Chlorpyrifos (CPF) is a widely used organophosphate insecticide, yet ecotoxicological evidence for marine organisms in Latin America, particularly under co-exposure with other pollutants, remains limited. We assessed the acute toxicity of CPF alone and in mixtures with low (100 µg/L) and high (1000 µg/L) concentrations of polyethylene nanoplastics (PE-NPs) in the marine amphipod Parhyale hawaiensis. Neonate mortality and immobility were evaluated over 96-h exposures. The CPF+NPs_Low mixture showed the highest toxicity for mortality (LC50 = 0.25 µg/L) and immobility (EC50 = 0.06 µg/L), compared with CPF+NPs_High (LC50 = 0.57 µg/L; EC50 = 0.11 µg/L) and CPF alone (LC50 = 0.32 µg/L; EC50 = 0.1 µg/L). Acute CPF toxicity data for marine organisms of Latin American origin were also compiled to develop a regional SSD and a preliminary ecological risk assessment (ERA), alongside a broader non-Latin American dataset for comparison. The analysis revealed substantial uncertainty across estimates, reflecting important gaps in the quantity, quality, and representativeness of regional ecotoxicological data. Overall, P. hawaiensis showed high sensitivity to CPF, and co-exposure to NPs modified its toxicity. These findings highlight the need to address regional ecotoxicological data gaps and to consider mixture effects in the CPF ERA for Latin American coastal ecosystems.

Aphis craccivora Koch (Hemiptera: Aphididae) is a major sucking pest of legumes. Neonicotinoid insecticides are extensively utilized for A. craccivora control. The extended use of neonicotinoids, including acetamiprid (ACP) to manage A. craccivora, has led to the development of resistance. However, the potential to delay the development of ACP resistance in A. craccivora has not yet been investigated. Our study aimed to examine the development of ACP resistance in A. craccivora over 20 generations, and the associated heritability (h[2]), fitness costs, biochemical mechanisms, and potential cross-resistance were evaluated. Gene expression of GST and Cyp-450 was measured under ACP exposure, and molecular docking of ACP with these proteins in the presence of diethyl maleate (DEM) and piperonyl butoxide (PBO) was analyzed. Our data showed that the ACP-resistant (ACP-R) strain of A. craccivora showed a 25.57-fold enhancement in LC50 compared to the Sus-strain, with realized heritability (h[2]) of 0.21 and reduced fitness (0.69). The net reproduction rate (R0), mean relative growth rate (MRGR), intrinsic rate of increase (r), and finite rate of increase (λ) were markedly lower in the ACP-R strain than in the Sus-strain of A. craccivora. Upregulation of Cyp-450 (CYP18A1, CYP4CJ14) and GST (GSTS3, GSTO1) genes enhanced enzyme activity, while Car-E showed no significant correlation with ACP susceptibility. Enzyme inhibitors PBO and DEM increased ACP toxicity, and molecular docking suggested their interaction with Cyp-450 and GST proteins contributes to resistance. Our findings offer key insights into ACP resistance in A. craccivora, supporting the development of management strategies and decision-making tools.

Ionisable environmental pollutants, including pharmaceutical residues, can be readily bioavailable, bioaccumulative, and potentially toxic for aquatic biota. Risks to organisms arise from continuous exposure, facilitated ion entry through cell membranes and various modes of action on cell receptors. In the present study, we examined behavioural changes in marbled crayfish Procambarus virginalis exposed to environmentally relevant concentrations (EC) and lowest observed effect concentrations (LOEC) of three selected pharmaceuticals. The anticonvulsant carbamazepine (neutral compound; EC = 11.6; LOEC = 116 µg/L), the anti-inflammatory diclofenac (ionisable weak acid; EC = 31; LOEC = 310 µg/L), and the antihistamine diphenhydramine (ionisable weak base; EC = 1.4; LOEC = 95 µg/L) were selected to investigate pharmaceutical-induced behavioural alterations in crayfish following a 96-hour exposure under laboratory conditions (water pH 7.6 and temperature 22 °C). The results showed that exposure to carbamazepine stimulated locomotor activity in crayfish, while no changes were observed in crayfish exposed to diclofenac or diphenhydramine. Specifically, crayfish exposed to EC of carbamazepine displayed an increased percentage of movement activity, nearly double the distance moved, and a higher walking speed compared to the solvent control. However, the exposure to the LOEC of carbamazepine resulted only in an increase in relative movement activity. This study demonstrates that the modes of action and physicochemical properties of pharmaceuticals may significantly influence how aquatic crustaceans respond to chemical stressors. Alterations in ecologically important behavioural traits may occur even at ECs of pharmaceuticals present in aquatic environments.

