4478
Arsenic and arsenic species in cultured oyster ( Crassostrea gigas and C . corteziensis ) from coastal lagoons of the SE Gulf of California , Mexico .
 Chemical: Arsenic; Chemical: arsenic
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: arsenic