Human Exposure Research Articles

High arsenic contamination in the breast milk of mothers inhabiting the Gangetic plains of Bihar: a major health risk to infants

Groundwater arsenic poisoning has posed serious health hazards in the exposed population. The objective of the study is to evaluate the arsenic ingestion from breastmilk among pediatric population in Bihar. In the present study, the total women selected were n = 513. Out of which n = 378 women after consent provided their breastmilk for the study, n = 58 subjects were non-lactating but had some type of disease in them and n = 77 subjects denied for the breastmilk sample. Hence, they were selected for the women health study. In addition, urine samples from n = 184 infants’ urine were collected for human arsenic exposure study. The study reveals that the arsenic content in the exposed women (in 55%) was significantly high in the breast milk against the WHO permissible limit 0.64 µg/L followed by their urine and blood samples as biological marker. Moreover, the child’s urine also had arsenic content greater than the permissible limit (< 50 µg/L) in 67% of the studied children from the arsenic exposed regions. Concerningly, the rate at which arsenic is eliminated from an infant’s body via urine in real time was only 50%. This arsenic exposure to young infants has caused potential risks and future health implications. Moreover, the arsenic content was also very high in the analyzed staple food samples such as rice, wheat and potato which is the major cause for arsenic contamination in breastmilk. The study advocates for prompt action to address the issue and implement stringent legislative measures in order to mitigate and eradicate this pressing problem that has implications for future generations.

Critical evaluation of high-resolution and low-resolution mass spectrometry for biomonitoring of human environmental exposure to pesticides

Despite increasing debates about their potential side effects on human health, data concerning the risks and the impacts associated with pesticides remains scarce. Analytical tools allowing the measurement of most pesticides and/or their metabolites to which the population can be exposed are also of need. In the present study, the limits of detection (LODs) of 3 different screening procedures based on either Low-Resolution and High-Resolution Mass Spectrometry (LR-MS and HR-MS) for the determination of pesticides in serum (among which carbamates, dithiocarbamates, neonicotinoids, organochlorines, organophosphates and pyrethroids) were explored. For HR-MS, a quadrupole time-of-flight was used in positive and negative electrospray ionization modes and data were obtained from either a targeted scheduled MSMS acquisition (HR-MSMS) or a data-independent acquisition (HR-DIA). For LR-MS, a triple quadrupole was used and data were acquired with a classical multiple-reaction monitoring (MRM) mode. Depending on the approach, the LOD values varied from 0.05 to 10 ng/mL. For the lowest concentrations, the proportion of molecules detected was systematically greater for the LR-MS approach, while those of HR-MSMS were better than those of HR-DIA. These differences in the LOD values were confirmed in a sample of 174 serums in which LR-MRM detected 89 compounds while HR-MSMS and HR-DIA detected 79 and 75 compounds, respectively. Nevertheless, for environmental and occupational purposes, HRMS approach could probably be efficient to detect most of pesticides and their metabolites in human serum and could be suitable for human biomonitoring studies or fundamental research exploring the impact of exposure to pesticides on human health.

Thyroid under Attack: The Adverse Impact of Plasticizers, Pesticides, and PFASs on Thyroid Function

Endocrine-disrupting chemicals (EDCs) are synthetic or natural compounds that interfere with the endocrine system, inducing harmful effects on organisms depending on the dose and period of exposure. Numerous studies have identified concerning amounts of EDCs in environmental and human samples. The thyroid gland is essential for thyroid hormone production and controls several body functions. Several EDCs have been classified as thyroid disruptors, impairing thyroid hormone production, synthesis, metabolism, transport, and/or actions. Notably, thyroid disorders are the second most prevalent endocrine disease worldwide, with incidence increasing significantly in recent years. Some studies have correlated this rise in thyroid dysfunctions and cancers with increased exposure to EDCs. Although many EDCs are linked to thyroid dysfunction, this review focuses on the deleterious effects of plasticizers, organochlorine pesticides, and per- and poly-fluoroalkyl substances on thyroid function. These contaminants are commonly found in food, water, and everyday products. Although the impact of human exposure to these EDCs is controversial, numerous epidemiological, in vivo, and in vitro studies have indicated their harmful effects on thyroid function. Given the critical role of thyroid function and hormone production in growth, metabolism, and development, this review summarizes the consequences of exposure to thyroid disruptors for human health.

