Dietborne Toxicity of Tebuconazole to a Benthic Crustacean, Heterocypris incongruens and Its Relative Contribution to the Overall Effects under Food-Water Equilibrium Partitioning.

Tebuconazole (TEB), a widely used and persistent pesticide, has garnered attention due to its frequent detection in sediments worldwide. This widespread occurrence has raised concerns about potential dietborne toxicity to benthic crustaceans, as they may ingest contaminated particles in their habitat. While bioaccumulation studies indicate the importance of TEB ingestion for benthic crustaceans, limited data exist on direct dietborne toxicity testing. This study investigated the diet-related toxicity of TEB by subjecting a benthic ostracod, Heterocypris incongruens, to a 6 day toxicity test under dietary and combined exposures. Subsequently, the importance of dietary exposure for TEB toxicity was uncovered, followed by quantification of relative dietborne toxicity contributions using a modified concentration-additive model. Results revealed that the dietary route was more toxicologically significant than the aqueous route in equilibrium. The dietborne lethal concentration (LC50) for TEB on H. incongruens was 200 (170-250) mg/kg, with an 80% relative dietborne toxicity contribution. To gain comprehensive insights into dietborne significance, toxicity data were collected from previous studies involving different pollutants to calculate relative contributions. Finally, the correlation between dietborne toxicity and the partitioning coefficient was analyzed to understand the pollutant behavior and its toxic impact when ingested through the diet.

Are We Justified in Modeling Human Exposure to Chlorinated Paraffin Mixtures Using the Average Properties of Congeners and Homologues?

Concern over human exposure to chlorinated paraffin (CP) mixtures keeps increasing. The absence of a comprehensive understanding of how human exposure varies with the physicochemical properties of CP constituents has hindered the ability to determine at what level of aggregation exposure to CPs should be assessed. We answer this question by comparing exposure predicted with either a "complex" method that utilizes isomer-specific properties or "simplified" methods that rely on median properties of congener, homologue, or short-/medium-/long-chain CP groups. Our results demonstrate the wide range of physicochemical properties across CP mixtures and their dependence on molecular structures. Assuming unit emissions in the environment, these variances translate into an extensive disparity in whole-body concentrations predicted for different isomers, spanning ∼11 orders of magnitude. CPs with 13-19 carbons and 6-10 chlorines exhibit the highest human exposure potential, primarily owing to moderate to high hydrophobicity and slow environmental degradation and biotransformation. Far-field exposure is dominant for most CP constituents. Our study underscores that using average properties of congener, homologue, or S/M/LCCP groups yields results that are consistent with those derived from isomer-based modeling, thus offering an efficient and practical framework for future risk assessments and human exposure studies of CPs and other complex chemical mixtures.

Lung versus gut exposure to air pollution particles differentially affect metabolic health in mice.

BACKGROUND: Air pollution has emerged as an unexpected risk factor for diabetes. However, the mechanism behind remains ill-defined. So far, the lung has been considered as the main target organ of air pollution. In contrast, the gut has received little scientific attention. Since air pollution particles can reach the gut after mucociliary clearance from the lungs and through contaminated food, our aim was to assess whether exposure deposition of air pollution particles in the lung or the gut drive metabolic dysfunction in mice. METHODS: To study the effects of gut versus lung exposure, we exposed mice on standard diet to diesel exhaust particles (DEP; NIST 1650b), particulate matter (PM; NIST 1649b) or phosphate-buffered saline by either intratracheal instillation (30 µg 2 days/week) or gavage (12 µg 5 days/week) over at least 3 months (total dose of 60 µg/week for both administration routes, equivalent to a daily inhalation exposure in humans of 160 µg/m3 PM2.5) and monitored metabolic parameters and tissue changes. Additionally, we tested the impact of the exposure route in a "prestressed" condition (high-fat diet (HFD) and streptozotocin (STZ)). RESULTS: Mice on standard diet exposed to particulate air pollutants by intratracheal instillation developed lung inflammation. While both lung and gut exposure resulted in increased liver lipids, glucose intolerance and impaired insulin secretion was only observed in mice exposed to particles by gavage. Gavage with DEP created an inflammatory milieu in the gut as shown by up-regulated gene expression of pro-inflammatory cytokines and monocyte/macrophage markers. In contrast, liver and adipose inflammation markers were not increased. Beta-cell secretory capacity was impaired on a functional level, most likely induced by the inflammatory milieu in the gut, and not due to beta-cell loss. The differential metabolic effects of lung and gut exposures were confirmed in a "prestressed" HFD/STZ model. CONCLUSIONS: We conclude that separate lung and gut exposures to air pollution particles lead to distinct metabolic outcomes in mice. Both exposure routes elevate liver lipids, while gut exposure to particulate air pollutants specifically impairs beta-cell secretory capacity, potentially instigated by an inflammatory milieu in the gut.

