Biomonitoring and food surveillance on heavy metals reveal need for food safety in a coastal region

Vegetables and seafoods are major sources of nutrients for human being. However, heavy metals can easily accumulate in these food types. Here we compared residents' blood As, Cd, Pb, Mn, Cu and Hg in one coastal city (Rizhao) and two inland cities (Zaozhuang and Jining) in Shandong province, China. From 180 participants we found that: blood As of Rizhao participants (8.03 ± 5.8 µg/L) was ∼7 fold of Jining participants and ∼10 fold of Zaozhuang participants; blood Cd (1.34 ± 1.72 µg/L) and Pb (17.05 ± 9.48 µg/L) in Rizhao participants demonstrated to be 1.29∼3.72 fold of that in Jining and Zaozhuang participants. To find reason for such difference, we examined food safety surveillance on heavy metals in vegetables, fruits, beans, tofu, peanuts 2020 to 2023. We also evaluated relevant reports on the heavy metal contamination. The health risks (P50∼P95) were assessed for 12 age/sex population types. Weekly intake limits and background levels from USA national survey were compared with Rizhao population exposure levels. We found that Pb, As and Cd intake from vegetables, beans, tofu and peanuts were not posing health risk. But when seafood intake was included, alarming health risk (target hazard quotient, THQ > 1) was found in children of 2∼5 years old (P75, P90, P95). While the weekly intake of heavy metals stayed within safe range, the daily intake of heavy metals in child groups exceeded population background levels in USA. Our study calls for extra attention on the food-contained heavy metals in coastal region.