The influence of heavy metals on toxicogenetic damage in a Brazilian tropical river

Biochemistry biomarkers and metal levels as indicators of environmental pollution in Danio rerio exposed to the Sorocaba River (S.P.), Brazil

Metal contamination of the environment poses a significant threat to human health and can cause significant damage to aquatic ecosystems. Danio rerio was exposed to Sorocaba River water for 96 h from two different sites in summer (S) and winter (W). Concentrations of Al, Cd, Cu, Mn and Zn were determined in the exposure water and in sediment. At the end of the exposure, the concentrations of Al, Cu and Mn at the Ibiúna point (P1) and Mn at the Itupararanga point (P2) decreased compared to the initial concentrations in the water. In summer and winter, the highest concentrations of Cu and Mn were found in the sediment. Exposure to the Sorocaba River water caused various responses both in summer and winter. For example, GPx decreased in winter, Glutathione S-Transferase (GST) increased in summer, and Nitric Oxide Synthase (NOS) decreased in both seasons in the viscera. In winter, SOD Superoxide Dismutase (SOD) increased, while GPx and GST (winter) decreased in muscle; regarding viscera carbonyl proteins, there was an increase in the summer at P2. Acetylcholinesterase activity decreased in the brain in winter at P2 and NOS decreased in the summer-exposed groups and increased in the winter P2-exposed group. Lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) decreased in viscera (S, P1) and increased in muscle (S, P1 and P2). The glucose and triglycerides increased in muscle, both in summer and winter. Correlation analysis revealed associations between biomarkers from different organs. These alterations suggest that the fish experienced oxidative stress in response to exposure to the Sorocaba River, contaminated with metals, highlighting their vulnerability to environmental pollutants.

Accumulation of Cd and Pb in sediments and Asian swamp eels (Monopterus albus) from downstream area of Cisadane River, Indonesia

This study examined the presence of two heavy metals (Cd and Pb) in the sediments and Asian swamp eels (Monopterus albus) in the downstream area of Cisadane River. The average concentrations of Cd and Pb in the sediments from all sampling locations were 0.594 ± 0.230 mg/kg and 34.677 ± 24.406 mg/kg, respectively. These concentrations were above the natural background concentration and the recommended value of interim sediment quality guidelines (ISQG), suggesting an enrichment process and potential ecological risk of studied metals to the ecosystem of Cisadane River. The increase in contamination within this region may be attributed to point sources such as landfill areas, as well as the industrial and agricultural land activities in surrounding area, and experienced an increasing level leading towards the estuary of Cisadane River. Meanwhile, the average concentrations of Cd and Pb in the eels from all sampling locations were 0.775 ± 0.528 μg/g and 28.940 ± 12.921 μg/g, respectively. This study also discovered that gill tissues contained higher levels of Cd and Pb than the digestive organ and flesh of Asian swamp eels. These concentrations were higher than Indonesian and international standards, suggesting a potential human health risk and therefore the needs of limitations in the consumption of the eels. Based on the human health risk assessment, the eels from the downstream of Cisadane River are still considered safe to be consumed as long as they comply with the specified maximum consumption limits.

A comprehensive overview on solid waste leachate effects on terrestrial organisms

Leachate is a highly complex waste with high toxicological potential that poses a significant threat to the terrestrial environment. Determining leachate physicochemical parameters and identifying xenobiotics alone is, however, not enough to determine the real environmental impacts. In this context, the use of terrestrial model organisms has been highlighted as a tool in ecotoxicological leachate assessments and as a guiding principle in risk assessments. In this context, this review aimed to present the most current state of knowledge concerning leachate toxicity and the bioassays employed in this evaluation concerning terrestrial plants and animals. To this end, a literature search on leachate effects on terrestrial organisms was carried out using ten search terms, in 32 different combinations, at the Web of Science and Scopus databases. A total of 74 eligible articles were selected. The retrieved studies analyzed 42 different plant and animal species and employed nine endpoints, namely phytotoxicity, genotoxicity, bioaccumulation, antioxidant system, cytotoxicity, reproduction, physiological changes, behavior and lethality. A frequent association of toxic leachate effects with metals was observed, mainly Pb, Cd, Cr, Mg, Zn and Cr, which can cause antioxidant system alterations and cyto- and genotoxicity. These elements have also been associated to reproductive effects in earthworms and mice. Specifically concerning plants, most of the retrieved studies employed Allium cepa in toxicity assays, reporting phytotoxic effects frequently associated to metals and soil parameter changes. Animal studies, on the other hand, mostly employed mice and evaluated genotoxicity and antioxidant system effects. Even with the description of toxic leachate effects in both plants and animals, a lack of knowledge is still noted concerning reproductive, physiological, cytotoxic, and behavioral effects in terrestrial species. We, thus, suggest that further studies be carried out on other animals, advancing our understanding on potential environmental leachate effects, also allowing for human health risk assessments.