Route of Arsenic Exposure Differentially Impacts the Expression of Genes Involved in Gut-Mucosa-Associated Immune Responses and Gastrointestinal Permeability.

First-pass metabolism alters arsenic biotransformation and its immunomodulatory activities. This study aims to determine the mRNA expression of intestinal-immunity- and permeability-associated genes, levels of cytokine/chemokines and levels of immunoglobulin isotypes when CD-1 mice were exposed to a single dose of intravenous (IV) sodium arsenite (50 µg/kg body weight (BW)) and to compare these responses to exposure via oral gavage (OG) (50 µg/kg BW). Samples were collected at 1, 4, 24 and 48 h post IV exposure and 24 and 48 h post OG. Sodium arsenite IV exposure led to a transient modulation of mRNA expression and protein levels of immunity-related genes involved in inflammation/apoptotic pathways and production of cytokines/chemokines, whereas it also led to downregulated expression of genes encoding tight junction, focal adhesion, and gap junction proteins, which are responsible for maintaining cell permeability. Oral exposure perturbed fewer cell-permeability-related genes at 24 and 48 h post exposure. At 24 h post exposure, OG decreased IgA and IgG2b levels; however, IV exposure significantly increased IgG2b, IgG3 and IgA in ileal tissue. Earlier, we showed significant downregulation of mRNA expression of genes involved in the immune-related pathways during OG in the intestinal mucosa of the same animals. Cumulatively, these results provide evidence that the exposure route of a xenobiotic can differentially impact the intestinal responses due to the impact of first-pass metabolism.

Food and human safety: the impact of microplastics.

Plastic waste pollution is one of the biggest problems in the world today. The amount of plastic in the environment continues to increase, and human exposure to microplastic (MP) has become a reality. This subject has attracted the attention of the whole world. The MP problem has also been noticed by the scientific community. The term microplastic is mostly used to define synthetic material with a high polymer content that can have a size range from 0.1 to 5000 µm. This paper aims to characterize the routes of exposure to MP, define its pollution sources, and identify food types contaminated with plastics. This review addresses the current state of knowledge on this type of particles, with particular emphasis on their influence on human health. Adverse effects of MP depend on routes and sources of exposure. The most common route of exposure is believed to be the gastrointestinal tract. Sources of MP include fish, shellfish, water as well as tea, beer, wine, energy drinks, soft drinks, milk, salt, sugar, honey, poultry meat, fruits, and vegetables. Studies have shown that particles of PET, PE, PP, PS, PVC, PA, and PC are the most frequently found in food.

Determining the Relative Importance of Dietborne and Waterborne Toxicity of 4-tert-Butylphenol and 4-tert-Octylphenol to the Benthic Crustacean, Heterocypris incongruens.

