As integral components of aquatic food webs, crustaceans serve as pivotal conduits for energy transfer and sensitive bioindicators of environmental quality. This study characterizes the toxicological consequences of settleable atmospheric particulate matter (SePM)—a byproduct of industrial iron-ore processing—utilizing the freshwater shrimp Macrobrachium rosenbergii as a model organism. Experimental exposure demonstrated that SePM significantly enhances the aqueous solubility of both conventional (Fe, Al, Zn, Cu, Mn) and emergent (Cr, Ni, Sr, Sn, La, Ce) metals, establishing it as a potent vector for multi-elemental contamination. Exposed individuals bioaccumulated 24 metals, with predominant enrichment of Fe, Ba, Sr, Cu, and Zn; these accumulation profiles were modulated by both external concentration and element-specific uptake kinetics. Notably, ultrastructural characterization revealed significant metal sequestration within the exoskeleton, identifying an incidental pathway for contaminant cycling through discarded carapaces (ecdysis). Biochemical assessments indicated impairment of redox homeostasis, characterized by the exhaustion of enzymatic (CAT, SOD, GPx, GST) and non-enzymatic (GSH) defenses, alongside elevated lipid peroxidation and DNA strand breaks. While bioaccumulation had a dose-dependent progression, oxidative distress was manifest even at the lowest exposure levels, underscoring that the toxicity of SePM as a complex mixture cannot be accurately predicted by the additive impacts of its individual constituents. These findings highlight SePM as a critical, yet largely overlooked, driver of air-to-water cross-contamination. Our results underscore the urgent need to incorporate such atmospheric deposition into environmental monitoring frameworks and to expand regulatory criteria to address emergent metals and potential synergistic effects of metallic mixtures.

The present study evaluated the embryonic–larval development of sea urchins (Echinometra lucunter) exposed to water-soluble fractions (WSF) of oil spilled on the Brazilian coast in 2019 and recovered post-accident in 2021. In 2019, organisms were exposed to WSF concentrations of 35.01

Water pollution caused by veterinary antibiotics is a growing concern. Phytoremediation, which employs plants to remove emerging contaminants from water, offers a promising solution. This study investigated Potamogeton pusillus L., a submerged macrophyte, for the phytoremediation of flumequine (FLU), a fluoroquinolone commonly used in veterinary medicine, through a 20-day hydroponic experiment. Macrophytes were exposed to 50 and 500 µg L-1 of FLU, and FLU removal, bioaccumulation, metabolite formation, and physiological responses were assessed. Results showed that P. pusillus effectively removed 73 % and 47 % of FLU at 50 and 500 µg L-1, respectively. The highest bioconcentration factors (BCFs) of 476 and 379 L kg⁻¹ d.w. were recorded at day 14. FLU accumulated primarily in roots, followed by leaves and stems. Nine FLU metabolites were tentatively identified, with hydroxylation products (phase I) predominant in roots, while methylation and glucoside conjugation products (phase II) were more abundant in leaves. Minor physiological changes indicated the macrophyte's tolerance. These findings highlight P. pusillus as a promising candidate for FLU phytoremediation.

The municipality of Vitória, state of Espírito Santo, Brazil, has recognized emissions of atmospheric particulate matter (APM) as an environmental and human health threat, emitted mainly by the mining and steel industries. The aim of this study was to characterize and quantify the chemical elements present in the metallic nanoparticles of APM from Vitória (PM2.5 and PM10) and to evaluate their biochemical effects and those of the sedimentable APM (PM45–75) on Allium cepa (onion) cells, as a bioindicator. The analyses consisted of characterization in aqueous solution; quantification of metals; X-ray diffraction analysis; and quantification of superoxide dismutase, catalase, reduced glutathione, ascorbate peroxidase, lipid peroxidation, and metallothionein in A. cepa cells exposed to seven concentrations of the collected materials. The results showed that these particles dissociate in water, forming agglomerates of different sizes, up to nanoparticles. The X-ray data demonstrated a higher proportion of hematite and quartz, corroborating the high quantification of Fe. Among the analyzed metals, Fe, Al, B, Mn, Se, Zn, Sr, Cu, Ni, Ba, and Ti (an emerging metal) had the highest concentrations. There was an increase in the antioxidant system of A. cepa cells. Therefore, it is essential to reinforce the monitoring and regulation of APM emissions, considering their chemical composition and biological effects.

