Determination of a guidance value for the communication of individual-level biomonitoring data for urinary arsenic.

Available guidance values to interpret individual-level biomonitoring data (ILBD) for the sum of urinary inorganic-related arsenic species (SUIAS) are generally based on population statistical descriptors and not on a predetermined exposure level that should not be exceeded. The objective of this study was thus to propose a range of SUIAS concentrations, reflecting an exposure corresponding to WHO's provisional guideline value (PGV) for arsenic in drinking water (10 μg/L), within which an exposure-based biomonitoring guidance value can be identified. METHOD A comprehensive literature review was carried out in order to identify studies that were relevant to the determination of a guidance value.

Biological monitoring of exposure to rare earth elements and selected metals in the Inuit population of Nunavik, Canada.

In Nunavik (Northern Quebec, Canada), some mining projects are envisioned, that could increase the contamination of the environment by various chemicals, including rare earth elements (REEs), and implicitly Inuit population exposure. The objective of this study was to determine the baseline biological exposure of the population to these elements, before the potential mining development occurs. In the framework of the 2017 Qanuilirpitaa? Inuit health survey, urine samples were obtained from a representative sample of the adult Nunavik population, which were used to constitute 30 pooled samples according to age, sex and Nunavik subregions.

A probabilistic toxicokinetic modeling approach to the assessment of the impact of daily variations of lead concentrations in tap water from schools and daycares on blood lead levels in children.

The aim of this study was to assess the impact of exposure to tap water lead concentration ([Pb]) occurring in schools or daycares on blood lead level (BLL) of attending children. Given the potentially wide variations in space and time of ([Pb]) documented in the literature, a simple probabilistic toxicokinetic (STK) model that allows the simulation of the time-varying evolution of BLL in response to these variations was developed. Thus, basic toxicokinetic equations were assembled to simulate BLL in a typical infant, toddler and pupil.

Estimation of toluene exposure in air from BMA (S-benzylmercapturic acid) urinary measures using a reverse dosimetry approach based on physiologically pharmacokinetic modeling.

This study aimed to use a reverse dosimetry PBPK modeling approach to estimate toluene atmospheric exposure from urinary measurements of S-benzylmercapturic acid (BMA) in a small group of individuals and to evaluate the uncertainty associated to urinary spot-sampling compared to 24-h collected urine samples. Each exposure assessment technique was developed namely to estimate toluene air exposure from BMA measurements in 24-h urine samples (24-h-BMA) and from distributions of daily urinary BMA spot measurements (DUBSM). Model physiological parameters were described based upon age, weight, size and sex.

Regional variations in human chemical exposures in Canada: A case study using biomonitoring data from the Canadian Health Measures Survey for the provinces of Quebec and Ontario.

The Canadian Health Measures Survey (CHMS), an ongoing national health survey conducted in two-year cycles, collects extensive biomonitoring data that is used to assess the exposure of Canadians to environmental chemicals of concern. Combining data from multiple cycles of the CHMS allows for the calculation of robust regional estimates of chemical concentrations in blood and urine. The objective of this work was to compare biomarkers of exposure to several environmental chemicals for the provinces of Quebec and Ontario, two major CHMS regions, as well as the entire CHMS (representing Canada) minus Quebec (CMQ), and the entire CHMS minus Ontario (CMO), and to interpret differences between regions.

WITHDRAWN: Corrigendum to "Biomarkers of cadmium, lead and mercury exposure in relation with early biomarkers of renal dysfunction and diabetes: Results from a pilot study among aging Canadian" [Toxicol. Lett. 312 (2019) 148-156].

The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.

Biomarkers of cadmium, lead and mercury exposure in relation with early biomarkers of renal dysfunction and diabetes: Results from a pilot study among aging Canadians.

Cadmium (Cd), lead (Pb) and mercury (Hg) are known nephrotoxicants that have been associated with the risk of developing type-2 diabetes (T2D). The aim of this pilot study was to explore relations between biomarkers of Cd, Pb and Hg exposure, early urinary biomarkers of renal dysfunction (kidney-injured molecule-1 (KIM-1), N-acetylglucosaminidase and retinol-binding protein (RBP)) and plasma biomarkers deemed predictive of the risk of developing T2D (adiponectin, leptin, branched-chain and aromatic amino acids), among 70 participants (age range: (46-87 yrs)) from the Canadian Longitudinal Study on Aging (CLSA) with normal glycemic control (glycated haemoglobin ≤ 6.5%) in all but four of them.

