Toxics, Volume 8, Issue 2 (June 2020) – 25 articles

Genotoxicity assessment is of high relevance for crude and refined petroleum products, since oil compounds are known to cause DNA damage with severe consequences for aquatic biota as demonstrated in long-term monitoring studies. This study aimed at the optimization and evaluation of small-scale higher-throughput assays (Ames fluctuation, micronucleus, Nrf2-CALUX^®) covering different mechanistic endpoints as first screening tools for genotoxicity assessment of oils. Cells were exposed to native and chemically dispersed water-accommodated fractions (WAFs) of three oil types varying in their processing degree. Independent of an exogenous metabolic activation system, WAF compounds induced neither base exchange nor frame shift mutations in bacterial strains. However, significantly increased chromosomal aberrations in zebrafish liver (ZF-L) cells were observed. Oxidative stress was indicated for some treatments and was not correlated with observed DNA damage. Application of a chemical dispersant increased the genotoxic potential rather by the increased bioavailability of dissolved and particulate oil compounds. Nonetheless, the dispersant induced a clear oxidative stress response, indicating a relevance for general toxic stress. Results showed that the combination of different in vitro assays is important for a reliable genotoxicity assessment. Especially, the ZF-L capable of active metabolism and DNA repair seems to be a promising model for WAF testing. Full article

Akita prefecture is located in the northern part of Japan and has many cadmium-polluted areas. We herein performed an exposure assessment of cadmium in 712 and 432 female farmers in two adjacent cadmium-polluted areas (A and B, respectively), who underwent local health examinations from 2001–2004. We measured cadmium concentrations in 100 food items collected from local markets in 2003. We then multiplied the intake of each food item by its cadmium concentration in each subject to assess cadmium intake from food and summed cadmium intake from all food items to obtain the total cadmium intake. Median cadmium intake levels in areas A and B were 55.7 and 47.8 µg/day, respectively, which were both higher than that of the general population and were attributed to local agricultural products, particularly rice. We also calculated weekly cadmium intake per body weight and compared it to the previous provisional tolerable weekly intake reported by the Joint FAO (Food and Agriculture Organization)/WHO (World Health Organization) expert committee on food additives or current tolerable weekly intake in Japan of 7 µg/kg BW/week. Medians in areas A and B were 7.2 and 6.0 µg/kg BW/week, respectively. Similar estimated values were also obtained by the Monte Carlo simulation. These results demonstrated that the cadmium exposure levels among the farmers were high enough to be approximately the tolerable weekly intake. Full article

Preeclampsia is one of the most common causes of perinatal and maternal morbidity/mortality. One suggested environmental risk factor is exposure to endocrine-disrupting pollutants such as per- and polyfluoroalkyl substances (PFAS). The present case-control study in southern Sweden aims to investigate the hypothesized association between serum concentrations of PFAS in early pregnancy and the risk of developing preeclampsia. The study included 296 women diagnosed with preeclampsia (cases) and 580 healthy pregnant women (controls). Maternal serum samples were obtained from a biobank of samples collected in early pregnancy in connection with screening for infections. Serum concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonate (PFHxS) were analyzed using liquid chromatography-tandem-mass-spectrometry (LC/MS/MS). Among primiparous women, there were no differences in PFAS concentrations in early pregnancy between the cases and the controls whereas among multipara women, the cases had significantly higher concentrations of PFNA (median concentrations were 0.44 and 0.38 ng/mL, p = 0.04). When individual PFAS were categorized into quartiles and adjustment for potential confounders was performed, the women in the highest quartiles had no significant increased risks of developing preeclampsia as compared with women in the lowest category. In conclusion, the present study provides limited support for the hypothesized association between PFAS and preeclampsia in a population with relatively low exposure levels. Full article

