Neurotoxicity of Combined Exposure to the Heavy Metals (Pb and As) in Zebrafish (Danio rerio)

Lead (Pb) and arsenic (As) are commonly occurring heavy metals in the environment and produce detrimental impacts on the central nervous system. Although they have both been indicated to exhibit neurotoxic properties, it is not known if they have joint effects, and their mechanisms of action are likewise unknown. In this study, zebrafish were exposed to different concentrations of Pb (40 μg/L, 4 mg/L), As (32 μg/L, 3.2 mg/L) and their combinations (40 μg/L + 32 μg/L, 4 mg/L + 3.2 mg/L) for 30 days. The histopathological analyses showed significant brain damage characterized by glial scar formation and ventricular enlargement in all exposed groups. In addition, either Pb or As staining inhibited the swimming speed of zebrafish, which was enhanced by their high concentrations in a mixture. To elucidate the underlying mechanisms, we examined changes in acetylcholinesterase (AChE) activity, neurotransmitter (dopamine, 5-hydroxytryptamine) levels, HPI axis-related hormone (cortisol and epinephrine) contents and neurodevelopment-related gene expression in zebrafish brain. The observations suggest that combined exposure to Pb and As can cause abnormalities in swimming behavior and ultimately exacerbate neurotoxicity in zebrafish by interfering with the cholinergic system, dopamine and 5-hydroxytryptamine signaling, HPI axis function as well as neuronal development. This study provides an important theoretical basis for the mixed exposure of heavy metals and their toxicity to aquatic organisms.

Prevalence of occupational co-exposure to biomechanical factors and neurotoxic chemicals in French workers

OBJECTIVES

Little is known about occupational co-exposure. The objective was to assess the prevalence of exposure and co-exposure to biomechanical factors and neurotoxic chemicals in French workers in 2017.

METHODS

Data from the French representative survey SUMER 2017 (SUrveillance Médicale des Expositions aux Risques professionnels) were analyzed. A total of 25 118 workers were included. Exposure to 4 biomechanical factors (manual handling of loads, forceful joint exertion, repetitive movements, and hand-arm transmitted vibrations) and 18 neurotoxic chemicals (n-hexane, perchloroethylene, trichloroethylene, etc.) were assessed using a questionnaire during face-to-face interviews with occupational physicians.

RESULTS

Among men, 22.9% were exposed to at least one biomechanical factor and 10.2% were exposed to at least one neurotoxic chemical, mainly single exposures. Among women, 10.8% were exposed to at least one biomechanical factor and 3.1% were exposed to at least one neurotoxic chemical, also mainly single exposures. Occupational co-exposure to biomechanical factors and neurotoxic chemicals was observed among 4.8% of men and 0.7% of women. Workers under 30 yr old, blue-collar workers and those working in small companies were more co-exposed than other workers. In men, the prevalence of co-exposure was higher in the construction sector compared to other economic activities.

DISCUSSION

This study stresses the importance of considering multiple occupational exposures while the current prevention measures are designed to focus on preventing occupational factors individually.

Silica Nanoparticle Size Determines the Mechanisms Underlying the Inhibition of Iron Oxide Nanoparticle Uptake by Daphnia magna

Aquatic environments are complicated systems that contain different types of nanoparticles (NPs). Nevertheless, recent studies of NP toxicity, and especially those that have focused on bioaccumulation have mostly investigated only a single type of NPs. Assessments of the environmental risks of NPs that do not consider co-exposure regimes may lead to inaccurate conclusions and ineffective environmental regulation. Thus, the present study examined the effects of differently sized silica NPs (SiO2 NPs) on the uptake of iron oxide NPs (Fe2O3 NPs) by the zooplankton Daphnia magna. Both SiO2 NPs and Fe2O3 NPs were well dispersed in the experimental medium without significant heteroaggregation. Although all three sizes of SiO2 NPs inhibited the uptake of Fe2O3 NPs, the underlying mechanisms differed. SiO2 NPs smaller than the average mesh size (∼200 nm) of the filtering apparatus of D. magna reduced the accumulation of Fe2O3 NPs through uptake competition, whereas larger SiO2 NPs inhibited the uptake of Fe2O3 NPs mainly by reducing the water filtration rate of the daphnids. Overall, in evaluations of the risks of NPs in the natural environment, the different mechanisms underlying the effects of NPs of different sizes on the uptake of dissimilar NPs should be considered.

In utero exposure to ionizing radiation and metabolic regulation: perspectives for future multi- and trans-generation effects studies

PURPOSE

The radiation protection community has been particularly attentive to the risks of delayed effects on offspring from low dose or low dose-rate exposures to ionizing radiation. Despite this, the current epidemiologic studies and scientific data are still insufficient to provide the necessary evidence for improving risk assessment guidelines. This literature review aims to inform future studies on multigenerational and transgenerational effects. It primarily focuses on animal studies involving in utero exposure and discusses crucial elements for interpreting the results. These elements include in utero exposure scenarios relative to the developmental stages of the embryo/fetus, and the primary biological mechanisms responsible for transmitting heritable or hereditary effects to future generations. The review addresses several issues within the contexts of both multigenerational and transgenerational effects, with a focus on hereditary perspectives.

CONCLUSIONS

Knowledge consolidation in the field of Developmental Origins of Health and Disease (DOHaD) has led us to propose a new study strategy. This strategy aims to address the transgenerational effects of in utero exposure to low dose and low dose-rate radiation. Within this concept, there is a possibility that disruption of epigenetic programming in embryonic and fetal cells may occur. This disruption could lead to metabolic dysfunction, which in turn may cause abnormal responses to future environmental challenges, consequently increasing disease risk. Lastly, we discuss methodological limitations in our studies. These limitations are related to cohort size, follow-up time, model radiosensitivity, and analytical techniques. We propose scientific and analytical strategies for future research in this field.

Polystyrene nanoplastics aggravate reproductive system damage in obese male mice by perturbation of the testis redox homeostasis

The potential impact of the combination of a high-fat diet (HFD) and polystyrene nanoplastics (PS-NPs) on fertility cannot be ignored, especially when the fertility rate is declining. However, it has not attracted considerable attention. In this study, an obese mouse model was established using an HFD, and the reproductive function of male mice was evaluated after intragastric administration of 100 μL of a 10 mg/mL PS-NP suspension for 4 weeks. By determining the morphology and vitality of sperm and related indicators of testosterone production, it was found that PS-NPs aggravated the destruction of sperm mitochondrial structure, decrease sperm activity, and testosterone production in HFD-fed mice. To comprehensively analyze the injury mechanism, the integrity of the blood testicular barrier (BTB) and the function of Leydig and Sertoli cells were further analyzed. It was found that PS-NPs could destroy BTB, promote the degeneration of Leydig cells, reduce the number of Sertoli cells, and decrease lactate secretion in HFD-fed mice. PS-NPs further interfered with redox homeostasis in the testicular tissues of HFD-fed mice. This study found that PS-NPs could aggravate the damage to the reproductive system of obese male mice by further perturbing its redox homeostasis and revealed the potential health risk of PS-NPs exposure under an HFD.

Nicotine Exposure in a Phencyclidine-Induced Mice Model of Schizophrenia: Sex-Selective Medial Prefrontal Cortex Protein Markers of the Combined Insults in Adolescent Mice

Tobacco misuse as a comorbidity of schizophrenia is frequently established during adolescence. However, comorbidity markers are still missing. Here, the method of label-free proteomics was used to identify deregulated proteins in the medial prefrontal cortex (prelimbic and infralimbic) of male and female mice modelled to schizophrenia with a history of nicotine exposure during adolescence. Phencyclidine (PCP), used to model schizophrenia (SCHZ), was combined with an established model of nicotine minipump infusions (NIC). The combined insults led to worse outcomes than each insult separately when considering the absolute number of deregulated proteins and that of exclusively deregulated ones. Partially shared Reactome pathways between sexes and between PCP, NIC and PCPNIC groups indicate functional overlaps. Distinctively, proteins differentially expressed exclusively in PCPNIC mice reveal unique effects associated with the comorbidity model. Interactome maps of these proteins identified sex-selective subnetworks, within which some proteins stood out: for females, peptidyl-prolyl cis-trans isomerase (Fkbp1a) and heat shock 70 kDa protein 1B (Hspa1b), both components of the oxidative stress subnetwork, and gamma-enolase (Eno2), a component of the energy metabolism subnetwork; and for males, amphiphysin (Amph), a component of the synaptic transmission subnetwork. These are proposed to be further investigated and validated as markers of the combined insult during adolescence.

Co-exposure to multiple vitamins and the risk of all-cause mortality in patients with diabetes

Objective

Although the effect of vitamins on the risk of mortality in diabetic patients has been reported, most studies focus on individual vitamins. However, humans are often exposed to multiple vitamins simultaneously in daily life. Therefore, it is worth exploring the effects of co-exposure to multiple vitamins on the risk of mortality in diabetic patients.

Methods

This study included diabetic patients aged ≥20WD years who participated in NHANES from 2003 to 2006. An unsupervised K-means clustering method was used to cluster eight vitamins in serum into several patterns of co-exposure to multiple vitamins, and the Cox proportional hazards model was used to evaluate the impact of different patterns of co-exposure to multiple vitamins on the risk of all-cause mortality in diabetic patients.

