Complex Chemical Mixtures Research Articles

Unraveling the toxicity of tire wear contamination in three freshwater species: From chemical mixture to nanoparticles

Tire wear particle (TWP) contamination is of growing concern as recent studies show the ubiquity and toxicity of this contaminant in various environmental compartments. The multidimensional aspect of TWPs makes it difficult to assess toxicity and predict impacts on ecosystems, as it combines a complex mixture of chemicals and can release micro- and nanoparticles when suspended in water. Our work aimed to shed light on the toxicity of the different components of TWP leachate, namely, the dissolved chemicals and the nanoparticle fractions, on three freshwater model species of different trophic levels: Chlorella vulgaris, Lemna minor, and Daphnia magna. Acute toxicity was observed for all three fractions in D. magna, and an additive effect was observed between the nanoparticles and dissolved chemicals. L. minor experienced phytotoxicity from the dissolved chemicals only with a decrease up to 50% in photosynthesis efficiency parameters. C. vulgaris showed minor signs of toxicity on apical endpoints in response to each of the fractions. Our study highlights that nanoparticles from TWP leachate that were mostly overlooked in several previous studies are as toxic as dissolved chemicals for the filter-feeder species D. magna, and we also show the toxicity to photosynthesis in aquatic plants.

Trends and challenges in analytical chemistry for multi-analysis of illicit drugs employing wastewater-based epidemiology.

Wastewater-based epidemiology (WBE) for quantification of illicit drug biomarkers (IDBs) in wastewater samples is an effective tool that can provide information about drug consumption. The most commonly quantified IDBs belong to different chemical classes, including cocaine, amphetamine-type stimulants, opioids, and cannabinoids, so the different chemical properties of these molecules pose a challenge in the development of analytical methods for multi-analyte analysis. Recent workflows include the steps of sampling and storage, sample preparation using solid-phase extraction (SPE) or without extraction, and quantification of analytes employing gas or liquid chromatography coupled with mass spectrometry. The greatest difficulty is due to the fact that wastewater samples are complex chemical mixtures containing analytes with different chemical properties, often present at low concentrations. Therefore, in the development of analytical methods, there is the need to simplify and optimize the analytical workflows, reducing associated uncertainties, analysis times, and costs. The present work provides a critical bibliographic survey of studies published from the year 2020 until now, highlighting the challenges and trends of published analytical workflows for the multi-analysis of IDBs in wastewater samples, considering sampling and sample preparation, method validation, and analytical techniques.

Rat bronchoalveolar lavage proteome changes following e-cigarette aerosol exposures.

E-cigarette liquids are complex mixtures of chemicals consisting of humectants, such as propylene glycol (PG) and vegetable glycerin (VG), with nicotine or flavorings added. Published literature emphasizes the toxicity of e-cigarette aerosols with flavorings whereas much less attention has been given to the biologic effects of humectants. The purpose of the current study was to provide a comprehensive view of the acute biologic effects of e-cigarette aerosols on rat bronchoalveolar lavage (BAL) using mass spectrometry-based global proteomics. Sprague-Dawley rats were exposed to e-cigarette aerosol for 3 h/day for three consecutive days. Groups included: PG/VG alone, PG/VG + 2.5% nicotine (N), or PG/VG + N + 3.3% vanillin (V). Right lung lobes were lavaged for BAL and supernatants prepared for proteomics. Extracellular BAL S100A9 concentrations and BAL cell staining for citrullinated histone H3 (citH3) were also performed. From global proteomics, ∼2,100 proteins were identified from rat BAL. The greatest change in number of BAL proteins occurred with PG/VG exposures alone compared with controls with biological pathways enriched for acute phase responses, extracellular trap formation, and coagulation. Extracellular BAL S100A9 concentrations and the number of citH3 + BAL cells also increased significantly in PG/VG and PG/VG + 2.5% N. In contrast to PG/VG or PG/VG + N, the addition of vanillin to PG/VG + N increased BAL neutrophilia and downregulated lipid transport proteins. In summary, global proteomics support e-cigarette aerosol exposures to PG/VG alone as having a significant biologic effect on the lung independent of nicotine or flavoring with increased markers of extracellular trap formation.