Per- and polyfluoroalkyl substances (PFAS) are a class of chemicals that were widely used in manufacturing and are now present in the environment throughout the world. It is known that various PFAS are quantifiable in human in blood, but potential adverse health outcomes remain unclear. Sentinel and non-traditional model species are useful to study potential toxicity of PFAS in order to understand the relationship between environmental and human health. Here, we present a critical review of studies on the neurotoxicity of PFAS in sentinel and non-traditional laboratory model systems, including Caenorhabditis elegans (nematode), Dugesia japonica (planarian), Rana pipiens (frogs), Danio rerio and Oryzias melastigma (fish), and Ursus maritimus (polar bears). PFAS have been implicated in developmental neurotoxicity in non-traditional and traditional model systems as well as sentinel species, including effects on neurotransmitter levels, especially acetylcholine and its metabolism. However, further research on the mechanisms of toxicity needs to be conducted to determine if these chemicals are affecting organisms in a similar manner. Overall, findings tend to be similar among the various species, but bioaccumulation may vary, which needs to be taken into account in future studies by quantifying target organ concentrations of PFAS to better compare different species. Furthermore, data on the majority of PFAS is lacking in neurotoxicity testing, and additional studies are needed to corroborate findings thus far. Full article

Cannabidiol (CBD) is a naturally occurring, non-psychotropic cannabinoid of the hemp plant Cannabis sativa L. and has been known to induce several physiological and pharmacological effects. While CBD is approved as a medicinal product subject to prescription, it is also widely sold over the counter (OTC) in the form of food supplements, cosmetics and electronic cigarette liquids. However, regulatory difficulties arise from its origin being a narcotic plant or its status as an unapproved novel food ingredient. Regarding the consumer safety of these OTC products, the question whether or not CBD might be degraded into psychotropic cannabinoids, most prominently tetrahydrocannabinol (THC), under in vivo conditions initiated an ongoing scientific debate. This feature review aims to summarize the current knowledge of CBD degradation processes, specifically the results of in vitro and in vivo studies. Additionally, the literature on psychotropic effects of cannabinoids was carefully studied with a focus on the degradants and metabolites of CBD, but data were found to be sparse. While the literature is contradictory, most studies suggest that CBD is not converted to psychotropic THC under in vivo conditions. Nevertheless, it is certain that CBD degrades to psychotropic products in acidic environments. Hence, the storage stability of commercial formulations requires more attention in the future. Full article

Microplastics have become one of the leading environmental threats due to their persistence, ubiquity and intrinsic toxic potential. The potential harm that microplastics impose on ecosystems varies from direct effects (i.e., entanglement and ingestion) to their ability to sorb a diversity of environmental pollutants (e.g., heavy metals, persistent organic compounds or pharmaceuticals). Therefore, the toxicological assessment of the combined effects of microplastics and sorbed pollutants can produce in biota is one of the hottest topics on the environmental toxicology field. This review aims to clarify the main impacts that this interaction could have on ecosystems by (1) highlighting the principal factors that influence the microplastics sorption capacities; (2) discussing the potential scenarios in which microplastics may have an essential role on the bioaccumulation and transfer of chemicals; and (3) reviewing the recently published studies describing toxicological effects caused by the combination of microplastics and their sorbed chemicals. Finally, a discussion regarding the need for a new generation of toxicological studies is presented. Full article

An evaluation of fraction composition and transformation of metal compounds emitted by metal ore processing enterprises and accumulated in soils is crucial for assessing the environmental risks of pollution and ecosystem benefit of remediation. The aim of this study was to develop a suitable sequential fractional procedure for metal pollutants for the peat soils matrix in the impact zone of a Cu-Ni smelter. Three experiment series were performed: (a) the study of the effect of ammonium acetate buffer pH in the range of 3.7–7.8 on the soil metal extraction; (b) the study of the effect of additional volume and frequency of soil treatment with solutions on the content of water-soluble, ammonium acetate extractable, and 0.1 N HNO₃ extractable fractions; and, (c) the determination of the metal fraction composition in the modified technique. Soil treatment with ammonium acetate buffer with a pH range of 4.5–5.5 was the most appropriate for the determination of mobile compounds of Cu and other metals in highly polluted peat soil. Triple soil treatment with water and ammonium acetate is necessary for the complete extraction of the water-soluble and exchangeable fractions, respectively. Additionally, we propose a procedure of full extraction of the exchangeable metal fraction from peat soils while using single treatment with 0.1 N HNO₃. This scheme allows evaluating geochemical mobility of metals and current environmental harm of polluted soils with a high content of organic matter. Full article

