16932
Compared with a previous study , sum 8 PBDE serum concentrations in the present study showed no change in order of magnitude , but the relative contribution of BDE - 209 to sum 8 PBDE was higher .
 Chemical: PBDE; Chemical: BDE - 209; Chemical: PBDE
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: PBDE; Chemical: BDE - 209; Chemical: PBDE