Seasonal Variation and Association of Heavy Metals in the Vital Organs of Edible Fishes from the River Jhelum in Punjab, Pakistan

The toxic effects of heavy metals are drastic, including accumulation. Fish species are important bio-indicators of heavy metal pollution in aquatic bodies. The current study aimed to assess the seasonal variation of heavy metals in the vital organs of mostly consumed fishes in River Jhelum, Pakistan. Samples of fish, including Wallago attu (Malhi), Rita rita (Khagga), and Mystus seenghala (Singhari), were collected from four different sites, i.e., Khushab, Muhammad Wala (M. Wala), 8.R.D and Rasool barrage during summer and winter seasons. Heavy metals such as iron (Fe), lead (Pb), chromium (Cr), cobalt (Co) and Cadmium (Cd) were estimated through acid digestion and spectrometric analysis. Results showed a significantly higher (P < 0.05) amount of these metals in the liver, followed by the kidneys of fish species. There were seasonal variations in the absorption of these metals as well. Cr (11.71) and Fe (58.66) were detected in higher amounts in Khagga which showed the greatest affinity for certain metals in some cases. In contrast, Singhari showed the greatest affinity to other metals in other cases. Comparative analysis revealed that there was a highly significant (P < 0.05) difference for the accumulation of almost all metals in both seasons and summer had the highest concentration of Cd, Pb, Co, Cr and Fe as compared to winter in all four sampling stations in the case of kidney and liver of all the three fishes. Elevated levels of heavy metals were detected in the summer due to increased temperature. Heavy metals found in the River Jhelum may demonstrate that metals can significantly affect the fish species.

Geochemical contamination of heavy metals and health risk assessment of coastal sediments along the North Chennai to Pondicherry, India using total reflection X-ray fluorescence spectroscopy (TXRF)

The present work aimed to assess the contamination and human health risk assessment of heavy metals (HMs) in 21 sediment samples collected from the North Chennai to Pondicherry coastal area of Tamil Nadu using total reflection X-ray fluorescence spectroscopy (TXRF). Enrichment factor (EF), contamination factor (CF), and geo-accumulation index (Igeo) were calculated to estimate sediment contamination. The average concentrations of HMs (mg kg-1 dry weight) were: Al (4305.12), V (25.77), Cr (15.08), Mn (83.39), Fe (4539.77), Ni (2.89), Cu (2.67), Zn (9.46), As (2.81), Hg (0.05), and Pb (0.92). Results of EF indicated no enrichment with Al, Ni, and Pb, moderate enrichment with V, and severe enrichment with As and Hg. Based on Igeo, all sediment samples showed unpolluted with HMs (except As and Hg). Based on total lifetime cancer risk (LCR), there are no significant health risks for people in the study area from carcinogenic Cr, As, and Pb.

Detection of heavy metal contamination in Batlama Stream (Turkiye) and the potential toxicity profile

In this study, heavy metal pollution in Batlama stream flowing into the Black Sea from Giresun (Turkiye) province and the toxicity induced by this pollution were investigated by Allium test. Heavy metal concentrations in stream water were analyzed by using ICP-MS. Germination percentage, weight gain, root length, micronucleus (MN), mitotic index (MI), chromosomal abnormalities (CAs), proline, chlorophyll, malondialdehyde (MDA), antioxidant enzyme activities were used as indicators of physiological, cytogenetic and biochemical toxicity. In addition, Comet assay was performed for detecting DNA fragmentation. Anatomical changes caused by heavy metals in the root meristem cells were observed under the microscope. A. cepa bulbs are divided into two groups as control and treatment. The bulbs in the control group were germinated with tap water and the bulbs in the treatment group were germinated with stream water. As a result, heavy metals such as Al, Ti and Co and radioactive heavy metals such as Rb, Sr, Sb and Ba were detected in the stream water above the acceptable parametric values. Heavy metals in the water caused a decrease in germination, root elongation, weight gain, MI and chlorophyll values, and an increase in MDA, proline, SOD, CAT, MN and CAs values. Comet assays indicated the presence of severe DNA damage. In addition, heavy metals in stream water caused different types of CAs and anatomical damage in root meristem cells. As a result, it was determined that there is intense heavy metal pollution in the stream water and this pollution promotes multi-dimensional toxicity in A. cepa, which is an indicator organism. For this reason, the first priority should be to prevent pollution of water resources in order to prevent heavy metal-induced toxicity in water.

