Reference Intervals for Lead, Arsenic, Mercury, and Cadmium in the Population of Southwest China: A Comparative Study of Direct and Indirect Sampling Techniques

Background

Environmental metal pollution poses a potential threat to public health, and reference intervals (RIs) are crucial tools for assessing exposure levels.

Aims

Our study was the first to systematically establish RIs for lead, arsenic, mercury, and cadmium in a population in southwest China, examining differences across genders and ages. The study also compared the differences between RIs obtained by two sampling techniques, including direct and indirect sampling, to assess the substitutability and limitations between the two techniques.

Materials and Methods

Direct sampling employed atomic absorption spectrometry (AAS) and inductively coupled plasma-mass spectrometry (ICP-MS) on human biomonitoring (HBM) data, while indirect sampling utilized a Gaussian Mixture Model (GMM) applied to a local Laboratory Information System (LIS) database. RIs were determined using the nonparametric method for both approaches.

Results

RIs were established for each metal, with variations observed across age groups for cadmium and lead, and across genders for lead in certain age groups. Most of the RIs established by the direct sampling technique had a narrower range compared to that established by GMM, and the RIs established by the two techniques were partially biased.

Discussion and Conclusion

These RIs offer a vital baseline for assessing environmental metal exposure and identifying metal poisoning in Southwest China. Additionally, this study highlights the potential of the GMM-based indirect sampling technique as a viable alternative to the traditional direct sampling technique, with the dual-technique comparison enhancing our understanding of their substitutability and limitations, thus opening new avenues for environmental health research.