Human biomonitoring reference values, exposure distribution, and characteristics of metals in the general population of Taiwan: Taiwan environmental survey for Toxicants (TESTs), 2013-2016

The influence of exposure to inorganic arsenic and other arsenic species on early renal impairment among young adults in Taiwan

Chronic kidney disease (CKD) poses a significant global public health challenge, with environmental toxins potentially contributing to its prevalence. In Taiwan, where arsenic (As) contamination is endemic in certain areas, assessing its impact on renal health is crucial due to the country's high rates of unexplained CKD. This cross-sectional study assessed associations between urinary As species and early renal impairment biomarkers-the microalbumin-to-creatinine ratio (ACR) and β2-microglobulin (B2MG)-in 248 young Taiwanese adults (aged 20-29 years). We measured urinary As species (including arsenite [As3+], arsenate [As5+], monomethylarsonic acid [MMA], and dimethylarsinic acid [DMA]) and early renal impairment biomarkers (urinary microalbumin and B2MG levels). Median concentrations of urinary As3+, As5+, MMA, DMA, inorganic As (iAs), and the sum of inorganic and methylated As species (iSumAs) were 1.43, 1.02, 3.79, 31.53, 2.82, and 39.22 μg/g creatinine (Cre.), respectively. We also evaluated the first methylation ratio (FMR) and the second methylation ratio (SMR). After adjusting for potential confounding factors, a multivariate linear regression showed significant associations between B2MG and urinary As5+ (β = 0.299, 95% confidence interval [CI]: 0.113-0.485) and iAs (β = 0.281, 95% CI: 0.061-0.502) concentrations. A generalized additive model revealed non-linear relationships among As5+, iAs, and B2MG concentrations. Moreover, there were elevated risks associated with the highest tertile of B2MG concentrations compared to the highest tertile of urinary As5+ (odds ratio [OR] = 2.366, 95% CI: 1.196-4.682), MMA (OR = 1.917, 95% CI: 1.002-3.666), DMA (OR = 1.952, 95% CI: 1.015-3.753), and iSumAs (OR = 2.302, 95% CI: 1.182-4.483). These results indicated that exposure to As was associated with early renal impairment, particularly evidenced by increased urinary B2MG concentrations.

Biomonitoring of firefighters' exposure to priority pollutant metal(loid)s during wildland fire combat missions: Impact on urinary levels and health risks

Wildland firefighters are exposed to metal(loid)s released during wildfires through vegetation combustion, which also promotes remobilization of accumulated anthropogenic metal(loid)s. Studies biomonitoring metal(loid)s exposure promoted exclusively by wildfire suppression activities are lacking. This work aimed to characterize, for the first time, the impact of real-life wildland firefighting operations on urinary levels of priority pollutant metal(loid)s [14 included in ATSDR, 11 in USEPA, and 4 in Human Biomonitoring for Europe Initiative priority lists] in firefighters. Spot urines were sampled pre-exposure (105 non-smokers, 76 smokers) and post-exposure to firefighting activities (20 non-smokers, 25 smokers); among those, paired samples were collected from 14 non-smoking and 24 smoking firefighters. Smokers displayed significantly higher baseline levels of zinc (28 %), lithium (29 %), cadmium (55 %), rubidium (13 %), and copper (20 %) than non-smokers. Following wildfire suppression, the concentration of the WHO potentially toxic metal(loid)s rose from 2 % to 3 % in smokers and 2 % to 5 % in non-smokers (up to 4 % for all firefighters and up to 5 % in paired samples). Levels of nickel (33-53 %), antimony (45-56 %), and cesium (40-47 %) increased significantly post-exposure in non-smokers (in all firefighters and in paired samples), whose urinary concentrations were generally more impacted by wildfire emissions than those of smokers. Arsenic (80 %) displayed the only significant increase post-exposure in smokers, being the best discriminant of exposure to wildfire emissions in these subjects. Significant positive correlations were found for age and/or career length with cadmium, lead, barium, strontium, and mercury, and for body mass index with arsenic. The reference/guidance values were exceeded for arsenic, zinc, cesium, nickel, antimony, cadmium, lead, thallium, mercury, copper, and cobalt in 1-90 % of firefighters suggesting augmented health risks due to wildfire combating and emphasizing the need of mitigation strategies. This study also provides biomonitoring data to help setting reference values for the occupationally exposed part of population.

