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Microplastic (MP) accumulation in the environment has become an issue of human and environmental importance. Great efforts were made recently to identify the sources of MP exposure to humans and their release into the environment. Here, we employed spectroscopic techniques to identify and characterize MP in consumer plastic food containers that are, in huge quantity, used for food delivery and disposable plastic cups for daily drinking. We determined the average weight of isolated MP per pack to be 12 ± 5.12 mg, 38 ± 5.29 mg, and 3 ± 1.13 mg for the round-shaped, rectangular-shaped plastic container and disposable plastic cups, respectively, with various morphological features including cubic, spherical, rod-like as well as irregular shapes, which may either be consumed by humans or released into the environment. This study demonstrates that new plastic containers can be an important source of direct human and environmental exposure to microplastics. Most importantly, our results indicated that necessary attention must be given to morphological features of realistic MPs when evaluating their risks to humans and the environment.

Despite many studies on the toxicity of nanoplastic particles (NPPs) to aquatic invertebrates, the effects of ecological constituents such as humic substances (HSs) are often neglected. In our study, Daphnia magna was used to evaluate the effects of three HSs, natural organic matter (NOM), fulvic acid (FA), and humic acid (HA), on NPP toxicity and corona formation. Acute toxicities of NPPs were reduced by all HSs at environmentally relevant concentrations. NPPs elicited the upregulation of all genes related to detoxification, oxidative stress, and endocrine activity after 7 days of exposure. The presence of NOM or HA resulted in the mitigation of gene expression, whereas significantly higher upregulation of all of the genes was observed with FA. The presence of FA led to increased protein adsorption on NPPs in D. magna culture medium (eco-corona, EC) and homogenates (protein corona, PC), while there was less adsorption in the presence of HA. The highly abundant proteins identified in EC are involved in immune defense, cell maintenance, and antipredator response, while those in PC are responsible for lipid transport, antioxidant effects, and estrogen mediation. Our findings revealed the key influence of HSs on the toxicity of NPPs and provide an analytical and conceptual foundation for future study.

With worldwide environmental accumulation of plastics and their recognized degradation into smaller particles, attention to their impacts on ecological systems and humans has been increasing recently. However, environmental factors and their impacts are seldom considered during their eco-toxicity evaluation. In this study, D. magna neonates were used to assess and compare the acute toxicities of polystyrene microplastic particles (MPPs) and nanoplastic particles (NPPs) in the absence and presence of humic acids (HAs), an important environmental factor in aquatic systems. Four stress response and detoxification genes (CAT, GST, HSP70, and P-GP) were used to characterize the toxic response of the neonates to the exposure. Our results showed that NPPs were much more toxic than MPPs in that 10 mg L-1 NPPs induced over 70% of death in 96 h but MPPs (as high as 400 mg L-1) caused no mortality under all tested conditions. More importantly, we revealed a potent protective role of HA against NPP toxicity at environmentally relevant concentrations. The effect was concentration dependent, as 50 mg L-1 HA subdued the NPP (400 mg L-1) toxicity effect completely. NPPs elicited the up-regulation of all examined genes while HA diminished the change appreciably, further confirming its detoxifying role against NPP toxicity. Through fluorescence and dynamic light scattering measurements, we found that HA was adsorbed on NPPs and formed a corona, without causing agglomeration or precipitation, but changed NPP distribution in the D. magna neonates in a way similar to that of MPPs, leading to alleviated toxicity. Our results suggest that it is essential to consider environmental factors in evaluating and monitoring NPP toxicity as this presents a more relevant exposure state.

Ingestion of perfluoroalkyl acids (PFAAs) via contaminated food contact materials (FCMs) is an important human exposure source. This study adopts a toxicity equivalent approach to evaluate the collective health risk of multiple PFAAs in FCMs. A comprehensive extraction and analysis of 21 PFAAs in FCMs was performed. Among the analyzed substances, 15 PFAAs were detected. Migration experiment using three food simulants revealed the migration range of seven PFAAs from FCMs into the simulant to be 0.47–46.7 ng/cm2. The hazard quotient results suggest minimal health risk, except for 9% of packaged samples where perfluorooctanoic acid (PFOA) poses a higher risk. Utilizing PFOA toxic equivalent concentrations, comprehensive risk calculations showed ∼77% of samples potentially posing elevated health risks due to PFAA exposure. This emphasizes the substantial contribution of PFAAs beyond PFOA and underscores the importance of considering them in related assessments. The aggregated risk assessment reflects actual exposure circumstances more accurately. [ABSTRACT FROM AUTHOR]

Taiyuan in the Shanxi Province of China has experienced significant air pollution from fine particulate matter (PM2.5) in the past years. Phthalate esters (PAEs), which are common semi-volatile chemical molecules in PM2.5 and that humans can breathe into their bodies, can have serious health consequences. This study looked at the levels, composition, sources, and incremental lifetime lung cancer risk factors for PM2.5-bound PAEs in Taiyuan. A QuEChERS extraction technique and gas chromatography-tandem mass spectrometry were used to evaluate 16 PAE compounds. All samples contained PAEs, and the overall PAE concentration ranged from 114 to 864 ng/m3. The most often detected compound was bis(2-ethylhexyl)phthalate (DEHP), and summer PAE concentrations were substantially greater than winter ones. A positive matrix factorization model showed that the main sources of PAE release were the indoor environment, industry source, automobile-related source, and construction source. The places within 300 km of Taiyuan were thought to have a significant impact on PAEs, according to the analysis of the prospective source contribution function. The calculated incremental lifetime lung cancer risk of DEHP exposure was 0.76 cases per million people. More of the risk of lung cancer has been attributed to indoor air pollution (53.2%). These findings will help us understand the features of PAE contamination and offer a solid scientific foundation for minimizing PAE pollution in the Loess Plateau. [ABSTRACT FROM AUTHOR]