Occurrence, Fate, Human Exposure, and Toxicity of Commercial Photoinitiators

Abstract

Photoinitiators (PIs) are a family of anthropogenic chemicals used in polymerization systems that generate active substances to initiate polymerization reactions under certain radiations. Although polymerization is considered a green method, its wide application in various commercial products, such as UV-curable inks, paints, and varnishes, has led to ubiquitous environmental issues caused by PIs. In this study, we present an overview of the current knowledge on the environmental occurrence, human exposure, and toxicity of PIs and provide suggestions for future research based on numerous available studies. The residual concentrations of PIs in commercial products, such as food packaging materials, are at microgram per gram levels. The migration of PIs from food packaging materials to foodstuffs has been confirmed by more than 100 reports of food contamination caused by PIs. Furthermore, more than 20 PIs have been detected in water, sediment, sewage sludge, and indoor dust collected from Asia, the United States, and Europe. Human internal exposure was also confirmed by the detection of PIs in serum. In addition, PIs were present in human breast milk, indicating that breastfeeding is an exposure pathway for infants. Among the most available studies, benzophenone is the dominant congener detected in the environment and humans. Toxicity studies of PIs reveal multiple toxic end points, such as carcinogenicity and endocrine-disrupting effects. Future investigations should focus on synergistic/antagonistic toxicity effects caused by PIs coexposure and metabolism/transformation pathways of newly identified PIs. Furthermore, future research should aim to develop “greener” PIs with high efficiency, low migration, and low toxicity.

Occurrence of Multiple Classes of Emerging Synthetic Antioxidants, Including p-Phenylenediamines, Diphenylamines, Naphthylamines, Macromolecular Hindered Phenols, and Organophosphites, in Human Milk: Implications for Infant Exposure

“…Synthetic antioxidants (AOs) are ubiquitous, high-productionvolume chemicals used as essential polymer additives in the manufacture of various industrial and consumer products to enhance product resistance to oxidative aging. 1 It has been reported that the global consumption of AOs is up to 700,000 tons per year for rubber manufacturing alone. 2 Generally, commercial synthetic AOs are divided according to their structures and functionalities into four categories: hindered phenol antioxidants (HPAs), aromatic amine antioxidants (AAs), organophosphite antioxidants (OPAs), and sulfurcontaining antioxidants (SAs).…”

“…6 Representative LMW HPAs include the well-known 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4di-tert-butyl-phenol (DBP). 1 In recent 20 years, to improve the performance of HPAs and slow their migration from products, a large number of BHT-derived MHPAs, represented by octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (AO 1076), have been introduced into the market. 8−10 To date, both LMW SPAs and MHPAs have been widely detected across multiple environmental media worldwide.…”

Unexpected Exposure Risks to Emerging Aromatic Amine Antioxidants and p-Phenylenediamine Quinones to Residents: Evidence from External and Internal Exposure as Well as Hepatotoxicity Evaluation

“…4,5,7−15 Commercial SAs are generally classified as aromatic amine antioxidants (AAs), sulfur-containing antioxidants (SAs), hindered phenolic antioxidants (HPAs), and organophosphate antioxidants (OPAs). 16,17 Among the various emerging SAs, amine antioxidants (AAs), containing aromatic amine groups based on anilines and structures with an aromatic ring and one or more amine groups, have recently attracted increasing attention. 7,15,18,19 AAs have been considered as new high-production volume (HPV) industrial chemicals, which include p-phenylenediamines (PPDs), diphenylamines (DPAs), naphthylamines (NPAs), and the DPG series of materials (e.g., 1,3diphenylguanidine (DPG), 1,2,3-triphenylguanidine (TPG), and 1,3-di-o-tolyguanidine (DTG)).…”

Exploring Prenatal Exposure to Halogenated Compounds and Its Relationship with Birth Outcomes Using Nontarget Analysis

“…Significantly negative association with newborn birth weight and length was monitored for chlorpyrifos levels in umbilical cord plasma samples collected in New York City . Factually, humans are exposed to a cocktail of contaminants, and the relevant adverse outcomes usually originate from the complex chemical mixtures. , To our knowledge, systematic study on the Cl/Br-HOCs exposome in the early life stage and its exposure risks is still lacking.…”