16740
Twenty - five elements were identifiable from 18 positions on the cardiac calculus by EDXRF spectrometer , in which the highest concentrations of toxic TEs ( Ni , Pt , Hg , Sn , Pb , W , Au , Al , Si ) and higher levels of essential TEs ( Ca , Sr , Cr , P ) were detected .
 Ni, Pt, Hg, Sn, Pb, W, Au, Al, Si, Ca, Sr, Cr, P
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Ni, Pt, Hg, Sn, Pb, W, Au, Al, Si, Ca, Sr, Cr, P