21120
Paraben detection in surface waters was as follows : methyl paraben ranged between 2 . 2 to 17 . 3 ppt ; ethyl paraben was not detectable ; propyl paraben was detected at 9 . 2 and 12 . 0 ppt ; butyl paraben was detected at 0 . 2 ppt .
 Chemical: Paraben; Chemical: methyl paraben; Chemical: ethyl paraben; Chemical: propyl paraben; Chemical: butyl paraben
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: Paraben; Chemical: methyl paraben; Chemical: ethyl paraben; Chemical: propyl paraben; Chemical: butyl paraben