Introduction Dietary intake is the main source of exposure to metals in the general population, however, among metal, chemical and mining workers, occupational exposure would be the most important source. Fish and seafood consumption can influence the levels of arsenic and mercury in blood and urine, but little information is available for other metals. We assessed the impact on metal levels of seafood, molluscs and fish consumption (SMFc) before urine and toenails sample donation in a group of exposed workers.

Methods Cross-sectional epidemiological study. We measured urinary (As, Ba, Be, Cd, Co, Cu, Hg, Li, Mo, Pb, Se, Sr, Tl, V, W and Zn), and toenail (same plus Al, Cr, Fe, Mn, Ni and U) metal levels. Information on SMFc and urine or toenail levels was obtained from 101 workers from the chemical and metal industry, and from 40 unexposed workers from the services sector. 84% of workers were male. Metal levels were measured using multielemental ICP-MS analysis. We compared the median for each metal between those with and without SMFc (U Mann-Whitney test). We used lineal regression models adjusted for age sex, and industry to assess the association between hours before SMFc and each metal level.

Results Urinary arsenic levels were higher among those workers who reported eating seafood or molluscs (102 ppm vs 55.4 ppm; p = 0.042) or fish (109 ppm vs 48 ppm; p = 0.007) 8 hours before sample donation. With respect to toenails, fish consumption was associated to aluminium (17 ppm vs 8.6 ppm; p = 0.012) and beryllium (5 ppb vs 1 ppb; p = 0.017). Arsenic urinary levels were associated with numbers of hours prior to sample collection since latest SMFc (p = 0.001).

Conclusion Seafood, molluscs and fish consumption is an important determinant of urinary arsenic levels, but not for other metals among exposed workers to metals.