Triclosan inhibits arbuscular mycorrhizal colonization in three wetland plants

► The effects of triclosan (TCS) on arbuscular mycorrhizal associations were assessed. ► We used a continuous flow-through exposure system and three wetland plant species. ► At 0.4 μg/L and 4.0 μg/L TCS, arbuscular and hyphal colonization levels were significantly reduced. ► 0.4 μg/L TCS is within the range of values obtained for North American surface waters. ► TCS may impair arbuscular mycorrhizal associations in North American wetlands.