**Preface to "Aquatic Emerging Contaminants and Their Ecotoxicological Consequences"**

This book concerns the collection of 15 scientific articles (13 research papers and 2 reviews), published in *Toxics*, *Waters*, the *Journal of Xenobiotics*, and the *Journal of Marine Science and Engineering* regarding the Topic "Aquatic Emerging Contaminants and Their Ecotoxicological Consequences".

We proposed the above-mentioned topic because of the importance of filling the knowledge gaps, in terms of presence and toxicity, associated with the impact of emerging contaminants in aquatic ecosystems. In support of the Environmental Risk Assessment (ERA), needed for the protection of ecosystems, which concerns the characterization of both the exposure to and the effects of contaminants, the following issues were considered: (i) the research and monitoring of emerging contaminants in both seawaters and freshwaters and (ii) adverse effect evaluation of emerging contaminants at different levels of biological organization and trophic levels, including their uptake measurement in biological organisms.

In this context, emerging contaminants concern a wide plethora of both chemical and physical pollutants not yet considered in regular monitoring programs. This class includes pharmaceuticals and personal care products (PPCPs), illicit drugs, nanomaterials, and micro(nano)plastic polymers. Some evidence related to PPCP monitoring and their effects (specifically referred to Ceftriaxone and Levonorgestrel), as well as the phenomenon of antibiotic resistance in aquatic ecosystems, were considered in this issue. We also included studies investigating the occurrence and effects of nanoand microplastics with their additives (Bisphenol A) and plastic's interaction with other emerging pollutants such as antibiotics (Enrofloxacin). In the plastic context, it is very important to also highlight the potential impact of the *non*-conventional plastic materials, represented, e.g., by tire particles, which massively contribute to the total plastic pollution. For this reason, a paper on the effect of end-of-life tires (ELTs) in the aquatic ecosystem was reported in this book. On the other hand, a new category of emerging pollutants, represented by the so-called ionic liquids, applied in a wide plethora of uses was considered and published in this book with a study on the potential effects of 1-butyl-3-methylimidazolium chloride ([BMIM]Cl).

We also included some studies with existing/legacy contaminants such as heavy metals, polycyclic aromatic hydrocarbons (PAHs), polybromodiphenyl ethers (PBDE), and pesticides, conferring to this volume a more holistic view of (aquatic) pollution.

> **Fran¸cois Gagn´e, Stefano Magni, and Valerio Matozzo** *Editors*
