Polyvinyl chloride plastics are often made by combining the stabilizer containing lead compounds. In an ivestigation into straws as a representative of the tableware made of this plastic, it was found that straws allowed to be immersed in 4% acetic acid solution for ten minutes yielded from 0 to more than 100μg of soluble lead. Even in water, pH 5.4, straws yielded soluble lead. Under several conditions, an amount of soluble lead from straws were investigated. Among them, pH was found to be a leading factor.
To protect beverages from lead dissolved out of these straws, treatment of straws with acid-washing was found to be most effective and feasible. For surveying these straws, purple color development by immersing them in an acidic rhodizonic soda solution might be well.