hike..i know Bemidji well,i went to the college there when i got out of the Army in 1969.it was said to be a good place to settle back in the old days because it was in heavy forest and not out on the prairie where the wind drove the heavy snows.the mercury is everywhere,they have the same warning for the native women in the far north of Canada.giardia is one of those "who you talk too" issues.i wish i had bookmarked the post at a science blog but a guy did a study that found it was not nearly as wide spread as it is said to be. a canoe buddy filters all of his water,pointed to a wilderness lake he told me "every drop" had the cyst.on the other hand i seldom filter and have never been effected.