How do polyhydroxyalkanoates aged by aerobic compost interact with steroidal estrogens to alter their adsorption and transport characteristics? Kinetics, isotherms, and influencing factors

Abstract

Despite evidence indicating a substantial presence of microplastics (MPs) in organic fertilizers, research exploring the differences of MPs among various types of organic fertilizers remains limited. Additionally, MPs can act as carriers for organic pollutants, influencing their environmental behaviors. This study investigated the presence of MPs in organic fertilizers and their effects on the environmental behaviors of steroidal estrogens. We compared the adsorption of estrone (E1) and estrone sulfate sodium (E1-3S) by original PHA and PHA aged through cattle manure-straw compost (CS) and vermicompost (VC). PHA-CS exhibited the highest adsorption capacities for E1 (47.97 ± 2.20μgg-1) and E1-3S (64.32 ± 2.09μgg-1). Dissolved organic matter (DOM) from CS and VC profoundly affected estrogen adsorption onto PHA, with VC-derived DOM inhibiting and CS-derived DOM promoting adsorption. In simulated avian digestive fluid, the desorption efficiency of E1 was 72.46% to -93.43% higher than that of E1-3S, indicating increased toxicity and bioavailability of E1 upon bird ingestion. Transport experiments strongly suggested that estrogens could be more easily retained in porous media containing aged PHA. This study advances our understanding of the adsorption mechanisms of aerobic compost-derived PHA on estrogens and their desorption behaviors under different environmental conditions.