Results

Three patterns of co-exposure to multiple vitamins were generated based on K-means clustering, namely, low-level, moderate-level, and high-level. Among the 484 diabetic patients, with a median follow-up of 13.7 years, a total of 211 deaths occurred. After adjusting for covariates, the individual vitamins had varying effects on the risk of all-cause mortality in diabetic patients. Compared to the low-level group of co-exposure to multiple vitamins, the high-level group significantly reduced the risk of all-cause mortality in diabetic patients, with a HR of 0.42 (95% CI: 0.20, 0.87). Subgroup analysis demonstrated that high levels of co-exposure to multiple vitamins significantly reduced the risk of all-cause mortality in males, individuals aged ≥ 60 years, and non-Hispanic White people with diabetes compared to the low-level group, with HR of 0.42 (95% CI: 0.18, 0.98), 0.53 (95% CI: 0.26, 0.98), and 0.26 (95% CI: 0.12, 0.58) respectively.

Conclusion

While individual vitamins had different effects on the risk of all-cause mortality in patients with diabetes, high-level co-exposure to multiple vitamins significantly reduced the risk of all-cause mortality in patients with diabetes, with differences observed among genders, ages, and race. This suggests that when developing vitamin intervention strategies for patients with diabetes, consideration should be given not only to the dosage of individual vitamins but also to the variations between different population groups.

Independent and Combined Associations of Blood Manganese, Cadmium and Lead Exposures with the Systemic Immune-Inflammation Index in Adults

Manganese (Mn), cadmium (Cd) and lead (Pb) have toxic effects on the immune system. However, their independent and combined effects on immune-inflammation responses are unclear. In recent years, the systemic immune-inflammation index (SII) has been developed as an integrated and novel inflammatory indicator. A retrospective cross-sectional study of 2174 adults ≥20 years old from the National Health and Nutrition Examination Survey (NHANES) 2015-2016 was conducted. Generalized linear models were used to evaluate the independent and combined associations of SII with blood Mn, Cd and Pb levels. As continuous variables, both blood Cd and Mn showed dose-dependent relationships with the SII before and after adjusting for all potential confounding factors. Metal concentrations were then converted into categorical variables. Compared with the adults in the lowest Cd or Mn tertile, those in the highest tertile had higher risks of elevated SII. Furthermore, co-exposure to Mn and Cd also showed a positive relationship with the SII after adjusting for all confounding factors. However, the single effect of Pb exposure and the joint effect of Pb and other metal exposures on the SII were not observed. This study provides important epidemiological evidence of the associations of SII with single and co-exposure effects of blood Mn, Cd, and Pb.

Developmental deficits in male rat pups caused by maternal and dietary administration of chlorpyriphos and cypermethrin: Melatonin's mitigating effect

The ability of melatonin to reduce growth dynamics induced by parental and nutritional combination administration to chlorpyriphos (Ch) and cypermethrin (Cy) was examined in male albino rats. Oral alimentation was given to gravid dams divided into six groups (n = 10; age: 12 weeks) from the first day of pregnancy to the 21st postnatal day. Distilled water (D_W), Soya oil (SYO) and melatonin (MeL) groups were exposed to 2 mL/kg, 2 mL/kg and 0.5 g/kg, respectively; the Ch + Cy group was co-exposed to Ch (1.9 mg/kg of LD50) and Cy (7.5 g/kg of LD50); the MChCy group was preconditioned with MeL (0.5 mg/kg), followed by co-exposure to Ch and Cy; and the ChCyM group was exposed to Ch and Cy and curated with MeL. Male offspring rats were tested for ontogeny criteria at various points after accouchement. MeL pre- and post-administration reduced the variation in litter size and weight, number of live/dead pups, anogenital distance crown-rump length timing of eye and ear openings, and testicular descent caused by fetal and nutritional co-administration to Ch + Cy in offspring male albino rats. As a result of MeL's apparent antioxidative capability, it demonstrated preventative and therapeutic promise.

Association of serum water-soluble vitamin exposures with the risk of metabolic syndrome: results from NHANES 2003-2006

Introduction

Existing evidence suggests an association between certain vitamins and metabolic syndrome (MetS), but few epidemiological studies have focused on the effects of multivitamin co-exposure on MetS. This study aims to investigate the associations of the individual or multiple water-soluble vitamins (i.e., vitamin C (VC), vitamin B9 (VB9), and vitamin B12 (VB12)) with co-exposure to MetS, as well as the dose-response relationships among them.

Methods

A cross-sectional study was conducted by employing the National Health and Examination Surveys (NHANESs) 2003-2006. Multivariate-adjusted logistic regression models were used to explore the association between individual serum water-soluble vitamins and the risk of MetS and its components, including waist circumference, triglyceride, high-density lipoprotein, blood pressure, and fasting plasma glucose. Restricted cubic splines were performed to explore the dose-response relationships among them. The quantile g-computation method was adopted to explore the associations of multiple water-soluble vitamins co-exposure with MetS risk and MetS components.

Results

A total of 8983 subjects were involved in the study, of whom 1443 were diagnosed with MetS. The MetS groups had a higher proportion of participants with age ≥60 years, BMI ≥30 kg/m², and insufficient physical activity. Compared with the lowest quartile, the third (OR=0.67, 95% CI: 0.48, 0.94) and highest quartiles (OR=0.52, 95%CI: 0.35, 0.76) of VC were associated with lower MetS risk. Restricted cubic splines showed negative dose-response relationships among VC, VB9 and VB12, and MetS. Regarding MetS components, higher VC quartiles were associated with lower waist circumference, triglyceride, blood pressure, and fasting plasma glucose, while higher VC and VB9 quartiles were associated with higher high-density lipoprotein (HDL). Co-exposure to VC, VB9, and VB12 was significantly inversely associated with MetS, with ORs (95% CI) of 0.81 (0.74, 0.89) and 0.84 (0.78, 0.90) in the conditional and marginal structural models, respectively. Furthermore, we found that VC, VB9, and VB12 co-exposure were negatively associated with waist circumference and blood pressure, while VC, VB9, and VB12 co-exposure were positively associated with HDL.

Conclusion

This study revealed negative associations of VC, VB9, and VB12 with MetS, while the high water-soluble vitamin co-exposure was associated with a lower MetS risk.

Selenium Biofortification Enhanced Grain Yield and Alleviated the Risk of Arsenic and Cadmium Toxicity in Rice for Human Consumption

Arsenic (As) and Cadmium (Cd) are toxic to rice plants. However, selenium (Se) has the potential to regulate As and Cd toxicity. The present study aimed to evaluate the co-exposure to As⁵⁺ and Se⁶⁺ species in two rice cultivars, BRS Pampa and EPAGRI 108. The plants were divided into six groups and cultivated until complete maturation of the grains, under greenhouse conditions. Regarding total As and inorganic As (i-As) accumulation in grains, the highest concentrations were found for BRS Pampa. For Se, EPAGRI 108 presented the highest concentration of inorganic and organic Se (i-Se and o-Se). The exposure assessments showed that Se biofortification can mitigate the As accumulation in rice and, consequently, the risk of As and Cd toxicity in grains for human consumption. The combined effect of As and Se in rice plants could represent an alternative to biofortify this food in a safe way and with a higher percentage of bioavailable Se. Although Se is able to mitigate As toxicity in rice plants, in the present study we showed that co-exposure in different cultivars under the same growing conditions may present different responses to As and Se exposure.

Impact of Enniatin and Deoxynivalenol Co-Occurrence on Plant, Microbial, Insect, Animal and Human Systems: Current Knowledge and Future Perspectives

Fusarium mycotoxins commonly contaminate agricultural products resulting in a serious threat to both animal and human health. The co-occurrence of different mycotoxins in the same cereal field is very common, so the risks as well as the functional and ecological effects of mycotoxins cannot always be predicted by focusing only on the effect of the single contaminants. Enniatins (ENNs) are among the most frequently detected emerging mycotoxins, while deoxynivalenol (DON) is probably the most common contaminant of cereal grains worldwide. The purpose of this review is to provide an overview of the simultaneous exposure to these mycotoxins, with emphasis on the combined effects in multiple organisms. Our literature analysis shows that just a few studies on ENN-DON toxicity are available, suggesting the complexity of mycotoxin interactions, which include synergistic, antagonistic, and additive effects. Both ENNs and DON modulate drug efflux transporters, therefore this specific ability deserves to be explored to better understand their complex biological role. Additionally, future studies should investigate the interaction mechanisms of mycotoxin co-occurrence on different model organisms, using concentrations closer to real exposures.