Tracking chemical feature releases from plastic food packaging to humans

Humankind are being exposed to a cocktail of chemicals, such as chemicals released from plastic food packaging. It is of great importance to evaluate the prevalence of plastic food packaging-derived chemicals pollution along the flow of food-human. We developed a robust and practical database of 2101 chemical features associated with plastic food packaging that combined data from three sources, 925 of which were acquired from non-target screening of chemical extracts from eight commonly used plastic food packaging materials. In this database, 625 features, especially half of the non-targets, were potential migrants who likely entered our bodies through dietary intake. Biomonitoring analysis of plastic chemical features in foodstuffs or human serum samples showed that approximately 78 % of the 2101 features were detectable and approximately half were non-targets. Of these, 17 plastic chemicals with high detection frequencies (DFs) in the human serum were confirmed to be functional chemical additives. Together, our work indicates that the number of plastic chemicals in our bodies could be far greater than previously recognized, and human exposure to plastic chemicals might pose a potential health risk.

The status of response to the flood early warnings in Kilosa District, Tanzania

Floods have been a challenging phenomenon, jeopardizing human life and property. Measures have been taken to alleviate flood effects, including using flood early warning systems (EWS), which give warnings to people. Despite the use of warnings from EWS, there is limited information on warnings contribution to mitigate flood effects. This study investigates the status of flood early warning response measures by communities in areas where floods frequently occur in Kilosa District. The data were collected from 375 household heads through surveys and triangulated by 17 participants via focus group discussions, 22 officials through key informant interviews, and a literature survey. The data were descriptively analysed, and chi-square tests and binary logistic regression analyses were done. Results indicate that 76.53 % of the respondents receive flood early warnings from word of mouth among relatives (54.21 %), phones (45.45 %), and radios (31.65 %). Upon receiving the early warnings, 45.43 % inform family members about what to do, 43.82 % vacate flood-prone areas, and 6.99 % make flood emergency response plans. Those flood warning response measures are significantly an outcome of the households’ distance from the rivers causing floods (p < .0001), chances of receiving flood warnings (p < .0001), past flood experience (p < .0001), and the nature of the houses (p < .0007). In conclusion, individuals can proactively protect against floods by diverting floodwaters away from populated areas and reducing human exposure to flood risks. To actively protect against floods, communities should implement multiple warning systems, establish reliable mechanisms to disseminate alerts and install water level gauges in all flood-prone rivers.

Evidence for widespread human exposure to food contact chemicals.

Over 1800 food contact chemicals (FCCs) are known to migrate from food contact articles used to store, process, package, and serve foodstuffs. Many of these FCCs have hazard properties of concern, and still others have never been tested for toxicity. Humans are known to be exposed to FCCs via foods, but the full extent of human exposure to all FCCs is unknown. To close this important knowledge gap, we conducted a systematic overview of FCCs that have been monitored and detected in human biomonitoring studies according to a previously published protocol. We first compared the more than 14,000 known FCCs to five biomonitoring programs and three metabolome/exposome databases. In a second step, we prioritized FCCs that have been frequently detected in food contact materials and systematically mapped the available evidence for their presence in humans. For 25% of the known FCCs (3601), we found evidence for their presence in humans. This includes 194 FCCs from human biomonitoring programs, with 80 of these having hazard properties of high concern. Of the 3528 FCCs included in metabolome/exposome databases, most are from the Blood Exposome Database. We found evidence for the presence in humans for 63 of the 175 prioritized FCCs included in the systematic evidence map, and 59 of the prioritized FCCs lack hazard data. Notwithstanding that there are also other sources of exposure for many FCCs, these data will help to prioritize FCCs of concern by linking information on migration and biomonitoring. Our results on FCCs monitored in humans are available as an interactive dashboard (FCChumon) to enable policymakers, public health researchers, and food industry decision-makers to make food contact materials and articles safer, reduce human exposure to hazardous FCCs and improve public health. We present systematically compiled evidence on human exposure to 3601 food contact chemicals (FCCs) and highlight FCCs that are of concern because of their known hazard properties. Further, we identify relevant data gaps for FCCs found in food contact materials and foods. This article improves the understanding of food contact materials' contribution to chemical exposure for the human population and highlights opportunities for improving public health.