Genotoxicity of surface waters in Brazil

Brazil has abundant surface water resources, huge aquatic biodiversity and is home to 213 million people. Genotoxicity assays are sensitive tools to detect the effects of contaminants in surface waters and wastewaters, as well as to determine potential risks of contaminated waters to aquatic organisms and human health. This work aimed to survey the articles published in 2000-2021 that evaluated the genotoxicity of surface waters within Brazilian territory to unveil the profile and trends of this topic over time. In our searches, we considered articles focused on assessing aquatic biota, articles that conducted experiments with caged organisms or standardized tests in the aquatic sites, as well as articles that transported water or sediment samples from aquatic sites to the laboratory, where exposures were performed with organisms or standardized tests. We retrieved geographical information on the aquatic sites evaluated, the genotoxicity assays used, the percentage of genotoxicity detected, and, when possible, the causative agent of aquatic pollution. A total of 248 articles were identified. There was a trend of increase in the number of publications and annual diversity of hydrographic regions evaluated over time. Most articles focused on rivers from large metropolises. A very low number of articles were conducted on coastal and marine ecosystems. Water genotoxicity was detected in most articles, regardless of methodological approach, even in little-studied hydrographic regions. The micronucleus test and the alkaline comet assay were widely applied with blood samples, mainly derived from fish. Allium and Salmonella tests were the most frequently used standard protocols. Despite most articles did not confirm polluting sources and genotoxic agents, the detection of genotoxicity provides useful information for the management of water pollution. We discuss key points to be assessed to reach a more complete picture of the genotoxicity of surface waters in Brazil.

Trace metal concentration along the Brazilian coast: An assessment of the influence of the Doce River plume

The Fundão Dam rupture released tons of iron ore tailings into the environment. This study analyzes the long-term impacts and provides a possible scenario of Doce River (DR) plume dispersion. For this, water and surface sediment were collected in November 2019 along three Brazilian states to determine metal concentrations and δ¹³C and δ¹⁵N compositions. The δ¹³C_sediment values of the DR plume showed a dispersion pattern mainly to the north but also in areas closer to the south of the DR mouth. Furthermore, the most negative values of δ¹³C and δ¹⁵N were observed in mud, followed by suspended particulate matter, sediment and the dissolved fraction, indicating that geological matrices are involved in the transport of organic matter coupled to metals to the ocean and pointing to the DR as the main source of metals in the region. Thus, this study highlights the need for continuous studies to monitor the environmental and biological conditions in these areas.

Using native fish in eco-genotoxic assessment of heavy metal contamination pollution arising from nearby large Brazilian rivers

Worldwide water quality has declined progressively due to continuous pollution of aquatic resources by agrochemicals in particular heavy metals. Fish genotoxicity biomarkers are vital to identify and complement chemical parameters for determining environmental risk of adverse effects. Therefore, it was of interest to examine the eco-genotoxicity attributed to water pollution over different stream sections of Brazilian rivers by using Cichlasoma paranaense (Teleostei: Cichlidae), a neotropical freshwater cichlid fish, as a biological model. Chemical analysis of water and sediments collected from different Brazilian rivers sites demonstrated contamination by metals. Cichlasoma paranaense were collected at a reference location (a permanent water preservation area), maintained in the lab under standard conditions (controlled temperature, lighting, daily feeding, and constant aeration) and exposed to environmental samples of water and sediments. Subsequently, micronucleus (MN) and nuclear abnormalities (NA) frequencies were assessed in erythrocytes obtained from the caudal and gill regions. The highest concentrations of Cu were found in samples from river sites with forest fragmentation attributed to intensive agriculture practices. Similarly, exposure of fish to samples from agricultural areas induced significantly higher number of genotoxic effects. There was no marked difference between the tissues (tail and gill) regarding the observed frequencies of MN and NA. Thus C. paranaense fish served as a reliable model for detecting genotoxic effects, especially when water samples were collected near the discharge of agrochemicals. Evidence indicates that this method be considered for other global river sites which are also exposed to agrochemicals discharges containing Cu.

Bioaccumulation, genotoxicity, and risks to native fish species from inorganic contaminants in the Pantanal Sul-Mato-Grossense, Brazil

The Aquidauana River is one of the most important rivers in the Pantanal region, Brazil. However, its waters have been contaminated by nearby anthropogenic activities, threatening native fish species. In this study, our objectives were: 1) to determine the concentrations of Al, As, Cd, Cu, Fe, Mn, Ni, Pb, and Zn in water and sediment samples from the Aquidauana River and to assess the risks posed to aquatic biota; 2) to quantify the concentration of these elements in muscle and liver tissue samples from four native fish species; 3) to evaluate the potential bioaccumulation of inorganic elements in the muscles and liver; and 4) to investigate genotoxicity biomarkers and their association with the inorganic element concentrations present in the muscle tissue. Water and fish samples were collected in November 2020. The concentrations of Al, As, Cd, Cu, Fe, and Pb in the water samples were in disagreement with the Brazilian legislation and presented risks to the aquatic biota. In terms of mixtures of inorganic elements, there was a great increase in the risk to biota. The As concentration did not meet the Brazilian standard for sediments in the sample collected at sampling site 6. The concentrations of Cd and Pb in the muscle tissue of Hypostomus regani, Prochilodus lineatus, Brycon hilarii, and Mylossoma duriventre exceeded the Brazilian standards for human consumption. H. regani showed greater genotoxic damage, and the higher the Al and Fe concentrations in the muscle tissue, the higher the frequencies of lobulated nuclei and nuclear invaginations. Together, our results demonstrate the negative impacts on native fish species from the Aquidauana River contamination and indicate risks to Pantanal biodiversity.

