Epidemiological profile and determinants of whole blood heavy metal levels in occupationally exposed populations: a cross-sectional study in Hunan Province, China.

OBJECTIVE

This study aims to characterize current whole blood levels of heavy metals including lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As) among occupational populations in Hunan Province, China, and identify exposure determinants to inform health management strategies.

METHODS

A cross-sectional study was conducted on 2,991 occupational workers. Demographic data, occupational exposure history, and lifestyle habits were collected. Whole blood samples were analyzed via atomic absorption spectrophotometry for Pb and Cd levels, and atomic fluorescence spectrophotometry for Hg and As concentrations. Multiple linear regression was used to identify exposure predictors, and K-means clustering to categorize exposure patterns.

RESULTS

Elevated exceedance rates were observed for all metals, with Hg showing the highest rate (17.39%). Significantly higher blood metal levels ( < 0.05) were associated with males, age > 50 years, employment duration > 20 years, mining occupations, residence in Chang-Zhu-Tan, smoking, and drinking. Regression analyses revealed gender, age, employment duration, occupation type, and smoking as significant predictors of Pb and Cd levels ( < 0.05); gender, age, employment duration, and drinking for Hg ( < 0.05); and gender, age, employment duration, occupation type, and geographic region for As ( < 0.05). K-means clustering stratified participants into low-, medium-, and high-exposure groups, with the latter exhibiting markedly elevated metal levels ( < 0.05), including some samples exceeding occupational exposure limits.

CONCLUSION

Whole blood heavy metal levels in Hunan occupational populations are significantly influenced by gender, age, employment duration, occupation type, and geographic factors. Targeted exposure mitigation and enhanced biomonitoring are urgently needed for high-risk subgroups.