Face mask as an indicator and shield of human exposure to traditional and novel organophosphate esters

Cresyl diphenyl phosphate (a novel organophosphate ester) induces hepatic steatosis by directly binding to liver X receptor α: From molecule action to risk assessment

Cresyl diphenyl phosphate (CDP), a novel organophosphate ester (OPE), has been increasingly detected in various environmental and human samples. However, its toxicity, mechanisms, and health risks remain largely unknown. In this work, we investigated CDP-induced hepatic steatosis through Liver X Receptor α (LXRα) pathway across the molecular interactions, signaling pathways, cell functions, animal effects, and population risks, and compared them to triphenyl phosphate (TPHP) and tricresyl phosphate (TCRP). Receptor binding results showed that all three OPEs bound to LXRα directly in the order of TCRP > CDP > TPHP. Docking results suggested that the three aryl groups played an essential role in the binding of these chemicals to LXRα. They also activated LXRα-mediated lipogenesis pathway and promoted lipid accumulation in HepG2 cells. The intracellular concentration and LXRα-bound concentration of the chemicals in HepG2 cells followed a consistent order of CDP > TCRP > TPHP. In mice, exposure to CDP activated LXRα-mediated de novo lipogenesis pathway, leading to hepatic steatosis. Risk assessment results suggested that few populations (5.38 %) face a LXRα-mediated hepatic steatosis risk from CDP exposure. Collectively, our results demonstrate that CDP could bind to LXRα, activate the subsequent de novo lipogenesis pathway, inducing hepatic steatosis, and increasing adverse health risks.

Estimated daily intake and cumulative risk assessment of organophosphate esters and associations with DNA damage among e-waste workers in Hong Kong

Organophosphate esters (OPEs) are extensively used as additives in various products, including electronic equipment, which becomes e-waste when obsolete. Nevertheless, no study has evaluated OPEs exposure levels and the related health risks among e-waste workers in Hong Kong. Therefore, 201 first-spot morning urine samples were collected from 101 e-waste workers and 100 office workers to compare eight urinary OPE metabolites (mOPEs) levels in these groups. The concentrations of six mOPEs were similar in e-waste workers and office workers, except for significantly higher levels of diphenyl phosphate (DPHP) in e-waste workers and bis(1-chloro-2propyl) phosphate (BCIPP) in office workers. Spearman correlation analysis showed that most non-chlorinated mOPEs were correlated with each other in e-waste workers (i.e., nine out of ten pairs, including di-p-cresyl phosphate (DpCP) and di-o-cresyl phosphate (DoCP), DpCP and bis(2-butoxyethyl) phosphate (BBOEP), DpCP and DPHP, DpCP and dibutyl phosphate (DBP), DoCP and BBOEP, DoCP and DPHP, DoCP and DBP, BBOEP and DPHP, DPHP and DBP), indicating that handling e-waste could be the exposure source of specific OPEs. The median values of estimated daily intake (EDI) and hazard quotient (HQ) suggested that the health risks from OPEs exposures were under the recommended thresholds. However, linear regression models, Quantile g-computation, and Bayesian kernel machine regression found that urinary mOPEs elevated 8-hydroxy-2-deoxyguanosine (8-OhdG) levels individually or as a mixture, in which DPHP contributed prominently. In conclusion, although e-waste might not elevate the internal OPEs levels among the participating Hong Kong e-waste workers, attention should be paid to the potential DNA damage stimulated by OPEs under the currently recommended thresholds.

Persistent pollution of genetic materials in a typical laboratory environment

From the onset of coronavirus disease (COVID-19) pandemic, there are concerns regarding the disease spread and environmental pollution of biohazard since studies on genetic engineering flourish and numerous genetic materials were used such as the nucleic acid test of the severe acute respiratory syndrome coronavirus (SARS-CoV-2). In this work, we studied genetic material pollution in an institute during a development cycle of plasmid, one of typical genetic materials, with typical laboratory settings. The pollution source, transmission routes, and pollution levels in laboratory environment were examined. The Real-Time quantitative- Polymerase Chain Reaction results of all environmental mediums (surface, aerosol, and liquid) showed that a targeted DNA segment occurred along with routine experimental operations. Among the 79 surface and air samples collected in the genetic material operation, half of the environment samples (38 of 79) are positive for nucleic acid pollution. Persistent nucleic acid contaminations were observed in all tested laboratories and spread in the public area (hallway). The highest concentration for liquid and surface samples were 1.92 × 108 copies/uL and 5.22 × 107 copies/cm2, respectively. Significant amounts of the targeted gene (with a mean value of 74 copies/L) were detected in the indoor air of laboratories utilizing centrifuge devices, shaking tables, and cell homogenizers. Spills and improper disposal of plasmid products were primary sources of pollution. The importance of establishing designated experimental zones, employing advanced biosafety cabinets, and implementing highly efficient cleaning systems in laboratories with lower biosafety levels is underscored. SYNOPSIS: STATEMENT. Persistent environmental pollutions of genetic materials are introduced by typical experiments in laboratories with low biosafety level.