Closely related aquatic species often exhibit marked differences in their sensitivity to organic contaminants, yet the physiological mechanisms underlying this variability remain incompletely understood. This study investigated whether differences in glutathione S-transferase (GST) responsiveness are associated with contrasting phenanthrene tolerance in two congeneric crustaceans, Artemia franciscana and Artemia salina. Phenanthrene was used as a model polycyclic aromatic hydrocarbon to probe detoxification responses rather than to derive environmental toxicity thresholds. Acute toxicity was evaluated in nauplii after 24 and 48 h of exposure, whereas adult organisms were exposed for 7 days to assess survival and GST activity. Marked interspecific differences in acute sensitivity were observed. After 24 h, the EC50 was 380.8 µg L[-1] for A. salina, whereas no EC50 could be calculated for A. franciscana. After 48 h, the EC50 values were 28.81 µg L[-1] for A. salina and 186.5 µg L[-1] for A. franciscana, confirming the greater tolerance of the latter species. In adults, mortality remained low in both species throughout the 7-day exposure. GST activity increased significantly in A. franciscana, showing a clear dose-dependent induction of approximately 1.7-, 1.9-, and 2.0-fold at 16, 64, and 256 µg L[-1], respectively. In contrast, A. salina exhibited a weaker response, with GST activity increasing significantly at 16 µg L[-1] but remaining relatively constant at higher concentrations. Overall, the observed differences in GST responsiveness were consistent with the contrasting phenanthrene sensitivity of the two species, suggesting that inducible phase II detoxification may contribute to interspecific differences in tolerance. These findings support the use of comparative biomarker approaches to improve the interpretation of species-specific responses to organic xenobiotics in marine invertebrates.

Aquatic organisms in eutrophic brackish and freshwater systems are chronically exposed to natural and anthropogenic contaminants, including cyanotoxins, metals and pesticides, mainly driven by cyanobacterial blooms and human activities. However, the environmental risks posed by their combinations to the aquatic environment remain poorly understood. This study investigated the growth response of Chlorella vulgaris exposed to four single-chemical compounds (microcystin-LR, cylindrospermopsin, terbuthylazine, and cadmium) and five binary mixtures for 7 days. In single-chemical exposures, terbuthylazine was the most toxic to C. vulgaris, followed by cadmium, cylindrospermopsin and microcystin-LR. The obtained growth data were compared with concentration addition predictions based on individual toxicities using the MIXTOX tool, testing deviations for synergistic/antagonistic interactions, dose ratio and dose level dependencies. Mixture effects varied with composition and exposure time. Antagonism was the prevailing type of interaction between the chemical compounds after 4 days of exposure, while dose level dependency was the only deviation observed after 7 days. Regarding dose level dependency, synergism was observed at low doses of each chemical in three of the five tested binary mixtures. Time was an important factor in the change in the toxicity pattern. This synergistic effect poses a significant risk to aquatic organisms exposed simultaneously to cyanotoxins and anthropogenic contaminants in the environment.

Short-chain per- and polyfluoroalkyl substances (PFAS), including fluorinated acids, have expanded as replacements for legacy per- and polyfluoroalkyl substances, yet aquatic safety assumptions are challenged by emerging fish toxicity data and the realities of persistence and exposure. This review synthesizes fish toxicology evidence for three environmentally important short-chain fluorinated acids selected to represent distinct chemical and exposure contexts: perfluorohexanoic acid (PFHxA) as a short-chain perfluorocarboxylic acid, hexafluoropropylene oxide dimer acid (HFPO-DA) as an ether-based replacement compound, and trifluoroacetic acid (TFA) as an ultrashort terminal transformation product characterized by exceptional persistence and mobility. Across fish models, perfluorohexanoic acid is generally less bioaccumulative than many long-chain analogs, but can still elicit biologically meaningful neurobehavioral and molecular alterations depending on life stage and exposure scenario. Hexafluoropropylene oxide dimer acid, widely known as a replacement for perfluorooctanoic acid, shows patterns consistent with endocrine and metabolic disturbance in fish development, including thyroid-axis-related endpoints and transcriptomic or metabolomic disruptions. Trifluoroacetic acid differs fundamentally: it is extremely persistent and highly mobile, with evidence of increasing environmental burdens and unresolved thresholds for long-term ecological effects. The comparison is further interpreted in the context of other short-chain perfluorocarboxylic acids, particularly PFBA, PFPeA, and PFHpA, to clarify the position of the selected compounds within the broader short-chain PFAS spectrum. Overall, the comparison shows that short-chain fluorinated acids should not be interpreted through a single safety gradient, because PFHxA, HFPO-DA, and TFA represent distinct but connected risk logics shaped by exposure persistence, internal-dose dynamics, and pathway-specific biological responses. Future priorities include harmonized exposure verification, tissue-dose reporting, mixture-relevant designs, and cross-life-stage endpoints that better predict population-relevant outcomes.

