Mercury in Macrolepiota procera (Scop.) Singer and Its Underlying Substrate—Environmental and Health Risks Assessment

Abstract

Wild-growing edible mushrooms are valuable food with a high content of proteins, fibers, antioxidants, and they are characterized by their specific taste and flavor. However, from an ecotoxicological point of view, they are a risk commodity because of their extremely high bioaccumulative capacity to accumulate the risk elements and contaminants from the environment. In the present study, we examined mercury (Hg) contamination in 230 fruiting bodies of Macrolepiota procera (Scop.) Singer and 230 soil/substrate samples, which were collected in foraging seasons 2015–2019 from 22 different locations in Slovakia. Total mercury content was determined by cold-vapor AAS analyzer AMA 254. The level of contamination and environmental risks were assessed by contamination factor (Cf), index of geoaccumulation (Igeo), and potential environmental risk index (PER). Bioaccumulation factor (BAF) was calculated for individual anatomical parts of M. procera. Mercury content in the soil/substrate samples varied between 0.02 and 0.89 mg kg−1 DW, and in mushroom samples between 0.03 and 2.83 mg kg−1 DW (stems), and between 0.04 and 6.29 mg kg−1 DW (caps). The obtained results were compared with the provisional tolerable weekly intake for Hg defined by WHO to determine a health risk resulting from regular and long-term consumption of M. procera.

Risk Assessment of the Wild Edible Leccinum Mushrooms Consumption According to the Total Mercury Content

“…The average Hg content detected in Leccinum scabrum was 1.41 (0.674–2.94) mg kg −1 DW. Jančo et al [ 41 , 49 ] also confirmed the significant effect of the locality on the total Hg content in edible parts of mushrooms. Some previous studies showed that Macrolepiota procera collected from Central Slovakia (Banská Bystrica) had an average Hg concentration of 1.98 mg kg −1 (from 0.41 to 3.20 mg kg −1 ) in the caps and 1.40 mg kg −1 (from 0.12 to 1.75 mg kg −1 ) in stems.…”

“…al. [ 41 ], specifically in the locality Snina (0.68 mg kg −1 ). Lower values of Hg content in soil/substrate from Central Slovakia were recorded by Árvay et al [ 42 ] where the content of total Hg in the soil/substrate varied between 0.05 and 0.27 mg kg −1 DW.…”

“…However, the efficiency of the element accumulation does not always depend on their content in soil/substrate, but the element contents in such cases depend on mushroom species, genus, or the families to which they belong. Increasing age of mycelium, up to decades in wild-growing species, and a protracted interval between fructifications significantly elevate the contents of many elements in fruiting bodies, and usually higher levels occur in caps than in stems [ 20 , 41 , 45 ].…”

“…In the case of caps, the Hg concentration varied between 0.16 ± 0.05 mg kg −1 DW (Králiky) and 5.82 ± 2.28 mg kg −1 DW (Spišské Tomášovce). The EU limit value in the fruiting bodies of edible mushrooms for Hg is 0.75 mg kg −1 FW [ 41 ]. The dry matter content in all samples was approximately 10%.…”