Fish liver damage related to the wastewater treatment plant effluents.

Wastewater treatment plants (WWTPs) continuously release a complex mixture of municipal, hospital, industrial, and runoff chemicals into the aquatic environment. These contaminants are both legacy contaminants and emerging-concern contaminants, affecting all tissues in a fish body, particularly the liver. The fish liver is the principal detoxifying organ and effects of consistent pollutant exposure can be evident on its cellular and tissue level. The objective of this paper is thus to provide an in-depth analysis of the WWTP contaminants' impact on the fish liver structure, physiology, and metabolism. The paper also gives an overview of the fish liver biotransformation enzymes, antioxidant enzymes, and non-enzymatic antioxidants, their role in metabolizing xenobiotic compounds and coping with oxidative damage. Emphasis has been placed on highlighting the vulnerability of fish to xenobiotic compounds, and on biomonitoring of exposed fish, generally involving observation of biomarkers in caged or native fish. Furthermore, the paper systematically assesses the most common contaminants with the potential to affect fish liver tissue.

Toxicological Assessment of Particulate and Metal Hazards Associated with Vaping Frequency and Device Age.

Electronic nicotine delivery systems (ENDS) aerosols are complex mixtures of chemicals, metals, and particles that may present inhalation hazards and adverse respiratory health risks. Despite being considered a safer alternative to tobacco cigarettes, metal exposure levels and respiratory effects associated with device aging and vaping frequency have not been fully characterized. In this study, we utilize an automated multi-channel ENDS aerosol generation system (EAGS) to generate aerosols from JUUL pod-type ENDS using tobacco-flavored e-liquid. Aerosol puff fractions (1-50) and (101-150) are monitored and sampled using various collection media. Extracted aerosols are prepared for metal and toxicological analysis using human primary small airway epithelial cells (SAEC). ENDS aerosol-mediated cellular responses, including reactive oxygen species (ROS), oxidative stress, cell viability, and DNA damage, are evaluated after 24 h and 7-day exposures. Our results show higher particle concentrations in later puff fractions (0.135 mg/m3) than in initial puff fractions (0.00212 mg/m3). Later puff fraction aerosols contain higher toxic metal concentrations, including chromium, copper, and lead, which elicit increased levels of ROS followed by significant declines in total glutathione and cell viability. Notably, a 30% increase in DNA damage was observed after 7 days because of later puff fraction exposures. This work is consistent with ENDS aerosols becoming more hazardous across the use of pre-filled pod devices, which may threaten respiratory health.

Explaining the persistence of hazardous chemicals in the Doce River (Brazil) by multiple sources of contamination and a major environmental disaster

High concentrations of hazardous chemicals may be introduced into aquatic ecosystems during episodes of acute and chronic environmental contamination. This study aimed to quantify inorganic and organic contaminants along the Doce River Basin (DRB), evaluate spatial and temporal variations of their concentrations, and their associations with the respective potential anthropogenic sources, considering the cumulative effects of a tailing dam rupture event. Multivariate analysis indicated that higher levels of trace elements in the Upper DRB were related to its proximity to the mining activities in this region, while organic contaminants such as PAHs are probably introduced by industrial effluents and urban centers along the DRB. In addition, seasonal variation showed to be an important factor influencing the distribution of chemicals, with wet season increasing levels of trace elements in the water. Despite the contribution of natural geological features in the Upper DRB, it becomes clearer that intense mineral exploitation for decades, combined with the dam failure disaster are responsible for the increased levels and spread of these inorganic contaminants along the DRB. Furthermore, other sources of organic contaminants contribute to this contamination scenario, resulting in complex mixtures of chemicals and increasing the ecological risks in the region.

Effects of coffee intake on airway hypersensitivity and immunomodulation: an in vivo murine study.