In silico assessment of mixture toxicity mechanisms involved in the pathogenesis of thyroid diseases: the combination of toxic metal(oid)s and decabrominated diphenyl ether

The current study aimed to assess the connection between the mixture of lead (Pb), cadmium (Cd), arsenic (As), methylmercury (MeHg) and decabrominated diphenyl ether (decaBDE) and thyroid function, by using in silico toxicogenomic data-mining approach. To obtain the linkage between investigated toxic mixture and thyroid diseases (TDs), the Comparative Toxicogenomics Database (CTD) was used, while gene ontology (GO) enrichment analysis was performed by ToppGeneSuite portal. The analysis has shown 10 genes connected to all chemicals present in the mixture and TDs (CAT, GSR, IFNG, IL1B, IL4, IL6, MAPK1, SOD2, TGFB1, TNF), most of which were in co-expression (45.68%), or belonged to the same pathway (30.47%). Top 5 biological processes and molecular functions affected by the investigated mixture emphasized the role of two common mechanisms - oxidative stress and inflammation. Cytokines and inflammatory response was listed as the main molecular pathway that may be triggered by simultaneous exposure to toxic metal(oid)s and decaBDE and connected to TDs. The direct relations between Pb/decaBDE and redox status impairment in thyroid tissue was confirmed by our chemical-phenotype interaction analysis, while the strongest linkage between Pb, As and decaBDE and thyroid disorders was found. The obtained results provide better understanding of molecular mechanisms involved in the thyrotoxicity of the investigated mixture, and can be used to direct further research.

Impact of Deoxynivalenol and Zearalenone as Single and Combined Treatment on DNA, Cell Cycle and Cell Proliferation in HepG2 Cells

The study aimed to investigate toxicity and the mechanism of toxicity of two Fusarium mycotoxins, deoxynivalenol (DON) and zearalenone (ZEA). DON and ZEA were applied to HepG2 cells as single compounds and in combination at low environmentally relevant concentrations. HepG2 cells were exposed to DON (0.5, 1, and 2 µM), ZEA (5, 10, and 20 µM) or their combinations (1 µM DON + 5 µM ZEA, 1 µM DON + 10 µM ZEA and 1 µM DON + 20 µM ZEA) for 24 h and cell viability, DNA damage, cell cycle and proliferation were assessed. Both mycotoxins reduced cell viability, however, combined treatment with DON and ZEA resulted in higher reduction of cell viability. DON (1 µM) induced primary DNA damage, while DON (1 µM) in combination with higher ZEA concentrations showed antagonistic effects compared to DON alone at 1 µM. DON arrested HepG2 cells in G2 phase and significantly inhibited cell proliferation, while ZEA had no significant effect on cell cycle. The combined treatment with DON and ZEA arrested cells in G2 phase to a higher extend compared to treatment with single mycotoxins. Potentiating effect observed after DON and ZEA co-exposure at environmentally relevant concentrations indicates that in risk assessment and setting governments' regulations, mixtures of mycotoxins should be considered.

Aerosol physicochemical determinants of carbon black and ozone inhalation co-exposure induced pulmonary toxicity

Air pollution accounts for more than 7 million premature deaths worldwide. Using ultrafine carbon black (CB) and ozone (O3) as a model for an environmental co-exposure scenario, the dose response relationships in acute pulmonary injury and inflammation were determined by generating, characterizing, and comparing stable concentrations of CB aerosols (2.5, 5.0, 10.0 mg/m3), O3 (0.5, 1.0, 2.0 ppm) with mixture CB + O3 (2.5 + 0.5, 5.0 + 1.0, 10.0 + 2.0). C57BL6 male mice were exposed for 3 h by whole body inhalation and acute toxicity determined after 24 h. CB itself did not cause any alteration, however, a dose response in pulmonary injury/inflammation was observed with O3 and CB + O3. This increase in response with mixtures was not dependent on the uptake but was due to enhanced reactivity of the particles. Benchmark dose modeling showed several-fold increase in potency with CB + O3 compared with CB or O3 alone. Principal component analysis provided insight into response relationships between various doses and treatments. There was a significant correlation in lung responses with charge-based size distribution, total/alveolar deposition, oxidant generation, and antioxidant depletion potential. Lung tissue gene/protein response demonstrated distinct patterns that are better predicted by either particle dose/aerosol responses (interleukin-1β, keratinocyte chemoattractant, transforming growth factor beta) or particle reactivity (thymic stromal lymphopoietin, interleukin-13, interleukin-6). Hierarchical clustering showed a distinct signature with high dose and a similarity in mRNA expression pattern of low and medium doses of CB + O3. In conclusion, we demonstrate that the biological outcomes from CB + O3 co-exposure are significantly greater than individual exposures over a range of aerosol concentrations and aerosol characteristics can predict biological outcome.

Co-exposures to physical and psychosocial work factors increase the occurrence of workplace injuries among French care workers

Objective

The aim of this study was to analyze the effect of co-exposures to physical and psychosocial factors (PSF) regarding the incidence of workplace injuries (WI) among care workers. Additional objective was to identify the work factors associated with the co-exposure combinations leading to the highest rates of WI.

Methods

The study sample consisted of 4,418 care workers participating to the French Working Conditions Survey both in 2013 and 2016. WI were assessed during the 4-year follow-up by matching the databases of the National Health Insurance Funds' compensation system. We assessed exposure for physical factors and PSF using factorial analyses and hierarchical clustering. We implemented a Poisson regression model with the WI incidence as the outcome and the clusters as independent variables of interest. Logistic regression model allowed identifying the work factors that predicted co-exposure combinations with a WI rate > 40%.

Results

WI were highly related to both physical and psychosocial exposures. With low exposure to one or the other, there was no increased risk of WI. Physical factors and PSF potentiated each other and their co-exposure significantly increased the risk of WI, with model predicted rates per 1,000 persons-year for those most exposed to physical risk of 14.6 [4.5-24.8] with low PSF and 38.0 [29.8-46.3] with high PSF. Work factors that predicted co-exposure combinations with a rate > 40 WI% were: working as nursing assistant or hospital services officer, lack of predictability and flexibility of schedules, overtime, controlled schedules, work-family imbalance and insufficient preventive measures.

Conclusions

Our findings highlight the need to take into account psychosocial factors in addition of only considering physical factors when analyzing WI occurrence, as usually done. Prevention actions must be taken to reduce both physical and psychosocial exposure. These results provide keys points for the prevention of WI among care workers.

Association between environmental chemicals co-exposure and peripheral blood immune-inflammatory indicators

Chronic inflammation is closely related to chronic inflammatory diseases, autoimmune diseases and cancer. Few studies have evaluated the effects of exposure to multiple chemical combinations on immunoinflammatory related indicators and their possible molecular mechanisms. This study explored the effect of exposure to various chemicals on immune-inflammatory biomarkers and its molecular mechanism. Using data from 1,723 participants in the National Health and Nutrition Examination Survey (NHANES, 2011-2012), the aim was to determine the association between chemical mixtures and immunoinflammatory biomarkers [including White blood cell (Wbc), neutrophil (Neu), lymphocytes (Lym), and Neutrophil-to-lymphocyte ratio (NLR)] using linear regression model, weighted quantile sum regression (WQSR) model, and bayesian nuclear machine regression (BKMR) model. Meanwhile, functional enrichment analysis and protein-protein interaction network establishment were performed to explore the molecular mechanism of inflammation induced by high-weight chemicals. In the linear regression model established for each single chemical, the four immunoinflammatory biomarkers were positively correlated with polycyclic aromatic hydrocarbons (PAHs), negatively correlated with perfluoroalkyl substances (PFASs), and positively or negatively correlated with metallic and non-metallic elements. WQSR model showed that cadmium (Cd), perfluorooctane sulfonic acid (PFOS) and perfluorodecanoic acid (PFDE) had the highest weights. In BKMR analysis, the overall effect of chemical mixtures was significantly associated with Lym and showed an increasing trend. The hub genes in high-weight chemicals inflammation-related genes were interleukin-6 (IL6), tumor necrosis factor (TNF), and interleukin-1B (IL1B), etc. They were mainly enriched in inflammatory response, Cytokine-cytokine receptor interaction, Th17 cell differentiation and IL-17 signaling pathway. The above results show that exposure to environmental chemical cocktails primarily promotes an increase in Lym across the immune-inflammatory spectrum. The mechanism leading to the inflammatory response may be related to the activation of IL-6 amplifier by the co-exposure of environmental chemicals.

Individual and Combined Effect of Bisphenol A and Bisphenol AF on Prostate Cell Proliferation through NF-κB Signaling Pathway

The ubiquitous environmental endocrine disruptor bisphenol A (BPA) can induce prostatic dysfunction. However, to date, studies have focused little on the perturbations of prostate health initiated by the BPA derivative bisphenol AF (BPAF) and co-exposure to bisphenol compounds. An in vivo study orally administrated male rats with BPA (10, 90 μg/kg), BPAF (10, 90 μg/kg) and the inhibitor of nuclear transcription factor-κB (NF-κB), pyrrolidinedithiocarbamate (PDTC, 100 mg/kg). Based on the anatomical analysis, pathological observations and PCNA over-expression, we considered that low-dose BPA and BPAF facilitated ventral prostatic hyperplasia in rats. The results of IHC and ELISA mirrored the regulation of NF-κB p65, COX-2, TNF-α and EGFR in BPA- and BPAF-induced prostatic toxicity. An in vitro study found that the additive effect of combined exposure to BPA (10 nM) and BPAF (10 nM) could cause an elevation in the proliferation of and a reduction in the apoptosis level of human prostate stromal cells (WPMY-1) and fibroblasts (HPrF). Meanwhile, the underlying biomarkers of the NF-κB signaling pathway also involved the abnormal proliferative progression of prostate cells. The findings recapitulated the induction of BPAF exposure and co-treatment with BPA and BPAF on prostatic hyperplasia and emphasized the modulation of the NF-κB signaling pathway.

