19049
We observed that PFOS and PFOA showed a steady increase in whole body burden during the exposure period , with a slight decrease after the recovery period .
 Chemical: PFOS; Chemical: PFOA
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: PFOS; Chemical: PFOA