Gold nanoparticles (AuNPs) are increasingly used in industrial and biomedical applications, raising concerns about their release into aquatic environments and their potential effects on non-target organisms. This study evaluated Au uptake by larvae of Rhinella arenarum and the aquatic macrophyte Lemna minor under different exposure scenarios in order to assess the influence of aquatic vegetation on nanoparticle transfer. Three 96-h bioassays were performed: (i) individual exposure of larvae and plants to AuNPs (1 and 10 mg L[- 1]), (ii) simultaneous exposure of larvae and plants, and (iii) exposure of larvae to previously contaminated plants in clean medium. Gold concentrations were quantified in both organisms, and accumulation factors (AF) were calculated. Simultaneous exposure resulted in markedly higher Au accumulation in larvae compared with individual exposure, with AF values reaching 6666 ± 1020 L kg[- 1] and 10,089 ± 760 L kg[- 1] at 1 and 10 mg L[- 1], respectively, suggesting enhanced nanoparticle availability under combined exposure conditions. Larvae exposed only through ingestion of previously contaminated plants also accumulated Au, although at lower levels, indicating that trophic transfer contributes to nanoparticle accumulation but less efficiently than direct aqueous exposure. Plants accumulated Au under both isolated and simultaneous exposure conditions, confirming their role as nanoparticle reservoirs in aquatic systems. These findings demonstrate that aquatic vegetation can significantly modulate nanoparticle transfer and availability in freshwater amphibians.

The co-occurrence of heavy metals and antibiotics in aquatic environments raises concerns regarding the complex interactions that alter their bioavailability and ecotoxicological effects on primary producers, such as algae. Four ciprofloxacin-metal complexes (CIP-Ms): CIP-Fe(III), CIP-Co(II), CIP-Ni(II), and CIP-Cu(II), were synthesized, and characterized using FT-IR, UV-visible spectroscopy, MALDI-TOF, and ICP-MS. The comparative toxicities of CIP, free metal ions, and CIP-Ms were evaluated with freshwater algae (Spirogyra columbiana) under controlled laboratory conditions. Algal growth inhibition and chlorophyll content were measured using UV-visible spectroscopy after 72 h of exposure. The CIP-Ms exhibited higher toxicity than CIP and free metal ions. Among them, CIP-Cu(II) exhibited the strongest inhibitory effect. The enhanced toxicity of CIP-Ms is attributed to increased lipophilicity, improved bioavailability, and oxidative stress induced by high levels of reactive oxygen species (ROS). These findings suggest that assessing individual contaminants may underestimate environmental risks, and emphasize the need to consider pollutant interactions for more realistic ecological risk assessment.

The high ecotoxicity of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) has directed global attention to substituted p-phenylenediamines (PPDs) and their quinone derivatives (PPD-Qs). To date, however, comprehensive evaluations of their toxicity and associated ecological risks in aquatic ecosystems remain scarce. This study utilized an integrated approach combining quantitative structure-activity relationship and interspecies correlation estimation (QSAR-ICE) model predictions, species sensitivity distribution analysis, and ecological risk assessment to evaluate the potential ecological risks of PPDs and PPD-Qs in major river basins of China. Model performance indicated acceptable predictive reliability, with QSAR predictions meeting r[2] > 0.8 and q[2] > 0.7 for all compounds and ICE-based predictions yielding R[2] of 0.66-0.99 and MSE of 0.0070-0.46. The integrated QSAR-ICE framework provided useful screening-level toxicity estimates. Sensitivity distribution analysis based on Chinese native species revealed that 6PPD, 7PPD, and 77PD had the lowest predicted no-effect concentrations. The ecological risk assessment revealed overall low ecological risks in major river basins of China, with risk quotient values mostly below 0.1. However, high exposure levels in the Pearl River and Tarim River basins suggested localized risks. This study provides a comprehensive assessment of the ecological risks of PPDs and PPD-Qs in Chinese freshwater environments, filling gaps in ecotoxicological data related to species sensitivity distribution and chronic toxicity endpoints for Chinese native species, and offering scientific evidence for environmental management.