The concentration of metals/metalloids in settleable particulate matter (SePM) from industrial area and in the muscles were determined in the estuarine fish, Centropomus parallelus, after 96 h-exposure to different SePM concentrations. Antioxidant defenses, oxidative damage and neurotoxicity were also determined. The risk for human consumption was evaluated by estimating daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) and compared with fish collected close to the industries. Eighteen metals/metalloids were quantified in SePM and the muscles. In red muscle, the antioxidant enzymes were unchanged, and the acetylcholinesterase (AChE) activity and protein carbonyls (PC) increased. In white muscle, the glutathione-S-transferase (GST) activity and glutathione content (GSH) decreased, PC levels and lipid peroxidation (LPO) increased; the AChE was unchanged. Metals/metalloids bioaccumulated in muscles induced oxidative damage which may affect muscle function and consequently, fish performance. After short-term exposure to SePM there was no risk for human consumption. However, the EDI of fish collected in field exceeded the acceptable DI for children concerning to As and Hg. HI were lower than 1 revealing no carcinogenic risk.

Atmospheric particulate material (PM10), collected near to a metallurgical industrial area, caused internalisation of metallic nanoparticles. This is the first study of the bioavailability and detoxification pathway of metallic nanoparticles (NP) internalised into lung cells. Adenocarcinoma human alveolar epithelial lung cells (A549) were exposed to PM10 arising from a polluted area affected by smelting activity in Brazil (Vitória, ES). A time-course ultrastructural analysis (0, 3, 6, 9, 12 and 24h) was used to verify the internalisation process and its subsequent detoxification. The metal bioaccumulation, biochemical changes and cytotoxicity analyses were evaluated in lung cells after 24 h exposure to 0, 1, 5, 10, 20 and 40 μg PM10 mL-1. Time-course ultrastructural analysis showed that NP were internalised in both cytoplasm and nucleus after 1h exposure. Vesicles around internalised NP started forming after 3h; detoxification vesicles increased accumulating more NP between 6 and 12h exposure. Exocytosis was observed after 24h exposure. Five out of 28 analyzed metals (Al, Ti, Y, Fe and Ce) were bioaccumulated in the exposed cells. The emerging contaminants Ce, Y and Ti were mainly responsible for cytotoxicity effects. To our knowledge, this is the first record of the sequence of internalisation-toxicity, followed by physiological and biochemical responses, in lung cells exposed to atmospheric PM10 from a metallurgical area. This indicates the need for specific regulation of atmospheric PM from the smelting industry worldwide, considering the presence and toxic levels of emerging metallic contaminants (EMCs).

Anthropogenic activity associated with metallurgy affects nearby aquatic ecosystems by contaminating them with metallic effluents (e.g., liquid and aerosols). This study evaluated the metal/metalloid contamination of two coastal lagoons with different physical and chemical water characteristics, Carapebus (brackish water) and Maembá (freshwater), located near metallurgical industries, and an aquaculture facility, Alegre (freshwater), located far away from the industries. The lagoons are in the state of Espirito Santo, the largest steel producer and iron ore exporter in Brazil. Relative condition factor (Kn) and multiple blood biomarkers in Nile tilapia (Oreochromis niloticus), a common species in all sites, were evaluated in these sites. A total of 27 metals/metalloids were analyzed in water, sediment, and fish blood (cells and plasma). The hematological, immunological, physiological, and genetic biomarkers were analyzed in blood. Metal/metalloid concentrations varied in each matrix of each site. Fish from Maembá (site M1) had lower Kn, presented anemia, and had higher leukocytes and plasma lysozyme and glucose levels. Fish from Carapebus had higher micronucleus and cortisol levels. Fish from the lagoons exhibited higher respiratory leukocyte activity. Multivariate analysis separated Alegre from the two lagoons and emphasized the difference between them and fish responses. The correlation of some metals with erythrocyte DNA damage (Zn, Sr, Sn, and Ag), total leukocytes (Zn, Sr, Sn, Ag, V, Cr, and La), lymphocytes (Cu and Ni), and eosinophils and cortisol (Fe, As, and, Pb) in fish from Maembá and Carapebus showed that toxicity depends on the physical and chemical characteristics of water, which affect metal speciation. The interaction of abiotic factors and metals/metalloids in water also implies that fish adjust to maintain homeostasis.

