Phytoremediation Potential of Crotalaria pumila (Fabaceae) in Soils Polluted with Heavy Metals: Evidence from Field and Controlled Experiments.

Phytoremediation is a useful, low-cost, and environmentally friendly alternative for the rehabilitation of heavy-metal-contaminated (HM) soils. This technology takes advantage of the ability of certain plant species to accumulate HMs in their tissues. Crotalaria pumila is a herbaceous plant with a wide geographical distribution that grows naturally in environments polluted with HMs. In this work, the bioaccumulation capacity of roots and leaves in relation to five HMs (Cr, Cu, Fe, Pb, and Zn) was evaluated, as well as the morphological changes presented in C. pumila growing in control substrate (without HMs) and mine-tailing substrate (with HMs) under greenhouse conditions for 150 days. Four metals with the following concentration pattern were detected in both tissues and substrates: Fe > Pb > Cu > Zn. Fe, Pb, and Zn concentrations were significantly higher in the roots and leaves of individuals growing on mine-tailing substrate compared to the control substrate. In contrast, Cu concentration increased over time in the exposed individuals. The bioconcentration factor showed a similar pattern in root and leaf: Cu > Fe > Pb > Zn. Around 87.5% of the morphological characters evaluated in this species decreased significantly in individuals exposed to HMs. The bioconcentration factor shows that C. pumila is efficient at absorbing Cu, Fe, and Pb from the mine-tailing substrate, in the root and leaf tissue, and the translocation factor shows its efficiency in translocating Cu from the roots to the leaves. Therefore, C. pumila may be considered as a HM accumulator plant with potential for phytoremediation of polluted soils with Cu, Pb, and Fe, along with the ability to establish itself naturally in contaminated environments, without affecting its germination rates. Also, it exhibits wide geographical distribution, it has a short life cycle, exhibits rapid growth, and can retain the mine-tailing substrate, extracting HMs in a short time.

Use of lichens as bioindicators of contamination by agrochemicals and metals.

The presence or absence of lichens serves as an indicator of the condition of an ecosystem and the degree to which it is contaminated by various agents, such as agrochemicals and metals. Evaluating the use of lichens as bioindicators of agrochemical contamination could provide a more comprehensive perspective of current contamination levels. Monitoring was conducted over a 4-month period in two study areas: one was a well-conserved area contaminated by metals, and the other was an area surrounded by agricultural crops contaminated by agrochemicals. Data on the presence and abundance of lichens in each study area were recorded at 10 monitoring points, a procedure that was repeated 16 times (every 15 days), and concentrations of heavy metals and "organophosphate" agrochemicals in the lichens collected were measured by means of Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES) and Gas Chromatography (GC), respectively. Generalized linear mixed models were used to assess abundance and richness, while general linear mixed models were used to attain Shannon diversity and Simpson dominance indices. Moreover, a multivariate analysis was performed in order to compare the lichen communities in both areas. The results indicated differences between the area contaminated by metals and that contaminated by agrochemicals in terms of abundance and Simpson's dominance index, while no differences were found in the case of the richness and diversity models. The PERMANOVA analysis additionally showed differences between the lichen communities in the two areas. The results also demonstrated that Canoparmelia caroliniana bioaccumulated metals in both areas. The levels of barium, cadmium, and sodium were higher in the area contaminated by metals, while concentrations of chromium and copper were higher in the area contaminated by agrochemicals. Finally, the concentrations of agrochemicals were higher in the area contaminated by agrochemicals and included toxic substances such as Methylparathion and Parathion, which are prohibited in Ecuador. In conclusion, this research underscores the importance of lichens as precise indicators of environmental health and contamination by agrochemicals and metals.

Occurrence and potential ecological risks of PFAS in Pampulha Lake, Brazil, a UNESCO world heritage site.

