0.784* 0.528* 0.332* 0.478* 0.250* 0.267*0.0760.0660.050
        注(Note):*表示蔬菜样品 Cd 含量超标 Cd content of vegetable samples exceeds the standard;蔬菜限量标准 Vegetable limited standard (Cd < 0.2 mg/kg,FW)[24].

        表5所示,叶类蔬菜As含量在0~0.256 mg/kg,均未超标。单砷污染土壤上,蔬菜砷含量随土壤砷含量的增加具有增加趋势。除了油麦菜外,单镉污染土壤 (Cd-1) 对其他蔬菜的As含量影响不显著。单砷污染和复合污染土壤上供试蔬菜As含量没有显著差异,说明镉砷复合污染并没有促进蔬菜对砷的吸收。

        表 5  7种叶菜可食部As含量 (mg/kg)

        Table 5.  As content of edible parts of seven leafy vegetables

        处理
        Treatment
        菠菜
        Spinach
        油菜
        Cole
        生菜
        Cos lettuce
        油麦菜
        Romaine lettuce
        苋菜
        Edible amaranth
        空心菜
        Water spinach
        茼蒿
        Garland chrysanthemum
        叶Leaf茎Stem叶Leaf茎Stem叶Leaf茎Stem
        CK-10.0250.0540.0120.0180.0060.0610.0860.0290.0850.027
        CK-20.0270.0270.0000.0200.0120.0120.0820.0510.0390.011
        CK-30.0270.0340.0080.0340.0270.0120.0690.0530.0830.048
        CK-40.0410.0310.0600.0070.0420.0700.1190.0700.1100.063
        As-10.0440.0670.0480.0350.0460.0480.0750.0220.1140.078
        As-20.0670.0940.0690.1000.0810.0440.1860.1010.1140.068
        As-30.1640.1280.1150.1290.1240.1150.1410.0870.1750.088
        As-40.1410.1490.1250.1740.1110.1140.2560.1390.1450.090
        Cd-10.0330.0550.0680.0420.0470.0490.1290.0630.12 0.065
        Cd+As-10.0750.0990.1300.0640.0970.06 0.1130.1000.1810.104
        Cd+As-20.1590.1210.0730.0770.1330.0960.1990.1790.1260.083
        Cd+As-30.0480.0610.0570.0210.0470.0830.0910.0570.1460.033
        注(Note):蔬菜限量标准 Vegetable limited standard (As < 0.5 mg/kg,FW)[24].
      • 蔬菜镉与砷的安全阈值见表6,菠菜、油菜和生菜Cd安全阈值分别为0.33、0.38、0.46 mg/kg,与菜地土壤“二级标准”相当;其余四种蔬菜均高于国标值,其中空心菜阈值是1.49~8.16 mg/kg,茼蒿是8.98~17.11 mg/kg。7种供试蔬菜As安全阈值为57.21~105.06 mg/kg,均高于菜地土壤“二级标准”。

      • 蔬菜Cd平均富集系数为0.083~0.491,As富集系数是0.002~0.006(图1)。油菜、菠菜、生菜和苋菜叶Cd富集系数较大,而空心菜茎和茼蒿茎叶较低,油麦菜、苋菜茎和空心菜叶富集系数介于二者之间。苋菜和空心菜叶片Cd富集系数均高于其茎秆。7种叶菜As富集系数变异较小,空心菜叶和茼蒿叶富集系数均显著高于其他蔬菜。

        图  1  7种叶菜可食部Cd、As富集系数 (n = 36)

        Figure 1.  The bioconcentration factor of Cd and As in the edible parts of seven leafy vegetables

        蔬菜可食部分对Cd和As的富集量见表7。菠菜Cd富集量最大,而空心菜和茼蒿较低,油菜、生菜、油麦菜、苋菜的富集量介于二者之间。菠菜、油麦菜、苋菜、空心菜在镉超标土壤 (Cd-1、Cd+As) 上的吸Cd量高于无污染土壤和单砷污染土壤,且吸Cd量随土壤镉浓度升高而增加。油菜和生菜在单镉污染土壤上吸Cd量与单砷污染土壤相比没有显著差异,这可能是由于镉胁迫造成生物量下降导致。茼蒿在较高浓度镉污染土壤 (Cd+As) 上的吸Cd量并没有显著增加。

        表 7  四个处理七种叶菜可食部位Cd、As的富集量 (μg/plant)

