【作者】 罗丹；

【导师】 王果；

【作者基本信息】 福建农林大学 ， 生态学， 2009， 博士

【摘要】 本文调查了福建省7个地区水稻和20个蔬菜品种及其相应表层土壤钴和镍含量,研究影响钴和镍在土壤中的累积和有效性的因素、钴和镍在土壤-作物系统中的转移规律,并采用盆栽法研究了钴和镍对作物的毒害效应。根据上述结果推算了区域土壤中钴和镍的环境基准值。主要结果如下：1、供试土壤全钴含量范围为3.48～21.70 mg/kg,均值为12.30 mg/kg;有效钴含量为0.01～1.52 mg/kg,均值为0.30 mg/kg。供试土壤全镍含量变化范围在1.41-79.24mg/kg之间,平均含量为17.86 mg/kg;有效镍含量在0.03～24.84 mg/kg之间,平均含量为1.16 mg/kg。土壤理化性质(pH、游离铁、全锰、CEC和颗粒组成等)对土壤钻、镍全量和有效含量均有不同程度的影响。2、各种作物可食用部分钴含量范围在未检出～104.66μg／kg之间。瓜豆类钴含量较高,其次为叶菜类和水稻,根菜类和茄果类钴含量较低。作物可食用部分镍含量范围在未检出～3.61 mg/kg之间。水稻中镍含量最高,果菜类和叶菜类镍含量居中,根菜类镍含量最低。3、与土壤全钴和全镍含量相比,土壤有效钴和有效镍均能更好地反映土壤钴、镍的生物有效性。作物钴含量与土壤游离铁、有机质、pH、阳离子交换量(CEC)和全锰含量均有较为密切的关系,作物镍含量与土壤游离铁和pH有较为密切的关系。用转移系数来表示作物对钴和镍的富集能力,发现转移系数无论是以土壤中钴、镍全量还是以有效钴、有效镍含量为基础均随土壤中钴、镍含量的提高而减小。4、培养液中适量的钴、镍均能促进多种蔬菜根系和地上部的生长。但钴、镍过量时则会对蔬菜产生毒害,且随着钴、镍浓度的升高和时间的延长而加剧。蔬菜受钻、镍毒害均最先是出现在幼叶,表现为上部嫩叶绿色变浅,接着出现脉间失绿,然后整片叶子黄白化。严重者,植株明显矮小,黄化叶片上出现暗色斑点,斑点面积不断扩大并伴随不同程度的失水,甚至整株干枯。5、综合表观症状和蔬菜地上部生物量(干重)减少20%的效应浓度(EC20)的最低值确定大白菜(早熟5号)和黄瓜为钴敏感作物,清江白和蕹菜为镍敏感作物。莴笋钴、镍毒害表观症状均较其它蔬菜轻,且效应浓度(EC20)较大,为钴、镍耐性较强作物。不同种类蔬菜对钴、镍的敏感程度存在很大差别,相同种类亦存在品种间差别。6、土培条件下,钴不同添加量处理时,黄瓜地上部生物量(鲜重)比对照下降21.97%-95.36%；镍不同添加量处理时,蕹菜地上部生物量(鲜重)比对照下降29.59%-93.84%。钴、镍毒害均不同程度地影响了蔬菜对营养元素的吸收及其向地上部的转移。钴、镍与铁、铜均表现出较强的拮抗作用。7、采样区近五分之四的菜园土和四分之三的水稻土全钴含量超过福建A层土壤钴背景值；有近一半的菜园土和水稻土全镍含量超过福建A层土壤镍背景值,表明人类生产活动影响钴和镍在土壤中的累积。绝大多数的采样区土壤均符合国家土壤环境质量二级标准和福建省农业土壤重金属污染分类一级标准。采样区88.8%的蔬菜样品镍含量符合我国食品卫生内控标准,而只有49.23%的水稻样品镍含量符合我国食品卫生内控标准。就本地区而言,钴通过土壤—作物食物链进入人体并不会对健康造成危害。若考虑其他的摄入途径,本地区农产品镍的健康风险值得关注。8、以作物可食用部位含量的食品卫生标准(或限量参考值)推算了土壤中钴和镍的临界值；同时通过土培试验推算对作物减产10%时的土壤钴和镍的临界值。比较这两个土壤临界值,提出研究区域土壤钴和镍的全量基准值分别为97和36mg／kg,相应有效含量分别为2.7和2.2mg／kg。更多还原

