6992
The reached limits of detection and quantification were 0 . 48 and 1 . 61 ng g - (1) respectively , and the precision ( as relative standard deviation ) was 3 . 28 % and 1 . 56 % for rice samples with a mercury content of 3 . 63 and 5 . 81 ng g - (1) , respectively .
 mercury
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 mercury