The potential for toxicants to harm organisms in the environment is influenced by the physicochemistry of the substances and their environmental behaviors and transformation within ecosystems. This special issue is composed of 20 papers that report on studies which have investigated the fate and toxicity of various toxicants including engineered nanoparticles, pharmaceuticals and personal care products, antibiotics, pathogens, heavy metals, and agricultural nutrients. The environmental transformations of these substances and how these processes affect their toxicity are emphasized. This paper highlights the important findings and perspectives of the selected papers in this special edition, with an aim of providing insights into full-scale evaluation on the toxicity of various contaminants that exist in ecosystems. General suggestions are provided for the future directions of toxicological research.
Keywords: Heavy metals; Nanoparticles; Nutrient; PPCP; Pathogen; Toxicity.