Roe deer exposure to trace metals and pesticides in forests and agricultural plains of North-eastern France.

Human activities related to agriculture and industrial development result in the emission of different types of pollutants in the environment. The phytosanitary pressure depends on the time of the year, the type of habitat, and the used treatments. Wildlife, particularly ungulates, can be exposed to pesticides and trace metals through their herbivorous diet directly impregnated by the environmental contamination. Wild game thus plays a sentinel role but can also represent a risk for human health by exposing venison consumers to these contaminants. The present study explored this dual problem in two types of habitat: forests and agricultural plains located in North-eastern France. Samples of liver and muscle were taken from ten roe deer, five caught on the forests and five others in the plains, to determine contaminant levels. There was no significant difference in contamination of roe deer livers according to the habitat for three trace metals (chromium, nickel, and copper), while lead concentrations were higher in samples from the plain (0.85 vs. 0.74mg·kg-1 dry matter DM; P < 0.01). Conversely, zinc concentrations were higher in forest roe deer (110 vs. 95mg·kg-1 DM; P < 0.05). Cadmium concentrations did not differ significantly between the two habitats, but forest samples showed strong inter-individual variability, with some values close to those observed on the plains and others higher (1.8 vs. 0.3mg·kg-1 DM for forest and plain, respectively; P = 0.11). Mercury was not detected in any sample. The majority of pesticides investigated were not detected. Only a few pesticides were in trace amount (from 1 to 8µg·kg-1 fresh matter), either in the liver (e.g., heptachlor and oxychlordane) or in both tissues, liver and muscle (e.g., pyridalyl). Some compounds were only detected in plain (e.g., cypermethrin and fenpropidin) and others in forest (piperonyl butoxide and pyridalyl) samples. Analyses mainly detected insecticides in samples taken from forests and agricultural plains. Fungicides and a few herbicides were mainly detected in plain sampled animals. Pesticides and copper concentrations in roe deer tissues were lower than maximum residue levels established for farm (copper) or wild terrestrial (pesticides) animals. Cadmium concentrations were also lower than the maximum level for most samples, except for some forest roe deer. However, both forest and plain roe deer exceeded the maximum level for lead in liver. Human exposure was simulated according to different amounts of meat consumed and compared with toxicological reference values. This study highlighted an overall low risk to human health for both pesticides, copper and lead, with more reservations about cadmium for some roe deer shot in forest. The differences in roe deer contamination between forests and agricultural plains for some trace elements and organic pollutants confirmed the sentinel role of this species.

A new approach for risk assessment of pulmonary toxicants: a preliminary study using didecyldimethylammonium chloride.

Current human risk assessments often rely on animal toxicity data to establish point of departure (POD) values, followed by the application of uncertainty factors. Consequently, there is growing interest in alternative toxicity testing methods that reduce reliance on animal models. In this study, we propose a novel approach for inhalation toxicity risk assessment that integrates in silico and in vitro methods. Human primary alveolar epithelial cells were exposed to aerosolized didecyldimethylammonium chloride (DDAC) to assess cytotoxicity. This was followed by transcriptome analysis and biological pathway investigation, utilizing adverse outcome pathway (AOP), to calculate the POD. Additionally, human DDAC exposure was simulated using a multiple-path particle dosimetry (MPPD) model to predict exposure levels in the human alveolar region via inhalation. The results from in silico and in vitro studies were then compared, and a comprehensive risk assessment was performed. The POD for AOP 452 key events-oxidative stress, inflammation, epithelial-mesenchymal transition (EMT), apoptosis, and autophagy-was found to range between 19.0 and 23.89ng/cm2, according to benchmark dose calculation tools. The estimated human exposure to DDAC in the alveolar region under actual exposure conditions was 0.164ng/cm2/day, resulting in a margin of exposure (MOE) ranging from 121 to 145, suggesting caution regarding DDAC inhalation exposure. This study presents a novel risk assessment method that compares estimated human inhalation exposure values to in vitro results, applying the human equivalent concentration concept. Our findings demonstrate the potential for conducting human risk assessments using both in silico and in vitro methods as alternatives to traditional in vivo studies.

