15674
A comparison between cattle ' s age and gender vs . the concentration of contaminants revealed higher concentrations of PCDD / Fs and DL - PCBs in cattle aged more than 3 years ; no difference between genders was apparent .
 Chemical: PCDD / Fs; Chemical: DL - PCBs
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: PCDD / Fs; Chemical: DL - PCBs