Trace elements repartition in body fluids, hair and organs in an autopsied population evaluated by ICP-MS high resolution

A comprehensive library of lifetime physiological equations for PBK models: Enhancing dietary exposure modeling with mercury as a case study

Dietary risk assessment of food contaminants requires a well-established understanding of the exposure in a heterogeneous population. There are many methods for estimating human exposure to food contaminants, such as intake calculations and internal biomarkers of exposure measured in individuals. However, those methods are expensive, partly invasive, and often provide a momentary exposure snapshot. Physiologically Based Kinetic (PBK) modelling is increasingly used to overcome those challenges that traditional human exposure methods encounter. Still, PBK models are often restricted to certain life stages (e.g., children, adolescents, adults). This study outlines a strategy for implementing nonlinear organ growths in age-specific PBK models to enhance dietary risk assessment from lifetime exposure. To this end, lifetime physiological equations calculating organ growth for both sexes were inventoried from literature and a library was established for 24 organs. We then assessed total lifelong mercury exposure via foodstuff by combining two existing age-specific PBK models for methylmercury (MeHg) and inorganic mercury (iHg) that simulated internal exposure to total mercury, the speciation typically measured in hair and urine. We implemented a set of physiological equations in the PBK model that fitted best the total mercury measured in individuals' organs, hair, and urine from heterogeneous populations. For refined dietary risk assessment, we ultimately estimated total mercury concentration in hair and urine based on i) maximum limits defined by the regulation for MeHg in seafood, ii) the health-based guidance values for MeHg and iHg, and iii) realistic intakes considering French demographic parameters and food consumption data. These exposure scenarios demonstrated that total mercury concentrations in hair and urine estimated from realistic intakes are below critical effect level measures at all ages. The result of this study is the creation of easily accessible tools in Excel and R that facilitate the implementation of physiological equations in Next Generation PBK models.

Integrating the lifelong exposure dimension of a chemical mixture into the risk assessment process. Application to trace elements

Lifelong, the general population is exposed to mixtures of chemicals. Most often, risk assessment is performed to estimate the probability of adverse effects in the population using external exposures to a single chemical and considering one route of exposure. To estimate whole exposure to a chemical, human biomonitoring studies are used to measure chemical concentrations in biological matrices. The limitations of these studies are that it is not possible to distinguish the sources or the routes of exposure. Moreover, only the concentrations of a limited number of chemicals are usually determined due to the associated cost. In this study, a methodology has been developed to estimate the internal exposures of the population to a mixture of trace elements (inorganic As, Cd, Pb and Hg) throughout lifetime. This methodology uses realistic lifetime exposure trajectories coupled to physiological based kinetic modeling, considering several sources of exposure. Then, the estimated biomarkers of exposure were compared to human biomonitoring data to estimate the robustness of the methodology. Finally, risk characterization was performed based on the simulated biomarkers of exposure considering an additive effect of chemicals. This methodology allows to determine the contribution of chemicals to the overall risk of renal effect.

Target Organs of Metals Released from Metal-on-Polyethylene Knee and Hip Arthroplasty Implants: Implications for Tissue Metal Profiles

Metals are used in orthopedic implants. The wear of arthroplasty implant can lead to the release of arthroprosthetic metals, both locally and systemically, after migration into the organs. While the toxicity of metal-on-metal arthroplasty implants is well-known and monitored, the toxicity associated with metal-on-polyethylene (MoP) ones is not as comprehensively understood. This study aimed to investigate the release of metals from MoP arthroplasty implants and their impact on the tissue metal profile in autopsied individuals, comparing them to deceased controls without prostheses. High-resolution ICP-MS was employed to analyze 39 metals in the blood, urine, hair, organs, and periprosthetic tissue of 25 deceased individuals with arthroplasty implants and 20 control subjects (Prometox study, protocol ID: APHP180539, NCT03812627). Eight metals (beryllium, chromium, cobalt, lanthanum, molybdenum, nickel, tellurium, titanium) exhibited significant impacts in arthroplasty implant wearers across various organs. Increased concentrations of La and Be were observed, the origin of which could not be precisely defined within the scope of this study. Notably, the lungs emerged as the primary target organ for metallic ions contained in implants. This study suggests that MoP arthroplasty implants, even when functional and not visibly worn, release arthroprosthetic metals into the body, potentially causing disturbances. Furthermore, considering the presence of an arthroplasty implant in autopsy reports may be relevant, as the released metals could influence the tissue metal profile.

Characterizing the risk related to the exposure to methylmercury over a lifetime: A global approach using population internal exposure

Seafood products accumulate methylmercury throughout the food chain and are the main source of methylmercury exposure. Methylmercury may trigger a number of adverse health effects, such as neurodevelopmental or nephrotoxic effects, the risk of which cannot be ruled out for the French high consumers of seafood. The characterisation of methylmercury-related risks is generally based on short-term dietary exposure without considering changes in consumption and exposure over the lifetime. Additionally, focusing on short-term dietary exposure, the fate of methylmercury (especially its accumulation) in the organism is not considered. The present study proposes a methodology basing risk characterization on estimates of body burden over a lifetime. First, trajectories of dietary exposures throughout lifetime were constructed based on the actual concentrations of total diet studies for a fictive representative French population, taking into account the social, economic and demographic parameters of individuals. Next, the fate of methylmercury in the body was estimated, based on these trajectories, using a specific physiologically-based kinetic (PBK) model that generated a representative pool of body burden trajectories. Simulated hair mercury concentrations were closed to previously reported French representative human biomonitoring data. Results showed that at certain stages of life, concentrations of methylmercury in hair were higher than the human biomonitoring guidance value set at 2.5 μg/g of hair by JECFA. This study showed the added value, in the case of substances accumulating in the body, of estimating dietary exposure over a lifetime and using exposure biomarkers estimated by a PBK model characterize the risk.

Determination of lithium in the blood of the deceased by inductively coupled plasma mass spectrometry in a case of lithium-ion battery fire

In this study, a case of lithium-ion battery fire is presented. The blood of the deceased was analyzed for lithium (Li) using ICP-MS (inductively coupled plasma mass spectrometry). When compared to normal individuals in the same region, the deceased had much higher levels of Li in their blood. Therefore, conducting quantitative analyses of Li in the bodies of individuals who die in lithium-ion battery fire can provide valuable information into the specific circumstances surrounding their deaths.

Overview of systematic toxicological analysis strategies and their coverage of substances in forensic toxicology

Systematic toxicological analysis (STA) is the process of using an adequate analytical methodology to detect and identify as many potentially toxicologically relevant compounds as possible in biological samples. STA is an important part of everyday routine work within forensic toxicology, and several methods for STA have frequently been published and reviewed independently. However, the many drugs and other substances involved, as well as the constant emergence of new ones, may pose a major challenge in STA, which often demands a strategy involving multiple analytical methods in parallel. Such strategies have been published and evaluated less frequently despite their relevance in forensic toxicology. This mini-review briefly summarizes commonly applied methods for STA in forensic toxicology, including gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-MS (LC-MS) methods, and highlights some of their potential pitfalls. Second, it provides an overview of previously reported strategies to conduct STA, including a presentation of the STA strategy applied in the authors' laboratory. This involves broad drug screening by LC-high-resolution MS, supported by targeted screening and quantification using LC-tandem MS, headspace (HS)-GC-MS, HS-GC-flame ionization detector and other complementary methods. The STA strategy aims to cover as many potentially relevant drugs as possible and seeks to reduce potential pitfalls arising in forensic casework. The review underlines that not every substance can be identified in all circumstances even with a comprehensive STA strategy.