Uptake of toxic and nutrient elements by foraged edible and medicinal mushrooms (sporocarps) throughout Connecticut River Valley, New England, USA

Abstract

Foraging for edible and medicinal mushrooms is a cultural and social practice both globally and in the United States. Determining the toxic and nutrient element concentrations of edible and medicinal mushrooms is needed to ensure the safe consumption of this food source. Our research examined wild, foraged mushrooms in New England, USA to assess nutrient (Ca, K, Mg, P) and toxic (As, Hg, Pb, Cd) element relationships between mushrooms, substrates, and soils. We examined a gradient in nutrient and toxic elements from more rural Mountain and Hill Zones in Massachusetts, Vermont, and New Hampshire to more developed and urban Valley and Coastal Zones in Connecticut. Substrates and mineral soils were moderate to weak predictors of mushroom tissue concentrations. We found significant differences in nutrient and toxic element concentration among the five common genera: Ganoderma, Megacollybia, Pluteus, Pleurotus, and Russula. In particular, Pluteus had consistently higher toxic element concentrations while Pleurotus and Russula had the highest Bioaccumulation Factors (BAFs). We found that the urban areas of the Valley and Coastal zones of Connecticut had Cd Target Hazard Quotient (THQ) values and ΣTHQ values > 1.0, indicating potential non-carcinogenic health hazard. However, the trend was largely driven by the > 2.0 Cd THQ for Pluteus. Our results suggest that foraging in more urban areas can still yield mushrooms with safe concentrations of toxic elements and abundant nutrients. Further research of this kind needs to be conducted within this region and globally to ensure humans are consuming safe, foraged mushrooms.

Keywords: Forest fungi; Macronutrients; Pollution; Risk assessment; Trace elements.