Adverse Effects of Co-Exposure to Cd and Microplastic in Tigriopus japonicus

There is increasing concern about the adverse impact of exposure to microplastic, as an emerging pollutant, on wild organisms, and particularly on organisms co-exposed to microplastic and other environmental contaminants. It has been widely reported that the combination of microplastics and heavy metals showed obvious toxicity to organisms in terms their growth and development. The present study was performed to determine the impact of binary metal mixtures of cadmium (Cd) and polystyrene microplastic (PS-microplastic) on Tigriopus japonicus, a typical marine model organism, using a titration design. Increasing concentrations of PS-microplastic (2 μg/L, 20 μg/L, and 200 μg/L) were titrated against a constant concentration of Cd (15.2 μg/L). The results showed no significant impact of exposure to this dose of Cd or co-exposure to Cd and the lowest dose of PS-microplastic examined (2 μg/L). However, the feeding rate, filtration rate, oxygen consumption rate, and hatching number declined significantly in T. japonicus co-exposed to Cd and higher concentrations of PS-microplastic (20 μg/L and 200 μg/L) (p < 0.05). Furthermore, the development of F1 larvae from nauplius stage (N) to adult stage (A) was markedly delayed when co-exposed to Cd and higher doses of PS-microplastic (20 and 200 μg/L), and the effects persisted to the F2 larval stage. Interestingly, the present titration design did not affect the sex ratio or number of oocysts in either the F1 or F2 generation. These results indicated that the current marine environmental concentrations of Cd and microplastic are safe for wild organisms. Further studies are required to address the knowledge gap regarding toxicological effects at the cellular and molecular levels.

Prenatal Co-Exposure to Manganese, Mercury, and Lead, and Neurodevelopment in Children during the First Year of Life

Lead (Pb), mercury (Hg), and manganese (Mn) are neurotoxic, but little is known about the neurodevelopmental effects associated with simultaneous prenatal exposure to these metals. We aimed to study the associations of Pb, Hg, and Mn prenatal levels (jointly and separately) with neurodevelopment in the first year of life. Methods: Pb, Hg, and Mn blood lead levels were measured in 253 pregnant women. Their offspring's neurodevelopment was assessed through the Bayley Scale of Infant Development III^® at one, three, six, and twelve months. The metals' mean blood levels (µg/L) were Pb = 11.2, Hg = 2.1, and Mn = 10.2. Mean language, cognitive, and motor development scores of the infants at each age were between low-average and average. Multilevel models' results showed that language development coefficients of the offspring decreased by 1.5 points per 1 µg/dL increase in maternal blood lead levels (p = 0.002); the magnitude of the aforementioned association increased in children with maternal blood Mn < 9.6 µg/L (ß = -1.9, p = 0.003) or Hg > 1.9 µg/L (ß = -1.6, p = 0.013). Cognitive and motor development had negative associations with maternal blood Pb levels; the latter was statistically significant when the interaction term between Pb, Mn, and Hg was included (ß = -0.037, p = 0.03). Prenatal exposure to low Pb levels may impair infants' neurodevelopment in the first year of life, even more so if they are exposed to Hg or deficient in Mn.

Maternal Passive Smoking, Vitamin D Deficiency and Risk of Spontaneous Abortion

Background: Maternal passive smoking and vitamin D deficiency might elevate risk of spontaneous abortion. The study aimed to investigate the association of co-exposure to passive smoking and vitamin D deficiency with the risk of spontaneous abortion. Methods: A population-based case-control study was performed among non-smoking women in Henan Province, China, with 293 spontaneous abortion cases and 496 liveborn controls with term, normal birthweight. Results: Compared to women without exposure to passive smoking nor vitamin D deficiency, women with deficient vitamin D alone and women with exposure to passive smoking alone had increased risk of spontaneous abortion (OR = 1.76, 95%CI: 1.08~2.89; OR = 1.73, 95%CI: 1.11~2.69, respectively). The risk of spontaneous abortion was even higher for those with co-exposure to passive smoking and vitamin D deficiency (OR = 2.50, 95%CI: 1.63~3.84). A dose-response relationship was found of an incremental risk of spontaneous abortion with rising numbers of exposures to passive smoking and vitamin D deficiency (p < 0.001). Conclusion: Co-exposure to passive smoking and vitamin D deficiency was associated with an elevated risk of spontaneous abortion, and the risk of spontaneous abortion rose with rising numbers of exposures. Intervention programs need to specifically target the vulnerable groups of pregnant women with both malnutrition and unfavorable environmental exposure.

Occupational Exposure to Hexavalent Chromium, Nickel and PAHs: A Mixtures Risk Assessment Approach Based on Literature Exposure Data from European Countries

Hexavalent chromium (Cr(VI)), nickel (Ni) and polycyclic aromatic hydrocarbons (PAHs) are genotoxic co-occurring lung carcinogens whose occupational health risk is still understudied. This study, conducted within the European Human Biomonitoring Initiative (HBM4EU), aimed at performing a mixtures risk assessment (MRA) based on published human biomonitoring (HBM) data from Cr(VI), Ni and/or PAHs occupational co-exposure in Europe. After data extraction, Risk Quotient (RQ) and Sum of Risk Quotients (SRQ) were calculated for binary and ternary mixtures to characterise the risk. Most selected articles measured urinary levels of Cr and Ni and a SRQ > 1 was obtained for co-exposure levels in welding activities, showing that there is concern regarding co-exposure to these substances. Similarly, co-exposure to mixtures of Cr(VI), Ni and PAHs in waste incineration settings resulted in SRQ > 1. In some studies, a low risk was estimated based on the single substances’ exposure level (RQ < 1), but the mixture was considered of concern (SRQ > 1), highlighting the relevance of considering exposure to the mixture rather than to its single components. Overall, this study points out the need of using a MRA based on HBM data as a more realistic approach to assess and manage the risk at the workplace, in order to protect workers’ health.

Cocktails of Mycotoxins, Phytoestrogens, and Other Secondary Metabolites in Diets of Dairy Cows in Austria: Inferences from Diet Composition and Geo-Climatic Factors

Dairy production is a pivotal economic sector of Austrian and European agriculture. Dietary toxins and endocrine disruptors of natural origin such as mycotoxins and phytoestrogens can affect animal health, reproduction, and productivity. This study characterized the profile of a wide spectrum of fungal, plant, and unspecific secondary metabolites, including regulated, emerging, and modified mycotoxins, phytoestrogens, and cyanogenic glucosides, in complete diets of lactating cows from 100 Austrian dairy farms. To achieve this, a validated multi-metabolite liquid chromatography/electrospray ionization−tandem mass spectrometric (LC/ESI−MS/MS) method was employed, detecting 155 of >800 tested metabolites. Additionally, the most influential dietary and geo-climatic factors related to the dietary mycotoxin contamination of Austrian dairy cattle were recognized. We evidenced that the diets of Austrian dairy cows presented ubiquitous contamination with mixtures of mycotoxins and phytoestrogens. Metabolites derived from Fusarium spp. presented the highest concentrations, were the most recurrent, and had the highest diversity among the detected fungal compounds. Zearalenone, deoxynivalenol, and fumonisin B1 were the most frequently occurring mycotoxins considered in the EU legislation, with detection frequencies >70%. Among the investigated dietary factors, inclusion of maize silage (MS) and straw in the diets was the most influential factor in contamination with Fusarium-derived and other fungal toxins and metabolites, and temperature was the most influential among the geo-climatic factors.

In Vitro Hepatotoxic and Neurotoxic Effects of Titanium and Cerium Dioxide Nanoparticles, Arsenic and Mercury Co-Exposure

Considering the increasing emergence of new contaminants, such as nanomaterials, mixing with legacy contaminants, including metal(loid)s, it becomes imperative to understand the toxic profile resulting from these interactions. This work aimed at assessing and comparing the individual and combined hepatotoxic and neurotoxic potential of titanium dioxide nanoparticles (TiO₂NPs 0.75–75 mg/L), cerium oxide nanoparticles (CeO₂NPs 0.075–10 μg/L), arsenic (As 0.01–2.5 mg/L), and mercury (Hg 0.5–100 mg/L) on human hepatoma (HepG2) and neuroblastoma (SH-SY5Y) cells. Viability was assessed through WST-1 (24 h) and clonogenic (7 days) assays and it was affected in a dose-, time- and cell-dependent manner. Higher concentrations caused greater toxicity, while prolonged exposure caused inhibition of cell proliferation, even at low concentrations, for both cell lines. Cell cycle progression, explored by flow cytometry 24 h post-exposure, revealed that TiO₂NPs, As and Hg but not CeO₂NPs, changed the profiles of SH-SY5Y and HepG2 cells in a dose-dependent manner, and that the cell cycle was, overall, more affected by exposure to mixtures. Exposure to binary mixtures revealed either potentiation or antagonistic effects depending on the composition, cell type and time of exposure. These findings prove that joint toxicity of contaminants cannot be disregarded and must be further explored.