Exposure patterns and the risk factors of Crimean Congo hemorrhagic fever virus amongst humans, livestock and selected wild animals at the human/livestock/wildlife interface in Isiolo County, upper eastern Kenya.

Crimean Congo hemorrhagic fever (CCHF) is a tick-borne zoonotic disease caused by CCHF virus (CCHFV). The disease has a complex transmission cycle that involves a wide range of hosts including mammalian and some species of birds. We implemented a sero-epidemiological study in Isiolo County, Kenya, to determine relative seroprevalences of CCHFV in humans, livestock and in wild animals. A seropositive herd was defined as having at least one seropositive animal. In addition, we identified subject and environment level factors that could promote exposure to CCHFV. Humans (n = 580) and livestock species (n = 2,137) were recruited into the study through a multistage random sampling technique, and in addition, various species of wild animals (n = 87) were also sampled conveniently. Serum samples from all recruited humans and animals were collected and screened for CCHFV antibodies using ID Screen multispecies, double-antigen IgG enzyme-linked immunosorbent assay (ELISA). The overall anti-CCHFV IgG seroprevalences in humans, cattle, goats, sheep and camels were 7.2% [95% CI: 3.1-15.8%], 53.9% [95% CI: 30.7-50.9%], 11.6% [95% CI: 7.2-22.5%], 8.6% [95% CI: 3-14%] and 89.7% [95% CI: 78-94%], respectively. On average, the sampled wild animals had CCHFV seroprevalence of 41.0% [95% CI: 29.1-49.4%]; giraffes had the highest mean CCHF seroprevalence followed by buffaloes, while impala had very low exposure levels. Statistical analyses using mixed effects logistic regression models showed that CCHFV exposure in humans was significantly associated with male gender, being over 30 years of age and belonging to a household with a seropositive herd. In livestock, a combination of animal- and environment level factors including older animals, high normalized difference vegetation indices (NDVI) and high vapour pressure deficit were significantly associated with CCHFV infection. Age, sex and species of wild animals were considered the key risk factors in the analysis, but none of these variables was significant (P-value = 0.891, 0.401 and 0.664, respectively). Additionally, RT-qPCR analysis revealed the presence of CCHFV RNA in camels (30%), cattle (14.3%), and goats (3.8%), but not in humans, sheep, or wild animals. This study demonstrates that environmental factors, such as NDVI and vapor pressure deficit, affect CCHFV exposure in livestock, while the presence of infected livestock is the key determinant of human exposure at the household level. These findings underscore the importance of using One Health approaches to control the disease in human-livestock-wildlife interfaces. For instance, the existing CCHF surveillance measures could be enhanced by incorporating algorithms that simulate disease risk based on the environmental factors identified in the study. Additionally, tick control in livestock, such as the use of acaricides, could reduce CCHFV exposure in livestock and, consequently, in humans.

AnophelesModel: An R package to interface mosquito bionomics, human exposure and intervention effects with models of malaria intervention impact.

In recent decades, field and semi-field studies of malaria transmission have gathered geographic-specific information about mosquito ecology, behaviour and their sensitivity to interventions. Mathematical models of malaria transmission can incorporate such data to infer the likely impact of vector control interventions and hence guide malaria control strategies in various geographies. To facilitate this process and make model predictions of intervention impact available for different geographical regions, we developed AnophelesModel. AnophelesModel is an online, open-access R package that quantifies the impact of vector control interventions depending on mosquito species and location-specific characteristics. In addition, it includes a previously published, comprehensive, curated database of field entomological data from over 50 Anopheles species, field data on mosquito and human behaviour, and estimates of vector control effectiveness. Using the input data, the package parameterizes a discrete-time, state transition model of the mosquito oviposition cycle and infers species-specific impacts of various interventions on vectorial capacity. In addition, it offers formatted outputs ready to use in downstream analyses and by other models of malaria transmission for accurate representation of the vector-specific components. Using AnophelesModel, we show how the key implications for intervention impact change for various vectors and locations. The package facilitates quantitative comparisons of likely intervention impacts in different geographical settings varying in vector compositions, and can thus guide towards more robust and efficient malaria control recommendations. The AnophelesModel R package is available under a GPL-3.0 license at https://github.com/SwissTPH/AnophelesModel.

