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Since most people in developed countries and urban areas obtain their fish and other seafood commercially , we examined selenium : mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago .
 Chemical: selenium; Chemical: mercury
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: selenium; Chemical: mercury