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Predicting the Accumulation of Ionizable Pharmaceuticals and Personal Care Products in Aquatic and Terrestrial Organisms
Citation:
Carter, L., J. Armitage, B. Brooks, J. Nichols, AND S. Trapp. Predicting the Accumulation of Ionizable Pharmaceuticals and Personal Care Products in Aquatic and Terrestrial Organisms. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 43(3):502-512, (2024). https://doi.org/10.1002/etc.5451
Impact/Purpose:
Pharmaceuticals and personal care products (PPCPs) are released to the environment from domestic and industrial wastewater treatment plant discharges and in poorly treated or raw sewage, with additional inputs from veterinary use and land application of biosolids. A large percentage of PPCPs are ionized at environmentally relevant pH levels. As such, current bioaccumulation prediction models, which have been developed for neutral chemicals, are not applicable. This paper, which is part of a special issue on PPCPs, reviews the state-of-the-science with respect to predicting the bioaccumulation of PPCPs in aquatic and terrestrial organisms, excluding higher vertebrates. Special emphasis is given to the challenge of dealing with strongly ionized and permanently chemicals. The topics covered include passive diffusion of ionized PPCPs across membranes, the role of membrane transporters in facilitating membrane flux, binding of ionized chemical species to membranes and other biological macromolecules, and biotransformation. Concluding sections identify research needed to address these topics and develop predictive bioaccumulation models for PPCPs. This review will be of interest to regulators charged with assessment environmental risks associated with PPCPs and in particular risks that can be attributed to bioaccumulation. More generally, models developed for ionizable PPCPs will have substantial utility for environmental assessments of ionizable chemicals that fall outside the domain of PPCPs including numerous pesticides and industrial chemicals.
Description:
The extent to which chemicals bioaccumulate in aquatic and terrestrial organisms represents a fundamental consideration for chemicals management efforts intended to protect public health and the environment from pollution and waste. Many chemicals, including most pharmaceuticals and personal care products (PPCPs), are ionizable across environmentally relevant pH gradients, which can affect their fate in aquatic and terrestrial systems. Existing mathematical models describe the accumulation of neutral organic chemicals and weak acids and bases in both fish and plants. Further model development is hampered, however, by a lack of mechanistic insights for PPCPs that are predominantly or permanently ionized. Targeted experiments across environmentally realistic conditions are needed to address the following questions: (1) What are the partitioning and sorption behaviors of strongly ionizing chemicals among species? (2) How does membrane permeability of ions influence bioaccumulation of PPCPs? (3) To what extent are salts and associated complexes with PPCPs influencing bioaccumulation? (4) How do biotransformation and other elimination processes vary within and among species? (5) Are bioaccumulation modeling efforts currently focused on chemicals and species with key data gaps and risk profiles? Answering these questions promises to address key sources of uncertainty for bioaccumulation modeling of ionizable PPCPs and related contaminants.
URLs/Downloads:
DOI: Predicting the Accumulation of Ionizable Pharmaceuticals and Personal Care Products in Aquatic and Terrestrial Organisms
FINAL PUBLISHED MANUSCRIPT.PDF (PDF, NA pp, 352.458 KB, about PDF)
https://pubmed.ncbi.nlm.nih.gov/35920339/