Evaluation of the water quality in a conservation unit in Central-West Brazil: Metals concentrations and genotoxicity in situ

One-point calibration and matrix-matching concept for quantification of potentially toxic elements in wood by LA-ICP-MS

The aim of this work is to evaluate two quantitative methods, based on the external calibration applied in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis, known as (i) analytical curve and (ii) one-point calibration, using the concept of matrix matching to quantify three potentially toxic elements (PTEs) in wood samples. These can biologically register changes in the abiotic environment and be applied to monitoring climate change or environmental toxicity. In this case, standard sample preparation was evaluated to prepare the standard pellets using Pinus taeda species as a matrix-matching concept. Six pellets of P. taeda, with different Pb, Cd, and Ba concentrations, were prepared to build the analytical curve and one-point calibration strategies. The LA-ICP-MS parameters were optimised for 206Pb, 208Pb, 112Cd, 114Cd, 137Ba, and 138Ba isotope analysis in wood samples. The two calibration strategies provided 74-110% analytical recovery from certified reference materials and similar results to those obtained by ICP-MS through the acid digestion of environmental wood samples from São Paulo City (Brazil). This demonstrated the applicability of the one-point calibration strategy in quantifying PTEs in wood samples, which could be used with environmental analyses. Differences observed between the Ba isotope results obtained via LA-ICP-MS and ICP-MS quantification were related to sampling by LA-ICP-MS and the ICP-MS sample introduction, as well as to laser matrix and transport effects because of the difference between the wood species evaluated.

Potentially toxic elements contamination in the water resources: an integrated risk assessment approach in the upper Citarum watershed area

The Citarum watershed is West Java Province's most important water resource; hence, harmful compounds should be monitored regularly. This study assessed pollution levels along with ecological and health risks from Cd, Pb, Mn, Fe, Cu, Cr, and Hg contamination in river water, sediment, groundwater, and soil in Citarum's upper watershed. In river water, the average amounts of Cd, Pb, Mn, Fe, Cu, Cr, and Hg were 0.002, 0.05, 0.092, 0.649, 0.022, 0.001, and 0.421 mg/L. In sediment, they were 7.4, 1175.1, 32,289.9, 37.3, 3.9, and 0.015 mg/kg. The mean concentrations of Cd, Pb, Mn, Fe, Cu, Cr, and Hg in groundwater were 0.004, 0.046, 0.567, 0.366, 0.019, 0.001, and 0.177 mg/L, and in soil, BDL, 10.2, 744.6, 50,094.1, 45.6, 5.9, and 0.015 mg/kg. The river water and groundwater were highly polluted by PTEs, with HPI values of 14,733 and 933, respectively. While PTEs pollution levels and risk in sediment and soil were low based on I-geo, CF, PLI, and M-ERM-Q values, PTEs contamination in river water may cause adverse impacts on aquatic living organisms (HQ > 1). The population doing recreational activities in river ecosystems was still safe from non-carcinogenic and carcinogenic impacts due to PTEs exposure from river water and sediment (THI < 1 and TCR value < 1E-04), while the population in the upper Citarum River was not safe from the carcinogenic risk due to PTE exposure from groundwater and soil (TCR > 1E-04). The sensitivity analysis showed that Cd concentration in groundwater is the most influential factor in cancer risk, with a total contribution of 99.9%. Therefore, a reduction in Cd concentration in groundwater is important to reduce cancer risk in the population.

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.

Genotoxicity biomarkers on native fish species from the Araguari River (Amazon biome)

The Araguari River, one of the most important waterways in the Brazilian state of Amapá, is ecologically relevant and essential for the conservation of Amazonian fish biodiversity. Our previous studies demonstrated contamination of water and fish by metals. In particular, water samples showed genotoxic damage in Danio rerio. Here, we extended our studies of potential genotoxic damage to native fish from sampling sites located in the Araguari River lower section. To accomplish this, we collected samples of fish with different feeding behaviors, but in the same sampling sites, and evaluated the same genotoxicity biomarkers in erythrocytes. All eleven species of fish collected in the Araguari River lower section showed profiles and frequencies of genotoxic damage similar to those previously observed in tests with D. rerio, confirming that genotoxic pollutants present in these waters are also causing damage to native fish species.

Metal bioaccumulation in fish from the Araguari River (Amazon biome) and human health risks from fish consumption

Recently, high concentrations of metals have been found in the waters from sampling sites located in the Araguari River lower section. These metals can be bioaccumulated by fish, but also biomagnified, representing a potential risk through human consumption. Here, we aimed to (1) determine the metal concentrations in muscle samples from fish; (2) evaluate bioaccumulation of metals in muscle tissue of fish species with different feeding behaviors; and (3) investigate the risks of single metals, as well as mixture of metals, to human fish consumption. Eleven fish species were sampled (3 carnivorous, 5 omnivorous, and 3 detritivorous). In four fish species, Cd and Pb concentrations exceeded the Brazilian maximum limits (MLs) for human consumption. Individually, Pb and Cd concentrations in the muscle of these fish indicate risks to human health. When considering the mixture of metals, the consumption of all fish species represents risks. The highest risks implicate detritivorous species. For all fish species evaluated, the estimated daily intake (EDI) of Hg shows values above its reference dose (RfD). Our results suggest the need to establish an environmental monitoring program that aims to preserve environmental quality, biodiversity, and human health. It is also necessary to develop actions that aim to educate Amazonian populations on safe fish preparation and consumption.

