My friend asked, "I heard that plastic bags cannot be used repeatedly, why?". In fact, her problem is very representative, because in daily life, the repeated use of packaging items is commonplace, and people do not realize what adverse effects it will have on the human body when plastic bags are reused. Plastic food bags should not be used repeatedly.

　　 Some foreign scholars tested the printed part of 17 different types of plastic bread bags, and the average lead content in each bag was 26 mg. If a weak acid solution is used for extraction, less than 10 minutes can measure 6% of the total lead. According to a survey of 106 parents, 41% of the parents who have a good cultural education have the habit of repeatedly using plastic bread bags. What''s more serious is that 16% of people are used to turning over the food when reusing the plastic bread bag, which makes the food directly contact with the printed lead. According to estimates by people concerned, the use of weak acids such as vinegar can filter out 0.1 mg of lead from the lead-sized packaging of bread slices, which is twice the amount of lead ingested by people in a day. Although this lead content is not enough to cause a significant threat to human health, its potential adverse effects on the human body exist. Therefore, relevant experts suggest that lead printing should be prohibited on food packaging bags, and at the same time, it should be more careful not to reuse plastic bags.