E-cigarette smoking (ECS) is a new method of tobacco smoking that is gaining popularity as it is thought to be a “healthy method” of tobacco consumption. The adverse outcomes of ECS on the respiratory and cardiovascular systems in humans have been recently demonstrated. Nevertheless, the effect of e-cigarette liquid (ECL) on the early stage of embryogenesis and angiogenesis has not been explored yet. Chicken embryo at 3 days of incubation and its chorioallantoic membrane (CAM) of 5 days were used to explore the outcome of ECL on the embryo. Real-time PCR was also employed to study the regulation of a set of key controller genes of embryogenesis as well as angiogenesis. Our study revealed that ECL exposure is associated with a high rate of mortality in embryos as around 70% of treated embryos, at 3 days of incubation, die after 5 days of exposure. Additionally, ECL inhibits angiogenesis of the CAM of 5 days of incubation by more than 30%. These effects could be explained by the upregulation of ATF-3, FOXA2, INHBA, MAPRE-2, and RIPK-1, as well as the downregulation of SERPINA-4 and VEGF-C genes, which are important key controller genes of embryogenesis as well as angiogenesis. Our data suggest clearly that ECS can have dramatic toxic outcomes on the early stage of embryogenesis as well as angiogenesis. Accordingly, we believe that further studies to assess the effects of ECS on human health are essential. Full article

Microplastics (MPs) occur widely in terrestrial ecosystems. However, information on the interaction of MPs with metals in terrestrial ecosystems is lacking in the literature. The present study investigated the effects of two types of MPs (high-density polyethylene (HDPE) and polystyrene (PS)) with different dosages (i.e., 0, 0.1%, 1%, and 10%) on the uptake and effects of Cd in maize plants grown in an agricultural soil. Results showed that addition of Cd at a 5 mg/kg caused inhibited plant growth and resulted in high Cd accumulation in plant tissues. Polyethylene alone showed no significant phytotoxic effects, but a high-dose of HDPE (10%) amplified Cd phytotoxicity. Polystyrene negatively affected maize growth and phytoxicity further increased in the presence of Cd. Both HDPE and PS caused soil diethylenetriaminepentaacetic acid (DTPA)-extractable Cd concentrations to increase but did not significantly affect Cd uptake into plant tissues. In the soil without Cd addition, HDPE decreased soil pH, while PS did not significantly alter soil pH. However, in the soil spiked with Cd, both HDPE and PS increased pH. Overall, impacts on plant growth and Cd accumulation varied with MP type and dose, and PS induced substantial phytotoxicity. In conclusion, co-occurring MPs can change Cd bioavailability, plant performance, and soil traits. Our findings highlight the ecological impacts that could occur from the release of MPs into soil. Full article

Much of the seafood that humans consume comes from estuaries and coastal areas where microplastics (MPs) accumulate, due in part to continual input and degradation of plastic litter from rivers and runoff. As filter feeders, oysters (Crassostrea virginica) are especially vulnerable to MP pollution. In this study, we assessed MP pollution in water at oyster reefs along the Mississippi Gulf Coast when: (1) historic flooding of the Mississippi River caused the Bonnet Carré Spillway to remain open for a record period of time causing major freshwater intrusion to the area and deleterious impacts on the species and (2) the spillway was closed, and normal salinity conditions resumed. Microplastics (~25 µm–5 mm) were isolated using a single-pot method, preparing samples in the same vessel (Mason jars) used for their collection right up until the MPs were transferred onto filters for analyses. The MPs were quantified using Nile Red fluorescence detection and identified using laser direct infrared (LDIR) analysis. Concentrations ranged from ~12 to 381 particles/L and tended to decrease at sites impacted by major freshwater intrusion. With the spillway open, average MP concentrations were positively correlated with salinity (r = 0.87, p = 0.05) for sites with three or more samples examined. However, the dilution effect on MP abundances was temporary, and oyster yields suffered from the extended periods of lower salinity. There were no significant changes in the relative distribution of MPs during freshwater intrusions; most of the MPs (>50%) were in the lower size fraction (~25–90 µm) and consisted mostly of fragments (~84%), followed by fibers (~11%) and beads (~5%). The most prevalent plastic was polyester, followed by acrylates/polyurethanes, polyamide, polypropylene, polyethylene, and polyacetal. Overall, this work provides much-needed empirical data on the abundances, morphologies, and types of MPs that oysters are exposed to in the Mississippi Sound, although how much of these MPs are ingested and their impacts on the organisms deserves further scrutiny. This paper is believed to be the first major application of LDIR to the analysis of MPs in natural waters. Full article

