Proper water treatment is important to one's health. When on a remote trip, the health of each individual is a group issue. Wash dishes and hands in a dishbowl on land. Dispose of dishwater in the forest well back from the campsite. Do not wash your hair and body in the lake.
Swimming is all that's needed to stay clean.
Avoid cooking more food than you will consume. Pack out what you do not eat. If you find garbage, please help by packing it out, too. The disposal of human excrement is a significant problem in Temagami and other wilderness areas. Knowing what to do will help keep the area pristine for others.