Identification and distribution of pathogens coinfecting with Brucella spp., Coxiella burnetii and Rift Valley fever virus in humans, livestock and wildlife

Zoonotic diseases, such as brucellosis, Q fever and Rift Valley fever (RVF) caused by Brucella spp., Coxiella burnetii and RVF virus, respectively, can have devastating effects on human, livestock, and wildlife health and cause economic hardship due to morbidity and mortality in livestock. Coinfection with multiple pathogens can lead to more severe disease outcomes and altered transmission dynamics. These three pathogens can alter host immune responses likely leading to increased morbidity, mortality and pathogen transmission during coinfection. Developing countries, such as those commonly afflicted by outbreaks of brucellosis, Q fever and RVF, have high disease burden and thus common coinfections. A literature survey provided information on case reports and studies investigating coinfections involving the three focal diseases. Fifty five studies were collected demonstrating coinfections of Brucella spp., C. burnetii or RVFV with 50 different pathogens, of which 64% were zoonotic. While the literature search criteria involved ‘coinfection’, only 24/55 studies showed coinfections with direct pathogen detection methods (microbiology, PCR and antigen test), while the rest only reported detection of antibodies against multiple pathogens, which only indicate a history of co‐exposure, not concurrent infection. These studies lack the ability to test whether coinfection leads to changes in morbidity, mortality or transmission dynamics. We describe considerations and methods for identifying ongoing coinfections to address this critical blind spot in disease risk management.

Heavy metals exposure is associated with early liver dysfunction among rural residents aged 40-75 years in southwest China

Heavy metals exposure has been associated with liver dysfunction in recent reports, while the hepatoxicity of lead (Pb) and cadmium (Cd) has been well established. However, the combined effects of multi-metal in real-world scenario on liver dysfunction are still unclear. This cross-sectional study examined associations between 10 biomarkers of early liver injury and multiple heavy metals levels. The levels of heavy metals/metalloid (magnesium [Mg], calcium [Ca], iron [Fe], zinc [Zn], arsenic [As], Cd, copper [Cu], and Pb) were measured in blood and urinary sample collected from 725 participants in a Cd-polluted area and an unpolluted area in southwest China. The early liver dysfunction biomarkers included the liver enzymes (ALT, ALP, AST, and GGT), proteins (TP, ALB, and GLO), and bilirubin (TBIL, DBIL, and IBIL). Confounder-adjusted beta coefficients were determined using multiple linear regression model analysis for the group-classified and gender-classified samples. Our results showed that blood Fe, Cd, and Cu levels were found to be positively related to elevated ALT levels and blood Cu was positively associated with AST levels in the Cd-polluted area, while the highest blood Zn quartile in the polluted area and blood Mg quartile in the unpolluted area were associated with lower ALT levels. Our finding implies that industrial pollution results in heavy metals of Cd and Pb exposure and effects of Fe, Cd, Cu, and Pb in the Cd-polluted area may be the main contributors to increase the risk of liver dysfunction while Zn in the Cd-polluted area and Mg in the unpolluted area may be the protective factors.

Effects of Co-Exposure of Nanoparticles and Metals on Different Organisms: A Review

Wide nanotechnology applications and the commercialization of consumer products containing engineered nanomaterials (ENMs) have increased the release of nanoparticles (NPs) to the environment. Titanium dioxide, aluminum oxide, zinc oxide, and silica NPs are widely implicated NPs in industrial, medicinal, and food products. Different types of pollutants usually co-exist in the environment. Heavy metals (HMs) are widely distributed pollutants that could potentially co-occur with NPs in the environment. Similar to what occurs with NPs, HMs accumulation in the environment results from anthropogenic activities, in addition to some natural sources. These pollutants remain in the environment for long periods and have an impact on several organisms through different routes of exposure in soil, water, and air. The impact on complex systems results from the interactions between NPs and HMs and the organisms. This review describes the outcomes of simultaneous exposure to the most commonly found ENMs and HMs, particularly on soil and aquatic organisms.

Co-occurrence of Conazole Fungicide Residues in Raw Agricultural Commodities Sampled by the United States Department of Agriculture Pesticide Data Program

In this study, the residue data for conazole fungicides were collated and analyzed in all crop samples reported by the United States Department of Agriculture Pesticide Data Program over the period of 2009-2019. Considering all individual samples, the overall detection frequencies (DFs) of conazoles are less than 13%. Among the 18 conazoles, imazalil had the highest overall DF of 6%, followed by tebuconazole and myclobutanil, with 4% each. Conazoles were detected most frequently in raisins with 28% DF, followed by cherries (frozen and fresh) and grapes, with 12, 10, and 10%, respectively. The presence of multiple conazoles in single commodity samples is very low, below 2%. The analyses found no more than four conazoles present in any given sample. Out of the 18 conazoles, 8 of them were not detected in more than 99.9% of the commodity samples from 2009 to 2019 and, therefore, can be eliminated from screening-level cumulative risk assessment for dietary contributions from food items. While conazoles are widely used on food commodities, co-occurrence of conazole residues was observed only in a very limited number of food commodities, including raisins, grapes, cherries (frozen), nectarines, and peaches. Considering the remaining individual food commodities, the co-occurrence of conazole residues in single commodity samples is very low or not even present.

The Effects of Mixed Fusarium Mycotoxins at EU-Permitted Feed Levels on Weaned Piglets' Tissue Lipids

At exactly the individual permitted EU-tolerance dietary limits, fumonisins (FB: 5 mg/kg diet) and mixed fusariotoxins (DZ: 0.9 mg deoxynivalenol + 0.1 mg zearalenone/kg diet, and FDZ: 5 mg fumonisins + 0.9 mg deoxynivalenol + 0.1 mg zearalenone/kg diet) were administered to piglets (n = 6/group) for three weeks. Bodyweights of intoxicated piglets increased, while feed conversion ratios decreased. In FDZ, both the absolute and relative weight of the liver decreased. In the renal-cellular membrane, the most pronounced alterations were in FDZ treatment, followed by individual FB exposure. In both treatments, high proportions of C20:0 and C22:0 with low fatty acid (FA) unsaturation were found. In hepatocyte phospholipids, FDZ toxins exerted antagonistic interactions, and FB had the strongest increasing effect on FA monounsaturation. Among all investigated organs, the spleen lipids were the least responsive, in which FDZ expressed synergistic reactions on C20:0 (↑ FDZ vs. FB) and C22:0 (↓ FDZ vs. DZ). The antioxidant defense of the kidney was depleted (↓ glutathione concentration by FB-exposure). Blood plasma indicated renal injury (profound increase of urea and creatinine in FB vs. DZ and FDZ). FB strongly increased total-cholesterol and low density lipoprotein concentrations, whereas FDZ synergistically increased gamma-glutamyltransferase, alkaline-phosphatase, calcium and phosphorus levels. Summarized, individual and combined multiple fusariotoxins modified the membrane lipid profile and antioxidant defense of splanchnic organs, and serum biochemicals, without retarding growth in piglets.

In Vitro Evaluation of the Individual and Combined Cytotoxic and Estrogenic Effects of Zearalenone, Its Reduced Metabolites, Alternariol, and Genistein

Mycotoxins are toxic metabolites of filamentous fungi. Previous studies demonstrated the co-occurrence of Fusarium and Alternaria toxins, including zearalenone (ZEN), ZEN metabolites, and alternariol (AOH). These xenoestrogenic mycotoxins appear in soy-based meals and dietary supplements, resulting in the co-exposure to ZEN and AOH with the phytoestrogen genistein (GEN). In this study, the cytotoxic and estrogenic effects of ZEN, reduced ZEN metabolites, AOH, and GEN are examined to evaluate their individual and combined impacts. Our results demonstrate that reduced ZEN metabolites, AOH, and GEN can aggravate ZEN-induced toxicity; in addition, the compounds tested exerted mostly synergism or additive combined effects regarding cytotoxicity and/or estrogenicity. Therefore, these observations underline the importance and the considerable risk of mycotoxin co-exposure and the combined effects of mycoestrogens with phytoestrogens.

Potential Environmental Health Risk Analysis of Neonicotinoids and a Synergist

The extensive use of neonicotinoid pesticides has led to their widespread presence in the environment, resulting in considerable safety risks to the ecosystem and human health. In this study, we investigated the biotransformation behavior of a cocktail of multiple neonicotinoids and piperonyl butoxide (PBO) synergist in vivo and their potential environmental health risk. It was found that neonicotinoids with a cyano group, such as acetamiprid and thiacloprid, tended to accumulate in liver and spleen tissues, while others with nitro groups (imidacloprid, thiamethoxam, clothianidin, dinotefuran, and nitenpyram) were mostly excreted in urine. In the presence of the synergist PBO, the metabolism of neonicotinoids in vivo changed, mainly through the nitro reduction pathway, while a low abundance of related metabolites was observed in the conventional hydroxylation and demethylation metabolic pathways, due to inhibition of CYP450 enzymes by the synergist. Furthermore, DNA methylation damage in vivo was exacerbated by the induction of hydroxylamine metabolites formed in the intermediate process of neonicotinoid metabolism with the synergistic effect of PBO, which resulted in a higher level of the O⁶-methyldeoxyguanosine (O⁶-medG) biomarker in the liver. Therefore, during the comprehensive evaluation of pesticide environmental risks, attention should be paid not only to the co-exposure mode under real environmental conditions but also to the potential risks of intermediate metabolism and related intermediate metabolites. This study provides a referential strategy and theoretical support for the health risk assessment of co-exposure of chemicals.