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.

Genotoxicity assessment in two Amazonian estuaries using the Plagioscion squamosissimus as a biomonitor

Genotoxicity studies in coastal ecosystems have been a priority in Environmental Risk Assessment (ERA). This research aimed to study the genotoxicity by the micronucleus test and comet assay in two Brazilian Amazon estuaries (anthropized and control) using Plagioscion squamosissimus as a biomonitor. Blood samples were collected from 54 specimens. No significant genotoxic effects were detected in the cells analyzed, although the highest occurrence (MN and DNA damages) was observed in anthropized site. The percentage of genomic damage differed between the sites studied, being always higher in anthropizes site as well. Of the nucleoids analyzed in this site, on average, 28 ± 14.42% of the cells were classified in the highest damage class. The fish analyzed in the present study are direct influenced of xenobiont agents capable of producing damage to the genetic material of aquatic organisms in both sites and, consequently, may bring consequences still little reported in studies of morphophysiological alterations in humans.

Physicochemical, microbiological quality, and risk assessment of water consumed by a quilombola community in midwestern Brazil

The quality of the water consumed by a given community is related to its quality of life. In this sense, this study aimed to evaluate, from the perspective of health risk, the physical, chemical, and microbiological quality of drinking water, in a quilombola community, and the qualitative aspects intrinsic to its use and storage. For this, water samples, collected at the exits of the collective water supply system and from eight cisterns that store rainwater, used for human consumption, were analyzed. The samples were subjected to physical, chemical, and microbiological analysis, including adenovirus (HAdV) and enterovirus (EV). The probability of an individual acquiring infection through water consumption was determined by quantitative microbiological risk analysis using HAdV and Escherichia coli (EC) as reference pathogens. The results showed that the water in the deep tubular well had 270.8 mg/L of total hardness, leading to the rejection of its consumption by ingestion. Alternativity, the people in the community consume rainwater stored in cisterns. For this type of water, the presence of heterotrophic bacteria was found in 75%, total coliform was present in 100%, and Enterococci were detected in 25%. Furthermore, EC was present in 25%, EV in 50%, and HAdV in 100% of the samples. The probability of annual infection with HAdV and EC was, in the worst situation, 100% and 1.3%, respectively. Regarding the qualitative and quantitative aspects, there was a significant positive correlation between the absence of EC and the withdrawal of water from the cistern using a pump and the opposite when the withdrawal was carried out using a bucket or hose. Based on the results found, it is important to carry out actions aimed at improving water quality and, consequently, the quality of life of people living in the study community.

Bioaccumulation of metal in liver tissue of fish in response to water toxicity of the Araguari-Amazon River, Brazil

This study aimed to determine the concentration of metals in the water and in the liver tissue of fish (Anodus orinocensis, Hemiodus unimaculatus, Curimata vittata, and Plagioscion squamosissimus) in the lower Araguari River. Steps were also taken to estimate any difference in metal bioaccumulation in the liver of fish species at different trophic levels, determine any correlations between metals found in hepatic tissue of fish species relative to that found in river water, and evaluate the bioaccumulation factor. The metals analyzed in the water in the lower Araguari River (Cd, Pb, Fe, Hg, Cu, and Zn) exceeded the limits considered safe for aquatic life. We found a significant difference only in the bioaccumulation of Pb between A. orinocensis and C. vittata (F = 4.65, p = 0.005) and Cr between A. orinocensis and H. unimaculatus (F = 3.12, p = 0.03). Species of distinct trophic levels showed differences in metal concentration in liver. Cd and Cu showed bioaccumulation factor above 100, especially Cu with a relatively high value, for all fish species. The bioaccumulation of metals in the liver of fish species showed a positive correlation with the metals detected in the water of the Araguari River. In this sense, the lower course of the Araguari River is undergoing some type of environmental stress, making this study of additional valuable in diagnosing environmental quality pursuant to the development of environmental monitoring projects in order to guarantee the safety and maintenance of aquatic life.

Isolation, in vitro study, and stem cell markers for type A spermatogonia in a Characiformes species

The objective of this study was to establish a protocol for the characterization, isolation, and culture of type A spermatogonia using specific molecular markers for these cells in fish. To this end, adult Prochilodus lineatus testes were collected and digested enzymatically and the resulting testicular suspension was separated using a discontinuous Percoll gradient, followed by differential plating. The cell cultures obtained were monitored for 15 days and analyzed using the immunofluorescence method with anti-Vasa, anti-GFRα1, and anti-OCT4 antibodies. Spermatogonial enrichment was also performed using flow cytometry. Although discontinuous Percoll gradient centrifugation followed by differential plating enabled the removal of differentiated germ cells and somatic cells, enriching the pool of type A spermatogonia, the enrichment of type A spermatogonia through flow cytometry of samples without Percoll proved to be more efficient. Prominent cell agglomerates that were characterized according to different stem cell markers as type A spermatogonia were observed during the 15 days of the cell culture. The use of immunoperoxidase and western blot analysis methods confirmed the specificity of the markers for type A spermatogonia of P. lineatus. When combined with specific cell culture conditions, the positive characterization of these molecular markers clarified certain aspects of spermatogonial regulation, such as survival and proliferation. Finally, understanding the regulation of the in vitro germ cell maintenance process may contribute to the enhancement of in vivo and in vitro reproduction techniques of endangered or aquaculture fish species.