17959
Over the same 4 wk , positive control earthworms accumulated 9 . 2 - and 2 . 2 - fold higher cadmium and selenium , respectively , than negative controls for a much more substantial final body burden of the 2 elements .
 Chemical: cadmium; Chemical: selenium
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: cadmium; Chemical: selenium