Fumonisin B1 (FB1) is a neurodegenerative mycotoxin synthesized by Fusarium spp., but the potential neurobehavioral toxicity effects in organisms have not been characterized clearly. Caenorhabditis elegans (C. elegans) has emerged as a promising model organism for neurotoxicological studies due to characteristics such as well-functioning nervous system and rich behavioral phenotypes. To investigate whether FB1 has neurobehavioral toxicity effects on C. elegans, the motor behavior, neuronal structure, neurotransmitter content, and gene expression related with neurotransmission of C. elegans were determined after exposed to 20–200 μg/mL FB1 for 24 h and 48 h, respectively. Results showed that FB1 caused behavioral defects, including body bends, head thrashes, crawling distance, mean speed, mean amplitude, mean wavelength, foraging behavior, and chemotaxis learning ability in a dose-, and time-dependent manner. In addition, when C. elegans was exposed to FB1 at a concentration of 200 μg/mL for 24 h and above 100 μg/mL for 48 h, the GABAergic and serotonergic neurons were damaged, but no effect on dopaminergic, glutamatergic, and cholinergic neurons. The relative content of GABA and serotonin decreased significantly. Furthermore, abnormal expression of mRNA levels associated with GABA and serotonin were found in nematodes treated with FB1, such as unc-30, unc-47, unc-49, exp-1, mod-5, cat-1, and tph-1. The neurobehavioral toxicity effect of FB1 may be mediated by abnormal neurotransmission of GABA and serotonin. This study provides useful information for understanding the neurotoxicity of FB1.

To evaluate pesticide regulatory standards in agricultural crops, we introduced a regulatory modeling framework that can flexibly evaluate a population’s aggregate exposure risk via maximum residue levels (MRLs) under good agricultural practice (GAP). Based on the structure of the aggregate exposure model and the nature of variable distributions, we optimized the framework to achieve a simplified mathematical expression based on lognormal variables including the lognormal sum approximation and lognormal product theorem. The proposed model was validated using Monte Carlo simulation, which demonstrates a good match for both head and tail ends of the distribution (e.g., the maximum error = 2.01% at the 99th percentile). In comparison with the point estimate approach (i.e., theoretical maximum daily intake, TMDI), the proposed model produced higher simulated daily intake (SDI) values based on empirical and precautionary assumptions. For example, the values at the 75th percentile of the SDI distributions simulated from the European Union (EU) MRLs of 13 common pesticides in 12 common crops were equal to the estimated TMDI values, and the SDI values at the 99th percentile were over 1.6-times the corresponding TMDI values. Furthermore, the model was refined by incorporating the lognormal distributions of biometric variables (i.e., food intake rate, processing factor, and body weight) and varying the unit-to-unit variability factor (VF) of the pesticide residues in crops. This ensures that our proposed model is flexible across a broad spectrum of pesticide residues. Overall, our results show that the SDI is significantly reduced, which may better reflect reality. In addition, using a point estimate or lognormal PF distribution is effective as risk assessments typically focus on the upper end of the distribution.

Environmental pollution by pharmaceuticals such as diclofenac (DCF) is globally acknowledged to be a threat to the ecosystems. Nauphoeta cinerea is an important insect with valuable ecological role. The present investigation aimed to elucidate the impact of DCF on insects by assessing the behavior and antioxidant defense response in nymphs of N. cinerea exposed to DCF-contaminated food at 0, 0.5, 1.0 and 2.0 μg kg⁻¹ feed for 42 successive days. Subsequent to exposure period, neurobehavioral analysis using video-tracking software in a novel apparatus was performed before estimation of biochemical endpoints in the head, midgut and hemolymph of the insects. Results indicated that DCF-exposed insects exhibited marked reduction in the maximum speed, total distance traveled, mobile episodes, total mobile time, body rotation, absolute turn angle and path efficiency, whereas the total freezing time was increased compared with the control. The diminution in the exploratory activities of DCF-exposed insects was substantiated by heat maps and track plots. Additionally, DCF elicited marked diminution in antioxidant enzyme and acetylcholinesterase (AChE) activities along with increase in nitric oxide (NO), reactive oxygen and nitrogen species (RONS), and lipid peroxidation (LPO) levels in the head, midgut and hemolymph of the insects. Taken together, DCF elicited neurotoxicity and oxido-inflammatory stress in exposed insects. N. cinerea may be a suitable model insect for environmental risk assessment of pharmaceuticals in non-target insect species.