The safety and nutritional quality of leafy vegetables are influenced by various cultivation practices; however, data comparing agroecological, conventional, and hydroponic systems remain limited. This study aimed to evaluate differences in Eruca sativa (arugula) grown under these systems, focusing on microbiological quality, levels of inorganic elements, and potential health implications of consumption. Additionally, it explores whether combining these parameters with S15N analysis can effectively distinguish between arugula from different farming systems. Microbiological analysis revealed superior quality of hydroponic arugula, as fecal coliforms, Escherichia coli, and Salmonella spp. were not detected in any sample. Diverse essential and toxic elements were found in arugula, with Cd, Fe, Mn, Ni, Pb, and Sr present in higher concentrations in conventional and agroecological samples. Conversely, hydroponic arugula presented higher concentrations of Mg (3487 f 1250 mu g g- 1 d.w.) and Zn (56.6 f 30.1 mu g g- 1 d.w.). Health risk assessments indicate that consuming conventional, agroecological, or hydroponic arugula does not pose health risks for adults. S15N displayed similar values for conventional (8.1 f 3.1 %o) and agroecological systems (9.6 f 2.9 %o), with hydroponic arugula showing the lowest values (4.8 f 2.7 %o). Linear Discriminant Analysis classified arugula samples with high accuracy, particularly for hydroponic arugula (100%). These findings highlight the influence of cultivation systems on arugula's safety and quality, emphasizing the benefits of hydroponic farming for minimizing pathogen and metal contamination in leafy vegetables. Additionally, S15N combined with multi-elemental and microbiological analyses enable a clear differentiation between hydroponic arugula and either conventional or agroecological samples.

The metallurgy industry is a potent global source of particulate matter (PM) atmospheric emissions. A portion of this PM may settle in aquatic (SePM) carrying metal/metalloid particles and metallic nanoparticles. Surprisingly, this form of contamination has not received due attention from most environmental monitoring agencies. We analyzed the effect of exposure to SePM on shrimp post-larvae, a critical stage for the viability of shrimp populations and for the trophic chain. After acclimation, shrimp were exposed to contaminants using a randomized experimental design—a 4 × 4 factorial arrangement with 2 factors: exposure time (24, 48, 72, and 96 h) and SePM concentration (0.00, 0.01, 0.10, and 1.00 g L−1). The bioaccumulation of metals, contamination rates, mortality, and ROS-related biomarkers (lipid peroxidation – LPO; DNA strand breakage DNA SB and metallothionein content – MTs;) were evaluated. After contamination, the water contained 27 different metals/metalloids. Post-larvae accumulated metals, such as Cd, Pb, Al, As, Se, Sr, Zr, Ba, La, Ce, W, and Hg. However, the rise in SePM did not result in a proportional bioaccumulation rise, indicating that effective biological barriers may work for some metals. Although the different levels of SePM changed mortality dynamics, they resulted in a similar final lethality (60–80 %). SePM caused significant damage to lipids (increased LPO), genetic material (DNA SB), and increased Mts. Such effects may reflect a particularly deleterious ecological problem as it is present at such an early stage of life. These results identified a clear environmental risk since the lower level of exposure used was 102 times lower than that measured in the habitats affected by local industry. Consequently, our results emphasize the need for clear protocols for monitoring the effects of SePM in aquatic environments.