Per- and polyfluoroalkyl substances (PFAS) comprise >4000 synthetic substances used in industrial applications and consumer products. PFAS used daily in households and manufacturing plants end up in domestic sewage, and industrial effluents can be discharged to surface water. Urban watersheds located in low and middle-income countries (LMIC), which lack sanitation infrastructure, are potential recipients of waste containing PFAS. Yet, only a few studies report PFAS occurrence in urban reservoirs and lakes, especially those located in the Global South due to resource limitations. This is the first study aimed to assess PFAS occurrence and ecological risks in Pampulha Lake, Brazil, a site which represents the reality of many other urban watersheds in LMIC as it is surrounded by densely populated areas and manufacturing plants. Surface water samples were collected monthly for 1 year from four sampling points at Pampulha Lake. Sample analysis was based on US Environmental Protection Agency Method 1633, which employs solid phase extraction followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Species sensitivity distribution (SSD) curves were built to identify potentially susceptible species based on detected water concentrations. Bioaccumulation was estimated for fish tissue. Short-chain (perfluorobutanesulfonic acid, PFBS and perfluorohexanoic acid, PFHxA) and long-chain PFAS (perfluorodecanoic acid, PFDA; perfluorooctanoic acid, PFOA; perfluorododecanoic acid, PFDoA; and perfluorooctanesulfonic acid, PFOS) were detected at the µg L-1 range. Total PFAS concentrations in the wet season were generally higher than in the dry season, likely due to limited capacity of the treatment plant processing water from tributaries which receive raw sewage. More than 5 % of aquatic species are potentially susceptible to chronic effects of PFOS at detected concentrations (0.2-2.2 µg L-1). Predicted bioaccumulation of PFOS in fish was above advisory diet intake levels for humans. Results emphasize the need for studies related to PFAS occurrence in watersheds located in LMIC.

Contaminants of Emerging Concern (CECs): Assessment of health and dietary risk in the consumption of Plagioscion squamosissimus in one of the largest rivers in a semi-arid region (Rio São Francisco, Brazil).

The São Francisco River, significant in semi-arid areas, faces impacts from hydroelectric plants and agricultural pesticides. Despite extensive research on its aquatic life, especially fish reproductive biology, there's a notable lack of studies on toxicity and its human health implications. This gap highlights the need for targeted research in this vital ecological zone. Consequently, this study aimed to scrutinize the concentrations of Contaminants of Emerging Concern (CECs), including Polychlorinated Biphenyls (PCBs), Polybrominated Diphenyl Ethers (PBDEs), Organochlorine Pesticides (OCPs), pyrethroid pesticides (PPs), triazine pesticides (TPs), and Organophosphorus Pesticides (OPPs) in the water, sediment, and fish (Plagioscion squamosissimus). The findings revealed the presence of all compound classes in sediment, albeit in limited quantities in water. Biotic components exhibited higher concentrations in nerve tissue, followed by the liver and muscle, indicative of a bioaccumulation trend. It is noteworthy that more concerning levels were observed in both water and sediments. In particular, Fenvalerate in water and Prometon in sediments demonstrated the highest Bioaccumulation Factor (BAF) values. While for non-carcinogenic effects and Cancer Risk (CR), the parameters were calculated and all classified in the areas of acceptable or insignificant according to chemical safety agencies. However, the compounds under scrutiny demand vigilant attention, given their nearly ubiquitous presence across various matrices and demonstrated bioaccumulative capacity, potentially posing future repercussions for human health.

Metal cross-contamination relationships between sediments and loricariidae species (siluriform) in a neotropical riverine system.

