Study of mercury content in wild edible mushrooms and its contribution to the Provisional Tolerable Weekly Intake in Spain

The study determined total mercury (Hg) content of 10 wild edible mushroom species collected in southern Spain. Results indicated that the highest Hg level corresponded to Boletus aereus with 10.28 ± 2.92 mg/kg DW (dry weight), while the lowest Hg level was found in Terfezia arenaria with 0.09 ± 0.08 mg/kg DW. Regarding the anatomic parts of the mushrooms, caps showed significantly higher Hg concentrations than stems in B. aereus, Amanita caesarea and Macrolepiota procera. The percentage of contribution to the Provisional Tolerable Weekly Intake (PTWI) for Hg was also calculated. Based on consumption data in Spain (0.011 kg/person/week), %PTWI was calculated ranging between 0.06 and 3.5% for mean Hg levels. When a high level of consumption was assumed (0.100 kg/person/week), %PTWI ranged between 0.58 and 31%. Results suggest that wild edible mushrooms in southern Spain could contribute with high Hg levels to the Spanish diet. However, the lack of consumption data for wild edible mushrooms made it difficult to give more definitive conclusions; hence further studies including specific consumption data will be needed.