In vitro genotoxic and mutagenic effects of water samples from Sapucaia and Esteio streams (Brazil) under the influence of different anthropogenic activities

Pollution of aquatic ecosystems is associated with the discharge of mainly industrial and urban effluents, which may cause damage to public health. This study aims to evaluate the cytotoxic, genotoxic, and mutagenic potential of surface water samples under the influence of different anthropogenic effluents in a human-derived liver cell line (HepG2). Samples were collected in Esteio and Sapucaia streams (Rio Grande do Sul; Brazil), which flow into the Sinos River, a source of water supply for more than one million people. Physicochemical and microbiological analyses were performed as well as an analysis of inorganic elements using the PIXE technique (Particle-Induced X-Ray Emission). The presence of pharmaceutical compounds and caffeine was evaluated by gas chromatography coupled to mass spectrometry. The cytotoxicity, genotoxicity, and mutagenicity of the samples were evaluated in HepG2 cells by cell viability assays, alkaline Comet Assay and Cytokinesis-block micronucleus (CBMN) assay. We verified alterations in the physicochemical and microbiological parameters and detected caffeine, diethyltoluamide, and different inorganic elements that corresponded to elements from domestic and industrial effluents and agricultural runoff. Although the samples in the concentration used were not cytotoxic, water samples from all sites induced DNA damage. However, it is difficult to attribute these damages to a specific substance since the factors are a complex mixture of different compounds. Despite this, it is observed that both urban and industrial contributions had a similar effect in the cells evaluated. Such results demonstrate the need to perform biomonitoring of surface waters under anthropogenic influence, especially those that flow into rivers that are a source of public supply water. We also highlight the need for research into emerging pollutants in these aquatic environments.

Combination of Water Quality Parameters and Bioassays for the Assessment of Two Rivers, Southern Brazil

In the present study, water physicochemical and microbiological parameters, as well as bioassays using Allium cepa L. seeds and the fish species Astyanax jacuhiensis were used to assess the water quality of two rivers - Ilha River and Paranhana River -, located in southern Brazil. Water samples were collected at the source and mouth of the rivers and then, laboratory experiments were performed. The results evidenced high levels of aluminum and iron in water samples collected at the four sampling sites. The micronucleus (MN) test in fish showed significant difference in the frequencies of nuclear abnormalities (NA) in the mouth of the Paranhana River in comparison to control group in one sampling period, whereas the A. cepa test evidenced significant spatial differences in cytotoxicity between the source and mouth of both rivers. Therefore, these data evidence the poor water quality of the rivers studied as well as the potential toxicity to the aquatic organisms.

Temporal and spatial toxicogenetic damage in estuarine catfish Cathorops spixii from a marine protected area with evidence of anthropogenic influences

Taking action to contribute to the preservation of the natural coastal environment, which maintains a diversity of life, is important in today's world. In estuarine ecosystems that are included in marine protected areas (MPA), it is important to conduct biomonitoring over time to monitor the effects of xenobiotics on bioindicator species such as the catfish Cathorops spixii. This study aims to evaluate the toxicogenetic signals in C. spixii from a MPA (Cananéia-Iguape region, Brazilian coast). These genotoxic signals are demonstrated by the presence of micronuclei (MN) and abnormalities in erythrocytes (AE). This study also takes into account the environmental differences signaled by the water's properties (temperature, salinity, pH, DO, dissolved nutrients, and particulate material) over time (2009, 2014, 2017, and 2018). The results show that in the northern region of the estuary, and mainly in 2009, the water properties reveal the influence of the river in the form of the lowest levels of salinity and pH and the highest levels of nutrients. The most significant levels of suspended particulate material and chlorophyll-a are found in the southern region of the estuary, mainly in 2017 and 2018. In general, the C. spixii from the northern region had better well-being than catfish from the more preserved (southern) region. The data on MN and AE show evidence of toxicogenetic damage occurring over time and clastogenic/aneugenic effects mainly in fish sampled in 2018. The presence of a new AE, first recorded in C. spixii sampled in 2018, and named here as double bubbled, is another indicator of toxicogenetic effects. Finally, although the southern region of the estuary has better abiotic properties and conditions for primary production, the obtained toxicogenetic data for C. spixii reinforces the need for - and encourages the implementation of - monitoring actions in this marine protected area using bioindicator species of contamination.

