10034
Apportionment results showed that source of lead ore mining made the largest contribution ( 33 . 62 % ) , followed by atmospheric deposition ( 30 . 99 % ) , metal handcraft manufacture ( 30 . 09 % ) , and natural background ( 5 . 29 % ) .
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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:
 None