Coffee is a complex chemical mixture, with caffeine being the most well-known bioactive substance. The immunomodulatory and anti-inflammatory properties of coffee and caffeine impact health in various aspects, including the respiratory system. The objective is to investigate the effects of coffee and caffeine on airway hyperresponsiveness and allergic reactions, as well as to analyze and compare associated cytokine profiles. BALB/c mice were intraperitoneally sensitized with ovalbumin (OVA) and given OVA inhalation to induce airway hypersensitivity. Two weeks after sensitization, they were intragastrically gavaged with coffee or caffeine, both containing 0.3125 mg caffeine, daily for 4 weeks. Control mice were fed with double-distilled water. Serum OVA-specific antibody levels were measured beforehand and 5 weeks after the first gavage. Airway hyperresponsiveness was detected by whole body plethysmography after gavage. Cytokine levels of bronchoalveolar lavage and cultured splenocytes were analyzed. Coffee effectively suppressed T helper 2-mediated specific antibody response. Airway responsiveness was reduced in mice treated with either coffee or caffeine. Compared to the control, coffee significantly reduced OVA-specific immunoglobulin (Ig) G, IgG1 and IgE antibody responses (P < 0.05). Caffeine also attenuated specific IgG and IgG1 levels, though IgE level was unaffected. Coffee significantly reduced interleukin (IL)-4 and increased IL-10 concentration in spleen cells and bronchoalveolar lavage fluid (P < 0.05). Coffee effectively attenuated airway hyperresponsiveness and systemic allergic responses induced by OVA food allergen in mice. As a complex composition of bioactive substances, coffee displayed enhanced immunomodulatory and anti-inflammatory effects than caffeine.

Hormone receptor activities of complex mixtures of known and suspect chemicals in personal silicone wristband samplers worn in office buildings

Humans are exposed to increasingly complex mixtures of hormone-disrupting chemicals from a variety of sources, yet, traditional research methods only evaluate a small number of chemicals at a time. We aimed to advance novel methods to investigate exposures to complex chemical mixtures. Silicone wristbands were worn by 243 office workers in the USA, UK, China, and India during four work shifts. We analyzed extracts of the wristbands for: 1) 99 known (targeted) chemicals; 2) 1000+ unknown chemical features, tentatively identified through suspect screening; and 3) total hormonal activities towards estrogen (ER), androgen (AR), and thyroid hormone (TR) receptors in human cell assays. We evaluated associations of chemicals with hormonal activities using Bayesian kernel machine regression models, separately for targeted versus suspect chemicals (with detection ≥50%). Every wristband exhibited hormonal activity towards at least one receptor: 99% antagonized TR, 96% antagonized AR, and 58% agonized ER. Compared to men, women were exposed to mixtures that were more estrogenic (180% higher, adjusted for country, age, and skin oil abundance in wristband), anti-androgenic (110% higher), and complex (median 836 detected chemical features versus 780). Adjusted models showed strong associations of jointly increasing chemical concentrations with higher hormonal activities. Several targeted and suspect chemicals were important co-drivers of overall mixture effects, including chemicals used as plasticizers, fragrance, sunscreen, pesticides, and from other or unknown sources. This study highlights the role of personal care products and building microenvironments in hormone-disrupting exposures, and the substantial contribution of chemicals not often identifiable or well-understood to those exposures.

A Multimodel Investigation of Asian Summer Monsoon UTLS Transport Over the Western Pacific

AbstractThe Asian summer monsoon (ASM) as a chemical transport system is investigated using a suite of models in preparation for an airborne field campaign over the Western Pacific. Results show that the dynamical process of anticyclone eddy shedding in the upper troposphere rapidly transports convectively uplifted Asian boundary layer air masses to the upper troposphere and lower stratosphere over the Western Pacific. The models show that the transported air masses contain significantly enhanced aerosol loading and a complex chemical mixture of trace gases that are relevant to ozone chemistry. The chemical forecast models consistently predict the occurrence of the shedding events, but the predicted concentrations of transported trace gases and aerosols often differ between models. The airborne measurements to be obtained in the field campaign are expected to help reduce the model uncertainties. Furthermore, the large‐scale seasonal chemical structure of the monsoon system is obtained from modeled carbon monoxide, a tracer of the convective transport of pollutants, which provides a new perspective of the ASM circulation, complementing the dynamical characterization of the monsoon.

Treated tannery effluent and its impact on the receiving stream water: physicochemical characterization and cytogenotoxic evaluation using the Allium cepa test.

