Bioaccumulation of insecticide in Agaricus subrufescens

Agaricus subrufescens, known as Sun Mushroom, is a high-value mushroom because of its medicinal properties, used as nutraceutical food to stimulate the immune system and to prevent some diseases, including cancer. Mushrooms are generally characterized by their great ability to bioaccumulate heavy metals and other toxic substances from the mushroom compost. Sugarcane bagasse is a common raw material used in mushroom compost production for Agaricus subrufescens cultivation, whereas insecticides, such as fipronil, can be applied to combat several pests in sugarcane crops. For this reason, we aimed to assess mushroom yield and fipronil bioaccumulation in Sun Mushroom, regarding different concentrations added to the mushroom compost (0, 8, 16 and 32 mg kg(-1)) and casing layer (0, 2, 4 and 8 mg kg(-1)). Each experiment was arranged in a completely randomized design with four replicates. Regression analysis from mushroom production data was applied using SISVAR 5.1 program. Fipronil was quantified using gas-liquid chromatography (HP 6890) with thermionic detector (NPD). Mushroom yield was affected when fipronil was added, decreasing from 12% (compost with 0 mg kg(-1) of fipronil) to 4.8% (compost with 32 mg kg(-1)). However, bioaccumulation was not detected. In contrast, insecticide bioaccumulation was detected when adding fipronil to casing layer, increasing from <0.01 mg kg(-1) (casing layer with 2 mg kg(-1)) to 0.26 mg kg(-1) (casing layer with 8 mg kg(-1)), however, mushroom yield was not affected.