        Table 7.  Enrichment of Cd and As in edible parts of seven leafy vegetables in the four treatments

        蔬菜
        Vegetable
        CdAs
        CKAsCdCd+AsCKAsCdCd+As
        菠菜Spinach1.39 c1.47 c2.21 b4.40 a0.26 b0.94 a0.28 b0.77 a
        油菜 Cole0.79 b0.87 b1.05 b2.92 a0.19 b0.63 a0.25 b0.51 a
        生菜Cos lettuce0.84 c1.21 b1.18 b2.52 a0.15 c0.69 a0.39 bc 0.56 ab
        油麦菜 RL0.58 c0.69 c0.94 b1.37 a0.12 c0.65 a 0.25 bc0.35 b
        苋菜EA0.75 c0.78 c1.52 b2.16 a0.15 c 0.44 ab0.33 b0.60 a
        空心菜WS0.39 d0.48 c0.63 b1.11 a0.44 b0.76 a0.50 b0.74 a
        茼蒿GC0.16 b0.17 b0.25 a0.35 a0.53 b0.89 a0.83 a0.98 a
        注(Note):各处理蔬菜重金属富集量为样本平均值;CK、Cd、As、Cd & As等处理的样本数分别为 12、3、13、9;同行数值后不同小写字母表示同种蔬菜不同处理的重金属富集量在 5% 水平上差异显著。RL—Romaine lettuce;EA—Edible amaranth;WS—Water spinach;GC—Garland chrysanthemum. The enrichment amount was the average of samples in each treatment,and the each vegetable sample number in CK,Cd,As and Cd+As treatment was 12,3,13 and 9 respectively;values followed by different lowercase letters in the same row indicate significant difference among treatments for the enrichment of the same vegetable at the 0.05 level.

        不同蔬菜可食部分As富集量变异较小。在无污染土壤上,茼蒿和空心菜吸As量大于其余蔬菜;在镉污染土壤上,茼蒿As富集量高于其余蔬菜;在砷污染土壤上,菠菜吸As量较大,苋菜较小;在镉砷复合污染土壤中,茼蒿和菠菜As富集量较大,油麦菜较小。大多数蔬菜 (茼蒿除外) 在砷超标土壤 (As-1~As-4、Cd+As) 的吸As量均高于无污染土壤和单镉污染土壤。

      • 本研究中蔬菜未表现出毒害症状,在轻度As污染土壤上,产量有增加趋势。较高浓度镉砷复合污染土壤 (Cd+As-3),除生菜和油麦菜产量受到显著性抑制外,其他蔬菜产量下降幅度不显著。相关分析表明土壤有机质与蔬菜产量有显著性正相关关系 (相关系数R2 = 0.14,n = 36)。因此,As污染土壤对蔬菜生物量的正效应可能是由于As-1和As-2处理中较高的土壤有机质导致的。土壤Cd含量与蔬菜产量是显著性负相关关系 (相关系数R2 = –0.13,n = 36),说明土壤Cd抑制了蔬菜生长;土壤有机质有螯合与吸附镉离子的作用,可以减轻镉的危害[25-26]。叶菜生物量对土壤轻度镉砷复合污染有高耐受性,在大白菜[11, 27]、小青菜等叶菜[28-29]和大葱[13]等蔬菜上也有类似结论。原因可能是植物具有适应不良环境胁迫的能力,植物吸收的重金属只有少量向地上部转运[30-31],大部分被谷胱甘肽 (glutathione,GSH) 或植物络合素 (phytochelatins,PCs) 等重金属螯合物固定在根部液泡中,缓解了植物地上部受到的胁迫[32]。不同种类蔬菜BRS值差异可能与根部富集Cd和As能力、根向地上部转运重金属比例及重金属螯合物含量有关[33]。生菜根部合成PC2量远低于大麦,这解释了其较高的根向地上部转运Cd能力[32, 33]。不同种类植物GSH、PC2、PC3等含量有较大差异,这与植物对重金属的耐性有显著相关性[32, 34-36]。虽然污染土壤上生长的蔬菜无明显的毒害症状,但有些蔬菜镉含量已经超出国标限量标准 (表4),因此单凭借蔬菜生长情况或生物量无法判断其是否受到重金属污染[34]