Human activities have changed the natural rates at which metals are moved and accumulated in both land and water environments, resulting in negative impacts on local wildlife. In this study, concentrations of Cr, Ni, Cd, Pb, Cu, Mn, Co, and Zn were evaluated in water and riverbed sediment samples collected from the Verde River basin (VR), as well as in tissue samples from five native Loricariidae species. Sediment samples collected from the central section of the VR riverbed indicated the presence of metal concentrations, which were primarily attributed to scattered pollution sources linked to rural activities in the surrounding areas. The bioconcentration factor in the Loricariids liver presented the highest average values for Zn (1.27-58.21), Co (0.48-14.91) and Cu (1.15-11.14). The same pattern was observed in the muscle, but in a lower proportion. Regarding the bioaccumulation factor, Co (1.54-34.84), Cu (5.85-25.22) and Zn (0.64-18.08) attained the highest average values in the liver. The co-inertia analysis examined the spatial distribution of metal concentrations in riverbed sediments and in tissues of Loricariids from the upper, middle, and lower stretches of the river, including the river mouth. The analysis revealed varying patterns, with samples from some regions showing higher bioaccumulation levels. This suggests that riverbed sediments are a primary source of metal contamination in Loricariids from these areas. The pollution has had a significant impact on the bioaccumulation of metals in the VR' Loricariids, which are good indicators of sediment-associated metal bioaccumulation. The metal concentrations recorded in both the riverbed sediments and Loricariids surpassed international and Brazilian limits set for aquatic health and safe human consumption. Given the importance of the Verde River in terms of its ecological, social, cultural, and economic roles, it is essential to implement biomonitoring and control measures to safeguard both terrestrial and aquatic resources.

Assessment of genotoxicity of air pollution in urban areas using an integrated model of passive biomonitoring.

Atmospheric pollution is a major public health issue and has become increasingly critical for human health. Urban atmospheric pollution is typically assessed through physicochemical indicators aligned with environmental legislation parameters, providing data on air quality levels. While the effects of pollution on sensitive organisms serve as a warning for public health decision-makers, there remains a need to explore the interpretation of environmental data on pollutants. The use of species adapted to urban environments as sentinels enables continuous and integrated monitoring of environmental pollution implications on biological systems. In this study, we investigated the use of the plant species Tradescantia pallida as a biomonitor to evaluate the genotoxic effects of atmospheric pollution under diverse vehicular traffic conditions. T. pallida was strategically planted at the leading urban intersections in Uberlândia, Brazil. During COVID-19 pandemic lockdowns, we compared indicators such as physical, biological, and traffic data at different intersections in residential and commercial zones. The reduction in vehicular traffic highlighted the sensitivity of plant species to changes in air and soil pollutants. T. pallida showed bioaccumulation of heavy metals Cd and Cr in monitored areas with higher traffic levels. Additionally, we established a multiple linear regression model to estimate genotoxicity using the micronucleus test, with chromium concentration in the soil (X1) and particulate matter (PM) in the atmosphere (X2) identified as the primary independent variables. Our findings provide a comprehensive portrait of the impact of vehicular traffic changes on PM and offer valuable insights for refining parameters and models of Environmental Health Surveillance.

Toxicity of REEs, Th, and U: A Biodisponibility, Cytotoxicity, and Bioaccumulation Assessment in Marine Sediment.

In this work, bioaccessibility tests for rare earth elements (REEs), Th, and U in marine sediment were carried out, in addition to complementary tests for cytotoxicity and bioaccumulation for the elements La, Ce, Eu, and Gd. The evaluation of human health risk through dermal absorption and oral ingestion was performed using the hazard quotient (HQ). According to the gastric digestion simulation (SBET), it was observed that the elements Ce and Nd exhibited higher absorption capacities in the human body (> 2 µg g-1). La and Sc presented intermediate concentrations (close to 1 µg g-1), while the remaining elements displayed concentrations below 0.5 µg g-1. In the gastrointestinal digestion extraction stage (PBET), all the elements maintained a similar absorption capacity to that observed in SBET, except for the absorption of Y which increased. The results of the bioaccumulation test conducted with fibroblast cells (L929) indicated that La and Eu had a 25% probability of intracellular accumulation. The cell viability test, with exposure to a standard REEs, Th, and U solution in 2% v v-1 HNO3 medium (until 100 µg mL-1) and an aqueous solution of La2O3, Gd(NO3)3, Ce(NO3)3, and Eu2O3 (until 1000 µg mL-1), did not demonstrate cytotoxic effects on fibroblast cells. Considering the ingestion hazard quotient (HQing) and dermal hazard quotient (HQderm) obtained, it was suggested that there is no significant risk of non-carcinogenic effects (< 1). However, they had higher HQing values compared to HQderm, indicating that REEs pose more significant risk to human health through oral ingestion absorption than dermal absorption.

