【摘要】 通过对糙米镉含量的差异性分析和合理采样数量研究,为农用地污染效果评估提供依据和指导。将采样量设置了10个水平(依次为:10、20、30、40、50、60、70、80、90和100),在江西省新余市4 hm~2范围内镉污染农田进行稻谷采样,并分析不同采样量对糙米镉含量、超标率、变异系数等影响。结果表明:不同采样量下糙米镉含量为0.01～0.78 mg/kg,均值为0.20～0.29 mg/kg,标准差为0.10～0.13,变异系数为35.87%～63.88%,与采样量为10个相比,糙米镉含量随采样量的增加而递减,其降幅为7.14%～25.93%,研究区糙米镉含量均超过限量值(0.20 mg/kg)。相关性表明,糙米镉含量变异系数与采样量呈极显著正相关(y=29.45+0.35x,r=0.97,p<0.001);而糙米镉含量超标率与采样量呈显著负相关(y=80.76-0.46x,r=-0.98,p<0.001)。综合糙米镉含量、超标率、变异系数等因素,以及考虑人力、物力、时间等因素,采样量为50时,能较好地代表研究区糙米镉含量的整体水平。更多还原

【Abstract】 Through the analysis of the difference of cadmium content in brown rice and the study of reasonable sampling number,it provides the basis and guidance for the evaluation of agricultural land pollution effect. The sampling amount was set at 10 levels( 10,20,30,40,50,60,70,80,90 and 100). Paddy rice was carried out in Cd-contaminated farmland within 4 hm~2 in Xinyu City,Jiangxi Province.The effects of different sampling amounts on cadmium content,exceeding standard rate and coefficient of variation of brown rice were analyzed.Results showed that the cadmium content of brown rice was 0. 01 ～ 0. 78 mg/kg,the mean was 0. 20 ～ 0. 29 mg/kg,the standard deviation was 0. 10 ～ 0. 13,and the coefficient of variation was 35. 87% ～ 63. 88%. Compared with the sampling amount of10,the cadmium content in brown rice decreased with the increase of sampling amount,and the decrease was 7. 14% ～ 25. 93%. The cadmium content in brown rice in the study area exceeded the limit value( 0. 20 mg/kg). The correlation showed that the variation coefficient of cadmium content in brown rice was highly significantly positively correlated with the sampling amount( y = 29. 45+0. 35 x,r = 0. 97,p<0. 001).The excessive rate of cadmium content in brown rice was negatively correlated with sampling amount( y = 80. 76-0. 46 x,r =-0. 98,p < 0. 001). Considering factors such as cadmium content in brown rice,excessive rate,coefficient of variation,and considering factors such as manpower,material resources and time,50 samples can better represent the overall level of cadmium content in brown rice in the study area.更多还原