Tanneries are considered some of the most polluting industries due to the heavy use of toxic compounds, most of which are released into water bodies, thus exerting adverse effects on aquatic biota. However, the effects on organisms of treated effluents when released into the natural environment are rarely evaluated. This study aims to assess the physicochemical parameters of a tannery effluent after treatment (TE) at a Common Effluent Treatment Plant as well as the water of the receiving stream and to evaluate cytogenotoxic effects in Allium cepa. Three sampling sites (A: TE discharge point; B: 100m downstream from site A along the receiving stream; C: 100m upstream from site A along the stream) were selected. Onion bulbs were exposed to TE (100%, 80%, 60% v/v), water samples from sites B and C, and tap water for 72h. Chromosomal aberration and mitotic index were analyzed on the root cells of A. cepa. The TE was above the standard limits for ammoniacal nitrogen, COD, and total nitrogen. No cytogenotoxicity was observed in A. cepa exposed to samples from sites A and C. However, the stream water sampled downstream from the TE discharge site significantly reduced the mitotic index, indicating a cytotoxic effect. Therefore, this demonstrates the effects of interactions between the receiving water and the complex chemical mixtures in the TE. The findings thus showed that the toxicity assessment of treated effluents along with the receiving water body would provide valuable and more realistic information about the joint toxicity of chemical pollutants in aquatic environments.

Occupational Exposure to Volatile Organic Compounds (VOCs), Including Aldehydes for Swedish Hairdressers.

Working as a professional hairdresser involves the daily usage of many different hair treatment products containing chemicals in complex mixtures. Exposure may induce symptoms in the airways and on the skin. In this study, exposure of hairdressers to volatile organic compounds (VOCs), including aldehydes, was measured in the personal breathing zone in the spring of 2017. The study included 30 hairdressers evenly distributed over ten hair salons in the town of Örebro, Sweden. Work tasks and indoor climate were also surveilled. A hazard index (HI) based on chronic reference values for health was calculated to indicate combined exposure risk. In total, 90 VOCs, including nine aldehydes, were identified. Individual exposure expressed as a total concentration of VOCs (TVOCs) were in the range of 50-3600 µg/m3 toluene equivalent (median 460 µg/m3) and the HI was in the range 0.0046-13 (median 0.9). Exposure was more strongly influenced by variability among hairdressers than among salons. The HI indicated an increased risk of non-carcinogenic effects (HI ≥ 1) at four of the 10 hair salons. Individual working procedures, ventilation, volumetric usage of hair treatment products, certain chemicals in products (formaldehyde, isopropanol, and 2,4- and 2,6-toluene diisocyanate), and availability of reference values may have affected estimates of exposure risks. Nevertheless, the HI may be suitable as a screening tool to assess potential exposure risk posed to hairdressers since it considers the complexity of chemical mixtures and the chronic component of VOC exposure occurring in all indoor environments.

Childhood exposures to environmental chemicals and neurodevelopmental outcomes in congenital heart disease.

Children with congenital heart defects have an increased risk of neurodevelopmental disability. The impact of environmental chemical exposures during daily life on neurodevelopmental outcomes in toddlers with congenital heart defects is unknown. This prospective study investigated the impacts of early childhood exposure to mixtures of environmental chemicals on neurodevelopmental outcomes after cardiac surgery. Outcomes were assessed at 18 months of age using The Bayley Scales of Infant and Toddler Development-III. Urinary concentrations of exposure biomarkers of pesticides, phenols, parabens, and phthalates, and blood levels of lead, mercury, and nicotine were measured at the same time point. Bayesian profile regression and weighted quantile sum regression were utilized to assess associations between mixtures of biomarkers and neurodevelopmental scores. One-hundred and forty infants were enrolled, and 110 (79%) returned at 18 months of age. Six biomarker exposure clusters were identified from the Bayesian profile regression analysis; and the pattern was driven by 15 of the 30 biomarkers, most notably 13 phthalate biomarkers. Children in the highest exposure cluster had significantly lower adjusted language scores by -9.41 points (95%CI: -17.2, -1.7) and adjusted motor scores by -4.9 points (-9.5, -0.4) compared to the lowest exposure. Weighted quantile sum regression modeling for the overall exposure-response relationship showed a significantly lower adjusted motor score (β = -2.8 points [2.5th and 97.5th percentile: -6.0, -0.6]). The weighted quantile sum regression index weights for several phthalates, one paraben, and one phenol suggest their relevance for poorer neurodevelopmental outcomes. Like other children, infants with congenital heart defects are exposed to complex mixtures of environmental chemicals in daily life. Higher exposure biomarker concentrations were associated with significantly worse performance for language and motor skills in this population.

