摘要
位于西江上游的河池地区被誉为中国的"有色金属之乡",重金属产业经过多年选矿开矿的工业化发展使得当地生态环境受到严重的重金属污染。为评价广西西江流域中上游主要地区矿业活动对土壤和糙米质量安全的影响,采集研究区域内水稻及其对应土壤样本进行分析评价。调查发现,参照《食用农产品产地环境质量评价标准》(HJ332—2006),当p H<6.5、6.50≤p H≤7.50、p H>7.5时,土壤Cd含量超标率分别达到90.63%、96.97%、98.36%;参照《食品中污染物限量标准》(GB2762—2012),糙米Cd含量的超标率为19.34%。单因子污染评价表明,超过50%的调查样点土壤Cd处于重度污染,仅有10%左右调查样点的土壤Cd属于清洁等级,且上游地区土壤-水稻系统Cd污染较为严重。分别建立了水稻糙米Cd含量、糙米Cd生物富集系数与土壤有效态Cd含量、土壤p H值以及土壤有机质含量的定量关系,模型拟合度均高于50%。预测糙米Cd含量拟合度较好的模型为多元非线性回归模型,预测糙米Cd生物富集系数拟合度较好的为多元线性回归模型。多元回归模型的回代检验和残差分析表明,计算值与实测值的相关性较好,残差值较小且均匀分布,在一定程度上可以用来预测水稻糙米Cd的积累情况。
Hechi City is in the upper reaches of Xijiang River,which is the most famous town of non-ferrous metals in China.The ecological environment is suffering serious heavy metals pollution due to long-term mining,smelting,processing and industrialization.In order to assess the impact of mining activities on soil and quality and safety of brown rice in the main regions of the upper-middle reaches of Xijiang River draining in Guangxi province,soil samples and corresponding rice samples were collected from study area.According to the Environmental Quality Evaluation Standards for Edible Agricultural Products（HJ332—2006）,the exceed standard rates of Cd contents in soil were 90.63%,96.97%,98.36% when soil p H6.5,6.50≤p H≤7.50,and p H7.5,respectively.According to the Food Contaminants MRLs Standards（GB2762—2012）,the over standard rate of Cd content in brown rice was 19.34%.The single-factor evaluation showed that more than 50% of soil samples were severely polluted by Cd,and only 10% of soil samples contained Cd were in a clean level.Cd pollution in soil-rice system was more serious in the upper reaches of Xijiang River.Quantificational relationships were developed respectively for testing and quantifying the relations among Cd concentration in soil and bioconcentration factors（BCF） of Cd in brown rice with the soil available Cd concentration,soil p H and organic matters（SOM,%）.The fitting degrees of the model were higher than 50%.Results showed that multiple nonlinear regression was better to predict Cd contents in brown rice,while multiple linear regression was ideal to predict BCF of Cd.At the same time,the regression and residue analysis showed a good correlation with the computed and measured Cd concentration in rice grain which corresponded with a small and uniformly distributed residual,and this reveals the model used for the preliminary prediction of the Cd concentration in brown rice grains is reliable and reasonable to a certain extent.Research on the accumulation characteristics and respon
出处
《生态环境学报》
CSCD
北大核心
2016年第6期1039-1046,共8页
Ecology and Environmental Sciences
基金
广西自然科学基金项目(2013GXNSFBA019208)
“八桂学者”建设工程专项
关键词
土壤
水稻糙米
CD
响应关系
预测模型
soil
brown rice
cadmium
response relationship
prediction model