Acute Toxicity and DNA Instability Induced by Exposure to Low Doses of Triclosan and Phthalate DEHP, and Their Combinations, in vitro

Triclosan (TCS) is an antimicrobial agent widely used in personal care products (PCP) and the di-(2-ethyl hydroxy-phthalate) (DEHP) is a chemical compound derived from phthalic acid, used in medical devices and plastic products with polyvinyl chloride (PVCs). As result of their extensive use, TCS and DEHP have been found in the environment and previous studies demonstrated the association between their exposure and toxic effects, mostly in aquatic organisms, but there is a shortage in the literature concerning the exposure of TCS and DEHP in human cells. The aim of the present study was to assess the impact of exposure to TCS and DEHP, as well as their combinations, on biomarkers related to acute toxicity and DNA instability, in HepG2 cells, by use of cytokinesis-block micronucleus cytome (CBMNCyt) assay. For that, the cultures were exposed to TCS, DEHP and combinations at doses of 0.10, 1.0, and 10 μM for the period of 4 h and the parameters related to DNA damage (i.e., frequencies of micronuclei (MN) and nuclear buds (NBUDs), to cell division (i.e., nuclear division index (NDI) and nuclear division cytotoxic index (NDCI) and to cell death (apoptotic and necrotic cells) were scored. Clear mutagenic effects were seen in cells treated with TCS, DEHP at doses of 1.0 and 10 μM, but no combined effects were observed when the cells were exposed to the combinations of TCS + DEHP. On the other hand, the combination of the toxicants significantly increased the frequencies of apoptotic and necrotic cells, as well as induced alterations of biomarkers related to cell viability (NDI and NDCI), when compared to the groups treated only with TCS or DEHP. Taken together, the results showed that TCS and DEHP are also able to induce acute toxicity and DNA damage in human cells.

Polystyrene Nanoplastics Can Alter the Toxicological Effects of Simvastatin on Danio rerio

Once in the environment, nanoplastics (NPls) may interact with other contaminants, such as pharmaceuticals, potentially acting as carriers and modulating their toxicity. Thus, the main aim of the current study is to investigate how polystyrene (PS) NPls (mean diameter: 60 nm) interact with simvastatin (SIM), an anticholesterolemic drug, and modulate its toxicity to zebrafish (Danio rerio) embryos. PS NPls were carboxyl group functionalized, to promote the interaction/binding of NPls with SIM (worst-case scenarios) and it was fluorescently dyed, allowing to detect the intake. Exposure was 96 h to 0–150 mg/L NPls or 0–150 µg/L SIM, as well as to dual combinations (NPls 0.015 or 1.5 mg/L and SIM 12.5 or 15 µg/L). PS NPls alone did not exert effects whereas SIM (≥12.5 µg/L) significantly delayed the hatching, decreased the heartbeat, induced edemas and mortality. The combination of NPls (1.5 mg/L) and SIM (12.5 or 15 µg/L) had significant effects on the survival of the organisms while the correspondent NPls and SIM single exposures did not have significant effects on this endpoint. Concerning the malformations appearance, SIM alone had similar effects than when in co-exposures (0.015 mg/L NPls plus 12.5 or 15 µg/L SIM). Hatching and heartbeat increased after the co-exposures SIM and NPls comparing with SIM single exposures, showing that 0.015 mg/L NPls plus 12.5 or 15 µg/L SIM did not cause significant effects on these endpoints. This study shows that NPls effects on bioavailability and toxicity of other contaminants cannot be ignored when assessing the environmental behavior and risks of NPls.

Iprodione and chlorpyrifos induce testicular damage, oxidative stress, apoptosis and suppression of steroidogenic- and spermatogenic-related genes in immature male albino rats

The fungicide iprodione (IPR) and the insecticide chlorpyrifos (CPF) are concurrently applied for early disease control in fruits and other crops. However, there are no available data about the impacts of their co-exposure. Additionally, IPR and CPF are known as endocrine disruptors that can cause reproductive toxicity. The outcomes of their co-exposure on the development of male reproductive organs are still unknown. Therefore, this study aimed to assess the risk of exposure to these pesticides, particularly on the postnatal development of the male albino rat reproductive system from postnatal days 23-60. The results revealed that a single IPR or CPF exposure has harmful consequences on the reproductive development and function manifested by reduced testicular weight, serious changes in sperm characteristics, reproductive hormone level imbalance, testicular enzymes, oxidative stress and apoptosis-related enzymes, which correlated with transcription levels of steroidogenic- and spermatogenic-related genes. Histopathologically, both compounds caused severe damage in the testis and accessory glands architecture. Notably, co-exposure to IPR and CPF in rats caused more serious damage, indicative of an additive effect than individual exposure, so concurrent exposure should be avoided as it is more hazardous, especially on male fertility.

Ethanol exacerbates manganese-induced oxidative/nitrosative stress, pro-inflammatory cytokines, nuclear factor-κB activation, and apoptosis induction in rat cerebellar cortex

Manganese (Mn) exposure is causing public health concerns as well as heavy alcohol consumption. This study investigates the mechanisms of neurotoxicity associated with Mn and ethanol (EtOH) exposure in the rat cerebellar cortex. Experimental animals received 30 mg/kg of Mn alone, 5 g/kg of EtOH alone, co-exposed with 30 mg/kg of Mn and 1.25 or 5 g/kg EtOH, while control animals received water by oral gavage for 35 days. Subsequently, alterations in the neuronal morphology of the cerebellar cortex, oxidative/nitrosative stress, acetylcholinesterase (AChE) activity, neuro-inflammation and protein expression of p53, BAX, caspase-3, and BCL-2 were investigated. The results indicate that Mn alone and EtOH alone induce neuronal alterations in the cerebellar cortex, decrease glutathione level and antioxidant enzyme activities, along with an increase in AChE activity, lipid peroxidation, and hydrogen peroxide generation. Mn alone and EtOH alone also increased neuro-inflammatory markers, namely nitric oxide, myeloperoxidase activity, interleukin-1β, tumor necrosis factor-α, and nuclear factor-κB (NF-κB) levels in the cerebellar cortex. Immunohistochemistry analysis further revealed that exposure of Mn alone and EtOH alone increases the protein expression of cyclooxygenase-2, BAX, p53, and caspase-3 and decrease BCL-2 in the rat cerebellar cortex. Furthermore, the results indicated that Mn co-exposure with EtOH at 1.25 and 5 g/kg EtOH significantly (p ≤ .05) increases the toxicity in the cerebellum when compared with the toxicity of Mn or EtOH alone. Taken together, co-exposure of Mn and EtOH exacerbates neuronal alterations, oxidative/nitrosative stress, AChE activity, pro-inflammatory cytokines, NF-κB signal transcription, and apoptosis induction in the rat cerebellar cortex.

In vitro cytotoxicity of co-exposure to superparamagnetic iron oxide and solid lipid nanoparticles

Increased production and use of different types of nanoparticles (NPs) in the last decades has led to increased environmental release of these NPs with potential detrimental effects on both the environment and public health. Information is scarce in the literature on the cytotoxic effect of co-exposure to many NPs as this concern is relatively recent. Thus, in this study, we hypothesized scenarios of cell's co-exposure to two kinds of NPs, solid lipid nanoparticles (SLNs) and superparamagnetic iron oxide nanoparticles (SPIONs), to assess the potential cytotoxicity of exposure to NPs combination. Cytotoxicity of SPIONs, SLNs, and their 1:1 mixture (MIX) in six tumor and six non-tumor cell lines was investigated. The mechanisms underlining the induced cytotoxicity were studied through cell cycle analysis, detection of reactive oxygen species (ROS), and alterations in mitochondrial membrane potential (ΔΨM). Double staining with acridine orange and ethidium bromide was also used to confirm cell morphology alterations. The results showed that SPIONs induced low cytotoxicity compared to SLNs. However, the mixture of SPIONs and SLNs showed synergistic, antagonistic, and additive effects based on distinct tests such as viability assay, ROS generation, ΔΨM, and DNA damage, depending on the cell line. Apoptosis triggered by ROS and disturbances in ΔΨM are the most probable related mechanisms of action. As was postulated, there is possible cytotoxic interaction between the two kinds of NPs.

Rare cases of severe life-threatening lead poisoning due to accident or chronic occupational exposure to lead and manganese: Diagnosis, treatment, and prognosis

BACKGROUND

Chronic long-term, low-dose environmental and occupational exposure to lead (Pb) has been extensively studied in large cohorts worldwide among general populations, miners, smelters, or battery workers. However, studies on severe life-threatening Pb poisoning due to accidental or chronic occupational exposure to Pb and manganese (Mn) were rarely reported.