Bullfrog tadpoles, Aquarana catesbeiana, were exposed to settleable particulate matter (SePM), (1 g L−1, 96 h) and their organs were collected for analysis of metal/metalloid, oxidative stress and neurotoxicity in liver, muscle, kidney and brain. The SePM water of the exposed groups contained 18 of the 28 metals/metalloids detected in ambient particulate matter (APM). Fe56 and Al were those that presented the highest concentrations, Cr, Mn, Pb and Cu increased from 10 to 20 times and Ti, V, Sr, Rb, Cd, Sn and Ni increased from 1 to 3 times compared to the control. Bioaccumulation of metals/metalloids in the exposure water varied significantly between organs, with the muscle and liver showing the highest concentrations of metals, followed by the brain. Lipoperoxidation and malondialdehyde increased only in muscle, while carbonyl proteins increased only in the liver and brain. Regarding nitric oxide synthase, there was an increase in the liver and brain in the group exposed to SePM. Catalase activity decreased in the liver and muscle, while the activity of glutathione peroxidase, increased in the liver and kidney and decreased in muscle. Glutathione S-transferase, which is mainly responsible for detoxification, increased in the liver and decreased in muscle and the kidney. Cholinesterase activity increased only in the muscle. The results indicate oxidative stress, due to oxidation catalyzed by metals, components of SePM. Thus, the results contribute to the understanding that SePM has a deleterious effect on the aquatic environment, negatively affecting bullfrog tadpoles, in different ways and levels in relation to the analyzed organs.

Under the present investigation, the submerged plant Potamogeton pusillus has been tested for the removal of lead (Pb) and cadmium (Cd). P. pusillus removal efficiency and accumulation capacity were examined in separated Pb and Cd solutions, at 0.5, 1.0, and 2 mg L −1 , and in solutions where both metals were present at the same concentration (0.5, 1.0, and 2 mg L −1 ), under laboratory conditions for 3, 7, and 10 days. Also, we examined the removal efficiency and accumulation capacity when a set of plants were exposed to 0.5 mg L −1 of Pb (or Cd) and increasing concentrations (0.5, 1, and 2 mg L −1 ) of Cd (or Pb) for 10 days. The effect of Cd and Pb was assessed by measuring changes in the chlorophylls, carotenoids, and malondialdehyde contents. Results showed that P. pusillus could accumulate Cd and Pb from individual solutions. Roots and leaves accumulated the highest amount of Cd and Pb followed by the stems. Some phytotoxic effects were observed, especially at individual Cd exposures, but these effects were not observed in the two-metal system. The removal and accumulation of Pb by P. pusillus were significantly enhanced in the presence of Cd under certain conditions, presenting a good alternative for the removal of these metals from polluted aquifers. To the extent of our knowledge, this is the first report on both enhanced phytoextraction of Pb in the presence of Cd and bioaccumulation of these heavy metals by P. pusillus .

We use the sentinel mangrove crab, Minuca rapax, , as a model to investigate the effects of metallic settleable particulate matter (SePM) on wetland. Multiple levels of energetic responses, including (i) metabolic rate and energy budget, (ii) oxidative stress, and (iii) behavioral response by righting time, were assessed as well as the metal and metalloid content in crabs exposed to 0, 0.1 and 1 g.L-1- 1 of SePM, under emerged and submerged conditions over five days, simulating the rigors of the intertidal habitat. Al, Fe, Mn, Cr, and Y exhibited a concentration-dependent increase. Metal concentrations were higher in submerged crabs due to the continuous ingestion of SePM and direct exposure through gills. Exposure concentration up to 1 g.L-- 1 decreased metabolic rate and enzymatic activities, reduced assimilation efficiency and energy for maintenance, and induces a slower response to righting time, probably by metal effects on nervous system and energy deficits. In conclusion, SePM exposure affects the redox status and physiology of M. rapax depending on he submersion regime and SePM concentration. The disruption to the energy budget and the lethargic behavior in M. rapax exposed to SePM implies potential ecological alterations in the mangrove ecosystem with unknown consequences for the local population.

