Toxics | Issue Cover Articles in the First Half of 2026

1. “Micronuclei and Nuclear Abnormalities in Oral Mucosa as Indicators of Genotoxicity in Healthcare Professionals”
by Juana Sánchez-Alarcón, Stefano Bonassi, Mirta Milić, Ninfa Ramírez-Durán, Keila Isaac-Olivé and Rafael Valencia-Quintana
Toxics 2026, 14(1), 61; https://doi.org/10.3390/toxics14010061
Available online: https://www.mdpi.com/2305-6304/14/1/61

Cover Story: Occupational exposure to physical and chemical agents represents a potential risk for genomic instability in healthcare professionals. This cover illustrates the use of the buccal micronucleus cytome assay as a minimally invasive biomonitoring tool to detect early genotoxic effects in oral mucosal cells. By comparing different occupational groups, the figure highlights an increased frequency of micronuclei and nuclear abnormalities among nurses, suggesting a higher susceptibility to occupational genotoxic stress. These findings support the relevance of cytogenetic biomarkers for risk assessment and prevention strategies in healthcare settings.

2. “From Enrichment to Fate: Transport, Transformation, and Fate of Micro- and Nanoplastics in Marine Environments”
by Wei Ma, Xinjie Liang, Changling Ding, Yingying Ye and Jiji Li
Toxics 2026, 14(2), 120; https://doi.org/10.3390/toxics14020120
Available online: https://www.mdpi.com/2305-6304/14/2/120

Cover Story: Micro- and nanoplastics (MNPs) pervade marine environments, yet their ecological impacts remain unclear. This review examines how MNPs transport, transform, and affect ocean ecosystems. MNPs travel long distances while fragmenting, accumulating from surface waters to deep sediments. They threaten critical habitats like seagrass beds and coral reefs. Marine organisms ingest these particles, leading to oxidative stress, metabolic disruption, and immune impairment. The “Plastisphere” may also facilitate pathogen spread. Beyond direct effects, MNP pollution may disrupt carbon sequestration and food web stability. The authors outline research priorities: improved detection, long-term ecosystem studies, and understanding interactions with other pollutants—essential steps for addressing this growing marine threat.

3. “Machine Learning Prediction of Transthyretin Binding for Thyroid Hormone Transport Disruption for Chemical Risk Assessment”
by Shuaikang Hou, Chao Ji, Christopher M. Reh and Patricia Ruiz
Toxics 2026, 14(3), 240; https://doi.org/10.3390/toxics14030240
Available online: https://www.mdpi.com/2305-6304/14/3/240

Cover Story: Thyroid hormone balance is essential for development and metabolism, yet many environmental chemicals disrupt its transport by binding to transthyretin (TTR). This study leverages machine learning models trained on over 1500 compounds to predict TTR-binding affinity and identify structural features driving disruption. The results highlight key molecular determinants such as hydrophobicity and electronic properties while demonstrating acceptable predictive performance and reliability. This work advances non-animal screening approaches, enabling faster identification and prioritization of endocrine-disrupting chemicals for risk assessment.

4. “Common Carp Kidney as a Multipurpose Biomarker Organ: Insights from Perfluorooctanoic Acid Exposure”
by Maurizio Manera, Cosma Manera and Luisa Giari
Toxics 2026, 14(4), 287; https://doi.org/10.3390/toxics14040287
Available online: https://www.mdpi.com/2305-6304/14/4/287

Cover Story: The common carp kidney uniquely integrates renal, hematopoietic, and thyroid functions, positioning it as a multipurpose biomarker organ. Subchronic waterborne exposure to perfluorooctanoic acid (PFOA)—a prototype per- and polyfluoroalkyl substance (PFAS)—induces concentration-dependent nephrotoxic effects (glomerular filtration barrier disruption and proximal tubule vesiculation), immunotoxic rodlet cell recruitment/activation in hematopoietic tissue, and thyrotoxic follicle increase and colloid vesiculation. A novel hierarchical multipurpose index, via z-scoring of morphological endpoints, synthesizes these into modular subindices. Toxicologic pathology researchers are encouraged to extend this modular framework to other waterborne contaminants, supporting One Health monitoring.

5. “Early Pregnancy Targeted Exposome: Biological Response and Maternal BMI”
by Nadia Saadat, Soundara Viveka Thangaraj, Jasmin Chovatiya, Ravikumar Jagani, Syam S. Andra and Vasantha Padmanabhan
Toxics 2026, 14(5), 421; https://doi.org/10.3390/toxics14050421
Available online: https://www.mdpi.com/2305-6304/14/5/421

Cover Story: Pregnancy is a uniquely sensitive window during which metabolic, hormonal, and physiologic adaptations may amplify susceptibility to environmental chemicals. Maternal BMI may further modify exposure–response relationships by influencing toxicokinetics, bioaccumulation, metabolism, inflammation, and stress-pathway activation. This study provides an integrated understanding of how complex urinary exposome signatures are linked to maternal stress biomarkers, and the role played by BMI in modifying these biological responses with the potential to influence pregnancy outcomes. By evaluating real-world mixtures within the context of maternal metabolic health, this study may help improve identification of high-risk pregnancies, uncover mechanisms of environmental susceptibility, and inform prevention strategies to improve maternal and fetal health.

6. “Time- and Temperature-Dependent Effects of PHBV on Physiological Responses in Brine Shrimp”
by Natalia S. Buzzi, Anna Jáuregui, Anna Marín, Juan C. Navarro, Mar Llorca, Myriam Lizanda, María Constanza Díaz Andrade, Ana Carolina Moya, José Gámez-Pérez, Luis Cabedo et al.
Toxics 2026, 14(6), 533; https://doi.org/10.3390/toxics14060533
Available online: https://www.mdpi.com/2305-6304/14/6/533

Cover Story: Aquatic organisms face multiple stressors, including microplastic pollution and rising temperatures, yet the impacts of bioplastics remain poorly understood. Here, the biopolymer PHBV was evaluated in Artemia franciscana across different exposure scenarios. PHBV increased growth and development at higher concentrations, longer exposure, and warming. These effects were accompanied by changes in enzymatic activity, lipid peroxidation, fatty acids, and gut structure, with marked damage at high temperature. Despite these alterations, no oxidative damage was detected. The results show that PHBV induces distinct, condition-dependent responses and underscore the importance of comprehensive multi-stressor ecotoxicological assessments of bioplastics promoted as sustainable alternatives.