Toxicity and genotoxicity of domestic sewage sludge in the freshwater snail Biomphalaria glabrata (Say, 1818)

Waste produced in homes is one of the main sources of pollutants in freshwater ecosystems. Therefore, it is imperative to implement methodologies that aid in environmental monitoring procedures. The use of organisms as biomonitors has grown increasingly prevalent as they are models that provide data that can be adequately evaluated. In this work, we investigated the genotoxic and cytotoxic effects caused by domestic sewage sludge through an analysis of biomarkers in the mollusk Biomphalaria glabrata. For the tests, increasing concentrations of 50, 100, 150, and 500 mg L^-1 of domestic sewage sludge were standardized, in addition to control groups. Assays were performed after the mollusks were exposed to the domestic sewage sludge in acute (48 h) and chronic (15 d) manner. Toxicity tests were performed with embryonic and adult snails. The cytoplasmic and nuclear changes were analyzed in the hemocyte cells. Lastly, genotoxic damage was analyzed using the comet assay. Adult snails and embryos of B. glabrata showed no significant morphological changes. Domestic sludge caused deleterious effects on mollusks as confirmed after cell genotoxicity tests. Therefore, based on the results obtained from the analysis of B. glabrata hemocytes, we can affirm that domestic sewage sludge causes genotoxic and cytotoxic effects on mollusk cells. Therefore, it is possible to conclude that the mollusk Biomphalaria glabrata can be used as a good low-cost alternative to assist in the biomonitoring of freshwater environments. Graphical Abstract.

Physiological assessment of fish health in mineral-rich areas of Ganjam, Odisha, India, and chronic toxicity of zirconium oxychloride on the fishes of Channa punctata

The high concentration of metal toxicants in aquatic ecosystems has a detrimental impact on fish health that ultimately jeopardizes human health. Such threats mostly arise in mineral-rich areas where an increase in metal concentrations occurs in aquatic bodies due to anthropogenic activities like mining. The present study assessed the health of food fish Channa punctata from the mineral-rich areas of Ganjam, Odisha, India, mined for heavy and transition metal ores like ilmenite, zircon, monazite. The fishes collected from these areas showed histopathological anomalies in vital organs like the liver, kidney, gills, stomach and intestine while cytological analysis revealed vacuolated cytoplasm and micronuclei. Biochemical analysis showed a significantly lower lipid concentration in muscle (i.e., 0.177 ± 0.177 mg/gm) and liver (i.e., 0.169 ± 0.002 mg/gm) as compared to non-exposed fishes from adjoining non-mineral rich areas having a mean protein concentration of 87.48 ± 8.16 and 77.75 ± 0.892 mg/gm tissue in the muscle and liver, respectively, and a mean lipid concentration of 0.29 ± 0.009 mg/gm muscle and 0.34 ± 0.009 mg/gm liver. Chronic exposure to sublethal concentrations of zirconium oxychloride, a salt of zirconium, resulted in a significant decline in the concentration of protein, ranging from 57.5 ± 0.929 - 63.88 ± 1.95 mg/gm in muscle and 45.35 ± 2.332 - 51.98 ± 1.036 mg/gm in the liver. The lipid concentrations in muscle (0.03 ± 0.009 - 0.17 ± 0.009 mg/gm) and liver (0.06 ± 0.012 - 0.19 ± 0.007 mg/gm) were also significantly lower than the non-exposed fishes. Marked degenerative changes were identified in the histological sections of the gill, intestine, stomach, liver and kidney of zirconium oxychloride-treated fishes along with various nuclear deformities and micronucleus.

Bioassays to screen the toxicity in drinking water samples collected in Brazilian rural area

Agriculture activities have increased the concentration of pesticides and metals in the environment. The excessive use of pesticides can generate an environmental impact and contribute to the development of human diseases. This study aimed to determine the presence of pesticides and metals in water samples collected in the Brazilian rural area in two different periods (before and after pesticide application) and to evaluate the alternative bioassays Lactuca sativa, Allium cepa, and Caenorhabditis elegans to monitoring toxicity in human drinking water samples. Eight sites in the rural area were selected and water samples were collected in two different periods of the year (before and after pesticide application). The presence of the pesticides was determinated by ultra-high performance liquid chromatography-tandem mass spectrometry and metals by inductively coupled plasma mass spectrometry. The potential toxicity of the water samples was performed with three different alternatives in vivo models (L. sativa, A. cepa, and C. elegans). Fifty-seven pesticides were analyzed and, according to the results, the most found ones were clomazone, atrazine, tebuconazole, metconazole, pyrimethanil, and carbofuran-3-hydroxide, which is a metabolic degradation product of insecticide carbofuran. The most detected metals were Cu, Cr, Mg, Fe, and Mn. The assays with L. sativa and A. cepa showed alterations in the period after pesticide application, while C. elegans presented changes in both periods compared to the same collection sites. These results indicate that bioassays, especially C. elegans, could be complementary and useful tools for monitoring the toxicity in drinking water samples.

