Endocrine Disrupting Activity of Mixtures Composed of Pharmaceuticals and Nanoplastics ^†

Endocrine disrupting chemicals (EDCs) are defined as “an exogenous chemical or mixture of chemicals that can interfere with any aspect of the hormone action” [1,2]. Thus, they have been considered among the strong risk factors in the development of obesity, metabolic disorders, infertility, endocrinopathies, diabetes, and hormone-dependent cancers globally. Combined exposure to EDCs may have more pronounced adverse effects on human health and may trigger stronger (or occasionally weaker) toxicological effects than exposure to an individual chemical, even at concentrations that are regarded as non-adverse (i.e., where no effects are expected) [3]. This study is focused on the endocrine-disruptive (ED) effects of the mixture of pharmaceuticals with nanoplastics. Paracetamol, ibuprofen, and fluoxetine were selected as scientific cases of pharmaceuticals, while commercially available 25 nm sized polystyrene nanoparticles (PNPs) were used as nanoplastics. The ED effects of each pharmaceutical and PNP, as well as of their mixtures, were evaluated using an in vitro estrogen receptor activity assay based on a T47D-KBluc cell line [4]. This cell line is stably transfected with a triplet ERE (estrogen-responsive element)-promoter-luciferase reporter gene construct, and therefore, it can be used to screen chemicals for estrogenic and anti-estrogenic effects. The obtained results showed estrogenic effects of the PNPs and all tested pharmaceuticals. The mixture of pharmaceuticals with PNPs demonstrated a higher agonistic affinity towards estrogen receptors (ERs) compared with individual components of the mixture. This study unambiguously shows that the health hazard potential of environmental contaminants should not be investigated exclusively as individual pollutants, but as complex mixture components.