Impact of hydrocarbon extraction on heavy metal concentrations in lowland paca (Cuniculus paca) from the Peruvian Amazon.

Oil has been extracted from the Western Amazon since the 1920s, leading to severe environmental contamination due to frequent occurrence oil spills and the dumping of produced water. Local inhabitants, along with environmental and human rights organizations, have reported the adverse effects of oil-related pollution on their livelihoods and the ecosystems they depend on. Here, we study accumulation of oil-related heavy metals in wildlife, and its subsequent incorporation into the trophic chain. We analysed the concentration of 14 heavy metals (Cd, Cr, Hg, As, Ni, V, Ba, Se, Be, Fe, Cu, Zn, Mn, Al) in liver samples from 78 lowland pacas (Cuniculus paca) hunted for subsistence in an oil-polluted area from the northern Peruvian Amazon where oil has been extracted since the 1970s (n = 38), and two control areas, the Yavari-Mirín River basin (n = 20), and the Pucacuro River basin (n = 20). Pacas in the oil-polluted area have significantly higher concentrations of Cd (P < 0.01) and Ba (P < 0.0001) compared to those in control areas, suggesting bioaccumulation of oil-related pollution. Conversely, Se levels were significantly lower in the oil-polluted area (P < 0.0001), likely due to the sequestration of Se by other heavy metals, particularly Cd. Additionally, minor variations in other heavy metals, e.g., Fe and Zn, were observed in pacas from the oil-polluted area, whereas control areas showed higher concentrations of Ni and Cu. Mn and Al levels did not significantly differ between the study areas. These results underscore the impact of oil extraction on the absorption and assimilation of heavy metals in wildlife, point at oil activities as the source of the high and unsafe blood Cd levels reported for the indigenous population of the studied oil extraction area and raise concerns about the long-term health risks from oil extraction posed to local Indigenous People who rely on subsistence hunting.

Potential of Pinus radiata, Eucalyptus globulus and Acacia dealbata for the long-term phytostabilization of copper mine tailings.

Many contaminated tailings throughout the world cause environmental and human-health related problems due to air and water drift. Tailing phytostabilization is a promising solution, but only certain plant species may tolerate and grow in these contaminated areas. We analyzed the chemical properties of a vegetated and unvegetated area in a tailing site in Central Chile. In addition, in the vegetated area we analyzed the metals content of roots, stems, and foliage in 41-years old plantations of Pinus radiata, Acacia dealbata, and Eucalyptus globulus (the only three species that survived from a total of 34 species planted), and determined height (H), and diameter at breast height (DBH). The results indicated that, except for pH, Se, Pb, and organic matter, all components (nutrients and metals) were two- to three- fold lower in the vegetated tailing compared to that of the unvegetated tailing. The analysis of plant tissues indicated that Cu was higher in the roots of P. radiata (2,073 mg kg-1) and lower in the stems of the same species (4.1 mg kg-1). However, the ability to take up and transport Cu to the shoots was higher in A. dealbata and lower in P. radiata (bioaccumulation factor of 0.19 and 0.06, respectively).

Here we present results for the first long-term phytostabilization project of copper mine tailings in Chile. From the 34 native and exotic species established in 1980 in a mine tailing disposal site with 1,000 mg Cu kg⁻¹, only the exotic Pinus radiata, Acacia dealbata and Eucalyptus globulus were able to survive and adapt to the tailing conditions the last 41 years. This corroborates their potential for the future phytostabilization of copper mine wastes.

Selenized lactic acid bacteria microencapsulated by spray drying: A promising strategy for beef cattle feed supplementation.

