摘要
为了保障太湖流域稻米安全,采用建立土壤-稻米镉传输模型及基于模型输出结果的地质统计学方法筛选稻米禁产区。监测数据的统计结果表明,本区域稻田土壤Cd超过土壤环境质量标准(0.3mg.kg-1)的比率为4.85%,2005年的监测结果与60年代背景值相比土壤Cd平均含量增加了50%。采用逐步回归分析分别建立了晚稻及高、低吸收型早稻土壤-稻米Cd传输模型。结果表明,除水稻自身内因影响其对土壤Cd的吸收外,在大田条件下土壤Cd含量、Zn含量、土壤pH值、土壤质地(土壤粘粒含量、土壤砂粒含量)等是影响水稻吸收Cd的主要环境因子。以土壤-稻米Cd传输模型输出结果为数据源,采用地质统计学中的序贯高斯条件模拟值法计算研究区不同类型稻米禁产区,结果表明研究区有0.05%的区域种植晚稻存在超标情况,1.47%的区域种植高吸收型早稻存在超标情况,所有的稻田如种植低吸收型早稻都不会导致稻米Cd超标,这一结果与采用《土壤环境质量标准》(GB15618—1995)二级值筛选的3.3%的超标区有较大的差别性,说明仅以《土壤环境质量标准》(GB15618—1995)为依据筛选稻米禁产区有其应用限制性。
Tai Lake Basin is one of the major rice production areas in Jiangsu,Zhejiang,Anhui provinces and Shanghai.However,soil pollution especially cadmium（Cd） has adversely affected rice safety during the production.In this study,soil-rice Cd transfer models have been established.The geostatistical method based on the models output results was applied to screen dangerous-rice-cropping areas for ensuring rice safety.The statistical data of the paddy field Cd contents in 2005 showed that 4.85% of the samples exceeded Soil Environmental Quality Standard（0.3 mg·kg-1）,and the Cd average content increased by 50% compared with the 1960s background value（0.12 mg·kg-1）.Soil-rice Cd transfer models of early rice with or low absorption Cd capability and late rice with absorption Cd capability were constructed using Stepwise Regression Analysis,separately.The models also showed that the rice absorption of Cd in paddy field was mainly affected by soil cadmium-zinc content,pH and soil texture（clay and sand content） with exception of the rice types.Based on the data obtained from the soil-rice Cd transfer models of different rice type,the geostatistical method sequential Gaussian conditional simulation was applied to discriminate dangerous-rice-cropping areas.Under the planting late and early rice with high Cd absorption capability,the simulation results indicated that the unqualified rates were 0.05% and 1.47%,respectively.And non-exceeding rice was produced when early rice with low Cd absorption capability was planted.Based on model calculation,the results were extremely different from the value of 3.3% obtained from the basis of soil Environmental Quality Standard（GB 15618—1995）,which demonstrated that there were limits for application of the soil Environmental Quality Standard to screen dangerous-rice-cropping area in the Tai Lake Basin.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2012年第1期75-84,共10页
Journal of Agro-Environment Science
基金
国家环保公益性行业科研专项(201009032)
国家自然科学基金重点项目(40930739)
关键词
太湖流域
稻米
镉
禁产区
Tai Lake Basin
rice
cadmium
dangerous-rice-cropping areas