An assessment of the impact of multi-route co-exposures on human variability in toxicokinetics: A case study with binary and quaternary mixtures of volatile drinking water contaminants.

This study aimed to assess the impact of multi-route co-exposures to chemicals on interindividual variability in toxicokinetics. Probabilistic physiologically based pharmacokinetic multi-route interaction models were developed for adults and four younger subpopulations. Drinking water-mediated multi-route exposures were simulated for benzene alone or in co-exposure with toluene, ethylbenzene and m-xylene, for trichloroethylene or vinyl chloride (VC), alone and in mixture.

Reverse dosimetry modeling of toluene exposure concentrations based on biomonitoring levels from the Canadian health measures survey.

Biomonitoring might provide useful estimates of population exposure to environmental chemicals. However, data uncertainties stemming from interindividual variability are common in large population biomonitoring surveys. Physiologically based pharmacokinetic (PBPK) models might be used to account for age- and gender-related variability in internal dose.

A Physiologically-Based Pharmacokinetic Modeling Approach Using Biomonitoring Data in Order to Assess the Contribution of Drinking Water for the Achievement of an Optimal Fluoride Dose for Dental Health in Children.

Due to an optimal fluoride concentration in drinking water advised for caries prevention purposes, the population is now exposed to multiple sources of fluoride. The availability of population biomonitoring data currently allow us to evaluate the magnitude of this exposure. The objective of this work was, therefore, to use such data in order to estimate whether community water fluoridation still represents a significant contribution toward achieving a suggested daily optimal fluoride (external) intake of 0.

Deriving A Drinking Water Guideline for A Non-Carcinogenic Contaminant: The Case of Manganese.

Manganese is a natural contaminant of water sources. It is an essential oligo-element, which may exert toxicity at high doses, particularly via inhalation. Its toxicity by the oral route is less known, but epidemiological and experimental studies tend to support its neurodevelopmental toxicity in infants and children.

Public Health Consequences of Lead in Drinking Water.

Purpose Of Review: Lead can enter drinking water from lead service lines and lead-containing plumbing, particularly in the presence of corrosive water. We review the current evidence on the role of drinking water as a source of lead exposure and its potential impacts on health, with an emphasis on children. Drinking water guidelines and mitigation strategies are also presented.

Human health risk assessment on the consumption of fruits and vegetables containing residual pesticides: A cancer and non-cancer risk/benefit perspective.

Pesticide residues in food is a public health concern. This study aimed to evaluate health risk and benefit associated with chronic consumption of fruits and vegetables (F&V) containing residual pesticides in the province of Quebec, Canada. Based on a representative sample of Quebecers (n=4727, aged 1-79) enrolled in the Canadian nutrition survey, population's mean chronic dietary exposure through consumption of F&V was evaluated for 169 different pesticide active ingredients (PAI), including 135 for which toxicological reference values (TRV) were available in the literature.

Evolution of chemical-specific adjustment factors (CSAF) based on recent international experience; increasing utility and facilitating regulatory acceptance.

The application of chemical-specific toxicokinetic or toxicodynamic data to address interspecies differences and human variability in the quantification of hazard has potential to reduce uncertainty and better characterize variability compared with the use of traditional default or categorically-based uncertainty factors. The present review summarizes the state-of-the-science since the introduction of the World Health Organization/International Programme on Chemical Safety (WHO/IPCS) guidance on chemical-specific adjustment factors (CSAF) in 2005 and the availability of recent applicable guidance including the WHO/IPCS guidance on physiologically-based pharmacokinetic (PBPK) modeling in 2010 as well as the U.S.

Pesticide exposures and chronic kidney disease of unknown etiology: an epidemiologic review.

The main causes of chronic kidney disease (CKD) globally are diabetes and hypertension but epidemics of chronic kidney disease of unknown etiology (CKDu) occur in Central America, Sri Lanka, India and beyond. Althoug also being observed in women, CKDu concentrates among men in agricultural sectors. Therefore, suspicions fell initially on pesticide exposure, but currently chronic heat stress and dehydration are considered key etiologic factors.