Organic pollutants with high solid-water equilibrium partition coefficients are adsorbed into solid particles and are easily ingested by benthic organisms, potentially causing dietborne toxicity. Whether dietborne toxicity is more important than waterborne toxicity for such chemicals remains to be determined. In this study, we identify the most relevant uptake route for the toxicity of two alkylphenols, 4-tert-butylphenol (4tBP), and 4-tert-octylphenol (4tOP). To achieve this, 6-day toxicity tests under two exposure conditions, namely dietary exposure (clean water + contaminated food) and combined exposure (contaminated water + contaminated food) were conducted on a benthic ostracod, Heterocypris incongruens. The toxicologically important exposure routes were confirmed by the consistency of dietary and aqueous dose-response relationships under different exposure conditions. During the test, frequent renewal of water and food was performed to reduce variability in the exposure conditions. The results showed that, under the equilibrium condition, the dietary exposure route was toxicologically more important than the aqueous route for 4tBP, whereas the waterborne exposure route was more important than the dietary exposure route for 4tOP. This study provides a novel approach to identify the most relevant uptake pathways for chemical toxicity, which better explains the importance of exposure routes in toxicity effects.

Mutagenicity, health risk, and disease burden of exposure to organic micropollutants in water from a drinking water treatment plant in the Yangtze River Delta, China.

A wide variety of organic micropollutants in drinking water pose a serious threat to human health. This study was aimed to reveal the characteristics of organic micropollution profiles in water from a drinking water treatment plant (DWTP) in the Yangtze River Delta, China and investigate the mutagenicity, health risk and disease burden through mixed exposure to micropollutants in water. The presence of organic micropollutants in seven categories in organic extracts (OEs) of water from the DWTP was determined, and Ames test was conducted to test the mutagenic effect of OEs. Meanwhile, health risk of exposure to organic micropollutants in finished water through three exposure routes (ingestion, dermal absorption and inhalation) was assessed with the method proposed by U.S. EPA, and disability-adjusted life years (DALYs) were combined to estimate the disease burden of cancer based on the carcinogenic risk (CR) assessment. The results showed that 28 organic micropollutants were detected in the raw and finished water at total concentrations of 967.28 ng/L and 1073.45 ng/L, respectively, of which phthalate esters (PAEs) were the dominant category (95.79% in the raw water and 96.61% in the finished water). Although the results of the Ames test for OEs were negative and the non-carcinogenic hazard index of the organic micropollutants in the finished water was less than 1 in all age groups, the total CR was 2.17 × 10-5, higher than the negligible risk level (1.00 × 10-6). The total DALYs caused by the organic micropollutants in the finished water was 2945.59 person-years, and the average individual DALYs was 2.21 × 10-6 per person-year (ppy), which was 2.21 times the reference risk level (1.00 × 10-6 ppy) defined by the WHO. Exposure to nitrosamines (NAms) was the major contributor to the total CR (92.06%) and average individual DALYs (94.58%). This study demonstrated that despite the negative result of the mutagenicity test with TA98 and TA100 strains, the health risk of exposure to organic micropollutants in drinking water should not be neglected.

A new exposure route to trace elements in indoor particulate matter.

Concentrations and emission rates of sixteen trace elements in emitted PM during heating soybean oil using three types of pans, including Teflon, granitium, and cast-iron, were investigated. Statistically significant decreases in Mn and Co emission rates were observed when the oil was heated in the cast-iron pan compared to Teflon and granitium pans. Among the released trace elements, Ni, Ba, Zn, and Cr had more contribution to the emission rate. The concentrations of Fe in the emitted PM1 were found to be higher when cast-iron pan (8.49 ± 3.35 µg/m3 ) was utilized compared to Teflon (8.05 ± 2.27 µg/m3 ) and granitium (7.45 ± 1.38 µg/m3 ). However, these increases were statistically insignificant. The results of our study support the hypothesis that the trace elements translocate from cooking pans into the heated oil and subsequently to the particulate phase. This translocation creates a new inhalation exposure route to trace elements in indoor environments.

The impact of exposure route for class-based compounds: a comparative approach of lethal toxicity data in rodent models.

