6387
After 20 months , the average loss was 11 % on POCIS , with only 2 , 4 - dichlorophenoxyacetic acid , atrazine , chlorpyrifos , and gemfibrozil showing a statistically significant decline compared with initial concentrations .
 Chemical: 2 , 4 - dichlorophenoxyacetic acid; Chemical: atrazine; Chemical: chlorpyrifos; Chemical: gemfibrozil
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: 2 , 4 - dichlorophenoxyacetic acid, atrazine, chlorpyrifos, gemfibrozil 
Answer:
 Chemical: 2 , 4 - dichlorophenoxyacetic acid; Chemical: atrazine; Chemical: chlorpyrifos; Chemical: gemfibrozil