20994
Adult male rats were pre - exposed to two different doses of nicotine ( 0 . 75 and 3 mg / kg , intraperitoneally ) for 7 days followed by 30 days of arsenic exposure ( 50 ppm sodium arsenite in drinking water ) .
 Chemical: nicotine; Chemical: arsenic; Chemical: sodium arsenite
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: nicotine; Chemical: arsenic; Chemical: sodium arsenite