Comparative evaluation of four biosolids formulations on the effects of triclosan on plant-arbuscular mycorrhizal fungal interactions in three crop species.

Triclosan (TCS) is an antimicrobial ingredient found in personal care products that include soaps, shampoos, and other sanitation goods. TCS is moderately hydrophobic and has been shown to be resistant to wastewater treatment and thus accumulates in biosolids. Biosolids are commonly applied to agricultural land but little is known about the risk that TCS in biosolids poses to soil fungal communities following land application. The purpose of this study was to characterize the effects of TCS on the symbiotic colonization of roots in three field crops (soybean, corn, and spring wheat) by arbuscular mycorrhizal fungi (AMF) in soils amended with four different types of biosolids (liquid, dewatered, composted, alkaline and hydrolyzed). Crops were grown to maturity in pot-exposure systems under controlled temperature settings. Biosolids treatments were spiked with concentrations of TCS typically found in amended fields. Analysis of AMF colonization by hyphae, and the production of arbuscules and vesicles indicated no significant TCS concentration-dependent effects in the three plant species for any of the biosolids formulations. The data indicate that TCS present in municipal biosolids applied to agricultural lands likely poses minimal risks to AMF or its establishment of a symbiotic relationship in the three species tested.