The steel industry is a significant worldwide source of atmospheric particulate matter (PM). Part of PM may settle (SePM) and deposit metal/metalloid and metallic nanoparticles in aquatic ecosystems. However, such an air -towater cross -contamination is not observed by most monitoring agencies. The region of Vitoria City is the main location of iron processing for exports in Brazil, and it has rivers, estuaries, and coastal areas affected by SePM. We have evaluated the effects of SePM on a local representative fish species, the fat snook, Centropomus parallelus . After acclimation, 48 fishes (61.67 +/- 27.83 g) were individually exposed for 96 h to diverse levels of SePM (0.0, 0.01, 0.1 and 1 g/L -1 ). The presence of metals in the blood and several blood biomarkers were analyzed to evaluate the impact of SePM on stress signaling, blood oxygen transport capacity, and innate immune activity. Metal bioaccumulation was measured from blood in two separately analyzed compartments: intracellular (erythrocytes plus white blood cells) and extracellular (plasma). The major metals present at all contamination levels in both compartments were Fe and Zn, followed by Al and Cu, plus traces of 'Emerging metals ': Ba, Ce, La, Rb, Se, Sr, and Ti. Emerging metals refer to those that have recently been identified in water as contaminants, encompassing rare earth elements and critical technology elements, as documented in previous studies (See REEs and TCEs in Cobelo-Garc & iacute;a et al., 2015; Batley et al., 2022). Multivariate analysis revealed that SePM had strong, dose -dependent correlations with all biomarker groups and indicated that blood oxygen -carrying capacity had the highest contamination responsiveness. Metal contamination also increased cortisol and blood glucose levels, attesting to increased stress signaling, and had a negative effect on innate immune activity. Knowledge of the risks related to SePM contamination remains rudimentary. However, the fact that there was metal bioaccumulation, causing impairment of fundamental physiological and cellular processes in this ecologically relevant fish species, consumed by the local human population, highlights the pressing need for further monitoring and eventual control of SePM contamination.

Metallurgical activities are a significant source of settleable atmospheric particulate matter (SePM). The material is exposed to wind action, leading to its deposition throughout terrestrial and aquatic ecosystems, thus promoting contamination by metals and metalloids. However, knowledge of the impacts on biota is scarce. In aquatic coastal zones, evaluating hemolymph in invertebrates makes it possible to have insights into the pre -pathogenic effects and health status of organisms. Our study aimed to evaluate bioaccumulation and the sublethal effects of SePM on the mangrove crab Ucides cordatus by assessing biomarkers of cito-genotoxicity in the hemolymph. Organisms underwent a 30 -day experiment with four treatments: control; 0.01 g.L -1 , 0.1 g.L -1 , 1 g.L -1 of SePM, with hemolymph sampled at 2, 7, 15, and 30 days of exposure to assess lipid peroxidation (LPO), DNA damage (strand break), cholinesterase (ChE) and lysosomal membrane stability (LMS). The results revealed metals' bioaccumulation in soft tissues (Al, Fe + , Fe ++ , Cu, Zr, Nb) and dose -time -dependent responses for LPO, DNA strand break, ChE, and LMS. Significant correlation was found between LPO and Cu (tissue), reduced LMS and Al and Fe (tissue), and Cu, Zn, Ag, and Bi in water. Hemolymph was related to the toxicokinetic and toxicodynamic of metals and metalloids from SePM in Ucides cordatus . New toxicological evidence was obtained to shed light on the impacts of SePM on the ecological status of coastal zones.

