DNA adductome monitoring: insights from the Swedish experience. Since 2017, DNA adductome analysis was conducted jointly with the Swedish National Marine Monitoring Program (SNMMP) in the Baltic Sea, using amphipods Monoporeia affinis and Pontoporeia femorata as sentinel species. In the context of SNMMP, the prevalence of embryo aberrations in sediment-dwelling amphipods serves as a key indicator of pollution effects. This indicator is based on the high sensitivity of embryo development to chemical exposure, leading to the manifestation of diverse developmental aberrations observable in gravid females \cite{Reutgard_2014,sea} used to assess the biological effects of contaminants in the Baltic Sea \cite{L_f_2016}. The measured embryo aberration rate serves as a specific health condition when evaluating the female DNA adductome, establishing baselines, and identifying biomarkers linked to an elevated risk of developmental disorders. Furthermore, the association between exposure and specific adductome profile can be categorized based on pollution loads in sediment at monitoring sites. Here, drawing from this experience, we offer insights into how DNA adductome can enhance the current effect-based assessment of biological effects in environmental monitoring.
DNA adductomics: advancing environmental monitoring
OMICS-based ecosurveillance. Current discussions center on integrating OMICS-based technologies into ecosurveillance monitoring frameworks. This integration aims to capture the comprehensive biological responses of ecosystems under perturbation \cite{Beale2022,Bahamonde2016}. These technologies and the data they provide have already enhanced our grasp of how environmental chemicals impact ecosystems and human health. However, despite progress, most environmental OMICS are currently in the data collection phase, with crucial gaps in linking toxicity data with OMICS endpoints \cite{Machuca-Sepúlveda2023a}. Future efforts are expected to address real environmental challenges, focusing on issues like chemical mixture toxicity, biomarker identification, baseline variability, and the development of approaches for deriving environmental quality standards from the OMICS data \cite{Henke2023,Machuca-Sepúlveda2023,Ebner2021} towards more effective risk monitoring, and sustainable natural resource utilization \cite{Beale2022}.
DNA adductome - an exposome component. Adductomics, an emerging research field, provides structural insights into chemical exposures and serves as a platform for discovering biomarkers to identify both the occurrence of exposure and associated effects. DNA adductomics, one of the newest OMICS techniques, is particularly well suited for assessing exposure and effects of environmental contaminants \cite{Lockridge2023} and elucidating genotoxic and epigenetic changes due to chemical stressors. However, whereas the DNA adductome approach is well-established in human toxicology due to its direct relevance to human health \cite{Balbo2014,Villalta2017}, its use in environmental studies has been limited despite the wide acceptance of DNA adducts as exposure biomarkers in wildlife.
DNA adducts are well-established biomarkers in (eco)toxicology. They are chemical modifications occurring when certain chemicals bind covalently to DNA molecules (Figure 1). Unrepaired DNA adducts can disrupt DNA structure and function, potentially leading to mutations and adverse biological effects \cite{Phillips_2009}. These adducts are associated with health issues, reproductive toxicity, genotoxicity, and epigenetic alterations in humans and wildlife. For the last 50 years, DNA adducts have been used as biomarkers of exposure in environmental toxicology, where the focus has mainly been on the adducts derived from polycyclic aromatic hydrocarbons (PAHs) in fish and mussels as exposure biomarkers \cite{Pampanin2017,Dolcetti2002}. In environmental toxicology, PAHs have been most commonly linked to DNA adduct formation \cite{Skarphédinsdóttir2007,Amat_2004,Meier2020}, both in the laboratory and in field observations after oil spills. However, other contaminants have also been found to induce DNA modifications \cite{Guilherme_2012,letters}. Also, in amphipods, abundant epigenetic DNA modifications have been associated with contaminated environments \cite{Martella2023} and females that carry embryos with various developmental disorders \cite{Gorokhova2020}. Thus, ample evidence supports the informative value of detecting and quantifying DNA adducts in biological samples for assessing contaminant exposure and genomic effects.