【Abstract】 The contents and availability of cobalt and nickel in the agricultural soils in Fujian Province were investigated and the main soil factors influencing the accumulation in the soils and their availability, the transfer characteristics of Co and Ni from the soils to the edible parts of rice and 20 major vegetable species in the region and the toxic effects on the crops were studied. The environmental reference values of Ni and Co in the soils were estimated. The main results were as follows:1. The total Co concentrations of the soils ranged from 3.48 mg kg-1 to 21.70 mg/kg with an arithmetic mean of 12.30 mg/kg and the DTPA-extractable Co varied between 0.01 and 1.52 mg/kg with an average of 0.30 mg/kg. The total Ni contents of the soils ranged from 1.41 mg/kg to 79.24 mg/kg with a mean of 17.86 mg/kg and the DTPA-extractable Ni were between 0.03 and 24.84 mg/kg with an average of 1.16 mg/kg. The pH, clay, CEC and the contents of free Fe and total Mn of the soils influenced the accumulation of Ni and Co in the soils and their availability.2. The concentrations of Co in the edible parts of crops (FW) ranged from not detected to 104.66μg/kg. The Co concentrations of the different crops generally followed the order of fruit vegetables>leafy vegetables and rice>rhizome vegetables. The Ni concentration in the edible parts of the crops (FW) varied from not detected to 3.61 mg/kg. The concentrations of Ni in the crops generally followed the order:rice>fruit and leafy vegetables>rhizome vegetables.3. DTPA-extractable Co and Ni were better than total Co and Ni in indicating the bio-availabilitiy of Co and Ni in the soils. The concentrations of Co in the edible parts of the crops (FW) had close relationships with pH, CEC and the contents of free iron, organic matter and total Mn. The concentration of Ni in the edible parts of vegetables (FW) and rice had only close relationships with free iron content and pH. The soil-to-crop transfer factors of Co and Ni generally decreased with the increase of soil Co and Ni no mater based on total or available concentration.4. Low concentrations of Co and Ni in the culture solutions had hormesis effects to same vegetable species under water culture. However, when the concentrations of Co and Ni increased, toxic effects to the crops appeared. The typical Co and Ni toxicity symptoms were chlorosis in new leaves, withering in leaf margin or in whole leaf, growth inhibition, water loss or even death.5. Base on the apparent symptoms and the EC20 value (effective concentration causing a 20% reduction of shoot biomass) of each species, Early ripening No.5 (Brassica pekinensis Rupr.) and cucumber (Cucumis sativus L.) were selected as the most Co sensitive vegetables and Qingjiang Pakchoi (Brassica chinensis L..) and Water spinach (Lpomoea aquatica Forsk.) were as the most Ni sensitive vegetables. 6. Under soil culture condition, the shoot mass of cucumber with different dosage of Co addition decreased from 21.97% to 95.36% and the shoot mass of water spinach with different Ni treatments decreased from 29.59% to 93.84% compared to the control. High concentration of Co and Ni all influenced the uptake of other nutrients and their transfer from root to shoot, especially for iron and copper.7. The concentrations of Co in about four fifth of the vegetable soils and three quarter of the paddy soils were above the background value of Co in the surface soils of Fujian, and those of Ni in about half of the vegetable soils and the paddy soils were above the background value of Ni in the surface soils of Fujian, indicating the accumulation of Co and Ni in the soils as result from anthropogenic activities. However, the concentrations of Ni in most of the soils were below the Ni limits (China Environmental quality standard for soils and Standard for heavy-metal pollution classification for agricultural soils in Fujian Province).88.8% of the vegetables and 49.23% of the rice contained lower Ni than the interior-controlling standard of national food hygiene standard for Ni. According to the above results, the intake of Co through soil-plant path would not lead to human health risk. However, the daily intake for Ni would be of concern if all the sources of Ni exposure were taken into account,8. The limit values of Co and Ni for the soils were calculated based on the standard of national food hygiene standard (or reference value) and the EC10 values derived from the soil culture. The soil reference values of Co and Ni were developed according to the lower value of the two limit values. The soil reference values of Co were 97 mg/kg (total Co) and 2.7 mg/kg (DTPA-Co), respectively, and those of Ni were 36 mg/kg (total Ni) and 2.2 mg/kg (DTPA-Ni), respectively.更多还原