Amphibians are more susceptible to environmental stressors than other vertebrates due to their semipermeable skin and physiological adaptations to living in very specific microhabitats. Therefore, the aim of the present study was to investigate the effects of a metal mixture from settleable particulate matter (SePM) released from metallurgical industries on Lithobates catesbeianus tadpoles. Endpoints analyzed included metal bioconcentration, morphological (biometrical indices), hematological parameters (hemoglobin and blood cell count), and erythrocyte DNA damage (genotoxicity and mutagenicity). American bullfrog tadpoles (Gosner's stage 25) were kept under control condition (no contaminant addition) or exposed to a sub-lethal and environmentally relevant concentration (1 g.L-1) of SePM for 96 h. Tadpoles exposed to SePM exhibited elevated whole blood levels of Fe56, AL, Sn, Pb, Zn, Cr, Cu, Ti, Rb, V, Ce, La, Ag, As. SePM-exposed tadpoles showed a significant decrease in condition factor (12%) and increases in hepatosomatic index (25%), hemoglobin concentration (17%), and total leukocytes (82%), thrombocytes (90%), and monocytes (78%) abundance. In addition, exposed tadpoles showed higher MN and ENAs (340 and 140%, respectively) frequencies, and erythrocyte DNA damage with approximately 1.2-to 1.8-fold increases in comet parameters. Taken together, these results suggest that the multimetal mixture found in SePM is potentially genotoxic and mutagenic to L. catesbeianus tadpoles, induces stress associated with hematological changes, and negatively affects growth. Although such contamination occurs at sublethal levels, regulatory standards are needed to control the emission of SePM and protect amphibian populations.

Exposure to environmentally relevant levels of settleable atmospheric particulate matter (SePM) limits the aerobic performance of inactive healthy adult fish. We evaluated the gill morpho-functional impacts (gill structure and ionic balance) caused by SePM exposure (96h) in Nile tilapia when fish is impelled to maximal aerobic swimming effort. In control fish, swimming reduced epithelial filament thickness (EFT, 25%), increased the distance between lamellae (DL, 21%), and reduced the plasma Na+ (5%). In resting fish, SePM exposure increased EFT (11%), reduced DL (30%), lamellar height (LH, 18%), and plasma Na+ (4%), whereas increased Cl- and K+ (8% and 20%). In SePM-exposure fish, swimming reduced EFT (40%), increased DL (30%) and LH (30%), while reduced Na+ and Cl- (9% and 18%), and increased K+ when compared to inactive SePM-exposed fish. These morpho-functional limitations may compromise whole-body maintenance and swimming recovery, affecting the fish ability to perform at higher activity levels.

Settleable atmospheric particulate matter (SePM), from steelmaking processes, contains a complex mixture of metals, metalloids, and metallic nanoparticles. The SePM is released airborne and disperses in water, representing a significant threat to aquatic life, particularly fish. This study investigated the effects of a sublethal and environmentally relevant concentration of SePM (1 g·L-1) for 96 h in the gill, liver, kidney, and white muscle of Nile tilapia (Oreochromis niloticus), employing exposure and effect biomarkers to test causality between metal accumulation and biochemical responses. The gills and liver showed the highest bioaccumulation of metals and integrated response index value, indicating susceptibility to metal accumulation. However, the gills produce a protective mucus layer that may mitigate metal toxicity. The kidneys and muscle tissue also showed bioaccumulation of metals, although to a lesser extent. The liver and kidneys experienced oxidative stress, characterized by reduced metallothionein and glutathione levels, as well as damage to lipids, proteins, and DNA. The accumulation of less-studied metals, particularly Rare Earth Elements (REEs), compromised the integrity of biomolecules in these tissues. In conclusion, the complex dynamics of metal bioaccumulation in Nile tilapia exposed to SePM reveal varied tissue responses and primary effects like oxidative damage. They also highlight the need for further research and regulation of other metals and their potential impacts on aquatic ecosystems and human health.