      • 叶菜的土壤Cd和As安全临界值与当地土壤理化性质和叶菜种类息息相关。本研究中,菠菜、油菜、生菜和苋菜叶Cd阈值与现有的国标限量值相当 (Cd 0.3~0.6 mg/kg),但油麦菜、空心菜、苋菜茎和茼蒿的阈值则要高于现行标准。供试叶菜As污染阈值均高于现行标准 (As 25~40 mg/kg)。他人研究也有类似结论,广东地区小白菜Cd污染阈值是1.74 mg/kg,土壤As污染阈值是113.58 mg/kg[37],均高于现行国家标准。但赵勇等[38]研究表明河南5种叶菜产地土壤Cd污染阈值均低于国标限量值;生菜土壤Cd临界值小于油麦菜。Lu等[11]研究表明5种土壤上白菜重金属安全阈值高于现行国家标准,而另外3种土壤低于国家标准。这说明蔬菜土壤重金属安全阈值必须考虑作物种类与土壤条件。土壤重金属安全阈值是联系土壤污染与农作物食品安全的关键指标,能够更直接反映作物受污染危害的真实情况,这些阈值与植物的吸收累积特性以及土壤理化性质密切相关,因此在修订土壤重金属污染标准时应该充分考虑作物因素和土壤条件。

      • 重金属通过食物链富集,蔬菜和粮食是其进入人体并危害人类健康的主要途径[4]。因此筛选叶菜Cd和As低富集品种对食品安全有重要意义。蔬菜重金属富集系数具有品种特异性,这已经在大白菜[27, 29]、空心菜[39]、小青菜[28]等叶菜以及大葱[13]等作物上得到证实。土壤Cd浓度在0.6 mg/kg时,菠菜、油菜、苋菜叶、生菜可食部分Cd含量已超出食品安全限量值标准0.2 mg/kg。土壤Cd含量在1.0 mg/kg时,除油麦菜、空心菜、茼蒿外,其余蔬菜Cd含量已经超出了叶菜Cd限量值 (表4)。茼蒿和空心菜茎在供试土壤Cd浓度范围内均未污染。这说明菠菜、油菜、生菜和苋菜等是Cd高富集型蔬菜,对镉污染很敏感;茼蒿和空心菜为低吸收型蔬菜,可以在轻度镉砷复合污染土壤上推荐种植。

        本文盆栽试验苋菜Cd富集系数与南宁市大田试验[40]结果一致;生菜和空心菜As富集系数与福建地区[41]大田采样结果基本相符;Cd富集系数为菠菜>生菜>油麦菜>空心菜,这与珠江三角洲[23]、台湾[42]、南宁市[40]三个地区蔬菜 (未见茼蒿相关数据)Cd富集系数排序一致,说明菠菜在多个地区种植的富集系数都较高,容易受到Cd污染,而空心菜属于Cd低富集蔬菜。这些数据来源[40-42]均为大田土壤–蔬菜“一对一”采样,说明盆栽试验结果与大田试验一致。盆栽试验蔬菜富集系数的品种差异性与大田数据结果相似[43],因此可以采用盆栽试验筛选重金属低富集品种。也有研究发现大田试验蔬菜的重金属Cd富集系数和Cd浓度低于盆栽试验[12],这可能与气候和栽培条件等因素有关。

      • 1) 镉污染土壤对蔬菜生物量有抑制效应 (苋菜、茼蒿除外),镉浓度越高,抑制作用越大。低浓度镉砷复合污染不会进一步影响蔬菜生长。

        2) 在镉污染土壤上,菠菜、油菜、苋菜叶、生菜可食部分Cd含量超出食品安全限量值标准,茼蒿和空心菜茎秆Cd含量未超标。在砷污染土壤上,供试叶菜并没有As超标,但蔬菜体内砷含量随着土壤砷含量升高有增加趋势。

        3) 菠菜、油菜和生菜Cd安全阈值与菜地土壤“二级标准”相当;油麦菜、苋菜、空心菜和茼蒿Cd安全阈值等均高于土壤环境质量标准。7种供试蔬菜As土壤安全阈值均高于菜地土壤“二级标准”。

        4) 供试蔬菜Cd富集系数和富集量具有显著差异,油菜、菠菜、生菜和苋菜叶Cd富集系数较大,而空心菜茎和茼蒿较小,油麦菜、苋菜茎和空心菜叶的富集系数介于二者之间。菠菜Cd富集量大,而空心菜和茼蒿较低。7种叶类蔬菜As富集系数、富集量变异较小。

    参考文献 (43)

    目录

      /

      返回文章
      返回