Environmental Sciences Europe最新文献

Background

Environmental nanoplastics pose a potential health risk due to human exposure, necessitating studies on their cellular effects. This study aims to assess the toxic and antibacterial properties of polystyrene nanoplastics (PS-NH₂) on MDA-MB-231 breast cancer cells and HFF-2 fibroblast cells, while also evaluating their oxidative stress responses. Additionally, the study explores the anti-tumor effects and apoptosis induction by PS-NH₂. The primary objectives were to determine the cytotoxicity, antibacterial efficacy, and oxidative stress response of PS-NH₂ at different concentrations and sizes. The study also aimed to investigate the mechanism of cell death, including apoptosis, necrosis, cell cycle arrest, and changes in antioxidant enzyme activity (SOD and GPx).

Methods

Nanoplastic properties were characterized using FTIR, FESEM, and zeta potential analysis. Antibacterial effects were assessed using the agar dilution method, while the MTT assay determined cytotoxicity in MDA-MB-231 and HFF-2 cells. Apoptosis, necrosis, cell cycle arrest, and antioxidant enzyme activities (SOD, GPx) were also evaluated.

Results

FTIR analysis confirmed the amino-functionalization of PS-NH₂ with a wide peak at 3386 cm-1, and zeta potential indicated a neutral charge. PS-NH₂ showed no antibacterial activity against E. coli or Staphylococcus aureus at sizes of 90, 200, and 300 nm. Cytotoxicity assays revealed dose-dependent decreases in cell viability for both cell lines. SOD and GPx activity decreased significantly with increasing PS-NH₂ concentrations. Both cell lines underwent apoptosis, with cell accumulation in the G1 and sub-G1 phases, indicating apoptotic cell death.

Conclusions

PS-NH₂ exhibits dose- and size-dependent cytotoxicity in MDA-MB-231 and HFF-2 cells. Smaller particle sizes and higher concentrations of PS-NH₂ enhance oxidative stress, leading to apoptosis and cell cycle arrest.

Graphical Abstract

Background

Pesticide application is one of the factors reported to contribute to the decline of pollinators, such as honey bees and bumble bees, and guidelines for risk assessment have been established recently. We collected a total of 1720 data sets of pesticide residue levels in pollen and nectar from EFSA documents and from the scientific literature, covering 71 different chemicals and 20 different crops. Out of this data set, 164 events for nectar with 27 different chemicals and 161 events for pollen with 32 different chemicals were chosen that describe the initial (t = 0–1 day) residue per unit dose (RUD) after spray application. Median RUD values were calculated to describe the typical realistic initial applied dose.

Results

Overall, we can confirm earlier findings found in the frame of risk assessment of plant protection products on bees. RUD pollen is higher than RUD nectar, and there is a wide variability of results. Polar pesticides had higher median RUD values, in particular in nectar, but the explained variability of substance properties is generally small (≤10%). There are clear indications that the setup and the conditions during the experiment override substance-specific differences. Factors contributing to the observed differences in RUD were identified: spray direction (up/sideward > downward), sampling method of nectar and pollen (from flower > by traps > from bees), experimental setting (greenhouse > field or tunnel) and geometry of flowers (Fabaceae had highest RUD nectar).

Conclusions

A goal of the study was to find a prediction method for initial pesticide residues in nectar and pollen after spray application to flowers and plants. Thus, median RUD values for the different conditions were provided. However, nothing can be said about how combinations of the mentioned factors affect RUD values.