Relationships of toxicities from intravenous (i.v.), intraperitoneal (i.p.), subcutaneous (s.c.) and intragastric (i.g.) exposure routes to mice were investigated. Regression analysis showed that the toxicities from i.v. route is strongly correlated with i.p. and s.c. routes, but poorly with i.g. route. Close toxicities from different routes for some compounds indicate that distribution rate is the determining step and dictates chemical concentration at the target site(s). On the other hand, the absorption rate is the determining step for many compounds, which lead to different toxicities between exposure routes. The classified compounds characterized as having either absorption or distribution rate determining step were based upon the comparison of toxicities from the different routes. We found that some aliphatic acids and benzoic acids have lower toxicity values from i.g. route compared to an i.v. route because of poor absorption. Many compounds show low toxic effects from i.g. route than those from other routes because of the first-pass metabolism in the gastrointestinal tract, resulting in the poor relationship for toxicities between i.g. and i.v. or other routes. Stepwise regression analysis showed that physicochemical properties of a compound, such as molecular volume, polarizability and hydrophobicity, significantly affect adsorption rate, which leads to different toxicities based upon exposure routes. Comparison of the toxicities between mice and rats indicate that toxic effect and the toxicokinetic processes in mice are very similar to that in rats. A universal correlation equation has been developed for the toxicities between rats and mice from different exposure routes, which can be applied to predict toxicities across species.

Toxicokinetics of Ag in the terrestrial isopod Porcellionides pruinosus exposed to Ag NPs and AgNO3 via soil and food.

Silver nanoparticles (Ag NPs) have been used in numerous consumer products and may enter the soil through the land application of biosolids. However, little is known about the relationship between Ag NP exposure and their bioavailability for soil organisms. This study aims at comparing the uptake and elimination kinetics of Ag upon exposures to different Ag forms (NPs and ionic Ag (as AgNO3)) in the isopod Porcellionides pruinosus. Isopods were exposed to contaminated Lufa 2.2 soil or alder leaves as food. Uptake and elimination rate constants for soil exposure did not significantly differ between Ag NPs and ionic Ag at 30 and 60 mg Ag/kg. For dietary exposure, the uptake rate constant was up to 5 times higher for Ag NPs than for AgNO3, but this was related to feeding activity and exposure concentrations, while no difference in the elimination rate constants was found. When comparing both routes, dietary exposure resulted in lower Ag uptake rate constants but elimination rate constants did not differ. A fast Ag uptake was observed from both routes and most of the Ag taken up seemed not to be eliminated. Synchrotron X-ray fluorescence showed Ag in the S-cells of the hepatopancreas, thus supporting the observations from the kinetic experiment (i.e. low elimination). In addition, our results show that isopods have an extremely high Ag accumulation capacity, suggesting the presence of an efficient Ag storage compartment.

Relationship between lethal toxicity in oral administration and injection to mice: effect of exposure routes.

The lethal toxicity (LD50) in oral administration, intravenous, intraperitoneal, intramuscular and subcutaneous injections were used to investigate relationships of log 1/LD50 from different exposure routes. Regression analysis showed that log 1/LD50 in oral route was related to the toxicity in injection route. This relationship in lethality between the two routes is apparently due to the same mechanisms of the compounds to the same species. However, the scatter in the correlation curve indicates that exposure route is an important factor that influences the relationship. Some compounds with low intestinal absorption exhibit much less toxicity in oral administration than that in the injection route. A systemic bias of log 1/LD50 between oral and injection routes indicates that tissue distribution of compounds between blood and target site is a very rapid process, leading to log 1/LD50 in injection greater than those in oral administration. Although compounds can be metabolized in the body both from oral and injection routes, first-pass metabolism occurs in oral route but not in injection route. This will result in decrease of toxicity in oral route for most compounds as compared with injection route. In addition, experimental uncertainty, differences in gender, and species can also affect relationships of log1/LD50 between exposure routes.

Effect of exposure routes on the relationships of lethal toxicity to rats from oral, intravenous, intraperitoneal and intramuscular routes.