First insight into the development of a new transcriptomic tool in French Corsica harbors.

Coastal harbor areas are subjected to a myriad of contamination sources with largely unknown effects. Such complex chemical mixtures are difficult to monitor but transcriptomics is a promising approach for such biomonitoring. The present study was designed to verify the use of the Coastal Biosensor for Endocrine Disruption (C-BED) assay, previously developed to detect emerging contaminants and their effects on Mytilus edulis, on another mussel species, Mytilus galloprovincialis. Mussels were caged on St-Florent harbor (contaminated) and on Revellata Bay (reference) for three months. A classical multibiomarkers approach was coupled to the C-BED assay. The results of both approaches were analysed using the Integrated Biomarkers Responses (IBR) and compared to each other. Both approaches demonstrated a higher contamination and probable endocrine disruption of mussels in St-Florent, compared to the reference station. These results confirm that the C-BED assay provides an innovative method to expand our ability to detect emerging contaminants.

Mixture Risk Assessment of Complex Real-Life Mixtures-The PANORAMIX Project.

Humans are involuntarily exposed to hundreds of chemicals that either contaminate our environment and food or are added intentionally to our daily products. These complex mixtures of chemicals may pose a risk to human health. One of the goals of the European Union’s Green Deal and zero-pollution ambition for a toxic-free environment is to tackle the existent gaps in chemical mixture risk assessment by providing scientific grounds that support the implementation of adequate regulatory measures within the EU. We suggest dealing with this challenge by: (1) characterising ‘real-life’ chemical mixtures and determining to what extent they are transferred from the environment to humans via food and water, and from the mother to the foetus; (2) establishing a high-throughput whole-mixture-based in vitro strategy for screening of real-life complex mixtures of organic chemicals extracted from humans using integrated chemical profiling (suspect screening) together with effect-directed analysis; (3) evaluating which human blood levels of chemical mixtures might be of concern for children’s development; and (4) developing a web-based, ready-to-use interface that integrates hazard and exposure data to enable component-based mixture risk estimation. These concepts form the basis of the Green Deal project PANORAMIX, whose ultimate goal is to progress mixture risk assessment of chemicals.

Cumulative Risk Meets Inter-Individual Variability: Probabilistic Concentration Addition of Complex Mixture Exposures in a Population-Based Human In Vitro Model.

Although humans are continuously exposed to complex chemical mixtures in the environment, it has been extremely challenging to investigate the resulting cumulative risks and impacts. Recent studies proposed the use of “new approach methods,” in particular in vitro assays, for hazard and dose–response evaluation of mixtures. We previously found, using five human cell-based assays, that concentration addition (CA), the usual default approach to calculate cumulative risk, is mostly accurate to within an order of magnitude. Here, we extend these findings to further investigate how cell-based data can be used to quantify inter-individual variability in CA. Utilizing data from testing 42 Superfund priority chemicals separately and in 8 defined mixtures in a human cell-based population-wide in vitro model, we applied CA to predict effective concentrations for cytotoxicity for each individual, for “typical” (median) and “sensitive” (first percentile) members of the population, and for the median-to-sensitive individual ratio (defined as the toxicodynamic variability factor, TDVF). We quantified the accuracy of CA with the Loewe Additivity Index (LAI). We found that LAI varies more between different mixtures than between different individuals, and that predictions of the population median are generally more accurate than predictions for the “sensitive” individual or the TDVF. Moreover, LAI values were generally <1, indicating that the mixtures were more potent than predicted by CA. Together with our previous studies, we posit that new approach methods data from human cell-based in vitro assays, including multiple phenotypes in diverse cell types and studies in a population-wide model, can fill critical data gaps in cumulative risk assessment, but more sophisticated models of in vitro mixture additivity and bioavailability may be needed. In the meantime, because simple CA models may underestimate potency by an order of magnitude or more, either whole-mixture testing in vitro or, alternatively, more stringent benchmarks of cumulative risk indices (e.g., lower hazard index) may be needed to ensure public health protection.

