Associations between fish consumption and human hair mercury: a multi-media assessment across urban and fishing communities in Guangdong Province, China.

Human exposure to mercury, particularly methylmercury (MeHg), through fish consumption remains a public health concern in coastal communities. This study conducted a multi-media assessment of total mercury (THg) and MeHg in fish (n = 284; 12 species), rice (n = 50), and human hair (n = 449) collected from four urban coastal areas and one fishing community in Guangdong Province, China, to examine associations between fish consumption and mercury accumulation in human hair. Mercury levels varied markedly across matrices and study areas. The fishing community showed substantially higher THg concentrations in fish (mean: 158.9 μg/kg) and hair (mean: 3317.6 μg/kg) than urban areas, whereas rice contributed minimally to exposure. Fish mercury accumulation was associated with source, habitat, trophic level, and species identity, with marine wild, carnivorous, and neritic species showing the highest burdens. Among participants with complete demographic and dietary data (n = 207), multivariable models identified fishing occupation, older age, fish consumption frequency, and daily fish intake as key associated factors of hair THg and MeHg, explaining > 60% of variance. A region-level ecological analysis further linked regional fish mercury profiles to hair mercury burdens, though this association should be interpreted at the regional rather than individual level. Fish consumption accounted for most MeHg intake, and a substantial proportion of fishing community residents exceeded the provisional tolerable daily intake for MeHg. These findings identify exposure patterns and potentially higher-risk groups, and support targeted, species- and population-specific fish consumption advisories based on updated food-contamination and biomonitoring data in high-exposure coastal communities.