The lethal toxicity values (log 1/LD(50)) of 527 aliphatic and aromatic compounds in oral, intravenous, intramuscular and intraperitoneal routes were used to investigate the relationships of log 1/LD(50) from different exposure routes. Regression analysis shows that the log 1/LD(50) values are well correlated between intravenous and intraperitoneal or intramuscular injections. However, the correlations between oral and intravenous or intraperitoneal routes are relatively poor. Comparison of the average residuals indicates that intravenous injection is the most sensitive exposure route and oral administration is the least sensitive exposure route. This is attributed to the difference in kinetic process of toxicity testing. The toxic effect of a chemical can be similar or significantly different between exposure routes, depending on the absorption rates of chemicals into blood. Inclusion of hydrophobic parameter and fractions of ionic forms can improve the correlations between intravenous and intraperitoneal or oral routes, but not between intraperitoneal and oral routes. This is due to the differences of absorption rate in different exposure environments from different routes. Several factors, such as experimental uncertainty, metabolism and toxic kinetics, can affect the correlations between intravenous and intraperitoneal or oral routes.

Investigation on baseline toxicity to rats based on aliphatic compounds and comparison with toxicity to fish: effect of exposure routes on toxicity.

The aim of this paper was to investigate baseline toxicity to rats and effect of exposure routes on toxicity in rats and fish. In this paper, 1588 industrial chemicals were selected to investigate baseline toxicity to rats. The results showed that rat toxicity varies around a constant for classified compounds or homologues. The toxic contributions of substituted functional groups have been calculated and alkanes were used as baseline toxicity. The toxic contributions, equal to toxic ratios (TR), show that small changes in chemical structure can result in different toxic effect in rat toxicity. However, this situation has not been observed in fish toxicity because the threshold of excess toxicity (e.g. log TR=1) was too high to distinguish differences in toxicity. Very close critical body residues (CBRs) calculated from percentage of absorption and bioconcentration factors indicate that most of aliphatic chemicals may share the same modes of toxic action between rat and fish species. The high estimation error of bioconcentration factor calculated from computer programs for some compounds suggests that classification of excess toxicity should be based on the CBRs, rather than the TR because the TR is closely related to the exposure routes.

Influence of dietary status on the obesogenic effects of erythromycin antibiotic on Caenorhabditis elegans.

As emerging pollutants, antibiotics were widely detected in water bodies and dietary sources. Recently, their obesogenic effects raised serious concerns. So far, it remained unclear whether their obesogenic effects would be influenced by water- and diet-borne exposure routes. In present study, Caenorhabditis elegans, nematodes free-living in air-water interface and feeding on bacteria, were exposed to water- and diet-borne erythromycin antibiotic (ERY). The statuses of the bacterial food, inactivated or alive, were also considered to explore their influences on the effects. Results showed that both water- and diet-borne ERY significantly stimulated body width and triglyceride contents. Moreover, diet-borne ERY's stimulation on the triglyceride levels was greater with alive bacteria than with inactivated bacteria. Biochemical analysis showed that water-borne ERY inhibited the activities of enzymes like adipose triglyceride lipase (ATGL) in fatty acid ß-oxidation. Meanwhile, diet-borne ERY inhibited the activities of acyl-CoA synthetase (ACS) and carnitine palmitoyl transferase (CPT) in lipolysis, while it stimulated the activities of fatty acid synthase (FAS) in lipogenesis. Gene expression analysis demonstrated that water-borne ERY with alive bacteria significantly upregulated the expressions of daf-2, daf-16 and nhr-49, without significant influences in other settings. Further investigation demonstrated that ERY interfered with bacterial colonization in the intestine and the permeability of the intestinal barrier. Moreover, ERY decreased total long-chained fatty acids (LCFAs) in bacteria and nematodes, while it decreased total short-chained fatty acids (SCFAs) in bacteria but increased them in nematodes. Collectively, the present study demonstrated the differences between water- and diet-borne ERY's obesogenic effects, and highlighted the involvement of insulin and nhr-49 signaling pathways, SCFAs metabolism and also the interaction between intestinal bacteria and the host.