This study aimed to assess the technical feasibility of incorporating selenized Lactobacillus spp. microencapsulated via spray drying into cattle feed. Gum Arabic and maltodextrin were used as encapsulating agents. The encapsulation process was carried out with a drying air flow rate of 1.75 m3/min, inlet air temperature of 90°C, and outlet air temperature of 75°C. The viability of the encapsulated microorganisms and the technological characteristics of the obtained microparticles were evaluated. Microorganisms were incorporated into beef cattle feed to supplement their diet with up to 0.3 mg of Se per kilogram of feed. The encapsulated particles, consisting of a 50/50 ratio of gum Arabic/maltodextrin at a 1:20 proportion of selenized biomass to encapsulant mixture, exhibited superior technical viability for application in beef cattle feed. Supplemented feeds displayed suitable moisture, water activity, and hygroscopicity values, ensuring the preservation of viable microorganisms for up to 5 months of storage, with an approximate count of 4.5 log CFU/g. Therefore, supplementing beef cattle feed with selenized and microencapsulated lactic acid bacteria represents a viable technological alternative, contributing to increased animal protein productivity through proper nutrition.

Oxidative stress and neurotoxicity induced by exposure to settleable atmospheric particulate matter in bullfrog tadpoles, Aquarana catesbeiana, (Shaw, 1802).

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.

Human exposure to elements through consumption of raw and cooked fish in an urban region of the central Brazilian Amazon biome: Health risks.

Fish is an important source of animal protein for local communities in the Amazon basin, whose food safety must be assured. However, certain potential toxicants elements, can bioaccumulate in fish species, which inhabit anthropogenically polluted waters, ultimately posing a risk to human health. In the present study, the concentrations of nine elements (Al, As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) were determined in raw and cooked samples of eight fish species consumed in Santarém (northern Brazil, Amazon biome). The potential for non- carcinogenic human health risks linked to the consumption of cooked fish were evaluated for adults and children in two different scenarios. Four carnivores, three omnivores and one detritivore, all of them regularly marketed and consumed by the Santarém population, were the target species. The safety reference values set by national and international guidelines for humans, in both raw and cooked preparations, were used. In most cases, the cooking process showed a trend to increase elements concentrations compared to raw samples, however the differences were not significant. Moreover, the risk assessment showed danger for children in relation to Hg from the consumption of fish, in both scenarios evaluated. For adults, in one of the scenarios, there was a health risk associated to Hg as a result of carnivorous fish consumption. In a context of combined exposure to all elements, children were at risk when consuming fish, especially carnivorous and omnivorous species. For adults, the mixture of elements posed a risk to health human only for carnivorous fish consumption. The results reveal an environmental scenario of Hg contamination, which requires monitoring actions to preserve the aquatic biodiversity and human health in the Brazilian Amazon biome.

Resilience of rotifers and cladocerans communities in four reservoirs with eutrophication pollution and lead concentrations in Aguascalientes, Mexico.

Pollution in aquatic ecosystems has been increasing drastically worldwide changing their water quality. Therefore, species must be adapted to these new scenarios. In Aguascalientes City, four representative urban reservoirs contain lead in the water column and extremely high concentrations of sediments. Therefore, an analysis was conducted to evaluate the resilience of zooplankton species to lead exposure in each reservoir using dormant and organisms. Results demonstrated a decrease range from 57.5 to 22.5% in overall diapausing egg hatching rate, while survivorship rate also decreased from 98 to 54% when organisms were exposed to the water of the four reservoirs and increasing lead concentrations. When Pb exposure increased, results showed a global negative effect on both hatching rate (decreasing from 58 to 30% at 0.09 mg L-1) and survivorship levels (decreasing from 100% to 0.07% at 0.09 mg L-1). We provide Species Sensitivity Distribution for both water reservoir dilutions and lead concentration to analyze diapausing eggs hatching and survivorship of offspring in the presence of same polluted conditions or lead of the autochthonous species found in reservoirs. Furthermore, specific analysis with two populations of the cladoceran Moina macrocopa showed clear dissimilar hatching patterns that suggested a different adaptive mechanism. Niagara population shows a hatching rate of approximately 25% in the first two days of reservoir water exposure, while UAA population drastically increased hatching rate to 75% on exposure at day seven. We provide the first record of bioaccumulation in ephippia of M. macrocopa.

Mercury distribution in organisms, litter, and soils of the Middle Araguaia floodplain in Brazil.

