I don't really know how to read this either, but the number 17 as such does not appear anywhere in that paper. This quote may be relevant: "Concentrations of As vary between 72,820 and 1,937 mg/kg" (page 13).

These commas appear to be thousands separators, so that's a maximum of 73 grams per kilogram or 7% per mass of a soil sample. I'm not a doctor, but I would advise against eating significant amounts of these soil samples.