Advancements in Assays for Micro- and Nanoplastic Detection: Paving the Way for Biomonitoring and Exposomics Studies.

Although plastic pollution and exposure to plastic-related compounds have received worldwide attention, health risks associated with micro- and nanoplastics (MNPs) are largely unknown. Emerging evidence suggests MNPs are present in human biofluids and tissue, including blood, breast milk, stool, lung tissue, and placenta; however, exposure assessment is limited and the extent of human exposure to MNPs is not well known. While there is a critical need to establish robust and scalable biomonitoring strategies to assess human exposure to MNPs and plastic-related chemicals, over 10,000 chemicals have been linked to plastic manufacturing with no existing standardized approaches to account for even a fraction of these exposures. This review provides an overview of the status of methods for measuring MNPs and associated plastic-related chemicals in humans, with a focus on approaches that could be adapted for population-wide biomonitoring and integration with biological response measures to develop hypotheses on potential health effects of plastic exposures. We also examine the exposure risks associated with the widespread use of chemical additives in plastics. Despite advancements in analytical techniques, there remains a pressing need for standardized measurement protocols and untargeted, high-throughput analysis methods to enable comprehensive MNP biomonitoring to identify key MNP exposures in human populations. This review aims to merge insights into the toxicological effects of MNPs and plastic additives with an evaluation of analytical challenges, advocating for enhanced research methods to fully assess, understand, and mitigate the public health implications of MNPs.

Migration patterns of organophosphate esters from plastic food packaging simulants to foods: Donors, behaviours, and influencing factors

In recent years, organophosphate esters (OPEs) have been widely produced and used as flame retardants and plasticizer additives, posing significant ecological and health risks. Dietary intake is considered to be the primary route of human exposure to OPEs. Plastic food packaging materials are considered a crucial source for contamination of OPEs in food. However, the migration behaviour of OPEs from plastic food packaging materials into foods has received limited attention. In this study, we employed a novel method to prepare migration donors containing 13 kinds of OPEs. The migration behaviours of OPEs from food packaging simulants (polypropylene) to foods (full-fat milk powder) were simulated, and factors influencing the migration of OPEs were examined, including the properties of the target compounds, migration temperature, fat content of the migration receptors, and mass transfer mode. The results indicated that OPEs exhibited a significant migration tendency. Low molecular weight OPEs (< 300 Da) had faster migration efficiency compared to high molecular weight OPEs. The mean migration efficiencies of various OPEs showed a significant negative correlation with their molecular weights (p < 0.01) and a significant positive correlation with temperature (p < 0.01). Except for resorcinol bis(diphenyl phosphate) (RDP), which showed almost no migration, the mean migration efficiencies of other OPEs at 25 °C, 40 °C, and 60 °C were 3.1–37.5 %, 9.0–60.0 %, and 23.9–80.4 %, respectively. Most of the OPEs demonstrated higher migration efficiency in high-fat content food than low-fat content food. The migration of OPEs from food packaging simulants to foods primarily occurred through contact rather than gas-phase mass transfer. Overall, this study uncovers the migration behaviours of OPEs from food packaging simulants to foods and scrutinized the relevant factors influencing the migration. It is expected that the research in terms of the contamination control of OPEs in food will benefit from this work.

Pharmacokinetic Analysis of Nicotine and Its Metabolites (Cotinine and trans-3'-Hydroxycotinine) in Male Sprague-Dawley Rats Following Nose-Only Inhalation, Oral Gavage, and Intravenous Infusion of Nicotine.

