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。
【Objectives】The response of vegetable to soil cadmium(Cd)and arsenic(As)stress and their enrichment and tolerance varies significantly.The uptake and accumulation characteristics of Cd and As of some leafy vegetables cultured in light to medium Cd and As co-contaminated soils were investigated,aiming to provide reference for the rational and safe use of light and medium contaminated soils.【Methods】Twelve Cd&As polluted soils were collected from the plough layers of vegetable fields in Xi’an suburbs,and seven kinds of leafy vegetables were assessed in the pot experiment,which was conducted in the greenhouse of the College of Resources and Environment of Northwest A&F University from March to May of 2015.The tested vegetables were:spinach(Spinacia oleracea L.),cos lettuce(Lactuca sativa L.),cole,Romaine lettuce(Lactuca sativa L.var.longifolia),edible amaranth(Amaranthus mangostanus L.),water spinach(Ipomoea aquatica forsk)and garland chrysanthemum(Chrysanthemum coronarium L.).The vegetable yields,Cd and As contents were determined,the safety thresholds of soil pollution of Cd&As were calculated using linear regression models.【Results】The soil Cd polluting level of 0.6–2.4 mg/kg reduced the biomass of most vegetables,medium or low co-contamination of Cd and As(Cd 1.1–2.4 mg/kg,As 24.9–26.8 mg/kg)did not exacerbate the inhibition.On the medium co-contaminated soil,Cd contents in the edible parts of spinach,cole,amaranth leaves,and lettuce exceeded the food safety critical value(0.2 mg/kg),and the Cd contents in spinach and cole were even 4 folds beyond the standards,while those of water spinach stem and garland chrysanthemum did not exceed the standard.Although the arsenic contents of all tested vegetables increased with increasing of soil arsenic concentrations,they did not exceed the standard.The enrichment coefficients of Cd in the seven kinds of vegetables were 0.083–0.491,with descend order of cole,spinach,cos lettuce,edible amaranth leaf>Romaine lettuce,edible amaranth stem,water spinach leaf>water spinach stem and garland chrysanthemum.The safety thresholds of soil Cd for spinach,cole,cos lettuce,Romaine lettuce,edible amaranth,water spinach and garland chrysanthemum were 0.33,0.38,0.46,1.15,0.59–1.79,1.49–8.16 and 8.98–17.11 mg/kg,respectively.Among them,the thresholds of spinach,cole and lettuce were similar to the current standards(0.3–0.6 mg/kg),while the Romaine lettuce,edible amaranth,water spinach,and garland chrysanthemum were all greater than the soil heavy metal limitation values.As enrichment coefficient was 0.002–0.006,and the As enrichment coefficient of leaves of water spinach and garland chrysanthemum were significantly higher than those of others.The critical thresholds of soil As for the seven kinds of vegetables were 62.31,70.35,70.21,67.41,67.86–90.43,57.21–75.70 and 72.43–105.06 mg/kg,respectively,which all were higher than the current standards(25 mg/kg).【Conclusions】The cadmium and arsenic enrichment coefficients of vegetables varied significantly,and so were their responses to light-mild cadmium-arsenic co-contamination soils.Water spinach and garland chrysanthemum had low Cd enrichment coefficients and could be recommended for cultivation on mild polluted soil,while spinach and cos lettuce should not be chosen because of the high enrichment of Cd from soil.
作者
孟媛
张亮
王林权
上官宇先
杨阳
李雪芳
李娜
MENG Yuan;ZHANG Liang;WANG Lin-quan;SHANGGUAN Yu-xian;YANG Yang;LI Xue-fang;LI Na(College of Natural Resources and Environment,Northwest A&F University,Yangling,Shaanxi 712100,China;Soil and Fertilizer Institute,Sichuan Academy of Agricultural Sciences,Chengdu 610066,China;Institute of Technical Biology & Agriculture Engineering,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China)
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2019年第6期972-981,共10页
Journal of Plant Nutrition and Fertilizers
基金
国家重点研发计划(2017YFD0200105)
关键词
镉
砷
富集系数
土壤阈值
菠菜
茼蒿
cadmium
arsenic
enrichment
soil thresholds
spinach
garland chrysanthemum