An introduction to environmental neurotoxicology: Lessons from a clinical perspective.

In 1992, the Committee on Neurotoxicology and Models for Assessing Risk of the National Academy of Sciences in Washington DC focused with a scientific perspective on the identification of substances with neurotoxic potential, studies of exposed populations, risk assessment, and biologic markers of disease. This Committee recommended: "all physicians should be trained to take a thorough occupational-exposure history and to be aware of other possible sources of toxic exposure". Although convened after several outbreaks of neurotoxic syndromes, clinical neurological considerations were lacking. After defining keys words, namely Environment, Neurotoxicology and Neurotoxicants, we present some demonstrative cases; e.g., the Epidemic Neuropathy in Cuba, Minamata disease, ALS/PDC on Guam, and the ALS hot spot in the French Alps. Always with a clinical and practical approach, we will then review the milieux that contain and convey potential neurotoxicants, the different exposure routes and the clinical presentations. Drawing lessons from clinical cases, we offer some thoughts concerning the future of Environmental Neurotoxicology (ENT). Pointing notably to the diffuse chemical contamination of ecosystems and living beings, including Homo sapiens, we question the real impact of agents with neurotoxic potential on the human brain, considering the effects, for example, of air pollution, endocrine disruptors and nanoparticles. Concern is expressed over the lack of knowledge of the non-monotonic kinetics of many of these chemicals, the major concern being related to mixtures and low-dose exposures, as well as the delayed appearance in clinical expression of prevalent neurodegenerative diseases.

Laboratory Animal Models for Rift Valley Fever Virus Disease.

Rift Valley fever virus (RVFV) is an arboviral pathogen of clinical and agricultural relevance. The ongoing development of targeted RVFV prophylactics and therapeutics is overwhelmingly dependent on animal models due to both natural, that is, sporadic outbreaks, and structural, for example, underresourcing of endemic regions, limitations in accessing human patient samples and cohorts. Elucidating mechanisms of viral pathogenesis and testing therapeutics is further complicated by the diverse manifestations of RVFV disease and the heterogeneity of the host response to infection. In this chapter, we describe major clinical manifestations of RVFV infection and discuss the laboratory animal models used to study each.

Electronic-waste-associated pollution of per- and polyfluoroalkyl substances: Environmental occurrence and human exposure.

Occupational exposure to per- and polyfluoroalkyl substances (PFASs) is of serious concern because their adverse health effects. Nevertheless, knowledge regarding contamination in e-waste dismantling regions is rather scarce. We therefore analysed seven neutral PFASs (n-PFASs) and forty ionized PFASs (i-PFASs) in dust and hand wipes collected from an e-waste dismantling plant and homes. Both dust (1370 ng/g) and workers' hand wipe (1100 ng/m2) in e-waste dismantling workshops contained significantly higher median levels of ∑PFASs than those from homes (684 ng/g and 444 ng/m2) (p < 0.01). ∑PFAS concentrations in dust and on workers' hand wipes from workshops were significantly higher than those from storage area. 8:2 fluorotelomer alcohol was the dominant n-PFAS in workshop dust (70.7%) and on worker's hand wipes (46.6%). Perfluoroalkyl carboxylic acids (C2 -C3) were the significant components (based on concentration) of i-PFASs in dust (57.9%) and on hand wipes (89.6%). A significant positive correlation (p < 0.001) of ∑PFAS concentrations between workshop dust and workers' hand wipes was observed, indicating that they come from common sources. Compared to dust ingestion, hand-to-mouth contact was highlighted as a vital exposure route, accounting for 68.8% for workers and 72.2% for residential population, respectively, of the sum of two exposure doses.

Bioaccumulation of CuO nanomaterials in rainbow trout: Influence of exposure route and particle shape.

