16328
Unlike Hg , nearly constant TSe concentrations were observed at 248 +/- 179 ng g ( - 1 ) in the food web , and the TSe - to - THg molar ratio was predicted by log10 ( CTSe / CTHg ) = - 0 . 10 x delta ( 15 ) N ( /1000 ) + 2 . 8 , R ( 2 ) = 0 . 60 .
 Hg, ( 15 ) N
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Hg, ( 15 ) N