Mercury (Hg) is a chemical element that, depending on its concentration, may become toxic to living organisms due to the ability of Hg to bioaccumulate in food chains. In this study, we collected samples of soil, litter, and organisms in the Middle Araguaia floodplain, Brazil. Total mercury (THg) concentrations in litter were significantly higher (p < 0.0001) than that in soil, ranging from 10.68 ± 0.55 to 48.94 ± 0.13 and 20.80 ± 1.07 to 55 .19 ± 1.59 ng g-1, respectively. Total mercury concentration levels in soil showed a linear, inversely proportional relationship with soil organic matter (SOM) contents and soil pH, consistent with the geochemical behavior of chemical elements in flooded environments. Ten orders of organisms were identified, and the average THg concentrations determined in their bodies were up to 20 times higher than those in soil and litter. We found a significant linear relationship between the levels of THg in litter and those found in soil organisms, thereby allowing the prediction of THg concentration levels in soil organisms through the analysis of litter at the sample units. The different dynamics and feeding habits of soil organisms and the concentration of THg in these organisms may be influenced by the river's course. This study provides evidence of the bioaccumulation of THg in soil organisms in the floodplain of the Middle Araguaia River, an important river basin in the Brazilian savanna.

The behavior of arsenic accumulation in onion (Allium cepa) structures by irrigation water: effect of phosphates and arsenic on the total bioactive compounds and antioxidant capacity.

The presence of arsenic (As) in irrigation water is a threat to agricultural crops as well as human health. The presence of arsenic and phosphorous in irrigation water influences the behavior of bioaccumulation, biotransfer, and total bioactive compounds in the distinct parts of the onion structure. The present work evaluates the behavior of the bioaccumulation and biotransfer of As in the structures of onion (Allium cepa) through a composite central design and response surface method. The factors employed include the concentration of arsenic (V) and phosphate (V) in the nutritive solution. Additionally, this study analyzes the behavior of the effect that the induced stress has on the total bioactive compounds (phenols and flavonoids) and antioxidant capacity (ABTS and DPPH) in the onion roots. The results showed that the physiological properties, bioaccumulation factors, As transference, and the total bioactive compounds in the onion structure are affected by the competition of As and phosphates (P(V)) in the irrigation water. For concentrations of As and phosphorous of 450 µg L-1 and 0.30 mg L-1 respectively in irrigation water, there are negative effects on the equatorial diameter of the bulb (DE), length, weight of the leaf, and weight of the bulb. Besides, the transference and bioaccumulation factors range from 0.02 to 0.22 and from 2.15 to 7.81, respectively, suggesting that the plant has the ability to accumulate As but exhibits a low translocation ability of As from the root to aerial organs. Besides, it is found for central concentrations of As and phosphorous (450 µg L-1 and 0.30 mg L-1, respectively) in irrigation water, a greater production occurs in total phenolic compounds and antioxidant capacity (ABTS and DPPH) as a response to the stress generated by As.

Distribution of rare earth elements (REEs) in the feathers of gentoo penguins (Pygoscelis papua) from different geographical locations of the Antarctic peninsula area.

Antarctica is the most remote and coldest regions of the planet, but the presence of REEs there has received little attention. This study assessed REE-contents in the feathers of adult gentoo penguins from Ardley Island, Kopaitic Island and Base O'Higgins. Field work was accomplished during 2011 (austral summer), and determination of elements was performed with ICP-MS. In general, REE-levels showed descending relations as follows: Ce > La > Y > Nd > Sc > Pr > Gd > Sm > Dy >Er > Yb > Eu > Ho > Tb > Tm > Lu. The data showed an increase of the levels of REEs from the lower part of the feather to the tip. This finding seems to be spatially dependent, but geochemical, anthropogenic conditions, feeding habits, sex, or even health status of birds should also be considered. It is a subject that requires deeper attention in future studies.

Heavy metal and trace element concentrations in the blood of scalloped hammerhead sharks (Sphyrna lewini) from La Paz Bay, México.