To characterise the mass concentration, size-distribution, and respiratory deposition of selected trace metals (Cr, Mn, Fe, Ni, Cu, Zn, Ba, and Pb) in size-segregated PM₂.₅, a long-term monitoring campaign was undertaken at an urban background site in Como (Northern Italy). 96-h aerosol samples were collected weekly, from May 2015 to March 2016, using a 13-stage low pressure impactor and analysed via laser ablation-inductively coupled plasma-mass spectrometry. Significantly higher levels of trace metals were generally found during the heating season (two to more than four times) compared to the non-heating period at all size ranges, especially for concentrations in PM₀.₁–₁. Distinct distribution profiles characterised the different elements, even though the corresponding heating and non-heating shapes always exhibited similar features, with negligible seasonal shifts in the average mass median aerodynamic diameters. Fe, Ba, and Cu had >70% of their mass in PM₁–₂.₅, whereas Pb, Zn, and Ni showed higher contributions in the accumulation mode (>60%). Finally, broad size-distributions were found for Cr and Mn. The multiple-path particle dosimetry model estimated the overall deposition fractions in human airways varying between 27% (Pb) and 48% (Ba). The greatest deposition variability was always registered in the head region of the respiratory system, with the highest contributions for those metals predominantly accumulated in the PM₂.₅ coarse modes. In contrast, the deposition in the deepest respiratory tract maintained nearly constant proportions over time, becoming notably important for Pb, Ni, and Zn (∼13%) with respect to their total deposition. The comparison with national limits established for Pb and Ni suggested the absence of significant risks for the local population, as expected, with average concentrations two orders of magnitude lower than the corresponding annual limit and objective value. Similar findings were reported for all the other metals, for which the estimated hazard quotients were always well <1.

Microplastics are a widespread environmental pollutant in aquatic ecosystems and have the potential to eventually sink to the sediment, where they may pose a risk to sediment-dwelling organisms. While the impacts of exposure to microplastics have been widely reported for marine biota, the effects of microplastics on freshwater organisms at environmentally realistic concentrations are largely unknown, especially for benthic organisms. Here we examined the effects of a realistic concentration of polyethylene microplastics in sediment on the growth and emergence of a freshwater organism Chironomus tepperi. We also assessed the influence of microplastic size by exposing C. tepperi larvae to four different size ranges of polyethylene microplastics (1–4, 10–27, 43–54 and 100–126 μm). Exposure to an environmentally relevant concentration of microplastics, 500 particles/kgsediment, negatively affected the survival, growth (i.e. body length and head capsule) and emergence of C. tepperi. The observed effects were strongly dependent on microplastic size with exposure to particles in the size range of 10–27 μm inducing more pronounced effects. While growth and survival of C. tepperi were not affected by the larger microplastics (100–126 μm), a significant reduction in the number of emerged adults was observed after exposure to the largest microplastics, with the delayed emergence attributed to exposure to a stressor. While scanning electron microscopy showed a significant reduction in the size of the head capsule and antenna of C. tepperi exposed to microplastics in the 10–27 μm size range, no deformities to the external structure of the antenna and mouth parts in organisms exposed to the same size range of microplastics were observed. These results indicate that environmentally relevant concentrations of microplastics in sediment induce harmful effects on the development and emergence of C. tepperi, with effects greatly dependent on particle size.

