3636
Thus , we not only demonstrated for the first time increased carcinogenicity by coexposure to arsenic and iron but also proposed a novel remediation system for well drinking water .
 Chemical: arsenic; Chemical: iron
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: arsenic; Chemical: iron