Bisphenol A (BPA) is leached out from plastic infant feeding bottles that are filled with warm milk/water due to high temperatures, exposing the infants to BPA. The present study aims to understand the effects of ingestion of BPA leached from plastic infant feeding bottle and delineate the underlying mechanisms in rats. In this study, adult rats of Wistar strain were divided into 3 groups. In the first group, the rats consumed normal food and tap water ad libitum. In the second group, the rats ingested BPA (20 µg/kg bodyweight/day, orally). In the third group, the rats drank water leached from plastic infant feeding bottles. After 30days, tests involving biochemical parameters, histopathological examination, and oxidative stress enzyme markers were performed, and the levels of BPA in plastic-leached water were estimated by HPLC analysis. There were significant biochemical changes in the form of increased alkaline phosphatase (ALP), creatine kinase-muscle/brain (CK-MB), and lactate dehydrogenase (LDH) levels in both treated groups as compared to control group, accompanied by structural damage to the vital organs, and lipid peroxidation, glutathione reductase, and catalase activity were also high in the treated groups. Further, the BPA concentration in plastic leached water was estimated to be 0.1 ± 0.02 µg/mL. Full article

Polyhexamethylene guanidine-phosphate (PHMG-P), a guanidine-based cationic antimicrobial polymer, is an effective antimicrobial biocide, potent even at low concentrations. Due to its resilient bactericidal properties, it has been used extensively in consumer products. It was safely used until its use in humidifiers led to a catastrophic event in South Korea. Epidemiological studies have linked the use of PHMG-P as a humidifier disinfectant to pulmonary fibrosis. However, little is known about its harmful impacts other than pulmonary fibrosis. Thus, we applied a zebrafish embryo/larvae model to evaluate developmental and cardiotoxic effects and transcriptome changes using RNA-sequencing. Zebrafish embryos were exposed to 0.1, 0.2, 0.3, 0.4, 0.5, 1, and 2 mg/L of PHMG-P from 3 h to 96 h post fertilization. 2 mg/L of PHMG-P resulted in total mortality and an LC₅₀ value at 96 h was determined at 1.18 mg/L. Significant developmental changes were not observed but the heart rate of zebrafish larvae was significantly altered. In transcriptome analysis, immune and inflammatory responses were significantly affected similarly to those in epidemiological studies. Our qPCR analysis (Itgb1b, TNC, Arg1, Arg2, IL-1β, Serpine-1, and Ptgs2b) also confirmed this following a 96 h exposure to 0.4 mg/L of PHMG-P. Based on our results, PHMG-P might induce lethal and cardiotoxic effects in zebrafish, and crucial transcriptome changes were linked to immune and inflammatory response. Full article

Contamination of shooting ranges by heavy metals in particular Pb represents a widespread environmental issue attracting concern worldwide. Contaminant accumulation in shooting range soils can pose potential ecological risks and health risks for shooters and workers. Based on the published data on metal contamination at five shooting ranges in China, potential ecological and human health risks of several metals, and in particular, Pb were assessed for the five surveyed shooting ranges. Data show the mean concentrations of Pb, Cu, Hg, Sb, Ni and Cr in various ranges were all higher than the local soil background values, implying their accumulation was induced by shooting activities. The degree of contamination varied with sites and metals, very high Pb contamination at Range 1, Range 2 and Range 5-1, while moderate Pb contamination at Range 3 and Range 5-2. Comparatively, As, Zn and Co showed no contamination. Among the surveyed metals, Pb, Cu, Hg and Sb in shooting range soils displayed relatively high potential ecological risks. The overall degree of potential ecological risk was very high at Range 1 and Range 2, considerable at Range 4 and Range 5-1, and low at Range 3 and Range 5-2. The mean HI (hazard index) of Pb at Range 2 and the maximum HI values at Range 1 and Range 4 were higher than 1, suggesting a possibility of non-carcinogenic risks of Pb contamination at these sites. However, Pb in other range soils and other metals, across the five ranges, all exhibited no non-carcinogenic risks. The cancer risks of the four carcinogenic contaminants (As, Co, Cr, and Ni) were acceptable or negligible at all ranges. In conclusion, contamination of Pb and other metals such as Cu, Hg and Sb can cause various potential ecological risks at all the surveyed ranges, but only Pb at three ranges shows possible health risks. Contamination of Pb in the surveyed shooting ranges should be managed to reduce its possible environmental and health risks. Full article

