Simulation of Cadmium and Lead Uptake into Saliva from Children's Pacifiers using the Joint Expert Speciation System

Abstract The ingestion of certain trace metals has been a major concern of the world and there have been links to cancer, renal failure, anemia, cardiovascular and reproductive complications. Pacifiers are amongst the childcare objects that may expose children to potentially toxic metals through mouthing behaviors. Despite high levels of hazardous chemicals reported in some childcare products including pacifiers, there has been limited information on the chemical species formed in saliva and as a result their bioavailability levels. Using the Joint Expert Speciation System, this study determined chemical speciation and predicted bioavailability at a range of 18–92% for cadmium and 1–23% for lead of the total metal concentrations through the creation of simulated saliva models at low and high pH. The degree of predicted uptake using a net-neutral species approach was dependent on the total concentrations of lead and cadmium within a standard range of low molecular mass ligands and the pH of the saliva. These saliva models predicted cadmium to be more bioavailable than lead, indicating there may be an elevated risk from the mouthing action of pacifiers or similar items containing cadmium compared to lead. This study, therefore, offers regulatory bodies opportunities to strengthen safety compliance monitoring for materials used in pacifiers.