“…Therefore, it may be a valuable early toxicological warning signal to recognize and identify biomarkers before those irreversible abnormalities. Molecular biomarkers, such as DNA methylation, histone modification, chromatin remodeling, and noncoding RNA related to epigenetic methods, have received widespread attention as early warning indicators of pollutant exposure. , Among these factors, DNA methylation can change the homeostasis of the genome, leading to conformational changes in chromatin DNA, alterations in DNA stability, and the abnormal expression of structural and functional proteins. These changes will cause normal cell cycle inhibition, abnormal differentiation, and cell apoptosis. , To date, environmental contaminants, including trace elements, persistent organic pollutants (POPs), and endocrine disruptors (EDCs) have been found to induce DNA methylation via in vitro and in vivo assays. , These results indicate that DNA methylation may be an important biomarker of environmental chemical exposure and consequent changes to the aquatic ecosystem. − …”