This paper presents a detailed study on the indoor air pollution in the Jokahng Temple at Tibet Plateau, and its implication to human health. The mean concentrations of PM1.0 and PM2.5 were 435.0 ± 309.5 and 483.0 ± 284.9 μg/m3, respectively. The PM2.5 concentration exceeded the National Ambient Air Quality Standard (75 μg/m3) by 6.4 times. The size-segregated aerosols displayed a bimodal distribution. One peak was observed in the fine mode (0.4–2.1 μm) and the other peak appeared in the coarse mode (2.1–9.0 μm). The concentration of the total size-resolved PM was 794.3 ± 84.9 μg/m3. The mass fraction of coarse particles shared by 41.1%, apparently higher than that reported at low altitudes, probably due to incomplete combustion at Tibet Plateau with hypoxic atmospheric environment. The total concentration of polycyclic aromatic hydrocarbons (PAHs) was 331.2 ± 60.3 ng/m3, in which the concentration of benzo(a)pyrene (BaP) was 18.5 ± 4.3 ng/m3, over ten times higher than the maximum permissible risk value of 1 ng/m3 on account of carcinogenic potency of particulate PAHs through inhalation. PAHs exhibited a trimodal distribution, of which two peaks were observed in the fine mode and one peak in the coarse mode. With the aromatic rings increasing, the peak intensity increased in the fine mode. Na, Ca, Al, Mg and K dominated the elemental mass profiles, and metals displayed a bimodal distribution with a dominant peak in the coarse range. The total PAH deposition flux was 123.6 and 53.1 ng/h for adults and children, respectively. Coarse particles contributed most deposition flux in the head region, while fine particles contribute most deposition flux in the alveolar region. The increment lifetime cancer risk (ILCR) of PAHs ranaged at 10−5-10−4, indicating potential cancer risk to human health. The total deposition flux of metals was estimated at 1.4–13.2 ng/h. With the size increasing, deposition flux increased in the head region while decreased in the alveolar region. The highest ILCR of Cr and Ni were 4.9 × 10−5 and 1.5 × 10−6, respectively, exceeding the permissible risk of 10−6. The hazard quotient (HQ) of Fe (10−5-10−4) and Zn (10−6-10−5) were much lower than the safe level of 1.0, and thus they were not considered as a health concern.

This study examines size-resolved heavy metal data for particles sampled near an urban site affected by non-ferrous metal smelting in China with a focus on how particle sizes impact regional respiratory deposition behavior. Particles with aerodynamic diameters between 0.43 and 9 μm were collected during winter haze episodes from December 2011 to January 2012. The results showed that concentrations of individual trace elements ranged from ∼10⁻²–∼10⁴ ng/m³. Mass size distributions exhibit that Cu, Zn, As, Se, Ag, Cd, TI, and Pb have unimodal peak in fine particles range (<2.1 μm); Al, Ti, Fe, Sr, Cr, Co, Ni, Mo, and U have unimodal peak in coarse range (>2.1 μm), and Be, Na, Mg, Ca, Ba, Th, V, Mn, Sn, Sb, and K have bimodal profiles with a dominant peak in the fine range and a smaller peak in the coarse range. The total deposition fluxes of trace elements were estimated at 2.1 × 10⁻² – 4.1 × 10³ ng/h by the MPPD model, and the region with the highest contribution was the head region (42% ± 13%), followed by the tracheobronchial region (11% ± 3%) and pulmonary region (6% ± 1%). The daily intake of individual element for humans occurs via three main exposure pathways: ingestion (2.3 × 10⁻⁴ mg/kg/day), dermal contact (2.3 × 10⁻⁵ mg/kg/day), and inhalation (9.0 × 10⁻⁶ mg/kg/day). A further health risk assessment revealed that the risk values for humans were all above the guidelines of the hazard quotient (1) and cancer risk (10⁻⁶), indicating that there are potential non-cancer effects and cancer risks in this area.