Recently, soluble forms of aluminum for human use or consumption have been determined to be potentially toxic due to their association with hepatic, neurological, hematological, neoplastic, and bone conditions. This study aims to assess the genotoxic effect of aluminum chloride on genomic instability associated with the onset of N-nitroso-N-methylurea (NMU)-induced breast cancer in Sprague Dawley rats. The dietary behavior of the rats was assessed, and the concentration of aluminum in the mammary glands was determined using atomic absorption spectroscopy. Genomic instability was determined in the histological sections of mammary glands stained with hematoxylin and eosin. Moreover, micronucleus in peripheral blood and comet assays were performed. The results of dietary behavior evaluation indicated no significant differences between the experimental treatments. However, aluminum concentration in breast tissues was high in the +2000Al/−NMU treatment. This experimental treatment caused moderate intraductal cell proliferation, lymph node hyperplasia, and serous gland adenoma. Furthermore, micronucleus and comet test results revealed that +2000Al/−NMU led to a genotoxic effect after a 10-day exposure and the damage was more evident after a 15-day exposure. Therefore, in conclusion, genomic instability is present and the experimental conditions assessed are not associated with breast cancer. Full article

Oral glucose tolerance tests, in which the concentration of glucose is monitored in the circulation over 2 h after ingesting a bolus, probe diabetic or pre-diabetic conditions. The resulting glucose curves inform about glucose turnover, insulin production and sensitivity, and other parameters. However, extracting the relevant parameters from a single complex curve is not straightforward. We propose a simple modeling method recapitulating the most salient features of the role of insulin-secreting pancreatic $\beta$ -cells and insulin sensitive tissues. This method implements four ordinary differential equations with ten parameters describing the time-dependence of glucose concentration, its removal rate, and the circulating and stored insulin concentrations. From the initial parameter set adjusted to a reference condition, fitting is done by minimizing a weighted least-square residual. In doing so, the sensitivity of $\beta$ -cells to glucose was identified as the most likely impacted function at weaning for the progeny of rats that were lightly exposed to cadmium in the perigestational period. Later in life, after young rats received non-contaminated carbohydrate enriched food, differences are more subtle, but modeling agrees with long-lasting perturbation of glucose homeostasis. Full article

The presence of pharmaceutical and personal care product (PPCP) residues in the aquatic environment is an emerging issue due to their uncontrolled release through gray water, and accumulation in the environment that may affect living organisms, ecosystems and public health. The aim of this study is to assess the toxicity of benzophenone-3 (BP-3), bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT), butyl methoxydibenzoylmethane (BM), methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT), 2-ethylhexyl salicylate (ES), diethylaminohydroxybenzoyl hexyl benzoate (DHHB), diethylhexyl butamido triazone (DBT), ethylhexyl triazone (ET), homosalate (HS) and octocrylene (OC) on marine organisms from two major trophic levels, including autotrophs (Tetraselmis sp.) and heterotrophs (Artemia salina). In general, results showed that both HS and OC were the most toxic UV filters for our tested species, followed by a significant effect of BM on Artemia salina due to BM—but only at high concentrations (1 mg/L). ES, BP3 and DHHB affected the metabolic activity of the microalgae at 100 µg/L. BEMT, DBT, ET, MBBT had no effect on the tested organisms, even at high concentrations (2 mg/L). OC toxicity represents a risk for those species, since concentrations used in this study are 15–90 times greater than those reported in occurrence studies for aquatic environments. For the first time in the literature, we report HS toxicity on a microalgae species at concentrations complementing those found in aquatic environments. These preliminary results could represent a risk in the future if concentrations of OC and HS continue to increase. Full article