Nicotine is an alkaloid found in tobacco. Human exposure to nicotine primarily occurs through the use of tobacco products. To date, limited nicotine pharmacokinetic data in animals have been reported. This study exposed male Sprague-Dawley rats to vehicle (and/or air) or four doses of nicotine via nose-only inhalation (INH), oral gavage (PO), and intravenous (IV) infusion. Plasma, six tissues (brain, heart, lung, liver, kidney, and muscle), and urine were collected at multiple timepoints from 5 minutes to 48 hours post-dose. The concentrations of nicotine, cotinine, and trans-3'-hydroxycotinine (3-OH-cotinine) were determined, and the pharmacokinetic profiles were compared among the four doses for each route. The results indicated that after single nicotine dose, nicotine bioavailability was 53% via PO. Across all the administration routes and doses, nicotine was quickly distributed to all six tissues; kidney had the highest nicotine and cotinine levels, and the lung had the highest 3-OH-cotinine levels; nicotine was metabolized extensively to cotinine and cotinine was metabolized to a lesser extent to 3-OH-cotinine; the elimination of plasma nicotine, cotinine, and 3-OH-cotinine followed first-order kinetics; plasma nicotine had a shorter half-life than cotinine or 3-OH-cotinine; the half-lives of plasma nicotine, cotinine, and 3-OH-cotinine were dose- and route-independent; and nicotine and cotinine were major urinary excretions followed by 3-OH-cotinine. Nicotine, cotinine, and 3-OH-cotinine levels in plasma, tissues, and urine exhibited dose-dependent increases. These study findings improve our understanding of the pharmacokinetics of nicotine, cotinine, and 3-OH-cotinine across different routes of exposure.

Thyroid hormones and oxidative stress moderated the association between urinary phthalate metabolites and cardiovascular risk factors

While previous studies suggested that phthalate exposure poses a risk to cardiovascular health, the results are mixed and indicated variability based on population characteristics and health outcomes assessed. Research that simultaneously investigates the association between urinary phthalate metabolites and multiple cardiovascular risk factors within a single study is relatively scarce. This study assessed human exposure to phthalates by determining urinary metabolite concentrations, and applied multiple statistical techniques to systematically evaluate the individual dose-response relationships and joint effects of phthalate exposure on blood lipids, blood pressure, and fasting blood glucose. The results revealed significant negative associations between urinary phthalate metabolites and low-density lipoprotein cholesterol, triglycerides, total cholesterol, diastolic blood pressure, systolic blood pressure, and fasting blood glucose. Significant nonlinear associations were obtained between specific individual metabolites and diastolic blood pressure. The oxidative stress biomarker 8-hydroxydeoxyguanosine levels in urine and thyroid hormone levels in paired serum were measured simultaneously. Then, we examined the indirect roles of thyroid hormones and oxidative stress in the association between urinary phthalate metabolites and cardiovascular risk factors by mediation and moderation analysis. While the mediation effect was not statistically significant, the negative associations of urinary phthalate metabolites with fasting blood glucose, triglyceride, and lipoprotein cholesterol were statistically significant at lower levels of thyroid hormones by moderation analysis. The association was also significant under certain levels of oxidative stress. The results demonstrated that phthalate exposure is associated with several cardiovascular risk factors, and maintaining appropriate oxidative stress levels and ensuring sufficient thyroid hormone levels may attenuate these associations.

Pre- and post-harvest aflatoxin contamination and management strategies of Aspergillus spoilage in East African Community maize: review of etiology and climatic susceptibility.

Globally, maize (Zea mays L.) is deemed an important cereal that serves as a staple food and feed for humans and animals, respectively. Across the East African Community, maize is the staple food responsible for providing over one-third of calories in diets. Ideally, stored maize functions as man-made grain ecosystems, with nutritive quality changes influenced predominantly by chemical, biological, and physical factors. Food spoilage and fungal contamination are convergent reasons that contribute to the exacerbation of mycotoxins prevalence, particularly when storage conditions have deteriorated. In Kenya, aflatoxins are known to be endemic with the 2004 acute aflatoxicosis outbreak being described as one of the most ravaging epidemics in the history of human mycotoxin poisoning. In Tanzania, the worst aflatoxin outbreak occurred in 2016 with case fatalities reaching 50%. Similar cases of aflatoxicoses have also been reported in Uganda, scenarios that depict the severity of mycotoxin contamination across this region. Rwanda, Burundi, and South Sudan seemingly have minimal occurrences and fatalities of aflatoxicoses and aflatoxin contamination. Low diet diversity tends to aggravate human exposure to aflatoxins since maize, as a dietetic staple, is highly aflatoxin-prone. In light of this, it becomes imperative to formulate and develop workable control frameworks that can be embraced in minimizing aflatoxin contamination throughout the food chain. This review evaluates the scope and magnitude of aflatoxin contamination in post-harvest maize and climate susceptibility within an East African Community context. The paper also treats the potential green control strategies against Aspergillus spoilage including biocontrol-prophylactic handling for better and durable maize production.

