18490
An atrazine concentration of 150 micro g / L contributed to a 15 % increase of the oscillation periods of both diatoms and copepods as well as a 52 % reduction of oscillation amplitudes compared with the control situation .
 Chemical: atrazine
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: atrazine