Co-exposure effects of butyl benzyl phthalate and TiO nanomaterials (anatase) on Metaphire guillelmi gut health.

Phthalic acid esters (PAEs) and TiO nanomaterials (nTiO) are commonly used as plastic additives, nano-fertilizers or nano-pesticides. Their excessive co-applications led to the co-occurrence, which can induce damage to soil organisms such as Metaphire guillelmi (an earthworm widespread in farmland). However, the co-exposure effects of butyl benzyl phthalate (BBP, a typical PAEs) and nTiO on Metaphire guillelmi at environmental-relevant concentrations remain unclear. In this study, 1 mg kg BBP and 1 mg kg nTiO (anatase) were added into the soil to assess: (1) their effects on oxidative damage, digestive system, and neurotoxicity in Metaphire guillelmi gut on days 14 and 28; and (2) whether BBP and nTiO affected Metaphire guillelmi gut health by disrupting intestinal microorganisms. The results demonstrated that BBP and nTiO had the potential to inhibit the activity of superoxide dismutase, cellulase, protease, NaK-ATPase, and Ca-ATPase, as well as cause oxidative damage by altering intestinal bacteria such as Marmoricola and Microvirga at genus levels after 28 d-exposure. However, the exposure did not cause disorders of the intestinal bacteria. The present study provides more evidence for the sustainable application and scientific management of BBP and nTiO, thus providing better guidance for PAEs and engineered nanomaterials regulations in agroecosystems.