Modulation of innate immune responses in the flame scallop Ctenoides scaber (Born, 1778) caused by exposure to used automobile crankcase oils

The used automobile crankcase oils are potential sources of contaminant elements for the coastal-marine ecosystems, affecting mainly the immunological system of organisms that feed by filtration, e. g. scallops. This study examined the effects of a water-soluble fraction of used automobile crankcase oils (WSF-UACO) on innate cellular- and humoral immune responses of the flame scallop Ctenoides scaber. The scallops were exposed to ascending concentrations of 0, 0.001, 0.01, and 0.1 of WSF-UACO under a static system of aquaria during 7 and 13 d. The viability, haemocyte total count (HTC), lysosomal membrane destabilization (LMD), phagocytosis, and protein concentration in hemolymph samples withdrawn taken from the blood sinus as well as lysozyme activity of the digestive gland were measured as immune endpoints. A decrease in cellular immune competence in scallops exposed to WSF-UACO was observed, with significant impairment of viability, HTC, and phagocytosis. LMD index increased about exposure concentrations, and plasma protein concentrations augmented to 0.01 and 0.1% during 13 d. Lysozyme activity increased in scallops exposed to WSF-UVCO during 7 d, to level off in the chronic period. Lysozyme activity and enhanced plasma proteins could act as compensatory responses when cell parameters tend to fall, helping to the regulation of microbial microflora and possible invasion of pathogenic microbes as well as defense against xenobiotics. The results demonstrate that the immunological responses of C. scaber are highly sensitive to the complex chemical mixture of contaminants, and it could be used for evaluating biological risks of hazardous xenobiotics in tropical marine environments. Republic of Ecuador

Bio-oil production from hydrothermal liquefaction of Pennisetum purpureum[formula omitted]Pennisetum typhoideum

Among renewable and sustainable energy resources, biomass plays a vital role. Agricultural residues/wastes, energy crops, and lignocellulosic biomass could potentially be major feedstocks for biorefineries. In Thailand, one of the most interesting energy crops is hybrid giant Juncao grass (GJG) or Pennisetum purpureum×Pennisetum typhoideum. GJG can be easily grown and has relatively high yields under tropical climates. Herein, conversion of GJG to biofuels via hydrothermal liquefaction (HTL) was investigated using batch reactors under varying reaction temperatures of 250–350 °C and biomass-to-deionized water concentrations of 15–25 wt% at a fixed residence time of 30 min. Changes in temperature and GJG-to-deionized water concentration were found to markedly affect the yields and distribution of products from HTL of GJG. Yields of the liquid product, or bio-oil, can be up to 50 wt% at 350 °C and 25 wt% GJG-to-deionized water concentration. The yields of solid char and gas products fluctuated within 10–25 wt% and 30–45 wt%, respectively. Higher heating values of the resulting bio-oil and char were remarkably better than those of the raw material. An energy recovery of over 50% from the bio-oil, as well as about 35% from the char, can be obtained. By gas chromatograph-mass spectrometry and nuclear magnetic resonance, the bio-oil obtained was found to be a complex chemical mixture, consisting mainly of phenols, nitrogenous compounds, aliphatic compounds, ketones, carboxylic acids, and aldehydes. The finding is useful in future utilization of GJG via HTL for biofuel and/or biochemical production.