Sharks are particularly susceptible to bioaccumulation due to their life history characteristics and trophic position within marine ecosystems. Despite this, studies of bioaccumulation cover only a small proportion of extant species. In this study we report concentrations of trace elements and heavy metals in blood samples of Sphyrna lewini for the first time. We report high concentrations of several trace elements and heavy metals, with concentrations of some elements exceeding the limit determined safe for human consumption. High elemental concentrations may reflect biochemical differences between blood plasma and other tissues; however, they may also be symptomatic of high levels of exposure triggered by anthropogenic activities. We also provide evidence of elemental accumulation through ontogeny, the nature of which differs from that previously reported. Ultimately, this baseline study increases our understanding of interspecific and intraspecific variation in bioaccumulation and ecotoxicology in elasmobranchs which may prove important in ensuring adequate management.

Trace metal biomonitoring in the farming of tambaqui (Colossoma macropomum), an Amazonian neotropical fish.

In Brazil, studies evaluating the concentration of trace metals in fish farms are scarce. Therefore, studies investigating the presence and levels of these metals in aquatic biota, particularly in fish tissues, are crucial for developing appropriate strategies to mitigate the impact of possible toxic metals. Herein, we investigated the levels of trace metals (Cr, Mn, Co, Ni, Cu, Zn, Al, Ag, Cd, Pb, Fe, Na, Mg, Ca, K, and Ba) in water, feed, and sediment, as well as the bioconcentration and bioaccumulation factors in tambaqui muscles (Colossoma macropomum). For this purpose, eight commercial fish farms, which are also engaged in other agricultural activities, were selected. Fe, Zn, Mg, and Cr concentration in tambaqui muscles exceeded the limits set by the Brazilian regulations for daily consumption by adults. Mn, Zn, Al, Pb, Fe, Na, Cu, Co, Ag, Cd, and Ba levels were substantially higher in the liver tissue of tambaquis than those in the muscle tissue. The most prevalent metals found in the feed were Ca, K, Na, Mg, and Fe. However, the levels of Cr and Cd in the sediment, as well as Pb, Mn, Cu, and Fe in the water, exceeded the maximum limits allowed by the Brazilian legislation. The highest bioconcentration factors were observed for the metals, Na, Zn, and K, with concentrations up to 4.74, 12.61, and 72.08 times, respectively, higher in tambaqui muscle compared to those in water. The bioaccumulation factors for Ca, Zn, Mg, Na, and K were 2.90, 6.96, 21.21, 212.33, and 492.02 times, respectively, higher in the muscle tissue than those in the sediment values in fishponds across all fish farms. Therefore, our findings suggest that tambaquis have a remarkable ability to bioaccumulate trace metals, particularly the essential ones, and can be categorized as a bioindicator species for environmental quality. Furthermore, we observed that, although water exhibits the highest prevalence and diversity of elements above the values recommended by the Brazilian legislation, sediment is the primary source of trace metal contamination for tambaquis.

Mercury and selenium in three fish species from a dam 20 months after a mine-tailing spill in the SE Gulf of California ecoregion, Mexico.

During January 2013, a mining spill occurred in the Santa Maria mining region, releasing around 300,000 m3 of tailings on Los Remedios river, which was transported through the San Lorenzo river and finally to El Comedero (EC) dam. Twenty months later, we examined the concentrations of Hg and Se in the muscle, liver, gills, and guts of three fish species (Cyprinus carpio, Oreochromis aureus, Micropterus salmoides) captured in the EC dam to assess the performance of the cleaning operations. A high Se concentration in the liver of all species (carp, 1.2 ± 0.4; tilapia, 3.9 ± 2.1; bass, 3.5 ± 1.1 µg g-1 ww) was consistently observed, while this behavior was only found in the blue tilapia for Hg (0.15 ± 0.11 µg g-1 ww). Tilapia (benthic-detritivorous) exhibited the highest Se concentrations compared to the carp (omnivore) and the largemouth bass (piscivore). In contrast, the largemouth bass had the highest Hg levels in the muscle compared with the other fishes. Such differences could be related to the different metabolism and feeding habits among species. Compared to a tilapia study carried out three months after the mine spill during a mortality event, a decrease was evident in the liver for Se and Hg by 7.2 and 4.7 times, respectively. This reveals that cleaning operations were more efficient for Se and less for Hg, and that a prolonged period was required for the partial recovery of the element levels in fish from sites impacted by mining. Considering the Mexican consumption scenarios for each fish species, it could be concluded that there will be no non-cancer risk by exposure to Hg or Se.