Cyto-histopathological and protein polymorphism alterations in five populations of Nile tilapia (Oreochromis niloticus) as biomonitor for water heavy metal pollution

Cytological, histopathological and sodium dodecyl sulphate polyacrylamide gel analyses were carried out on five populations of common Nile tilapia fish (Oreochromis niloticus) occurring in five sites - River Nile (reference site), Bahr Yusef canal, Ibrahimia canal, Irrigation drain and El Moheet drain of El Minia Province, Egypt - to evaluate the usability of Nile tilapia as a biomonitor for water heavy metal contaminants. Water surface samples were collected from the five sites, and lead (Pb) concentration was shown to surpass the limits defined by WHO. Ni and Cd levels were shown to be elevated in Ibrahimia canal samples. Moreover, the concentration of heavy metals in fish muscles collected from Bahr Yusef canal and El Moheet drain was the highest in comparison with those of the other water sites. Cytological examinations of blood smears showed not only a significant percentage of micronuclei in Irrigation drain population but also a significant percentage of binucleated cells in Ibrahimia canal and El Moheet drain populations. In addition, pathological alteration was observed in blood cells, especially in samples collected from Irrigation drain and El Moheet drain. Histopathological changes were strongly observed in the liver and the kidneys of El Moheet and Irrigation drain population. Moreover, total protein band pattern profiles showed extra bands in both Ibrahimia canal and Irrigation drain more than that recorded for the River Nile population. In conclusion, cyto-histopathological and total protein band pattern results confirmed that O. niloticus responds sensitively to the excess of heavy metals present in the water.

Cellular Responses Induced by Zinc in Zebra Mussel Haemocytes. Loss of DNA Integrity as a Cellular Mechanism to Evaluate the Suitability of Nanocellulose-Based Materials in Nanoremediation

Zinc environmental levels are increasing due to human activities, posing a threat to ecosystems and human health. Therefore, new tools able to remediate Zn contamination in freshwater are highly recommended. Specimens of Dreissena polymorpha (zebra mussel) were exposed for 48 h and 7 days to a wide range of ZnCl2 nominal concentrations (1-10-50-100 mg/L), including those environmentally relevant. Cellulose-based nanosponges (CNS) were also tested to assess their safety and suitability for Zn removal from freshwater. Zebra mussels were exposed to 50 mg/L ZnCl2 alone or incubated with 1.25 g/L of CNS (2 h) and then removed by filtration. The effect of Zn decontamination induced by CNS has been verified by the acute toxicity bioassay Microtox®. DNA primary damage was investigated by the Comet assay; micronuclei frequency and nuclear morphological alterations were assessed by Cytome assay in mussels' haemocytes. The results confirmed the genotoxic effect of ZnCl2 in zebra mussel haemocytes at 48 h and 7-day exposure time. Zinc concentrations were measured in CNS, suggesting that cellulose-based nanosponges were able to remove Zn(II) by reducing its levels in exposure waters and soft tissues of D. polymorpha in agreement with the observed restoration of genetic damage exerted by zinc exposure alone.

Bioaccumulation and bioconcentration of metals in Characidae from a Neotropical river basin under anthropic activities

Natural rates of metal mobilization and deposition in terrestrial and aquatic environments have been changed due to anthropic activities, exposing the native biota to dangerous effects related to bioconcentration and bioaccumulation of metals. This study assessed the concentrations of Cr, Ni, Cd, Pb, Cu, Mn, Co, and Zn in the water and riverbed sediment samples from the Verde River basin (VR), and in tissue samples from two native fishes, the Psalidodon paranae, a VR inhabitant, and the Psalidodon aff. fasciatus, a migratory species. Arithmetic mean values of metal concentrations recorded in waters were Cr: 46.16, Ni: 40.29, Cd 43.19, Pb: 57.74, Cu: 63.72, Mn: 98.36, Co: 64.53, Zn: 81.19, while for riverbed sediments were Cr: 11.84, Ni: 10.52, Cd: 7.14, Pb: 15.00, Cu: 22.16, Mn: 334.77, Co: 24.62, Zn: 434.44. For several analyzed samples, metal concentrations found were higher than Brazilian and international limits set for healthy aquatic life and human uses. Analyzed fish tissues also presented metal concentrations higher than Brazilian and international limits set, indicating a high ecological and health risk for the region. Psalidodon paranae showed affinity to bioconcentrate Pb, Zn, and Cd, while Psalidodon. aff. fasciatus tended to bioconcentrate Ni, Zn, and Cr. Multivariate analyses revealed spatial and temporal patterns in the metal contaminations in VR. These patterns were associated with rural and urban activities developed along VR, which practice inadequate soil handling, indiscriminate use of agrochemicals, and the dumping of domestic garbage and untreated and treated sewage into the river. The implementation of public policies for biomonitoring and pollution control by metals in VR is essential to safeguard regional water resources and their biota.

