Existing data on the concentrations of aluminum, lead, and total trihalomethanes in raw lake/river water and treated drinking waters were collected for six cities in the Great Lakes basin. These values are compared to existing goals and standards for drinking water quality. Two communities have often exceeded the WHO drinking water guideline for aluminum of 200 mug/L, and all communities exceed 10 mug/L most of the time, even in the raw water. Raw water lead concentrations for five of the communities studied were <1 mug/L or below the method detection limits. One U.S. community has exceeded the current WHO standard of 50 mug/L for lead in drinking water about 7% of the time, although the data collected were from the distribution system and not the treatment plant effluent. Occurrences of lead above the current Canadian drinking water guideline of 10 mug/L are rare except for the community mentioned above. Trihalomethane concentrations in raw water are below detection limits and in treated waters do not exceed the Canadian guideline of 350 and the U.S. standard of 100 mug/L for drinking water. However, two Ontario communities exceeded the proposed Canadian standard of 50 mug/L at least 20% of the time. The three communities studied which added ammonia during water treatment had the lowest THM levels in their drinking water.
