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Marc Edwards , an expert in plumbing corrosion , discovered lead levels at least 83 times higher than the accepted safe limit while performing research into premature pipe corrosion for the District of Columbia Water and Sewer Authority ( WASA ) .
 Marc Edwards, District of Columbia Water and Sewer Authority
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Marc Edwards, District of Columbia Water and Sewer Authority