3263
The dominating groups of contaminants were polybrominated diphenyl ethers ( PBDEs ) , polychlorinated biphenyls ( PCBs ) and dichlorodiphenyltrichloroethane metabolites ( DDTs ) .
 polybrominated diphenyl ethers, PBDEs, polychlorinated biphenyls, PCBs, dichlorodiphenyltrichloroethane
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 polybrominated diphenyl ethers, PBDEs, polychlorinated biphenyls, PCBs, dichlorodiphenyltrichloroethane