Approximately 1.6 million tons of conventional munitions were dumped in German coastal waters. Corrosion of munition shells facilitates the leakage of explosives, such as the toxic and carcinogenic 2,4,6-trinitrotoluene (TNT), into the marine environment. Consequently, TNT contamination was detected in seawater, sediments, and marine organisms near munition dump sites, and is known to cause adverse effects in marine organisms. Accordingly, avoidance of contaminated areas would be advantageous for fish. We therefore hypothesized that fish respond to dissolved TNT and exhibit an avoidance reaction. To test this, we exposed three-spined sticklebacks (Gasterosteus aculeatus) to environmentally relevant TNT concentrations and evaluated their behavioral response. Individual fish were placed in a behavioral test tank equipped with two hideout zones composed of artificial plants. The hideout zone occupied by the stickleback was infused with either TNT solution (100 µg/L) or control water. Behavioral readouts included the time stickleback spent in the infused hideout zone, time until the exposed hideout zone was first left, and number of transitions between hideout zones. Sticklebacks did not exhibit significant behavioral responses to environmentally relevant TNT exposure. Consequently, fish inhabiting munition dump sites may experience chronic TNT exposure, potentially increasing long-term toxicological risks.

This study evaluated the physiological impacts of acute-exposure of tambaqui (Colossoma macropomum) to different concentrations of cellulose acetate nanoparticles at different sampling times. A total of 120 juvenile C. macropomum (38.91 ± 5.57 g and 13.76 ± 0.74 cm in total length) were distributed in 12 tanks of 150 L, in a recirculating aquaculture system (RAS). The juveniles were kept in water containing cellulose acetate nanoparticles (CANs) at four different concentrations (treatments): 0 mg L[-][1], 0.01 mg L[-][1], 0.10 mg L[-][1] and 1.00 mg L[-][1]. Blood samples were collected after 1 and 24 h of exposure. The juveniles were then relocated to a tank with clean water, where they remained for another 24 h, after which a new blood sample was collected (24 h). Hemoglobin, serum protein and globulin were reduced after 1 h of exposure for the group exposed to 1.00 mg L[-][1] of CANs. Glucose levels increased after 24 h for the groups exposed to 0.10 and 1.00 mg L[-][1]. Urea increased after 1 h for the groups exposed to 0.10 and 1.00 mg L[-][1]. Triglycerides and cholesterol were reduced both after 1 h and 24 h of exposure for the 1.00 mg L[-][1] group, returning to baseline levels at 24 h. The activities of aspartate aminotransferase (AST) and alanine aminotransferase were altered after 24 h. Albumin was lower after 1 h and 24 h compared to after 24 h for the 1.00 mg L[-][1] group. Exposure of juvenile C. macropomum to CANs caused transient physiological changes, with partial recovery being observed after transfer to clean water.

Most studies examining microplastic uptake by aquatic amphibians have only examined uptake from water, disregarding other potentially important exposure pathways. Here, we compare the relative importance of water and food as sources of microplastics to the American bullfrog (Lithobates catesbeianus), as well as investigate how exposure pathway affects the concentration and size of microplastics in tadpoles. Following a 2 × 2 factorial design, 60 wild-caught tadpoles (Gosner stage 25;15 tadpoles per treatment) were exposed in outdoor mesocosms to one of four treatments, in which microplastics were present or absent in water and food. To assess water exposure, white polyethylene (PE) fragments were added to the water column (888 ± 514 particles/L), whereas to assess food exposure, grey PE fragments were added to food (12.3 ± 3.46 particles/g agar). Over the 10-d experiment, tadpoles were collected every 48 h to analyze the microplastics in their gastrointestinal tract (GIT) and carcass (body with the GIT removed). Here, we report evidence that tadpoles acquired microplastics from both water and food, with tadpoles that were simultaneously exposed through both pathways containing an average of 666 ± 699 particles/g waterborne microplastics and 120 ± 118 particles/g foodborne microplastics in their GIT. The waterborne pathway contributed significantly to total microplastic concentrations in both the GIT and carcass, whereas the foodborne pathway only contributed significantly to total microplastics concentrations in the GIT. On average, 71 ± 23% of microplastics in tadpoles were in their GIT, suggesting that ingestion was the dominant-but not exclusive-route of exposure. Microplastic size did not differ between exposure routes, however, microplastics were on average smaller in tadpoles (0.088 ± 0.099 mm) than in water (0.231 ± 0.094 mm) or food (0.139 ± 0.078 mm). Our study emphasizes the importance of considering multiple exposure pathways when assessing risks of plastic pollution to aquatic biota.

