20350
For the first time , our study demonstrates the effect of waterborne Zn exposure on lipid metabolism at the molecular levels in fish , which may contribute to understanding the mechanism of Zn - induced hepatic toxicity in fish .
 Chemical: Zn; Chemical: Zn
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: Zn; Chemical: Zn