16068
Chicken ( Gallus domesticus ) embryonic exposure in ovo to a 58 - congener polychlorinated biphenyl ( PCB ) mixture resulted in teratogenic heart defects in chick embryos at critical heart developmental stages Hamburger - Hamilton ( HH ) stages 10 , 16 , and 20 .
 Chemical: polychlorinated biphenyl; Chemical: PCB
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: polychlorinated biphenyl; Chemical: PCB