Decomposition of submerged plants releases organic matter, nitrogen, and phosphorus into water bodies, generating an important impact on the aquatic ecosystem. This study explored the influence of growth substrate with different compositions on the decomposition process of eelgrass (Vallisneria spinulosa Yan, V. spinulosa Yan). The sediment + iron–carbon fillers system exhibited significantly lower concentrations of total nitrogen (TN) and total phosphorus (TP) in the overlying water than other systems, with the maximum values of 5.68 and 7.05 mg/L, respectively. The addition of ceramic and calcium nitrate promoted the formation of HCl-extracted phosphorus (HCl–P) in the sediment, while the addition of iron–carbon fillers increased the content of NaOH-extracted phosphorus (NaOH–P). Three-dimensional fluorescence spectroscopy of dissolved organic matter (DOM) in overlying water showed that different substrate compositions did not significantly affect the compositions of organic matter released during the decomposition of V. spinulosa Yan. The microbial community and abundance in each experimental group changed significantly before and after the decomposition of V. spinulosa Yan. The sediment + iron–carbon fillers system showed significantly higher abundance of microbial community than other systems, with the enrichment of functional bacteria related to denitrification and sulfate reduction. In contrast, the sediment + calcium nitrate system exhibited a smaller change of microbial community abundance, with the enrichment of aerobic denitrifying bacteria. In this paper, it was found that the sediment + iron–carbon group had a good adsorption effect on nitrogen and phosphorus released during the decomposition process of V. spinulosa Yan, and had a good effect on water purification as the growth substrate of submerged plants.

The bioaccessibility of Zn, Ni, Cd, and Cu is a critical parameter for accurately assessing the human health risk associated with oral exposure to soils contaminated with heavy metals. However, most studies have evaluated the bioaccessibility of these metals without considering the impact of metallic chemical fractionations and human gut microbiota, which are important factors affecting the uptake of heavy metals. In this study, the bioaccessibility of Zn, Ni, Cd, and Cu in soils was measured in an improved in vitro model. The metallic chemical fractionations and bioaccessibility of heavy metals in the sterilized colon phase were also investigated. The results showed that the bioaccessibility of all four heavy metals was below 70%, indicating that relying solely on total metal concentration for assessing human health risks would result in overestimation. The exchangeable, bound to carbonates, and bound to iron and manganese fractions (F123) of heavy metals were found to be close to their bioaccessibility. Furthermore, the bioaccessibility of heavy metals in the gastric phase was strongly and positively correlated with their F123 values (r of Zn, Ni, and Cu were 0.80, 0.57, and 0.68, respectively), highlighting the close connection between metallic chemical fractionation and bioaccessibility. The bioaccessibility of Ni and Cd was found to be higher in the sterile colon phase compared to the active colon phase, whereas Cu showed lower bioaccessibility in the sterile colon phase. The significant differences in heavy metal bioaccessibility between the active and sterile colon suggested that human gut microbiota in vitro played a key role in the adsorption and desorption processes of heavy metals in the intestine. These findings underscore the importance of taking into account both metallic chemical fractionation and human gut microbiota in vitro when assessing the bioaccessibility of heavy metals and their associated health risks.

The ECHA guidance on persistence (P) assessment has been updated with respect to non-extractable residues (NER). Unless further characterized, total NER shall be considered as non-degraded parent compound. We investigated how different NER fractions affect degradation half-lives (DegT50) of chemicals and the P assessment. Total NER consist of the fractions sorbed/sequestered (NER I), covalently bound (NER II), and bioNER (incorporated into the biomass, NER III). NER I pose a risk due to potential release, NER II have much lower release potential, and bioNER do not have any. NER I and NER II are considered as xenoNER. Data from 46 degradation tests with 24 substances were analyzed to find DegT50 for four scenarios: (i) extractable parent compound, (ii) parent plus total NER, (iii) parent plus xenoNER, and (iv) parent plus NER I. The microbial turnover to biomass (MTB) model was applied to calculate bioNER, and then xenoNER were calculated as total NER minus bioNER. The half-lives were determined by the fit program CAKE, using single first-order kinetics (SFO) for all fits. We found increasing degradation half-lives for the scenarios: extractable parent only < parent + NER I < parent + xenoNER < parent + total NER. A third of all chemicals show half-lives above the persistence criterion (120 days in OECD 307 and 308, and 40 days in OECD 309) for scenario i, and two thirds with scenario ii and, therefore, would be classified as ‘persistent’. For two compounds, the subtraction of bioNER led to a change to ‘not persistent’. The inclusion of NER in the P assessment (ECHA 2017, 2023) will thus have significant effects on the DegT50 of compounds and the persistence assessment. Experimental quantification of NER I (scenario iv) significantly reduces half-lives, in comparison to total NER (scenario ii). The results are closer to half-lives for parent only (scenario i) and give the lowest acceptable DegT50 below the vP criteria under the latest guidance. In addition, refining the DegT50 based on modelled bioNER can provide a more realistic option for persistence assessment, without laborious and costly analyses for NER I determination, when considered in the regulatory assessment of persistence. Moreover, bioNER can also be calculated for existing test data.