It is important to evaluate how ambient particles are deposited in the human respiratory system in view of the adverse effects they pose to human health. Traditional methods of investigating human exposure to ambient particles suffer from drawbacks related either to the lack of chemical information from particle number-based measurements or to the poor time resolution of mass-based measurements. To address these issues, in this study, human exposure to ambient particulate matter was investigated using single particle analysis, which provided chemical information with a high time resolution. Based on single particle measurements conducted in the Pearl River Delta, China, nine particle types were identified, and EC (elemental carbon) particles were determined to be the most dominant type of particle. In general, the submicron size mode was dominant in terms of the number concentration for all of the particle types, except for Na-rich and dust particles. On average, around 34% of particles were deposited in the human respiratory system with 13.9%, 7.9%, and 12.6% being distributed in the head, tracheobronchial, and pulmonary regions, respectively. The amount of Na-rich particles deposited was the highest, followed by EC. The overall deposition efficiencies of the Na-rich and dust particles were higher than those of the other particle types due to their higher efficiencies in the head region, which could be caused by the greater sedimentation and impaction rates of larger particles. In the head region, the Na-rich particles made the largest contribution (30.5%) due to their high deposition efficiency, whereas in the tracheobronchial and pulmonary regions, EC made the largest contribution due to its high concentration. In summary, the findings of this initial trial demonstrate the applicability of single particle analysis to the assessment of human exposure to ambient particles and its potential to support traditional methods of analysis.

Several studies highlighted the ubiquitous presence of ibuprofen and aluminum in the aquatic environment around the world and demonstrated their potential to induce embryotoxic and teratogenic defects on aquatic species individually. Although studies that evaluate developmental alterations induced by mixtures of these pollutants are scarce; and, since environmental contamination presented in the form of a mixture of toxicants with different chemical properties and toxicity mechanisms capable of generating interactions; the objective of this study was to evaluate the developmental defects, teratogenic alterations, and oxidative stress induced by individual forms and the mixture of ibuprofen (IBU) and aluminum (Al) on zebrafish embryos. Oocytes exposed to environmentally relevant concentrations of IBU (0.1–20 μg L-1) and Al (0.01–8 mg L-1) and one binary mixture. The LC50 and EC50 were obtained to calculate the teratogenic index (TI). The IBU LC50, EC50, and TI were 8.06 μg L-1, 2.85 μg L-1 and 2.82. In contrast, Al LC50 was 5.0 mg L-1with an EC50 of 3.58 mg L-1 and TI of 1.39. The main alterations observed for individual compounds were hatching alterations, head malformation, skeletal deformities, hypopigmentation, pericardial edema, and heart rate impairment. The mixture also showed significant delays to embryonic development. Moreover, oxidative stress biomarkers of cellular oxidation and antioxidant defenses at 72 and 96 hpf significantly increased. Results show that environmentally relevant concentrations of ibuprofen (IBU), aluminum (Al), and their mixture promote a series of developmental defects, teratogenic effects, and oxidative disruption on D. rerio embryos, and the interaction of both substances altered the response. In conclusion, morphological and biochemical tests are suitable tools for assessing the health risk of aquatic wildlife by exposure to individual and mixed pollutants in freshwater bodies.

Pollution damages ecosystems around the globe and some forms of pollution, like oil pollution, can be either man-made or derived from natural sources. Despite the pervasiveness of oil pollution, certain organisms are able to colonise polluted or toxic environments, yet we only have a limited understanding of how they are affected by it. Here, we analysed phenotypic responses to oil pollution in guppies (Poecilia reticulata) living in oil-polluted habitats across southern Trinidad. We analysed body-shape and life-history traits for 352 individuals from 11 independent populations, six living in oil-polluted environments (including the naturally oil-polluted Pitch Lake), and five stemming from non-polluted habitats. Based on theory of, and previous studies on, responses to environmental stressors, we predicted guppies from oil-polluted waters to have larger heads and shallower bodies, to be smaller, to invest more into reproduction, and to produce more but smaller offspring compared to guppies from non-polluted habitats. Contrary to most of our predictions, we uncovered strong population-specific variation regardless of the presence of oil pollution. Moreover, guppies from oil-polluted habitats were characterised by increased body size; rounder, deeper bodies with increased head size; and increased offspring size, when compared to their counterparts from non-polluted sites. This suggests that guppies in oil-polluted environments are not only subject to the direct negative effects of oil pollution, but might gain some (indirect) benefits from other concomitant environmental factors, such as reduced predation and reduced parasite load. Our results extend our knowledge of organismal responses to oil pollution and highlight the importance of anthropogenic pollution as a source of environmental variation. They also emphasise the understudied ecological heterogeneity of extreme environments.