METHODS

We present one case of acute severe Pb poisoning and compare it with another severe chronic occupational exposure case involving Pb and Mn. A 27-year-old woman mistakenly took a large quantity of pure Pb powder as an herbal remedy; she developed abdominal colic, severe nausea, vomiting, fatigue, and cutaneous and sclera icterus. Laboratory tests showed her blood lead level (BLL) of 173.5 µg dL^-1 and urinary lead level (ULL) of 1240 µg dL^-1. The patient was diagnosed with acute Pb poisoning and acute liver failure. In another chronic exposure case, a 56-year-old man worked in a Pb and Mn smelting factory for 15 years. He was brought to the emergency room with severe nausea, vomiting, and paroxysmal abdominal colic, which was intolerable during the onset of pain. His BLL was 64.8 µg dL^-1 and ULL was 38 µg dL^-1, but his blood and urinary Mn levels were normal. The patient was diagnosed with chronic Pb poisoning. Both patients received chelation therapy with calcium disodium ethylene-diamine-tetraacetate (CaNa₂EDTA). The woman with acute severe Pb intoxication recovered well and was discharged from the hospital after treatment, and the man who survived severe Pb poisoning was diagnosed with lung cancer.

CONCLUSION

Clinical manifestations of acute and chronic severe Pb poisoning are different. Chelation therapy with CaNa₂EDTA is proven to be an effective life-saving therapy in both cases by reducing BLL. Occupational exposure to both Pb and Mn does not appear to increase Mn neurotoxicity; however, the probability that co-exposure to Mn may increase Pb toxicity in the same patient cannot be excluded.

Association of poor psychological well-being with co-exposure to psychosocial factors at work in Korean regular workers

BACKGROUND

This study evaluated the association of co-exposure to different psychosocial factors with poor psychological well-being of Korean regular workers.

METHODS

This was a secondary analysis of data from the fifth Korean Working Conditions Survey, conducted in 2017. Multiple logistic regression was used to determine adjusted odd ratios (aORs) and 95% confidence intervals for poor psychological well-being associated with self-reported psychosocial factors. Poor psychological well-being was measured using the Well-Being Index of the World Health Organization. For each question on psychosocial factors (long weekly working hours, lack of decision latitude, work pressure, lack of autonomy, lack of role clarity, organizational injustice, lack of reward, and lack of support from managers), answers of "always" and "most of the time" were classified as affirmative and answers of"sometimes," "rarely," and "never" were classified as negative.

RESULTS

Poor psychological well-being was significantly associated with most individual work stressors for both sexes (aORs = 1.22-1.83). Furthermore, poor psychological well-being had a positive association with co-exposure to different psychosocial factors (aORs = 1.71-8.08). Co-exposure to an increasing number of psychosocial factors showed greater association with poor psychological well-being.

CONCLUSION

We found that poor psychological well-being was associated with co-exposure to psychosocial factors in Korean workers in regular employment. Thus, we suggest that employers provide comprehensive measures that will protect workers from simultaneous exposure to adverse psychosocial factors.

Effect of the Albumin Corona on the Toxicity of Combined Graphene Oxide and Cadmium to Daphnia magna and Integration of the Datasets into the NanoCommons Knowledge Base

In this work, we evaluated the effect of protein corona formation on graphene oxide (GO) mixture toxicity testing (i.e., co-exposure) using the Daphnia magna model and assessing acute toxicity determined as immobilisation. Cadmium (Cd2+) and bovine serum albumin (BSA) were selected as co-pollutant and protein model system, respectively. Albumin corona formation on GO dramatically increased its colloidal stability (ca. 60%) and Cd2+ adsorption capacity (ca. 4.5 times) in reconstituted water (Daphnia medium). The acute toxicity values (48 h-EC50) observed were 0.18 mg L-1 for Cd2+-only and 0.29 and 0.61 mg L-1 following co-exposure of Cd2+ with GO and BSA@GO materials, respectively, at a fixed non-toxic concentration of 1.0 mg L-1. After coronation of GO with BSA, a reduction in cadmium toxicity of 110 % and 238% was achieved when compared to bare GO and Cd2+-only, respectively. Integration of datasets associated with graphene-based materials, heavy metals and mixture toxicity is essential to enable re-use of the data and facilitate nanoinformatics approaches for design of safer nanomaterials for water quality monitoring and remediation technologies. Hence, all data from this work were annotated and integrated into the NanoCommons Knowledge Base, connecting the experimental data to nanoinformatics platforms under the FAIR data principles and making them interoperable with similar datasets.

Increased Uptake of Silica Nanoparticles in Inflamed Macrophages but Not upon Co-Exposure to Micron-Sized Particles

Silica nanoparticles (NPs) are widely used in various industrial and biomedical applications. Little is known about the cellular uptake of co-exposed silica particles, as can be expected in our daily life. In addition, an inflamed microenvironment might affect a NP’s uptake and a cell’s physiological response. Herein, prestimulated mouse J774A.1 macrophages with bacterial lipopolysaccharide were post-exposed to micron- and nanosized silica particles, either alone or together, i.e., simultaneously or sequentially, for different time points. The results indicated a morphological change and increased expression of tumor necrosis factor alpha in lipopolysaccharide prestimulated cells, suggesting a M1-polarization phenotype. Confocal laser scanning microscopy revealed the intracellular accumulation and uptake of both particle types for all exposure conditions. A flow cytometry analysis showed an increased particle uptake in lipopolysaccharide prestimulated macrophages. However, no differences were observed in particle uptakes between single- and co-exposure conditions. We did not observe any colocalization between the two silica (SiO₂) particles. However, there was a positive colocalization between lysosomes and nanosized silica but only a few colocalized events with micro-sized silica particles. This suggests differential intracellular localizations of silica particles in macrophages and a possible activation of distinct endocytic pathways. The results demonstrate that the cellular uptake of NPs is modulated in inflamed macrophages but not in the presence of micron-sized particles.

Household Exposure to Secondhand Smoke among Chinese Children: Status, Determinants, and Co-Exposures

Smoking prevalence stays high among adults in China, which also makes children exposed to secondhand smoke (SHS) in their households. This study aimed to investigate the status of SHS exposure among Chinese children, identify the influencing factors, and determine "co-exposure" to tobacco and other smokes in households. A total of 41,439 children aged 6-17 years were recruited from 30 provinces in Mainland China through the first Chinese Environmental Exposure-Related Human Activity Model Survey for Children (CEERHAPS-C). Information regarding children's demographics, socioeconomic status, and exposures to SHS and solid fuel smoke (SFS) in households was collected using a comprehensive questionnaire. Factors that affected exposures to household smokes were identified using multivariable logistic regressions. The overall prevalence of household SHS exposure was 41.7%, and the average duration was 14.7 ± 14.6 min/day among the exposed participants. Prevalence of household SHS exposure increased among children in older age groups and with parents in lower education levels. Among SHS-exposed children, 34% had co-exposure to SFS, and they had a significantly higher risk of co-exposure than non-SHS exposed children (odds ratio = 1.12, 95% confidence interval: 1.061, 1.162). The prevalence of household SHS exposure remains high among school-age children, suggesting the need to develop and implement smoking-free home programs.

Toxicity to RAW264.7 Macrophages of Silica Nanoparticles and the E551 Food Additive, in Combination with Genotoxic Agents

Synthetic amorphous silica (SAS) is used in a plethora of applications and included in many daily products to which humans are exposed via inhalation, ingestion, or skin contact. This poses the question of their potential toxicity, particularly towards macrophages, which show specific sensitivity to this material. SAS represents an ideal candidate for the adsorption of environmental contaminants due to its large surface area and could consequently modulate their toxicity. In this study, we assessed the toxicity towards macrophages and intestinal epithelial cells of three SAS particles, either isolated SiO₂ nanoparticles (LS30) or SiO₂ particles composed of agglomerated-aggregates of fused primary particles, either food-grade (E551) or non-food-grade (Fumed silica). These particles were applied to cells either alone or in combination with genotoxic co-contaminants, i.e., benzo[a]pyrene (B[a]P) and methane methylsulfonate (MMS). We show that macrophages are much more sensitive to these toxic agents than a non-differenciated co-culture of Caco-2 and HT29-MTX cells, used here as a model of intestinal epithelium. Co-exposure to SiO₂ and MMS causes DNA damage in a synergistic way, which is not explained by the modulation of DNA repair protein mRNA expression. Together, this suggests that SiO₂ particles could adsorb genotoxic agents on their surface and, consequently, increase their DNA damaging potential.

Plastics in Cyanobacterial Blooms-Genotoxic Effects of Binary Mixtures of Cylindrospermopsin and Bisphenols in HepG2 Cells

Ever-expanding environmental pollution is causing a rise in cyanobacterial blooms and the accumulation of plastics in water bodies. Consequently, exposure to mixtures of cyanotoxins and plastic-related contaminants such as bisphenols (BPs) is of increasing concern. The present study describes genotoxic effects induced by co-exposure to one of the emerging cyanotoxins-cylindrospermopsin (CYN)-(0.5 µg/mL) and BPs (bisphenol A (BPA), S (BPS), and F (BPF); (10 µg/mL)) in HepG2 cells after 24 and 72 h of exposure. The cytotoxicity was evaluated with an MTS assay and genotoxicity was assessed through the measurement of the induction of DNA double strand breaks (DSB) with the γH2AX assay. The deregulation of selected genes (xenobiotic metabolic enzyme genes, DNA damage, and oxidative response genes) was assessed using qPCR. The results showed a moderate reduction of cell viability and induction of DSBs after 72 h of exposure to the CYN/BPs mixtures and CYN alone. None of the BPs alone reduced cell viability or induced DSBs. No significant difference was observed between CYN and CYN/BPs exposed cells, except with CYN/BPA, where the antagonistic activity of BPA against CYN was indicated. The deregulation of some of the tested genes (CYP1A1, CDKN1A, GADD45A, and GCLC) was more pronounced after exposure to the CYN/BPs mixtures compared to single compounds, suggesting additive or synergistic action. The present study confirms the importance of co-exposure studies, as our results show pollutant mixtures to induce effects different from those confirmed for single compounds.