In Vitro Metabolism of Quaternary Ammonium Compounds and Confirmation in Human Urine by Liquid Chromatography Ion-Mobility High-Resolution Mass Spectrometry.

Quaternary ammonium compounds (QACs) are high-production chemicals used as cleaning and disinfecting agents. Due to their ubiquitous presence in the environment and several toxic effects described, human exposure to these chemicals gained increasing attention in recent years. However, very limited data on the biotransformation of QACs is available, hampering exposure assessment. In this study, three QACs (dimethyl dodecyl ammonium, C10-DDAC; benzyldimethyl dodecylammonium, C12-BAC; cetyltrimethylammonium, C16-ATMAC) commonly detected in indoor microenvironments were incubated with human liver microsomes and cytosol (HLM/HLC) simulating Phase I and II metabolism. Thirty-one Phase I metabolites were annotated originating from 19 biotransformation reactions. Four metabolites of C10-DDAC were described for the first time. A detailed assessment of experimental fragmentation spectra allowed to characterize potential oxidation sites. For each annotated metabolite, drift-tube ion-mobility derived collision cross section (DTCCSN2) values were reported, serving as an additional identification parameter and allowing the characterization of changes in DTCCSN2 values following metabolism. Lastly, eight metabolites, including four metabolites of both C12-BAC and C10-DDAC, were confirmed in human urine samples showing high oxidation states through introduction of up to four oxygen atoms. This is the first report of higher oxidized C10-DDAC metabolites in human urine facilitating future biomonitoring studies on QACs.

Assessment of the annual effective dose and lifetime cancer risks associated with tritium in groundwater within different age groups

Tritium is a radioactive isotope of hydrogen that emits low-energy radiation. When humans are exposed to tritium, the primary concern is internal exposure through inhalation, ingestion, or absorption through the skin. The severity of the adverse health effects depends on the duration, amount, and route of exposure. Therefore, estimating the tritium levels in groundwater and the corresponding health risks within different age groups is essential. The annual effective dose is determined by considering several factors, including the concentration of tritium, the volume of water consumed, and the duration of exposure. The calculated annual effective doses were then compared to the safety limit as directed by international organizations. The estimated tritium concentration in the searched groundwater samples was significantly low, ranging from 0.014 to 0.114 Bq/L. The annual effective dose of tritium exposure for infants, children, and adults varies from 0.028 to 0.605 μSv/y and is within the safe limit recommended by the World Health Organization (WHO) and other international organizations. The lifetime cancer risk (LTCR) for the consumer in the searched areas was estimated for males and females based on the average lifetime. Mortality and morbidity rates varied slightly between males and females across samples due to differences in activity concentrations and locations. However, the estimated LTCR values were below the radiological cancer risk limit. These findings will provide valuable insights to regulatory authorities, assisting them in developing strategies to ensure public safety against human exposure to tritium.

Significant incidents during X-ray exposures in humans - assessment and findings of the Federal Office for Radiation Protection.

