Abstract:

The objective of this study is to establish an efficient and rapid method for directly measuring mercury (Hg) content in rice and to investigate the distribution characteristics of Hg in four different tissue parts of rice plants. Roots, stems, and grains (including husk and brown rice) from the same rice plants were used as test materials. After drying and pulverizing, Hg was determined by direct mercury analyzer with external standard quantification. The results showed that the direct mercury analysis method exhibited excellent linearity (correlation coefficient R=0.9999), with a detection limit of 0.064 μg/kg, precision ranging from 1.8% to 3.2%, and spike recovery rates between 103% and 109%; significant differences in Hg content were observed among different rice tissues, with an overall distribution pattern of root > stem > husk > brown rice, forming a three-stage distribution pattern of "root-stem-grain"; positive correlations were found between Hg content in soil and various rice tissues (correlation coefficients ranging from 0.329 to 0.693). The established direct mercury analyzer method eliminates complex sample pretreatment processes while maintaining simplicity, rapidity, and accuracy, making it suitable for Hg detection in rice. The distribution of Hg in different tissues of rice is significantly different. For Hg-contaminated areas, the risk of Hg accumulation in rice can be reduced by regulating soil Hg activity (such as applying modifiers) and screening low-enrichment varieties, so as to guide grain production and environmental governance.

Key words: direct mercury analyzer method, rice, different tissue parts, mercury element, distribution characteristics, enrichment capacity