Some atmospheric pollutants may affect aquatic ecosystems after settling, generating contamination, bioaccumulation, and threats to aquatic species. Metallurgical processes result in the emission of settleable atmospheric particulate mat-ter (SePM), including metals and metalloids, along with rare earth elements (REE) that are considered emerging con-taminants. We report the 30-day exposure of brown mussels (Perna perna) to SePM collected in a metallurgical area of southeast Brazil close to estuarine ecosystems, followed by a 30-day clearance period, to evaluate the toxic potential of SePM to this model mollusk. The bioaccumulation of 28 elements identified in SePM and the sublethal effects were evaluated. REEs were found in SePM (Ce, Y, and La). Significant bioaccumulation of eight metals (Fe, Ni, Cu, Zn, Rb, Sr, Cd, and Ba) was found in the bivalves and correlates with the cytotoxicity and genotoxicity, showing a dose -dependent mode and suggesting a pre-pathological condition that could lead to ecological disturbances over time. Con-versely, the unchanged lipid-peroxidation level after SePM exposure could indicate the effectiveness of the antioxidant system in protecting gills and digestive glands. The clearance period was not enough to successfully reverse the nega-tive effects observed. So far, the current results enhance the comprehension of the negative role of SePM on metal bioaccumulation and metal-induced toxicity to aquatic biota. Thus, this report adds innovative findings on the role of SePM in aquatic pollution in coastal areas affected by atmospheric pollution, which should be relevant for future public policies to verify and control the environmental pollution.

Metallic smoke released by steel industries is constitute by a mixture of fine and gross particles containing metals, including the emerging ones, which sedimentation contaminates soil and aquatic ecosystems and put in risk the resident biota. This study determined the metal/metalloids in the atmospheric settleable particulate matter (SePM, particles >10 μm) from a metallurgical industrial area and evaluated metal bioconcentration, antioxidant responses, oxidative stress, and the histopathology in the gills, hepatopancreas and kidneys of fat snook fish (Centropomus parallelus) exposed to different concentrations of SePM (0.0, 0.01, 0.1 and 1.0 g L-1), for 96 h. From the 27 metals (Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, Sn, Ba, La, Ce, W, Hg, Pb, Bi) analyzed, 18 were quantified in SePM and dissolved in seawater. Metal bioconcentrations differed among organs; Fe and Zn were the metals most bioconcentrated in all organs, Fe was higher in hepatopancreas and Zn > Fe > Sr > Al was higher in kidneys. The activity of superoxide dismutase (SOD) decreased in the gills; SOD, catalase (CAT) decreased, and glutathione peroxidase (GPx) increased in hepatopancreas and, CAT, glutathione-S-transferase (GST) and the level of glutathione (GSH) increased in kidneys. The unchanged levels of lipid peroxidation and oxidized protein in any organ indicate that the antioxidant responses were efficient to avoid oxidative stress. Organ lesion indices were higher in the gills > kidneys > hepatopancreas, being higher in fish exposed to 0.01 g L-1 SePM. All changes indicate a tissue-specific metal/metalloids bioconcentration, antioxidant and morphological responses that all together compromise fish health. Regulatory normative are needed to control the emission of these metalliferous PM to preserve the environment and biota.

Atmospheric particulate matter (APM) produced by the steel industry comprises a complex mixture of particles that includes a wide variety of metals and metallic nanoparticles. These particles settle out onto areas sur-rounding the industries. There is evidence that this 'settleable' APM (SePM) may cause air-to-water cross-contamination with significant effects on aquatic biota. Recent investigations have reported sublethal impacts on the gill structure and blood oxygen-carrying capacity of fishes, which raises the hypothesis that there will be consequences for gas exchange capacity and ability to support aerobic activities. Therefore, we investigated the effects of an environmentally relevant level of SePM contamination on swimming performance and associated aerobic metabolic rates in Nile tilapia, Oreochromis niloticus. Short-term exposure (96 h) to SePM reduced critical swimming speed, energetic efficiency of aerobic swimming, standard metabolic rate, maximum metabolic rate, and aerobic scope. The compromised swimming performance could have adverse ecological effects by limiting foraging ability, predator evasion, territorial protection, and migration. The impairments to aerobic capacity could also affect overall fish performance by influencing long-term energy balance and allocation to growth and reproduction. Thus, despite being sublethal, SePM contamination is considerably debilitating, and if its limiting effects are not compensated for in the longer term, this may reduce the survival and fitness of fish populations.