Sewage treatment plants are considered as important pathways for the transfer of perfluoroalkyl and polyfluoroalkyl substances (PFAS) to the environment. In conventional wastewater treatment, some of these compounds accumulate in sewage sludge via sorption onto suspended solids posing a potential environmental threat during sludge disposal and reuse. This review paper summarizes data for the occurrence of 182 PFAS from different classes in sludge matrices. Most of these monitoring data originate from Europe, Asia and North America, while limited data are available from Africa and South America. The most commonly studied classes of PFAS are perfluoroalkyl carboxylic acids, perfluoroalkyl sulfonic acids, and perfluoroalkyl sulfonamides, while few results are available for the occurrence of new generation PFAS such as GenX. The range of the observed concentrations varies between 0.01 ng/g d.w. for perfluorobutane sulfonic acid to some μg/g, depending on the compound, with the highest concentrations found for perfluorooctane sulfonic acid (8.2 μg/g d.w.). Limited information exists for the fate and removal of these substances in full-scale anaerobic digesters while recent articles indicate that some PFAS can be biotransformed under strictly anaerobic conditions. The exact mechanism remains unclear; additional data are needed to identify transformation products, apply mass balances, and understand the role of specific microorganisms. As regards novel thermal processes, encouraging results were recently published for the destruction of specific PFAS in hydrothermal liquefaction and carbonization, ranging between 55 and 100%, depending on the compound and the experimental conditions applied. Future studies should expand the list of studied compounds and focus on the mechanisms of their removal. PFAS are transferred to agricultural lands during sewage sludge reuse and their concentrations in soil are related to the applied biosolids’ loading rates. The parameters that affect leaching and desorption of PFAS from sludge, their plant uptake and possible threats for the environment and human health from the use of sewage sludge as soil amendment should be examined in long-term studies. ZeroPM project aims to address some of the literature gaps regarding the behavior of PFAS during sludge treatment focusing to the modification of anaerobic digestion and to the use of hydrothermal carbonization.

A risk-based strategy is presented aimed at prioritizing chemicals screened as potential persistent, mobile and toxic (PMT) or very persistent and very mobile (vPvM) substances. Prioritization is done to strengthen the decision-making process regarding actions that might be taken against chemicals screened as potential PMT/vPvM substances. Such actions can range from acquiring additional data aimed at reducing uncertainties in toxicological effect concentrations or internal exposure concentrations to—in case of acceptable uncertainty—suggesting compounds for prevention and/or removal measures in order to limit future exposure. The prioritization strategy is developed within the ZeroPM project and applies a variety of tools, including in silico and in vitro models for exposure and toxicity hazard assessment. These tools will be applied to chemicals identified as PMT/vPvM substances, with a preliminary emphasis on substances belonging to three chemical classes, i.e. perfluorinated compounds, triazines and triazoles. Here we describe the ZeroPM approach providing a proof-of-principle illustrative example, based on data-rich substances, results from which demonstrate how prioritization can be achieved using a risk-based approach that uses data obtained from new approach methodologies (NAMs) and environmental exposure concentrations, obtained either through modelling or monitoring studies. Results are communicated using a risk-based prioritization matrix, which can be used to help to communicate prioritization needs, such as identifying data gaps or for guiding actions aimed at mitigating exposure. The precision and accuracy of the prioritization matrix is evaluated using several data-rich chemicals, which identifies perfluorooctanoic acid and perfluorooctane sulfonic acid as high priority, due to a combination of toxicity and exposure estimates, whereas atrazine and melamine are observed at lower priority. The proposed risk-based prioritization framework thus represents a complementary source of information that should help support regulatory decision-making for PMT/vPvM substances.