Evaluation of transgenerational effects caused by metals as environmental pollutants in Daphnia magna

The present study aimed to evaluate the acute and chronic toxicity of environmentally relevant concentrations of metals (Mn, Al, Fe, and Pb) in Daphnia magna and the generational transposition of reproductive and morphological damages. The effective concentration for 10% of the organisms from each metal was obtained by the acute toxicity test (96 hours); then, another five concentrations lower than this one were defined for the chronic experimentation (21 days), in which the number of neonates generated by each individual was checked daily. At the end of the exposition, the lengths and number of morphological damages were recorded in each adult daphnid. During this, the molt generated on the 14th and 21st days were collected and cultivated for posterior evaluation of the same parameters. Alterations in the reproductive performance were observed in the organisms exposed to manganese and aluminum (4.0 and 0.5 mg L^-1, respectively). Organisms exposed to aluminum (0.05 mg L^-1) and iron (0.27 mg L^-1) showed a reduction in body length. It is also noteworthy that the molt of these adults and their respective offspring also presented reproductive alterations, especially the molt from the 14th day of lead exposure (0.02 mg L^-1) and the 21st day of manganese exposure (4.0 mg L^-1). Such effects allow us to conclude that environments polluted by metals can reduce the ability of the species to maintain themselves in the ecosystem. In addition, there is a need to increase the control and monitoring of metals, such as aluminum, which present risks even in low concentrations.

Heavy metal bioaccumulation, oxidative stress and genotoxicity in African catfish Clarias gariepinus from Orontes river

One of the major problems affecting the ecosystem health is the exposure of heavy metals due to anthropogenic activities. These exposures may induce toxiogenetic damage and carcinogenesis in aquatic organism. DNA damage biomarkers for fish species detect genotoxic parameters for ecological risk assessment. In the present study, the effect of heavy metals (Cr, Cd, Cu, Fe and Mn) on DNA damage and oxidative stress of Clarias gariepinus was examined by Comet assay at Reference site and two different sampling sites of the Orontes River. Moreover, the relationship between DNA damage and physiological response to oxidative stress caused in C. gariepinus was investigated by sampling seasonal water and fish samples for one year. In this study, Cr, Cd and Cu in water column of Orontes River and the concentrations of Fe and Mn in liver tissue of C. gariepinus were highly exceed the maximum permissible limit set by EPA (1999, 2016) WHO (1989) and TEG (2012) that can cause adverse effects on environment health. SOD activities in liver tissues were significantly higher than those in muscle tissues. SOD, CAT activity and MDA levels of both Site 1 and Site 2 at Orontes River were higher than those of the Reference site. In result of the COMET analysis, the highest levels of DNA damage were found at gill and liver tissues in Site 2 (17.746 ± 1.072% T-DNA; 16.014 ± 0.710% T-DNA respectively) at Orontes river. A higher level of DNA damage in gill cells compared to liver cells was observed in all regions of the Orontes River. In Principal component analysis (PCA), the heavy metals Cd, Cr and Cu (in the water column) and MDA in liver and muscle revealed strong contribution to the observed DNA damage that were scattered opposite to each other's along the principal components. Moreover, correlations between parameters revealed a positive significant relationship between Cd, Cr and Cu in water and DNA damage levels in C. gariepinus. Pearson correlation analysis detected a positive relationship between MDA, CAT and SOD and DNA damage levels in African catfish. Consequently, this study exposed genotoxic damage and oxidative stress of C. gariepinus due to metal pollution in Orontes River and lead to the better understanding of genotoxicty, oxidative stress and heavy metal relationships.

Effect of heavy metals on toxicogenetic damage of European eels Anguilla anguilla

Aquatic organisms are exposed to a variety of contaminants such as heavy metals introduced into the environment as a consequence of anthropogenic activities that usually cause genotoxic damage in aquatic organisms. DNA damage biomarkers for fish species detect genotoxic parameters for ecological risk assessment. In the present study, the effect of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn, Co, and Mn) on DNA damage of Anguilla anguilla was examined by comet assay at reference site and three different sampling sites of the Orontes River. The relative mean heavy metal concentrations in water column were in the order of Fe>Cr>Pb>Zn>Ni>Cu>Mn>Cd>Co in all the sampling sites. Cr, Cd, and Pb concentrations at all sampling sites were above the values allowed by the EPA (1999, 2016). With these results, negative effects of Cr, Cd, and Pb appeared on ecosystem health. The comet assay showed a higher level of DNA damage in the gill cells in comparison with the liver cells of A. anguilla. The highest level of DNA damage as %T-DNA, tail moment, and tail migration in gill cells were 20.007 ± 1.744 %; 2.899 ± 0.341 μm, and 12.383 ± 01.040 TM_i and 20.172 ± 1.944 %, 2.559 ± 0.265 μm, and 10.763 ± 0.910 TM_i at Site 2 and Site 3, respectively. The correlations between heavy metals and DNA damage parameters revealed that both Cu and Co in water showed significant negative correlations (p < 0.05) with DNA damage levels. Consequently, this study revealed the genotoxic damage of A. anguilla due to pollution in Orontes River and lead to the better understanding of genotoxicity and heavy metal relationships.

