8225
Benzo [ a ] pyrene ( BaP ) and 2 , 3 , 7 , 8 - tetrachlorodibenzo - p - dioxin ( TCDD ) are toxic environmental pollutants and are prototypes of aryl hydrocarbon receptor ( AHR ) ligands .
 Chemical: Benzo [ a ] pyrene; Chemical: BaP; Chemical: 2 , 3 , 7 , 8 - tetrachlorodibenzo - p - dioxin; Chemical: TCDD; Chemical: aryl hydrocarbon
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: Benzo [ a ] pyrene, BaP, 2 , 3 , 7 , 8 - tetrachlorodibenzo - p - dioxin, TCDD, aryl hydrocarbon 
Answer:
 Chemical: Benzo [ a ] pyrene; Chemical: BaP; Chemical: 2 , 3 , 7 , 8 - tetrachlorodibenzo - p - dioxin; Chemical: TCDD; Chemical: aryl hydrocarbon