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Mechanistic Acute-to-Chronic Extrapolation through Sediment Toxicokinetic-Toxicodynamic Modeling
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Researchers developed a mechanistic modeling framework to predict long-term toxic effects of sediment pollutants from short-term laboratory data, using the clam Ruditapes philippinarum as a test species. They derived acute-to-chronic toxicity ratios for copper, cadmium, and nanoplastic particles, and showed how environmental variables like salinity and particle size influence these ratios. The study demonstrates that computational toxicity modeling can provide transparent, reproducible alternatives to lengthy chronic exposure experiments.
Ecological risk assessment often requires extrapolation from short-term laboratory-derived effects data to predict long-term ecological impacts of pollution exposure. This study developed a mechanistic toxicokinetic-toxicodynamic (TKTD) modeling framework to derive acute-to-chronic ratios (ACRs) for the benthic clam Ruditapes philippinarum exposed to sediment-associated Cu. To facilitate model development in the sediment context, we derived physiological parameters (ke, CIT, kk) using aqueous toxicity tests and used diffusive gradients in thin-films (DGT) measurements to represent Cu bioavailability in sediments. The sediment TKTD model accurately predicted Cu accumulation in clam tissues and adequately predicted toxicity, with a 10% deviation from observed effects. Using model-predicted 7-day LC50 and no-effect concentration, an ACR of 17 was determined for Cu-induced clam mortality. The framework was then applied to derive ACRs for other contaminants using literature-derived aqueous TKTD parameters, including cadmium (ACRCd: 11-87) and nanoplastic particles (ACRNPs: 1.9-69). The new approach was also effective for elucidating how environmental variables (e.g., salinity, nanoplastic size) influence ACR values, thus offering insight which may be difficult to achieve by traditional empirical approaches. The study demonstrates the utility of TKTD modeling as a transparent and reproducible mechanistic method for acute-to-chronic extrapolation of toxicity as used for risk assessment applications.
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In Vitro Toxicity and Modeling Reveal Nanoplastic Effects on Marine Bivalves
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Researchers tested the effects of nanoplastics on Manila clams using both lab-based cell experiments and computer modeling, finding that the tiny particles caused growth inhibition, oxidative stress, and DNA damage. The computer models accurately predicted the real-world toxic effects seen in living clams. This approach could speed up safety testing for nanoplastics in seafood species, which matters because clams and other shellfish are a common route of human microplastic exposure.
Effects of nanoplastics on clam Ruditapes philippinarum at environmentally realistic concentrations: Toxicokinetics, toxicity, and gut microbiota
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Researchers exposed clams to nanoplastics at concentrations found in real marine environments and tracked how the particles accumulated in their tissues over 14 days. The nanoplastics caused physical damage and significantly altered the clams' gut bacteria. This is concerning because clams are widely consumed seafood, meaning nanoplastic contamination could affect both marine ecosystems and human food sources.
Integrated toxicokinetic/toxicodynamic assessment modeling reveals at-risk scleractinian corals under extensive microplastics impacts
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An integrated toxicokinetic/toxicodynamic modeling approach was applied to quantify microplastic-coral interaction dynamics across multiple scleractinian coral species, identifying species-specific vulnerability thresholds and predicting which coral species are most at risk under current microplastic pollution levels.
Assessing potential toxicity and metal bioavailability of secondary microplastics using in-vitro human gastric models
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This study assessed the potential toxicity and metal bioavailability of sediment samples from an aquatic environment, evaluating how co-occurring microplastics may influence metal toxicity by altering metal speciation and uptake. The results highlight complex interactions between plastic particles and metal contaminants in sediments.
Microplastic-associated metal risks in turbid coastal waters: limited vectoring but sensitivity effects at extreme loadings
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In turbid coastal waters, naturally occurring suspended particulate matter dominates particle-mediated metal uptake in clams, with field-aged microplastics contributing far less metal bioaccumulation than SPM at equivalent particle volumes. MP-associated metal toxicity effects only emerged at extreme, environmentally unrealistic microplastic loadings, suggesting current ecological risk models should prioritize natural particle vectors over microplastics.
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