Eating one tablespoon a day of some vinegars can raise a young child’s lead level by more than 30 percent, according to a report from Environmental Health News. Even though the amount of lead found in vinegar is relatively small, that small amount is significant for children. For three imported varieties tested in 2002, people who eat one tablespoon per day would be exposed to seven to 10 times the maximum daily level of lead set by California. Expensive, aged balsamic vinegars often contain the most lead. As a general rule, the longer the aging process, the most lead. The source of the lead in the vinegar is from the soil where the grapes are grown.
http://www.environmentalhealthnews.org/ehs/news/lead-in-vinegar