The bioaccumulation potential of spherical and rod-shaped CuO nanomaterials (NMs) was assessed in rainbow trout (Oncorhynchus mykiss) exposed via water and diet following the OECD Test Guideline No. 305. Fish were exposed via diet to both NMs at concentrations of 70 and 500 mg Cu/kg for 15 days, followed by 44 days of depuration. For water-borne exposure, only the rod-shaped CuO NMs were tested at 0.08 and 0.8 mg Cu/L for 28 days, followed by 14 days of depuration. The concentration of Cu was determined in fish whole body to derive biomagnification and bioconcentration factors (BMF and BCF). Different tissues were sampled to investigate the total Cu biodistribution and target organs as well as the particle number-based bioaccumulation of CuO NMs. Estimated BMF and BCF values were below the thresholds of concern. However, shape and route influenced depuration. Following dietary exposure, there was a higher depuration of Cu from fish exposed to the rod-shaped compared to the spherical CuO NMs. A higher depuration was also observed for rod-shaped CuO NMs following the dietary exposure compared the aqueous one. Despite the much higher dietary exposure concentrations of rod-shape CuO NMs, similar Cu body burdens were reached via water. Cu was found in particulate form in different tissues. Although these NMs had a low bioaccumulation potential, differences in distribution and elimination patterns of Cu were observed depending on the exposure route and particle shape. Careful consideration of the most relevant exposure route is needed when designing a bioaccumulation experiment for testing NMs.

Effects of micro(nano)plastics on the reproductive system: A review.

Microplastics (100nm-5 mm) and nanoplastics (1-100 nm) are collectively referred to as micro(nano)plastics (MNPs), which are refractory to degradation, easy to migration, small in size, strong in adsorption, and can widely present in human living environment. A number of studies have confirmed that MNPs can be exposed to the human body through a variety of routes, and can penetrate various barriers to enter the reproductive system, suggesting that MNPs may pose potential harm to human reproductive health. Current studies most were limited to phenotypic studies and their subjects were basically lower marine organisms and mammals. Therefore, in order to provide theoretical base for further exploring the effects of MNPs on the human reproductive system, this paper searched the relevant literature at home and abroad, mainly analyzed rodent experiments, and concluded that the main exposure routes of MNPs are dietary intake, air inhalation, skin contact and medical plastics. After entering the reproductive system, MNPs produce reproductive toxicity mainly through oxidative stress, inflammation, metabolic disorders, cytotoxicity and other mechanisms. More work is required to comprehensively identify the exposure routes, improve the detection methods to evaluate the effective exposure and deeply study the specific mechanisms of toxic effects, withing the aim of conducting relevant studies at the population level in the next step.

Health risk assessment of inorganic and organic constituents of the coarse and fine PM in an industrialized region of Brazil.

A health risk assessment of inorganic and organic species associated with coarse and fine particulate matter (PM) was conducted in Southeastern Brazil. TSP, PM10, and PM2.5 samples were collected, and their elemental (metals/metalloids) and organic (PAHs) composition were determined by EDXRF and GC-MS. The health risks were determined through hazard quotient (HQ) and cancer risk (CR). It was found that different elements and routes of exposure lead to different health risks, even for the PM concentration in compliance with air quality standards. The major routes of exposure for adults were inhalation and dermal contact whereas for children were ingestion and dermal contact. High non-cancer risks (HQ) caused by Cl and Fe exposure were associated with coarser fractions, PM10 and TSP, respectively, whereas high HQ for Se, Sb, and V exposure were associated with PM2.5. HQ values for children were near twice that for adults, and CR values were 65 % to 130 % higher for children than for adults. CR posed by PAHs was negligible. The results highlighted that the HQ might be over- or underestimated depending on the form in which the element Cl is determined (elemental or ion), reinforcing the need for an embracing chemical characterization of the PM. High HQ values were found related to the exposure to some elements present in the TSP, showing that this PM fraction should not be neglected.