Phthalates are esters of Pthalic acid, compounds mainly used as plasticisers. Phthalates are widely used chemicals which are of significant research interest as their exposure causes various consequences for human health. There are several categories of phthalates extensively used in many commercial productions with diverse uses, physicochemical properties and toxicological effects. This chapter discusses the toxicity of Phthalates and its potential risks to human health.

Phthalate esters (PAEs) are a ubiquitous kind of environmental endocrine-disrupting chemicals, causing environmental and health issues. EstJ6 is an effective phthalate-degrading hydrolase, and its mutant with a combination of three non-conservative distal mutations has an improved activity against PAEs with unknown molecular mechanisms. Herein, we attempt to fill the significant gap between distal mutations and the activity of this enzyme using computational approaches. We find mutations result in a redistribution of enzyme’s preexisting conformational states and dynamics changes of key functional regions, especially the lid over the active site. The outward motion of the lid upon mutations should make it easier for substrates or products to enter or exit. Additionally, the stronger substrate binding affinity and conformational rearrangements of catalytic reaction-associated residues in mutant, accompanied by the strengthened communication within the protein, might contribute to the elevated catalytic efficiency. Finally, an attempt has been done to improve the thermostability of EstJ6 upon introducing a distal disulfide bond between residues A23 and A29, and the simulation results are as expected. Together, our work explored the allosteric effects caused by distal mutations, which could provide insights into the rational design of esterases for industrial applications in the future.

The efficient extraction of phthalate acid esters (PAEs) is challenging due to their extremely low concentration, complicated matrices and hydrophilicity. Herein, hol-low microspheres, as an ideal coating, possesses significant potential for solid-phase microextraction (SPME) due to their fascinating properties. In this study, multi-walled carbon nanotubes hollow microspheres (MWCNTs-HMs) were utilized as a fiber coating for the SPME of PAEs from tea beverages. MWCNTs-HMs were ob-tained by dissolving the polystyrene (PS) cores with organic solvents. Interestingly, MWCNTs-HMs well maintain the morphology of the precursors MWCNTs@PS. The layer-by-layer (LBL) assembly of MWCNTs on PS microsphere templates was ac-quired through electrostatic interactions. Six PAEs, di-ethyl phthalate (DEP), di-iso-butyl phthalate (DIBP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP) and di-n-octyl phthalate (DOP), were se-lected as target analytes for assessing the efficiency of the coating for SPME. The stirring rate, sample solution pH and extraction time were optimized by using the Box-Behnken design. Under optimal working conditions, the proposed MWCNTs-HMs/SPME was coupled with gas chromatography-tandem mass spec-trometry (GC-MS/MS) to achieve high enrichment factors (118–2137), wide linearity (0.0004-10 μg L-1), low limits of detection (0.00011-0.0026 μg L-1) and acceptable recovery (80.2%-108.5%) for the detection of PAEs. Therefore, the MWCNTs-HMs coated fibers are promising alternatives in the SPME method for the sensitive detec-tion of PAEs at trace levels in tea beverages.

From 2020 to 2023 many people around the world were forced to wear masks for large proportions of the day based on mandates and laws. We aimed to study the potential of face masks for the content and release of inanimate toxins. A scoping review of 1003 studies was performed (database search in PubMed/MEDLINE, qualitative and quantitative evaluation). Twenty-four studies were included (experimental time 17 min to 15 days) evaluating content and/or release in 631 masks (273 surgical, 228 textile and 130 N95 masks). Most studies (63%) showed alarming results with high micro- and nanoplastics (MPs and NPs) release and exceedances could also be evidenced for volatile organic compounds (VOCs), xylene, acrolein, per-/polyfluoroalkyl substances (PFAS), phthalates (including di(2-ethylhexyl)-phthalate, DEHP) and for Pb, Cd, Co, Cu, Sb and TiO₂. Of course, masks filter bacteria, dirt and plastic particles and fibers from the air we breathe and have specific indications, but according to our data they also carry risks. Depending on the application, a risk-benefit analysis is necessary. However, mask mandates during the SARS-CoV-2 pandemic have been generating an additional source of potentially harmful exposition to toxins at population level with almost zero distance to the airways.

Humans are often exposed to various environmental contaminants, among which phthalates are prevalent due to their extensive use as plasticizers in various consumer goods. Di(2-ethylhexyl) phthalate (DEHP), a widely used phthalate, is recognized as an endocrine disruptor chemical (EDC). DEHP is reported to affect various organs. Few studies have addressed the effects of phthalates on bone. However, the effects of DEHP on the bone forming cells (osteoblasts) are obscure. The present study was peformed to determine the cytotoxic effects of DEHP on human osteoblasts in vitro and to delineate the mechansims. In this study, we exposed the human osteo-blastic cell line MG-63 to various concentrations of DEHP (1, 25, 50 and 100 µM) for 24, 48 and 72 h. Cell viability was assessed by MTT assay. Total RNA and protein were collected after 48 h treatment with 1 and 100 µM DEHP and determined for the mRNA and/or protein expression of alkaline phosphatase (ALP), sex steroid receptors (androgen and estrogen receptors), receptor activator of nuclear factor kappa-Β ligand (RANKL), runt-related transcription factor 2 (RUNX2) and peroxisome proliferator-activated receptor alpha (PPARα). The mRNA expression was stud-ied by real-time RT-PCR analysis and the protein expression was determined by western blot analysis. Statistical analyses were done by one-way analysis of variance (ANOVA) followed by the Students–Newman–Keuls (SNK) test. The exposure of MG-63 cells to DEHP caused a signifi-cant decrease in osteoblast viability in all the treatment groups and at all the time points stud-ied. Interestingly, DEHP exposure decreased the mRNA expression of ALP, a bone formation marker. DEHP had differential effects on estrogen receptor alpha (ERα) mRNA and protein ex-pression. However, DEHP treatment downregulated the mRNA and protein expression of ERβ, and androgen receptor (AR). Surprisingly, DEHP downregulated the RANKL mRNA expression. DEHP decreased the protein expression of RUNX2, the key transcription factor and master regu-lator of bone formation. Furthermore, DEHP increased the PPARα protein expression in the os-teoblasts. Importantly, DEHP increased the reactive oxygen species (ROS) molecules and thus oxidative stress in osteoblasts, as observed by increased hydrogen peroxide, hydroxyl radical levels and lipid peroxidation. On the other hand, it decreased the enzymatic and non-enzymatic antioxidant levels namely catalase, superoxide dismutase, glutathione peroxidase activity and reduced glutathione. Our study demonstrated that in vitro exposure to DEHP reduces the osteo-blast viability possibly through alterations in the oxidant-antioxidant system and modulation of the key genes involved in bone formation, highlighting the cytotoxic effects of DEHP on bone forming cells.