Can you please answer to my question soon? I need to submit this revision by tomorrow and have another document to submit to you online. First, I need to complete this SOON.<br /><br />My question to you was as follows.<br /><br />thanks for your edition, but I do think "the contaminant" should be plural form (e.g. I believe it should be "contaminants") since the contaminant refers to both phenol and PCBs. Please let me know soon after you see my message. thanks