In Germany, significant incidents must be reported to the competent authority since 12/31/2018 (section 108 Radiation Protection Ordinance (StrlSchV)). After assessment and evaluation of the reports, the competent authority submits the relevant information via a web-based reporting system (BeVoMed) to the Federal Office for Radiation Protection (BfS), which publishes the results derived therefrom. The present paper evaluates significant incidents related to X-ray exposures on humans.All reports on incidents in X-ray diagnostics and interventional radiology between 01/2019 and 10/2023, which were completed with detailed information until the reporting day (31/10/2023), were included. The following aspects were statistically evaluated: classification as an incident (section 1 subsection (22) StrlSchV), significance (section 108 StrSchV), classification to Annex 14 StrlSchV, assignment to the forms of care in the German healthcare system, and development of the reporting frequency over time. Furthermore, the content of the reports was systematically evaluated with regard to conspicuous clusters and typical problems.Until the reporting day, 383 reports (355 completed) were received. 252 reports (228 in X-ray diagnostics, 24 in interventional radiology) referred to significant incidents and were included in the detailed evaluation. Reporting frequency increased in X-ray diagnostics, whereas there was no trend in interventional radiology. Most of the significant incidents concerned examinations on an individual person (category I, criterion 2a or category II, criteria 2a and 3a) in the in-patient sector - especially in maximum care hospitals. Frequent errors concerned the inappropriate choice of parameters/protocols or were related to the administration of a contrast agent. Despite the overall positive trend, the establishment of awareness and error culture remains challenging. · In X-ray diagnostics, the reporting frequency of significant incidents increases.. · Most incidents concerned CT examinations in the in-patient sector.. · Main problems were selection of protocols/settings, contrast administration, and bolus-tracking.. · Uncertainties remain about the classification of an incident as significant and notifiable.. · Winter KS, Schweden M, Brix G et al. Significant incidents during X-ray exposures in humans - assessment and findings of the Federal Office for Radiation Protection. Fortschr Röntgenstr 2024; DOI 10.1055/a-2339-3684.

Widespread occurrence of glyphosate and aminomethylphosphonic acid in indoor dust from urban homes across the United States and its contribution to human exposure

Glyphosate is the most widely used herbicide worldwide, with concerns over human exposure and potential health risks. Nevertheless, little is known about the sources of human exposure to glyphosate and its degradation product, aminomethylphosphonic acid (AMPA). In this study, we measured glyphosate and AMPA in 99 indoor dust samples collected from urban homes in sixteen states in the USA. Glyphosate and AMPA were detected in all samples at geometric mean (GM) concentrations of 193 and 30.8 ng/g, respectively. We found a strong and significant positive correlation between glyphosate and AMPA concentrations (r = 0.70, p < 0.01), indicating that the latter mainly originated from glyphosate. The concentrations of glyphosate (r = 0.40, p < 0.01) and AMPA (r = 0.33, p < 0.01) in indoor dust were significantly correlated with the county-wide agricultural usage of this herbicide. Human exposure to glyphosate and AMPA through dust ingestion were in the ranges of 0.05–0.85 and 0.01–0.14 ng/kg body weight (BW)/day, respectively, for various age groups, which were more than two orders of magnitude below the acceptable daily intake for glyphosate (500 μg/kg BW/day). Further studies are needed to identify the sources and health outcomes of human exposure to glyphosate.

Occurrence and human exposure risk of antibiotic resistance genes in tillage soils of dryland regions: A case study of northern Ningxia Plain, China

Agricultural soils are important source and sink of antibiotic resistance genes (ARGs). However, little is known about the fate of ARGs in dryland soils, while its human exposure risks were seriously overlooked. Taking the northern Ningxia Plain as a case, this study explored the occurrence of ARGs and its relationship with mobile genetic elements (MGEs), pathogens, and environmental factors. Furthermore, the concentrations of airborne ARGs by soil wind erosion and the human exposure doses of soil ARGs were evaluated. The results showed the abundances of different regions ranged from 4.0 × 105 to 1.6 × 106 copies/g. Soil ARGs are driven by MGEs, but multiply impacted by soil properties, nutrition, and bacterial community. Vibrio metschnikovii, Acinetobacter schindleri, and Serratia marcescens are potential pathogenic hosts for ARGs. Further exploration revealed the concentration of ARGs loaded in dust by soil wind erosion reached more than 105 copies/m3, which were even higher than those found in sewage treatment plants and hospitals. Skin contact is the primary route of ARGs exposure, with a maximum dose of 24071.33 copies/kg/d, which is largely attributed to ARGs loaded in dust. This study bridged the gap on ARGs in dryland soils, and provided reference for human exposure risk assessment of soil ARGs.