The epidemiology of severe acute poisonings in the French overseas departments of the Americas remains poorly reported. The main objective of this study was to determine the epidemiology and characteristics of severe acutely poisoned adult patients. Methods: A retrospective descriptive study was conducted from 1 January 2000 to 31 December 2010 in severely poisoned patients presenting to the emergency department (ED) of the University Hospital of Martinique, and the general public hospitals of Lamentin and Trinité. Results: During the study period, 291 patients were admitted for severe poisoning, giving an incidence rate of 7.7 severe cases/100,000 inhabitants. The mean age was 46 ± 19 years and 166 (57%) were male. Psychiatric disorders were recorded in 143 (49.8%) patients. Simplified Acute Psychological Score (SAPS II) at admission was 39 ± 23 points and Poisoning Severity Score (PSS) was 2.7 ± 0.8 points. Death was recorded in 30 (10.3%) patients and hospital length of stay was 6 ± 7 days. The mode of intoxication was intentional self-poisoning in 87% of cases and drug overdose was recorded in 13% of cases. The toxic agent involved was a therapeutic drug in 58% and a chemical product in 52% of cases. The predominant clinical manifestations were respiratory failure (59%), hemodynamic failure (27%), neurologic failure (45%), gastrointestinal manifestations (27%), and renal failure (11%). Polypnea, shock, ventricular fibrillation or tachycardia, and gastro-intestinal disorders were the main symptoms associated with death. The main biological abnormalities associated with death in our patients were metabolic acidosis, hypokalemia, hyperlactatemia, hypocalcemia, renal injury, rhabdomyolysis, increased aspartate aminotransferases, and thrombocytopenia. Extracorporal membrane oxygenation (ECMO) was used in three patients and specific antidotes were used in 21% of patients. Conclusions: Acute poisonings remain a major public health problem in Martinique with different epidemiological characteristics to those in mainland France, with a high incidence of poisoning by rural and household toxins. Full article

Nano-scale zero-valent iron (nZVI) is among the most common nanoparticles widely used for the treatment of various environmental contaminants. However, little is known about the combined effects of nano-zero-valent iron (nZVI) and other soil amendments on soil remediation and plant performance. For the first time, we studied the remediation of Cr(VI)-contaminated soil using bare nZVI (B-nZVI) and starch-supported nZVI (S-nZVI) in combination with either biochar (BC) or humic acid (HA), and the consequent effects on plant growth and Cr accumulation. Both S-nZVI and B-nZVI decreased the contents of Cr(VI) and available Cr in soil, but increased available Fe content, with S-nZVI generally showing more pronounced effects at a higher dose (1000 mg/kg). B-nZVI exerted no inhibition and even stimulation on plant growth, but 1000 mg/kg S-nZVI produced significant phytotoxicity, resulting in decreased plant growth, low chlorophyll content in leaves, and excessive accumulation of Fe in roots. Each nZVI decreased shoot and root Cr concentrations. BC and HA produced synergistic effects with nZVI on Cr(VI) removal from soil, but HA decreased soil pH and increased the availability of Cr and Fe, implying a potential environmental risk. Addition of BC or HA did not alter the effects of either nZVI on plant growth. In conclusion, combined application of 100 mg/kg nZVI and BC could be an ideal strategy for the remediation of soil contaminated with Cr(VI), whereas high-dose S-nZVI and HA are not recommended in the remediation of agricultural soils for crop production or in the phytostabilization of Cr(VI). Full article

The Centers for Disease Control declared e-cigarette, or vaping, product use-associated lung injury (EVALI) a national outbreak due to the high incidence of emergency department admissions and deaths. We have identified chemical constituents in e-cig counterfeit cartridges and compared these to medical-grade and CBD containing cartridges. Apart from vitamin E acetate (VEA) and tetrahydrocannabinol (THC), other potential toxicants were identified including solvent-derived hydrocarbons, silicon conjugated compounds, various terpenes, pesticides/plasticizers/polycaprolactones, and metals. This study provides additional insights into the chemicals associated with EVALI cartridges and thus may contribute to the underlying disease mechanism of acute lung injury. Full article

