Estimated Risks of Water and Saliva Contamination by Phthalate Diffusion from Plasticized Polyvinyl Chloride
Phthalates are additives commonly used to convert hard polyvinyl chloride (PVC) resins into flexible and workable plastics employed in the production of chewable rubber toys and other soft-plastic products. In theory, phthalates can diffuse in small quantities to the surface of a product, and from there they can enter the environment and the human body. The purpose of this study was to determine the diffusion of phthalates from plasticized PVC in water and artificial saliva; to determine the migration of di(2-ethylhexyl) (DEHP) phthalate in human saliva using gas chromatography; to compare the experimental values with theoretical values calculated using a model based on the principles of molecular diffusion in fluids; and to use the experimental values to estimate daily doses of DEHP received by Mexican children and infants using plastic and soft-plastic products (e.g., pacifiers, chewable toys, and bottles). Our findings indicated phthalate diffusion of 0.36 g/cm2 per hour and 4.10 g/cm2 per hour, respectively, in water and artificial saliva. The average value of phthalate diffusion in vivo was 6.04 g/cm2 per hour. The daily oral phthalate exposure in Mexican infants and toddlers from oral use of rubber toys and soft-plastic products is 18.12 g/kg. These daily doses are considerably lower than the maximum daily phthalate intake recommended by an international public health committee.