Safety Evaluation of Disposable Baby Diapers Using Principles of Quantitative Risk Assessment

Abstract

Baby diapers are complex products consisting of multiple layers of materials, most of which are not in direct contact with the skin. The safety profile of a diaper is determined by the biological properties of individual components and the extent to which the baby is exposed to each component during use. Rigorous evaluation of the toxicological profile and realistic exposure conditions of each material is important to ensure the overall safety of the diaper under normal and foreseeable use conditions. Quantitative risk assessment (QRA) principles may be applied to the safety assessment of diapers and similar products. Exposure to component materials is determined by (1) considering the conditions of product use, (2) the degree to which individual layers of the product are in contact with the skin during use, and (3) the extent to which some components may be extracted by urine and delivered to skin. This assessment of potential exposure is then combined with data from standard safety assessments of components to determine the margin of safety (MOS). This study examined the application of QRA to the safety evaluation of baby diapers, including risk assessments for some diaper ingredient chemicals for which establishment of acceptable and safe exposure levels were demonstrated.

Safety Evaluation of Absorbent Hygiene Pads: A Review on Assessment Framework and Test Methods

“…Assuming that the applied pressure from a baby will not be on 100% of diaper area, rewetting fraction was adjusted to count 50% diaper area; the fraction of constituents transferred to skin by the reflux was estimated to be 0.32-0.66% (mean value of 0.46%). This value is higher than 0.25% that was suggested by Rai [24]. This conservative value of 0.46% was suggested by Dey et al as a default rewet as the worst scenario [3].…”

“…In Odio et al's study [36,37], a lotion was spread on the topsheet of a diaper, and then the transferred amount of lotion to the collection tape (Tegaderm TM , 3M, St. Paul, MN, USA) was measured during the children's diaper-wearing [37,38]. From this experiment, the lotion transfer to skin was estimated to be 3.0-4.3% of the initial amount of lotion per diaper [3,37,38,47]; this is half the amount that Rai et al [24] used (7%) as the skin transfer rate by the direct contact.…”

“…Hazard characterization is the qualitative or quantitative description of the inherent properties of chemicals that cause health risks, in terms of chemical toxicity, dose-response relationship, exposure route and time [23,24]. Based on the hazard characterization, health based references or point of departure (POD) are determined.…”

“…Components of absorbent pads that are not in direct skin contact can be solubilized in aqueous carrier such as urine or menstruation, and can be resurfaced to the topsheet under body weight [3]. Rai et al [24] explained that modern disposable diapers that contain SAP in the core have reflux value of merely about 0.25% as the resurfacing of liquid is minimized by SAP.…”

“…MOS considers uncertainty factor, and is determined by the ratio of a derived reference dose with no or minimal adverse effects-which includes RfD, RfC, ADI, etc.-to an estimated human exposure level [22,26,97]. With uncertainty factor implemented, MOS ≥ 1 is considered to be acceptable; that is, if the product is used in its intended way or in foreseeable misuse, the product is safe with adequate margin of safety [4,24]. When MOS is lower than the desired, it is recommended to refine the conservative default assumptions.…”