Cadmium (Cd) is an environmental pollutant known to cause dysfunctions of the tubular reabsorption of biomolecules in the kidney. Elevated levels of urinary excretion of low-molecular-weight proteins such as β₂-microglobulin (β₂-MG) have been used as an indicator of Cd-induced renal tubular dysfunctions. However, very few studies have examined the direct effects of Cd on the reabsorption efficiency of proteins using cultured renal cells. Here, we developed an in vitro assay system for quantifying the endocytic uptakes of fluorescent-labeled proteins by flow cytometry in S1 and S2 cells derived from mouse kidney proximal tubules. Endocytic uptakes of fluorescent-labeled albumin, transferrin, β₂-MG, and metallothionein into S1 cells were confirmed by fluorescence imaging and flow cytometry. The exposure of S1 and S2 cells to Cd at 1 and 3 µM for 3 days resulted in significant decreases in the uptakes of β₂-MG and metallothionein but not in those of albumin or transferrin. These results suggest that Cd affects the tubular reabsorption of low-molecular-weight proteins even at nonlethal concentrations. The in vitro assay system developed in this study to evaluate the endocytic uptakes of proteins may serve as a useful tool for detecting toxicants that cause renal tubular dysfunctions. Full article

Perfluoroalkyl carboxylic acids (PFCAs), such as perfluorooctanoic acid (PFOA, C8), are a group of industrial chemicals that are detected in the serum of people throughout the world. Long-chain PFCAs (C9 to C13) have high lipophilicity, therefore they may have a high transfer rate to breast milk. This study investigated the lactational transfer of PFCAs with carbon chain lengths of 8 to 13 in mice. Lactating dams were given a single intravenous administration of PFCAs (C8 to C13) during the postnatal period (8–13 days after delivery). Milk was collected from the dam 24 h after administration using a milking device built in-house. Plasma was obtained from the dam at the same time as milk collection. The observed milk/plasma (M/P) concentration ratios were 0.32 for C8, 0.30 for C9, 0.17 for C10, 0.21 for C11, 0.32 for C12, and 0.49 for C13. These results indicate that the M/P concentration ratio is not related to the lipophilicity of PFCAs. However, estimated relative daily intake, an indicator of how much PFCA is transferred from dams to pups per body weight, increased with chain length: 4.16 for C8, 8.98 for C9, 9.35 for C10, 9.51 for C11, 10.20 for C12, and 10.49 for C13, which may be related to the lower clearance of long-chain PFCAs. These results indicate the importance of future risk assessment of long-chain PFCAs. Full article

The presence of microplastics (MPs) in the world’s longest river, the Nile River, has yet to be reported. This small-scale study aimed to provide the first information about MPs in the Nile River by sampling the digestive tracts of two fish species, the Nile tilapia (Oreochromis niloticus, n = 29) and catfish (Bagrus bayad, n = 14). Fish were purchased from local sellers in Cairo, and then their gastrointestinal tracts were dissected and examined for MPs. Over 75% of the fish sampled contained MPs in their digestive tract (MP prevalence of 75.9% and 78.6% for Nile tilapia and catfish, respectively). The most abundant MP type was fibers (65%), the next most abundant type was films (26.5%), and the remaining MPs were fragments. Polyethylene (PE), polyethylene terephthalate (PET) and polypropylene (PP) were all non-destructively identified by attenuated total reflectance Fourier transform infrared spectroscopy. A comparison with similar studies from marine and freshwater environments shows that this high level of MP ingestion is rarely found and that fish sampled from the Nile River in Cairo are potentially among the most in danger of consuming MPs worldwide. Further research needs to be conducted, but, in order to mitigate microplastic pollution in the Nile River, we must act now. Full article

Environmental toxicants have been implicated in neurodegenerative diseases, and pesticide exposure is a suspected environmental risk factor for Alzheimer’s disease (AD). Several epidemiological analyses have affirmed a link between pesticides and incidence of sporadic AD. Meanwhile, in vitro and animal models of AD have shed light on potential neuropathological mechanisms. In this paper, a perspective on neuropathological mechanisms underlying pesticides’ induction of AD is provided. Proposed mechanisms range from generic oxidative stress induction in neurons to more AD-specific processes involving amyloid-beta (Aβ) and hyperphosphorylated tau (p-tau). Mechanisms that are more speculative or indirect in nature, including somatic mutation, epigenetic modulation, impairment of adult neurogenesis, and microbiota dysbiosis, are also discussed. Chronic toxicity mechanisms of environmental pesticide exposure crosstalks in complex ways and could potentially be mutually enhancing, thus making the deciphering of simplistic causal relationships difficult. Full article