6170
In the wetland , nutrient and atrazine relationships with periphyton were weaker , and when found , were often opposite of trends in chambers .
 Chemical: atrazine
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: atrazine 
Answer:
 Chemical: atrazine