Achatininae land snails, including the genera Achatina, Archachatina, and Lissachatina, have long been used in ecotoxicological studies, particularly in tropical environments where standardized terrestrial bioindicators remain limited. Their widespread distribution, close association with soils, and marked physiological sensitivity to contaminants have motivated their recurrent use in both field and laboratory investigations. In this context, Achatininae have often been proposed as functional counterparts to Cornu aspersum, which underpins international standards for growth inhibition and environmental bioavailability testing in temperate regions. This narrative review synthesises the use of Achatininae in terrestrial ecotoxicology. Specifically, we examine how these organisms have been employed to address mechanisms of action of chemical contaminants at the air-plant-soil interface, environmental and toxicological bioavailability of inorganic and organic pollutants through bioaccumulation and effect-based endpoints, and ecological disturbances at the level of malacological communities. Accumulation of metal(loid)s, pesticides and particulate contaminants is consistently documented across laboratory and field studies, whereas effect data are sparser, rarely replicated, and in places contradictory: identical polymer types have produced oxidative stress in one species and no measurable response in another, and the dose-response relationship reported for cadmium was not reproduced for lead. We therefore appraise the strength of the evidence endpoint by endpoint rather than presenting all studies as equivalent. Beyond classical ecological risk assessment, this review emphasizes the relevance of Achatininae within One Health-oriented risk frameworks. These snails are frequently harvested or farmed as a major protein source, placing them at the intersection of soil contamination, food safety, and human exposure. Cross-links between chemical contamination, microbiological hazards, and trophic transfer to predators and humans are discussed, extending the interpretation of ecotoxicological data beyond species-specific effects and secondary poisoning scenarios. Finally, we set out concrete harmonisation recommendations, distinguishing those specific to Achatininae from those generic to soil ecotoxicology, and identify where mechanistic and in silico new approach methodologies can extend the taxonomic reach of existing frameworks while reducing animal testing.

The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is widely used in tropical agriculture, yet its effects on non-target ectothermic vertebrates remain poorly understood. This study assessed the subchronic toxicological impact of 2,4-D on the liver and kidneys of Tropidurus torquatus, a neotropical lizard commonly found in agricultural areas. Seventeen adult males were divided into control (n = 9) and treatment (n = 8) groups. The treated group received 0.01 mg/kg body weight/day of 2,4-D orally for 30 days, based on the acceptable daily intake for mammals. Histopathological, stereological, and biochemical analyses were conducted. Hepatic histopathology showed no significant alterations, but stereology revealed a reduction in hepatocyte volume fraction in treated animals (p < 0.05). Renal histopathology showed significant degenerative changes, including hydropic-vacuolar degeneration, coagulative necrosis, and accumulation of brownish granular pigment (p < 0.0001). Biochemically, 2,4-D exposure triggered oxidative stress in both organs, with increased reactive oxygen species and lipid peroxidation, and reduced activities of superoxide dismutase and catalase. Despite these functional changes, renal stereology showed no significant differences in kidney volume or glomerular count. These findings indicate that even at doses considered safe for mammals, 2,4-D causes subclinical but relevant toxic effects in reptiles. This highlights the limitations of extrapolating mammalian safety thresholds to other taxonomic groups and reinforces the need for specific ecotoxicological assessments focused on tropical herpetofauna.

Glyphosate, one of the most widely used herbicides globally, is a significant environmental contaminant that may affect non-target organisms crucial to ecosystem services, including biological pest control. While glyphosate targets the shikimate pathway in plants, which is absent in animals, there is increasing evidence that glyphosate induces sublethal effects on arthropod predators. However, the factors modulating these effects remain unclear. Here, we investigated how physiological context, specifically pre-treatment with the broad-spectrum antibiotic tetracycline, commonly used to experimentally alter host associated microbial communities, modulates the sublethal hazard of glyphosate-based herbicide (GBH) on the predatory behavior of adult female Pardosa wolf spiders. Predation efficiency was measured using functional response assays across varying prey densities. Our results showed that GBH significantly reduced the spiders' predation rates, confirming its sublethal toxicity. However, spiders pre-treated with antibiotics exhibited higher capture rates following GBH exposure compared to the GBH only group. These findings demonstrate that the sublethal hazard of GBH on predators is context-dependent and can be altered by antibiotic-sensitive processes (such as host-symbiont interactions). This study highlights the complexity of pesticide effects on ecosystem services and suggests that the functional response of non-target predators depends strongly on their physiological background.