Bioaccumulation of lead in different organs of Ctenopharyngodon Idella (grass fish) and Tor putitora (Mahseer) fish / Bioacumulação de chumbo em diferentes órgãos de peixes Ctenopharyngodon idella (carpa-capim) e Tor putitora (Mahseer)

Bioaccumulation of toxic heavy metals in the human body can give rise to adverse health effects, the severity of which depends upon their dosage and duration of exposure. In this study, yearlings of two different species of edible fish, i.e., Tor putitora (Mahseer) and Ctenopharyngodon Idella (grass carp), were exposed to different concentrations of lead nitrate in a controlled environment of aquarium for three different lengths of duration (14, 28, and 60 days). The bioaccumulation of lead in different organs, including gills, skin, muscles, liver, intestine, and swim bladder of the fish, was assessed using atomic absorption spectrometry. Generally, the highest lead concentration was observed in the gills and lowest in the muscles for both species at each experimental dosage and duration. In 14-days exposure, the relative pattern of bioaccumulation in different organs was observed as gill > liver > skin > intestine > swim bladder > muscle for both fish species. Similarly, the pattern of bioaccumulation observed in 28-days exposure was as: gill > liver > intestine > skin > swim bladder > muscle in both species. Whereas, pattern in 60-days exposure was observed as gill > liver > intestine > swim bladder > muscle > skin. The data shows that grass carp had stored higher concentrations of lead than Mahseer, which may be attributed to the fact that they are omnivorous. Furthermore, the lowest bioaccumulation was recorded in the muscles until the 56th day of the exposure, after which the concentration steadily increased in the muscles. The observed pattern highlights the importance of exposure's duration to lead; chronic exposure could result in its bioaccumulation at toxic concentrations in the muscles, which is particularly of concern because the fish muscles are heavily consumed as food worldwide.

A bioacumulação de metais pesados tóxicos no corpo humano pode causar efeitos adversos à saúde, cuja gravidade depende de sua dosagem e duração da exposição. Neste estudo, filhotes de duas espécies diferentes de peixes comestíveis, ou seja, Tor putitora (Mahseer) e Ctenopharyngodon idella (carpa-capim), foram expostos a diferentes concentrações de nitrato de chumbo em um ambiente controlado de aquário por três diferentes períodos de duração (14, 28 e 60 dias). A bioacumulação de chumbo em diferentes órgãos, incluindo brânquias, pele, músculos, fígado, intestino e bexiga natatória dos peixes, foi avaliada por espectrometria de absorção atômica. Geralmente, a maior concentração de chumbo foi observada nas brânquias e a menor nos músculos para ambas as espécies em cada dosagem e duração experimental. Na exposição de 14 dias, o padrão relativo de bioacumulação em diferentes órgãos foi observado como brânquia > fígado > pele > intestino > bexiga natatória > músculo para ambas as espécies de peixes. Da mesma forma, o padrão de bioacumulação observado em 28 dias de exposição foi: brânquia > fígado > intestino > pele > bexiga natatória > músculo em ambas as espécies. Já o padrão de exposição de 60 dias foi observado como brânquia > fígado > intestino > bexiga natatória > músculo > pele. Os dados mostram que a carpa-capim armazenou maiores concentrações de chumbo do que a Mahseer, o que pode ser atribuído ao fato de serem onívoras. Além disso, a menor bioacumulação foi registrada nos músculos até o 56º dia de exposição, após o que a concentração aumentou de forma constante nos músculos. O padrão observado destaca a importância da duração da exposição ao chumbo; a exposição crônica pode resultar em sua bioacumulação em concentrações tóxicas nos músculos, o que é particularmente preocupante porque os músculos dos peixes são muito consumidos como alimento em todo o mundo.