北京菜园潮土-小白菜系统中铬的毒性评价  

The toxicity assessment of chromium in Beijing Kaleyard Alluvial Soil-Pakchoi System

作　　者：戴宇[1,2] 杨重法[1] 郑袁明[2] 季天委[3] 

机构地区：[1]海南大学农学院,儋州571737 [2]中国科学院生态环境研究中心城市与区域生态国家重点实验室,北京100085 [3]浙江省农业厅土肥站,杭州310020

出　　处：《地理研究》2009年第6期1682-1692,共11页Geographical Research

基　　金：国家自然科学基金项目(40671172);中国科学院知识创新工程重大项目(kzcx1-yw-06-03)

摘　　要：通过盆栽实验,以北京潮土为供试材料,研究了土壤中添加0-50 mg·kg^-1铬（VI）对小白菜（Brassica chinensis L.）生物量与铬含量、土壤微生物量碳含量、土壤微生物量氮含量以及土壤微生物呼吸速率的影响。结果表明,高铬浓度（添加量≥25 mg·kg^-1）处理下,小白菜植株中铬的总量相对于未添加铬的处理显著增加（P〈0.01）,且小白菜根部铬的含量要远大于叶片中的铬含量。相对于未添加铬的对照,小白菜叶片生物量在1 mg·kg^-1铬处理下显著增加,而高浓度铬（≥10 mg·kg^-1）显著地减少了小白菜叶片和根的生物量（P〈0.01）,减幅最高达到了78.2%,且50 mg·kg^-1铬处理下土壤微生物量碳、氮含量以及呼吸速率均要显著低于对照。小白菜叶片生物量与铬含量、土壤微生物量碳、土壤微生物量氮以及土壤微生物呼吸都能够作为生物指标来反映土壤铬污染程度。将这些指标与对应的土壤总铬含量拟合方程,按照作物减产、食品安全以及生态剂量概念可以计算得到北京潮土铬轻度污染临界浓度ED10为70.8 mg·kg^-1,中度污染临界浓度ED50为111.6 mg·kg^-1。In this study, pot experiments using the Beijing alluvial soils were conducted to examine the effects of hexavalent chromium （Cr）, concentrations ranging from 0 to 50 mg · kg^-1 , on the biomass and Cr concentrations of pakchoi （Brassica chinensis L. ）, soil microbial biomass carbon, soil microbial biomass nitrogen and soil microbial respiration. The results showed that in the high Cr concentration treatments （with addition ≥25 mg · kg^-1）, the Cr concentrations in pakchoi leaves increased significantly compared with the control treatment （P〈0. 01）. The total Cr concentrations in pakchoi roots were much greater than those in leaves. Compared with the control treatment, the biomass of pakchoi leaf increased significantly in the 1 mg · kg^-1 Cr treatment, while its biomass decreased significantly in the high Cr concentration treatments （≥10 mg · kg^-1） （P〈0.01） and the highest decreasing extent was up to 78.2%. In the 50 mg · kg^-1 Cr treatment, the soil microbial biomass carbon, microbial biomass nitrogen and respiration rate were significantly lower than these indicators of control treatments. The biomass and total Cr concentration of pakchoi leaves, soil microbial biomass carbon, soil microbial biomass nitrogen and soil microbial respiration rate could all be sensitively served as biological indicators to reflect the pollution extent of soil Cr. By using these indicators and the corresponding total Cr concentrations of soil, we could obtain the fitting equations. Based on the conceptions of crop yield reduction, food safety and ecological dose, we could calculate the Cr mild pollution critical concentration of Beijing alluvial soil ED10 （70.8 mg · kg^-1） and the Cr moderate pollution critical concentration of Beijing alluvial soil ED50 （111.6 mg· kg^-1）. The results would be helpful to the revision and rebuilding of soil environmental criteria.

关 键 词：铬 潮土 小白菜 土壤微生物 临界浓度 

分 类 号：S153.6[农业科学—土壤学]