Phytotoxicity and cytogenotoxicity of composted tannery sludge

Tannery sludge (TS) contains high levels of organic matter and chemical elements, mainly chromium (Cr). This can increase its toxicity, rendering it unsuitable for application to soil. However, composting has been proposed as an alternative method for detoxifying TS before its addition to soil. Thus, the aim of this study was to evaluate the phytotoxic and cytogenotoxic potential of untreated (TS) and composted (CTS) tannery sludge in solid and solubilized samples. Seed germination and root growth bioassays were performed with Lactuca sativa, while chromosomal aberrations were assessed using the Allium cepa bioassay. In solid samples, the L. sativa bioassay showed that TS adversely affected germination and root growth, while CTS had a negative affect only on root growth. In solubilized samples, only TS showed significant adverse effects on seed germination and root growth. In both solid and solubilized samples, TS and CTS showed cytotoxic, genotoxic, and mutagenic effects on A. cepa. Thus, results demonstrated that the composting of TS does not result in its complete detoxification. For this reason, TS and CTS cannot be recommended for agricultural use, since they may increase the risk of environmental contamination and crop damage.

Study of genotoxic and cytotoxic effects after acute and chronic exposures to industrial sewage sludge on Biomphalaria glabrata hemocytes

Industrial development has provided numerous benefits to improve quality of life in modern times, however, it has also led to the development and use of a large number of toxic chemicals which have caused damage to various ecosystems. Consequently, knowledge of techniques and organisms that can be used to monitor, identify and quantify environmental pollutants has become increasingly relevant. Therefore, the objective of this study was to use the mollusk Biomphalaria glabrata to analyze biomarker and biomonitoring parameters of industrial sewage sludge. To perform the tests, concentrations of 50, 100, 150 and 500 mg L^-1 of industrial sewage sludge were standardized. All the tests were performed after the animals were exposed to the sludge in acute and chronic forms. Embryos exposure to sludge did not show a significant percentage of the animals non-viable when compared to the control group. Subsequently, hemocytes were analyzed for the presence of cytoplasmic and nuclear alterations. Finally, the comet test was performed to quantify the genotoxic damage caused by exposure to industrial sludge. Analysis hemocytes showed a significant number of cellular alterations was observed, mainly due to the high frequency of apoptosis. Moreover, during the analysis of nucleoids several degrees of nuclear damage were identified, with the groups exposed to the highest concentrations presenting the greatest genotoxic damage. Thus, we can conclude that the parameters evaluated in the mollusk Biomphalaria glabrata have proven to be a good tool, along with other techniques and complementary organisms, to assist aspects related to biomonitoring of freshwater ecosystems.

Influence of Land Use and Cover on Toxicogenetic Potential of Surface Water from Central-West Brazilian Rivers

The objective of this study was to evaluate toxicogenetic potential of surface water samples from rivers of center-west Brazil and analyze the influence of land use and cover and physicochemical parameters in genetic damage. Samples were collected during winter (June) and summer (November) at sampling sites from Dourados and Brilhante Rivers (Mato Grosso do Sul/Brazil). The toxicogenetic variables, including chromosomal alterations, micronuclei, and mitotic index, were analyzed in meristematic cells of Allium cepa; and micronuclei, nuclear abnormalities, and DNA strand breaks (arbitrary units, AU_T) were analyzed in erythrocytes of Astyanax lacustris. The rivers presented physicochemical values outside the Brazilian laws, which can be a characteristic of human pollution (domestic sewage and local agriculture). The results of A. cepa test suggest that the water samples from Dourados and Brilhante rivers exerted significant (p < 0.05) cytotoxic and genotoxic effects, in both periods of collection, especially alterations in mitotic index. In blood cells of A. lacustris, genotoxic effect of the water samples from the rivers also was observed as significant nuclear abnormalities, DNA breaks (UA_T), in both sampling periods, compared with the negative control. Spearman correlation analyses revealed that data of land use and cover and physicochemical parameters were statistically correlated with DNA damages in bioassays. This study demonstrates toxicogenetic potential of water samples from Dourados and Brilhante rivers; furthermore, the type of land use and land cover and physicochemical parameters were revealed to have influence on toxicogenetic damage.