Studies on thermal comfort of multi-layered fabric assembly after wetting with sweat and distilled water

Textiles play a vital role in assuring the thermal stability of the human body. The absorption of perspiration or moisture from a humid environment might result in wet clothing. Protective and sports apparel are often wet when the wearer is involved in high level of activity; thereby affecting the comfort. In order to understand the comfort behaviour of textiles in wet state, most of the researchers used the distilled water or NaCl aqueous solution. However, human sweat is a very complex aqueous mixture of chemicals comprising of salts, lipids, urea, lactic acid, carbohydrates, and minerals. In the present study, the effect of simulated sweat solution on the thermal behaviour of multi-layered fabric assembly is studied and compared with that of distilled water. The multi-layered fabric assembly consists of breathable PU-coated nylon as an outer layer; polyester knitted fabric as an inner layer; and micro-polyester wadding/hollow-polyester wadding/spacer fabric as the middle layer. In addition, the inner layer (next to the skin) is also tested for thermal comfort for both dry and wet states. It is observed that thermal properties of fabrics are drastically affected under wet conditions. The inner layer of fabric wetted with distilled water shows higher thermal conductivity as compared to that wetted with simulated sweat. Among various multi-layered assemblies, the thermal resistance and thermal diffusion of multi-layered assembly having hollow polyester wadding as a middle layer is high as compared to that having spacer fabric in the middle, under both dry and wet conditions.

From molecular endpoints to modeling longer-term effects in fish embryos exposed to the elutriate from Doce River

Sediments represent a major sink and also a main source of contaminants to aquatic environments. An environmental disaster from a mining dam breakage in 2015 in South-East Brazil re-suspended complex mixtures of chemicals deposited in the sediment, spreading contaminants along the Doce River Basin (DRB) major river course. While high levels of contaminants in sediment were well described, toxicological effects in aquatic organisms were poorly investigated. Thus, the effects of these potentially toxic chemicals were assessed in the present study through different endpoints (biochemical to populational levels) in fish embryos of the South-American silver catfish exposed to elutriates from different sites of the DRB. Despite no significant mortality observed, our results showed that exposure to the elutriates, especially those from the closest site to the dam collapse, caused higher deformities rates and DNA damage in the fish embryos than in the control group. Multivariate analysis showed that these sublethal effects may be related to the high levels of metals introduced by mining activities, compromising long-term survival and reproduction success. In addition, it was possible to observe the influence of other sources of pollutants along the river. According to our data, the mathematical model simulated a significant impact on the population density at longer-term exposure, for the sites that showed the most prominent toxicity responses. The fish embryo toxicity test proved to be an effective assay to assess the ecotoxicological effects of the pollutants from a major river contaminated by a mining dam collapse and showed that the survival rate per se was not a suitable endpoint to assess the toxicity of the pollutants. As a consequence, we contributed to shed a light on a potential underestimated impact of pollutants in sediments of the DRB on the native organisms at distinct biological levels of organizations.

A comparison of personal care product use between undergraduate students attending military and non-military universities: Possible implications for exposure to endocrine-disrupting chemicals

Personal care products (PCPs) are widely used among adults and often contain endocrine-disrupting chemical additives (EDCs). EDCs can interfere with hormone synthesis and transport, leading to adverse reproductive, developmental, and metabolic impacts. Further, since multiple PCPs are often used concurrently, individuals can be exposed to complex chemical mixtures, thereby magnifying these health risks. Previous studies indicate higher PCP use among college females, thereby exacerbating their risk of EDC exposure. In this study, PCP use was compared between students attending two undergraduate universities with different policies regarding cosmetic use and personal grooming standards. Two hundred fifty-five students from a non-military (n = 121) and military (n = 134) university completed a self-administered survey on PCP use. Logistic regression modeling examined associations with demographic variables, and cohort-specific patterns of PCP use were identified using kappa tests. Comparisons between universities did not reveal significant differences in the total number of products used by males and females (military male median = 8.5; non-military male median=8.0; p = 0.47; military female median = 16.5; non-military female median=16.0; p = 0.78), but the types and patterns of product use varied between schools. Shaving and hair care product use was more common among military students (p < 0.05), and despite the rules against cosmetic use at the military university, significant differences were not observed between non-military and military females (p > 0.05). Despite regulatory differences regarding PCP use between universities, biological sex was the most significant predictor of product use, with females frequently using many different personal care products. Our findings suggest, for both university settings, female students are at a higher risk of EDC exposure than male students, which could influence their susceptibility to EDC-related health events.