Associations of Urinary Cadmium with Body Composition and Fat Distribution in US Adults: Findings from NHANES 2011-2018

The effects of cadmium (Cd) on metabolic physiology remain controversial. Given the varying metabolic impacts associated with different body compositions, investigating the relationship between Cd exposure and body composition may facilitate further research. Here, the associations of body composition and fat distribution with urine Cd (UCd) were evaluated. This analysis included 2979 adult participants from the 2011-2018 National Health and Demographic Survey (NHANES). UCd was measured using inductively coupled plasma mass spectrometry and adjusted for urinary creatinine. Body composition and fat distribution were estimated using dual-energy x-ray absorptiometry (DXA). The study results show that UCd was negatively associated with fat mass index (FMI) and percent fat mass (p for trend < 0.001), and the negative correlation between UCd and FMI was stronger in males and smokers (all p for interaction < 0.05). In terms of abdominal fat distribution, UCd was negatively associated with abdominal subcutaneous adipose tissue (SAT) mass (p for trend < 0.001), but with abdominal visceral adipose tissue (VAT) mass only in those with low percent fat mass (< 32.3%) (p for trend = 0.026 and p for interaction < 0.05). UCd was positively related to percent VAT (p for trend < 0.001) and visceral-to-subcutaneous (VAT/SAT) ratio (p for trend = 0.003). And there was a significant negative association between UCd and android-to-gynoid (A/G) ratio (p for trend = 0.001). Meanwhile, UCd was negatively correlated with fat-free mass index (FFMI) (p for trend < 0.001). And the negative correlation between UCd and FFMI was stronger in males, smokers, and individuals with < 32.3 percent fat mass (all p for interaction < 0.05). We found the association of UCd with body composition and fat distribution, with distinct patterns observed in different demographic groups. These findings underscore the importance of considering UCd exposure in the context of body composition and fat distribution.

Exposure of the general French population to metals and metalloids in 2014-2016: Results from the Esteban study

BACKGROUND

The purpose of the Esteban study was to describe levels of various biomarkers of exposure to several environmental pollutants, including metals and metalloids, among the French population. This paper describes the distribution of concentrations of 28 metals and metalloids in two different populations, and estimates the main determinants of exposure to total arsenic, the sum of inorganic arsenic (iAs) and its two metabolites monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), cadmium, chromium, copper, mercury and nickel.

METHODS

Esteban is a cross-sectional study conducted between 2014 and 2016 on a random sample of 2503 adults (18-74 years old) and 1104 children (6-17 years old) from the general population. The data collected included biological samples (blood, hair, and urines), socio-demographic characteristics, environmental and occupational exposure, and information on dietary factors and lifestyle. The geometric mean and percentiles of the distribution were estimated for each metal. Multivariate analyses were performed to identify the determinants of exposure using a generalized linear model.

RESULTS

Only four metals had a quantification rate below 90% in adults (beryllium, iridium, palladium, and platinum), and three metals in children (beryllium, iridium, and platinum). The concentrations of total arsenic, cadmium, chromium and mercury were higher than those found in most international studies. The determinants significantly associated with exposure were mainly diet and smoking.

CONCLUSIONS

Esteban provided a nationwide description of 28 metal and metalloid exposure levels for adults (some never measured before) and for the first time in children. The study results highlighted widespread exposure to several metals and metalloids. These results could be used to advocate public health decisions for continued efforts to reduce harmful exposure to toxic metals. The Reference values (RV95) built from Esteban could also be used to support future government strategies.