25969
While perfluorooctanoic acid ( PFOA ) and perfluorooctane sulfonate ( PFOS ) have been studied at length , less is known about the biological activity of other perfluoroalkyl acids ( PFAAs ) detected in the environment .
 Chemical: perfluorooctanoic acid; Chemical: PFOA; Chemical: perfluorooctane sulfonate; Chemical: PFOS; Chemical: perfluoroalkyl acids; Chemical: PFAAs
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: perfluorooctanoic acid, PFOA, perfluorooctane sulfonate, PFOS, perfluoroalkyl acids, PFAAs 
Answer:
 Chemical: perfluorooctanoic acid; Chemical: PFOA; Chemical: perfluorooctane sulfonate; Chemical: PFOS; Chemical: perfluoroalkyl acids; Chemical: PFAAs