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Empirical evidence demonstrates that the Druckrey - K u pfm u ller toxicity model , which was validated for chemical carcinogens in the early 1960s , is also applicable to a wide range of toxic compounds in ecotoxicology .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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