Assessment of internal exposure risk from metals pollution of occupational and non-occupational populations around a non-ferrous metal smelting plant

Metabolomic machine learning predictor for arsenic-associated hypertension risk in male workers

Arsenic (As)-induced hypertension is a significant public health concern, highlighting the need for early risk prediction. This study aimed to develop a predictive model for occupational As exposure and hypertension using metabolomics and machine learning. A total of 365 male smelting workers from southern regions were selected. Forty workers from high and low urinary arsenic (U-As) exposure groups were chosen for non-targeted metabolomics analysis. Univariate analysis revealed that U-As is a risk factor for blood pressure and hypertension (P < 0.05). Restricted cubic spline (RCS) analysis showed that both systolic and diastolic blood pressure, as well as hypertension risks, increased with U-As, with a threshold at 32 µg/L. Of 1145 metabolites, 383 differentially expressed metabolites (382 upregulated, 1 downregulated) were identified. Least absolute shrinkage and selection operator (LASSO) regression was used to construct a predictive model for occupational hypertension, with N-hexosyl leucine, myristic acid, gamma-glutamylvaline, and pregnanediol disulfate as predictors. The area under the curve (AUC) of the receiver operating characteristic (ROC) for the predictive model was 0.917, indicating strong predictability and accuracy. This model, based on metabolomics and machine learning, provides an effective tool for early identification and intervention for occupational populations at high risk of hypertension due to As exposure.

Urinary metabolic alterations associated with occupational exposure to metals and polycyclic aromatic hydrocarbons based on non-target metabolomics

Long-term occupational exposure to metals and organics have been reported to be under great health risks. However, limited data are available on the molecular mechanism between combined exposure to metals and polycyclic aromatic hydrocarbons (PAHs) and harmful health effects. In present work, non-target metabolomics study was conducted based on urine samples from nonferrous metal smelting workers (n = 207), surrounding residents (n = 180), and the control residents (n = 187) by using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). Differential and correlation analyses among metabolic features indicate that total 22 differential metabolites in smelting workers were associated (p < 0.05) with metal and PAH exposure. Particularly, amino acid metabolism was strongly disturbed, and other metabolic pathways, including steroid hormone biosynthesis, citrate cycle, and pantothenate and coenzyme A (CoA) biosynthesis were also perturbed. Among them, steroid hormone biosynthesis was more affected by PAH exposure than metals, especially for hydroxyphenanthrene. These altered pathways were closely associated with oxidative stress, inflammation, and energy metabolism disorder. Additionally, our results indicate that endogenous metabolism in surrounding residents were also affected by nonferrous metal smelting activities to some extent. Our work provides valuable insights into molecular mechanisms of adverse health effects probably induced by combined exposure to metals and PAHs.

Quantitative characterization of resident' exposure to typical semi-volatile organic compounds (SVOCs) around a non-ferrous metal smelting plant

To comprehensively characterize residents' exposure to major semi-volatile organic compounds (SVOCs), samples of indoor floor wipes, size-segregated airborne particles, gaseous air, food, and paired skin wipes were simultaneously collected from residential areas around a large non-ferrous metal smelting plant as compared with the control areas, and three typical SVOCs (including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and halogenated PAHs (HPAHs)) were determined. Comparison and correlation analysis among matrices indicated PAHs were the major contaminants emitted from metal smelting activities compared to HPAHs and PCBs, with naphthalene verified as the most important characteristic compound, and their accumulation on skin may be a comprehensive consequence of contact with floor dust and air. While patterns of human exposure pathways for the SVOCs were found to be clearly correlated to their vapor pressure, dermal absorption was the major contributor (51.1-76.3%) to total carcinogenic risk (TCR) of PAHs and HPAHs for surrounding residents, especially for low molecular weight PAHs, but dietary ingestion (98.6%) was the dominant exposure pathway to PCBs. The TCR of PAHs exceeded the acceptable level (1 × 10-4), implying smelting activities obviously elevated the health risk. This study will serve developing pertinent exposure and health risk prevention measures.