The COVID-19 pandemic has led to a cascade of health crises globally, but beyond its direct impact on human health, an alarming environmental fallout has begun to surface. Recent research published in the journal New Contaminants unveils a sobering discovery about the unintended ecological consequences of pharmaceuticals administered during the pandemic. Specifically, this study investigates the toxic effects of several drugs used in COVID-19 treatment on aquatic life, focusing on the brine shrimp Artemia salina, a standard bioindicator in marine ecotoxicology.
The study’s authors, including corresponding researcher Denis Moledo de Souza Abessa of São Paulo State University, embarked on a crucial investigation to understand how expanded pharmaceutical use during the pandemic translates into chemical stress on marine ecosystems. They concentrated on five widely used drugs: hydroxychloroquine, ivermectin, nitazoxanide, loratadine, and betamethasone. These substances, while intended to battle viral infection and related symptoms, find their way into natural water bodies through various vectors such as wastewater effluents, sewage discharge, and surface runoff.
Pharmaceutical contamination of aquatic environments has long been a concern, but the sheer scale and urgency imposed by the pandemic have amplified this issue, warranting rigorous scrutiny. Many of these compounds are designed to be bioactive, and their continued presence in the environment raises substantial questions about their bioaccumulation and chronic toxicity effects on marine biota. The study zeroed in on A. salina due to its ecological relevance and widespread use as a marine sentinel species, providing critical insights into potential broader ecosystem impacts.
Over 48-hour acute toxicity trials revealed a disparity in the drugs’ effects on Artemia salina mortality rates. Hydroxychloroquine, a controversial drug during the pandemic’s early stages, exhibited no significant toxic effects at tested concentrations, suggesting relative environmental safety under the study conditions. In stark contrast, ivermectin demonstrated extreme toxicity, with mortality rates surpassing 50% even at the lowest concentrations tested. This pronounced harmful effect highlights a grave environmental risk posed by ivermectin residues in aquatic settings.
Betamethasone, loratadine, and nitazoxanide also induced notable mortality in the crustaceans, albeit at different toxic threshold levels. Betamethasone showed toxic effects starting at concentrations as low as 4 micrograms per liter, while loratadine and nitazoxanide toxicity thresholds were observed at 0.02 milligrams per liter and 0.05 milligrams per liter, respectively. The varying toxicity levels are indicative of distinct biochemical interactions and bioavailability of these compounds in marine environments.
These findings bring to light the complex dynamic between pharmaceutical residues and marine toxicity. The ranking formulated by the researchers — ivermectin being the most toxic followed by betamethasone, loratadine, nitazoxanide, and hydroxychloroquine — underscores that not all pandemic-related drugs exert equal environmental pressure. This nuance is essential for prioritizing environmental safety strategies and remediation efforts.
One of the most critical implications of this research lies in recognizing that pharmaceuticals, intended solely for human or veterinary therapeutic use, can transcend their initial purpose and transform into environmental pollutants with multifaceted and potentially irreversible impacts on marine biodiversity. This emphasizes the necessity for integrated environmental risk assessments that encompass the afterlife of drugs post-consumption, a factor often underappreciated in drug approval processes.
The pathways through which these pharmaceuticals infiltrate aquatic ecosystems—such as insufficiently treated wastewater and urban runoff—represent crucial intervention points for environmental management. Current wastewater treatment plants are often not equipped to efficiently remove complex pharmaceutical compounds, allowing their accumulation in aquatic environments. This persistence can lead to sustained exposure for marine organisms, elevating risks of bioaccumulation and subtle sub-lethal effects that might disrupt marine food webs and biodiversity.
Furthermore, the study advocates for further exploration of the chronic toxicity, bioaccumulation potential, and environmental persistence of these drugs, aspects not fully elucidated in acute toxicity testing. Chronic exposure studies would provide a deeper understanding of long-term ecological impacts, including reproductive and developmental effects on key marine species and potential cascading effects across trophic levels.
Public awareness is an equally vital component in mitigating pharmaceutical pollution. Educating populations on the proper disposal of medications and supporting the implementation of green pharmacy practices can reduce the influx of active pharmaceutical ingredients into the environment. Coupled with technological advancements in wastewater treatment, these measures could play a transformative role in safeguarding marine ecosystems from chemical contamination.
This research represents a critical call to action for environmental scientists, policy makers, and public health officials to collectively address the intersection of human health interventions and their environmental ramifications. The pandemic has unintentionally spotlighted the vulnerability of aquatic ecosystems to pharmaceutical contaminants, demanding an interdisciplinary strategy that balances urgent healthcare needs with environmental stewardship.
In summary, the study compellingly demonstrates that several drugs extensively administered during the COVID-19 pandemic exert significant toxic effects on Artemia salina, a proxy for broader marine ecological health. Ivermectin, in particular, stands out as a potent marine toxin, while others like betamethasone and loratadine also pose considerable risks. These insights necessitate enhanced vigilance, better treatment infrastructure, and expanded research to prevent pharmaceutical contamination from emerging as a silent yet pervasive ecological crisis.
The pandemic transformed many aspects of society, including the environmental chemical landscape. As humanity moves forward, the urgent challenge is to integrate lessons from this period into sustainable practices that protect vulnerable aquatic ecosystems from pharmaceutical pollutants and secure the health of our planet’s vital marine biodiversity.
Subject of Research: Toxicological impact of COVID-19 pharmaceuticals on marine organisms
Article Title: Toxic effects of drugs used to treat COVID-19 on Artemia salina
News Publication Date: 27-Apr-2026
Web References: https://doi.org/10.48130/newcontam-0026-0012
References: de Souza Abessa DM, de Carvalho MU. 2026. Toxic effects of drugs used to treat COVID-19 on Artemia salina. New Contaminants 2: e013.
Image Credits: Denis Moledo de Souza Abessa, Maysa Ueda de Carvalho
Keywords: COVID-19, pharmaceutical pollution, marine toxicity, Artemia salina, ivermectin, hydroxychloroquine, betamethasone, loratadine, nitazoxanide, ecotoxicology, aquatic environments, wastewater contamination