Assessing human variability in kinetics for exposures to multiple environmental chemicals: a physiologically based pharmacokinetic modeling case study with dichloromethane, benzene, toluene, ethylbenzene, and m-xylene.

The objective of this study was to compare the magnitude of interindividual variability in internal dose for inhalation exposure to single versus multiple chemicals. Physiologically based pharmacokinetic models for adults (AD), neonates (NEO), toddlers (TODD), and pregnant women (PW) were used to simulate inhalation exposure to "low" (RfC-like) or "high" (AEGL-like) air concentrations of benzene (Bz) or dichloromethane (DCM), along with various levels of toluene alone or toluene with ethylbenzene and xylene. Monte Carlo simulations were performed and distributions of relevant internal dose metrics of either Bz or DCM were computed.

BTEX air concentrations and self-reported common health problems in gasoline sellers from Cotonou, Benin.

To examine the relation between BTEX exposure levels and common self-reported health problems in 140 gasoline sellers in Cotonou, Benin, a questionnaire documenting their socioeconomic status and their health problems was used, whereas 18 of them went through semi-directed qualitative individual interviews and 17 had air samples taken on their workplace for BTEX analysis. Median concentrations for BTEX were significantly lower on official (range of medians: 54-207 μg/m³, n = 9) vs unofficial (148-1449 μg/m³, n = 8) gasoline-selling sites (p < 0.05).

Characterization of the human kinetic adjustment factor for the health risk assessment of environmental contaminants.

A default uncertainty factor of 3.16 (√10) is applied to account for interindividual variability in toxicokinetics when performing non-cancer risk assessments. Using relevant human data for specific chemicals, as WHO/IPCS suggests, it is possible to evaluate, and replace when appropriate, this default factor by quantifying chemical-specific adjustment factors for interindividual variability in toxicokinetics (also referred to as the human kinetic adjustment factor, HKAF).

Lung cancer and mesothelioma risk assessment for a population environmentally exposed to asbestos.

Asbestos-related cancer risk is usually a concern restricted to occupational settings. However, recent published data on asbestos environmental concentrations in Thetford Mines, a mining city in Quebec, Canada, provided an opportunity to undertake a prospective cancer risk assessment in the general population exposed to these concentrations. Using an updated Berman and Crump dose-response model for asbestos exposure, we selected population-specific potency factors for lung cancer and mesothelioma.

Assessing the impact of child/adult differences in hepatic first-pass effect on the human kinetic adjustment factor for ingested toxicants.

The objective of this study was to evaluate the impact of interindividual differences in hepatic first-pass effect (FPE) on the magnitude of the human kinetic adjustment factor (HKAF) for ingested toxicants. This factor aims at replacing a default value of 3.2 used in non-cancer risk assessment.

Assessing the impact of the duration and intensity of inhalation exposure on the magnitude of the variability of internal dose metrics in children and adults.

The objective of this study was to assess the impact of the exposure duration and intensity on the human kinetic adjustment factor (HKAF). A physiologically based pharmacokinetic model was used to compute target dose metrics (i.e.

An assessment of the interindividual variability of internal dosimetry during multi-route exposure to drinking water contaminants.

The objective of this study was to evaluate inter-individual variability in absorbed and internal doses after multi-route exposure to drinking water contaminants (DWC) in addition to the corresponding variability in equivalent volumes of ingested water, expressed as liter-equivalents (LEQ). A multi-route PBPK model described previously was used for computing the internal dose metrics in adults, neonates, children, the elderly and pregnant women following a multi-route exposure scenario to chloroform and to tri- and tetra-chloroethylene (TCE and PERC). This scenario included water ingestion as well as inhalation and dermal contact during a 30-min bathroom exposure.

Probabilistic human health risk assessment for quarterly exposure to high chloroform concentrations in drinking-water distribution network of the Province of Quebec, Canada.

Because quarterly concentrations of total trihalomethanes (THM) exceeding the 80 μg/L guideline are often tolerated by the public health authorities of the Province of Quebec (Canada), this study examined whether quarterly episodes of high concentrations of THM may pose a risk to the health of its population. Using Monte Carlo simulations, a probabilistic risk assessment was performed for infants (0-<6 mo), toddlers (6 mo-<5 yr) and adults (≥20 yr). Multiroute exposure including ingestion of drinking water as well as inhalation and dermal exposure while showering or bathing was considered.