Approaches, limitations and challenges in development of biomarker-based strategy for impact assessment of neuroactive compounds in the aquatic environment

Abstract

© The Author(s) 2021. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/. Background and objective Neuroactive compounds (NCs) represent a large group of chemicals that affect the activity of the nervous system of target organisms through various primary modes of action (MoA). This group of compounds includes neuroactive pharmaceuticals (antidepressants, antipsychotics, anxiolytics, anticonvulsants, opioids, and morphine derivatives), stimulants, illicit drugs, and pesticides with neuroactive action (organophosphate, carbamate, organochlorine, pyrethroid and neonicotinoid insecticides). The global use of NCs is increasing with growing of urban population and adoption of urban lifestyle [1, 2]. Antidepressants, anxiolytics, and antipsychotics are among the most frequently prescribed drugs [2, 3], caffeine is one of the most widely consumed stimulants in the world [4, 5], while pesticides are still extensively used in agriculture worldwide [6]. Along with neuroactive pesticides, contamination of the aquatic ecosystems by neuroactive pharmaceuticals and illicit drugs lately came into the scientific spotlight, and the increasing trend of their consumption worldwide implies to even growing environmental concentrations in the years to come. Clearly, NCs represent a newly recognized hazard in the aquatic environment, with possible adverse effects on aquatic ecosystems and implications to human population. However, the questions whether and to what extent NCs present a risk for aquatic ecosystems still remain largely open, due to, as the paper will show, limitations of current approaches in environmental risk and ecological impact assessment of chemicals. We will explore the potential way forward by using the Adverse Outcome Pathway (AOP) concept for the development of biomarker-based strategy for identification and hopefully, prediction of ecological impacts of NCs in aquatic ecosystems.