Unravelling the Potential Cytotoxic Effects of Metal Oxide Nanoparticles and Metal(Loid) Mixtures on A549 Human Cell Line

Humans are typically exposed to environmental contaminants' mixtures that result in different toxicity than exposure to the individual counterparts. Yet, the toxicology of chemical mixtures has been overlooked. This work aims at assessing and comparing viability and cell cycle of A549 cells after exposure to single and binary mixtures of: titanium dioxide nanoparticles (TiO2NP) 0.75-75 mg/L; cerium oxide nanoparticles (CeO2NP) 0.0.75-10 μg/L; arsenic (As) 0.75-2.5 mg/L; and mercury (Hg) 5-100 mg/L. Viability was assessed through water-soluble tetrazolium (WST-1) and thiazolyl blue tetrazolium bromide (MTT) (24 h exposure) and clonogenic (seven-day exposure) assays. Cell cycle alterations were explored by flow cytometry. Viability was affected in a dose- and time-dependent manner. Prolonged exposure caused inhibition of cell proliferation even at low concentrations. Cell-cycle progression was affected by TiO2NP 75 mg/L, and As 0.75 and 2.5 μg/L, increasing the cell proportion at G0/G1 phase. Combined exposure of TiO2NP or CeO2NP mitigated As adverse effects, increasing the cell surviving factor, but cell cycle alterations were still observed. Only CeO2NP co-exposure reduced Hg toxicity, translated in a decrease of cells in Sub-G1. Toxicity was diminished for both NPs co-exposure compared to its toxicity alone, but a marked toxicity for the highest concentrations was observed for longer exposures. These findings prove that joint toxicity of contaminants must not be disregarded.

Occupational Co-exposures to Multiple Chemical Agents from Workplace Measurements by the US Occupational Safety and Health Administration

OBJECTIVES

The occupational environment represents an important source of exposures to multiplehazards for workers' health. Although it is recognized that mixtures of agents may have differenteffects on health compared to their individual effects, studies generally focus on the assessment ofindividual exposures. Our objective was to identify occupational co-exposures occurring in the United States using the multi-industry occupational exposure databank of the Occupational Safety and Health Administration (OSHA).

METHODS

Using OSHA's Integrated Management Information System (IMIS), measurement data from workplace inspections occurring from 1979 to 2015 were examined. We defined a workplace situation (WS) by grouping measurements that occurred within a company, within the same occupation (i.e. job title) within 1 year. All agents present in each WS were listed and the resulting databank was analyzed with the Spectrosome approach, a methodology inspired by network science, to determine global patterns of co-exposures. The presence of an agent in a WS was defined either as detected, or measured above 20% of a relevant occupational exposure limit (OEL).

RESULTS

Among the 334 648 detected exposure measurements of 105 distinct agents collected from 14 513 US companies, we identified 125 551 WSs, with 31% involving co-exposure. Fifty-eight agents were detected with others in >50% of WSs, 29 with a proportion >80%. Two clusters were highlighted, one for solvents and one for metals. Toluene, xylene, acetone, hexone, 2-butanone, and N-butyl acetate formed the basis of the solvent cluster. The main agents of the metal cluster were zinc, iron, lead, copper, manganese, nickel, cadmium, and chromium. 68 556 WS were included in the analyses based on levels of exposure above 20% of their OEL, with 12.4% of co-exposure. In this analysis, while the metal cluster remained, only the combinations of toluene with xylene or 2-butanone were frequently observed among solvents. An online web application allows the examination of industry specific patterns.

CONCLUSIONS

We identified frequent co-exposure situations in the IMIS databank. Using the spectrome approach, we revealed global combination patterns and the agents most often implicated. Future work should endeavor to explore the toxicological effects of prevalent combinations of exposures on workers' health to prioritize research and prevention efforts.

Multimycotoxin Exposure Assessment in UK Children Using Urinary Biomarkers-A Pilot Survey

Cereal foods are commonly contaminated with multiple mycotoxins resulting in frequent human mycotoxin exposure. Children are at risk of high-level exposure because of their high cereal intake relative to body weight. Hence, this study aims to assess multimycotoxin exposure in UK children using urinary biomarkers. Spot urines (n = 21) were analyzed for multimycotoxins (deoxynivalenol, DON; nivalenol, NIV; ochratoxin A, OTA; zearalenone, ZEN; α-zearalenol, α-ZEL; β-zearalenol, β-ZEL; T-2 toxin, T-2; HT-2 toxin, HT-2; and aflatoxin B₁ and M_1, AFB₁, AFM₁) using liquid chromatography-coupled tandem mass spectrometry. Urine samples frequently contained DON (13.10 ± 12.69 ng/mL), NIV (0.36 ± 0.16 ng/mL), OTA (0.05 ± 0.02 ng/mL), and ZEN (0.09 ± 0.07 ng/mL). Some samples (1-3) contained T-2, HT-2, α-ZEL, and β-ZEL but not aflatoxins. Dietary mycotoxin estimation showed that children were frequently exposed to levels exceeding the tolerable daily intake (52 and 95% of cases for DON and OTA). This demonstrates that UK children are exposed to multiple mycotoxins through their habitual diet.

Environmental exposure of arsenic and fluoride and their combined toxicity: A recent update

Environmental exposure to arsenic (As) and fluoride (F) in the recent year has been increased because of excessive use of naturally contaminated ground water. Surface water is also regularly contaminated with these elements in various industrial areas. Arsenicosis and fluorosis upon individual exposure of As and F are reported in many studies. A syndrome of endemic As poisoning and fluorosis occurs during concurrent exposure of As and F. Previous reports showed synergistic, antagonistic and independent effects of these two compounds, although few recent reports also revealed antagonistic effects after co-exposure. Interaction during intestinal absorption and influence of F on As metabolism might be the cause of antagonism. The synergism/antagonism is thought to depend on the dose and duration of the co-exposure. However, the detailed mechanism is still not fully understood and needs further studies. Removal technologies of As and F from contaminated water is available but removal of such contaminants from food is yet to be developed. Antioxidants are useful to mitigate the toxic effects of As and F. This review focused on the effect of co-exposure, amelioration as well as removal techniques of As and F.

The State-of-the Art of Environmental Toxicogenomics: Challenges and Perspectives of "Omics" Approaches Directed to Toxicant Mixtures

The last decade witnessed extraordinary advances in “omics” methods, particularly transcriptomics, proteomics and metabolomics, enabling toxicologists to integrate toxicokinetics and toxicodynamics with mechanistic insights on the mode-of-action of noxious chemicals, single or combined. The toxicology of mixtures is, nonetheless, a most challenging enterprise, especially for environmental toxicologists and ecotoxicologists, who invariably deal with chemical mixtures, many of which contain unknowns. Despite costs and demanding computations, the systems toxicology framework, of which “omics” is a major component, endeavors extracting adverse outcome pathways for complex mixtures. Still, the interplay between the multiple components of gene expression and cell metabolism tends to be overlooked. As an example, the proteome allocates DNA methyltransferases whose altered transcription or loss of function by action of chemicals can have a global impact on gene expression in the cell. On the other hand, chemical insult can produce reactive metabolites and radicals that can intercalate or bind to DNA as well as to enzymes and structural proteins, compromising their activity. These examples illustrate the importance of exploring multiple “omes” and the purpose of “omics” and multi-“omics” for building truly predictive models of hazard and risk. Here we will review the state-of-the-art of toxicogenomics highlighting successes, shortcomings and perspectives for next-generation environmental toxicologists.

Unexpected Size Effect: The Interplay between Different-Sized Nanoparticles in Their Cellular Uptake

The size effect on the cellular uptake of nanoparticles (NPs) has been extensively studied, but it is still not well understood. Herein, a reductionist approach is used to minimize all influencing factors except the particle size, and co-exposure of different-sized silica nanoparticles (SNPs) is adopted instead of the common single exposure. SNPs are found being internalized by Hela cells in serum-free medium mainly via clathrin-dependent endocytosis, thus simplifying the data analysis for reliable attribution to size effects. Remarkably, even though at conditions that the size effects seem very small or even undetectable in the common single exposure experiments, the co-exposure experiments reveal significant size effects due to an unexpected interplay between two different-sized SNPs. Namely, the bigger SNPs significantly promote the cellular uptake of the smaller ones, while the smaller SNPs inhibit the internalization of the bigger ones, with a total uptake increase of the particle number of SNPs in the cells. This strong interplay between different-sized NPs might unavoidably exist within most "single-sized" NP products, whose sizes actually distribute in certain ranges, thus urging reconsideration of the size effect on the cellular uptake of NPs, for the benefits of both bioapplications and safety assessment of nanomaterials.