Proteomic Changes in Paspalum fasciculatum Leaves Exposed to Cd Stress.

(1) Background: Cadmium is a toxic heavy metal that is widely distributed in water, soil, and air. It is present in agrochemicals, wastewater, battery waste, and volcanic eruptions. Thus, it can be absorbed by plants and enter the trophic chain. P. fasciculatum is a plant with phytoremediation capacity that can tolerate Cd stress, but changes in its proteome related to this tolerance have not yet been identified. (2) Methods: We conducted a quantitative analysis of the proteins present in P. fasciculatum leaves cultivated under greenhouse conditions in mining soils doped with 0 mg kg-1 (control), 30 mg kg-1, or 50 mg kg-1. This was carried out using the label-free shotgun proteomics technique. In this way, we determined the changes in the proteomes of the leaves of these plants, which allowed us to propose some tolerance mechanisms involved in the response to Cd stress. (3) Results: In total, 329 variable proteins were identified between treatments, which were classified into those associated with carbohydrate and energy metabolism; photosynthesis; structure, transport, and metabolism of proteins; antioxidant stress and defense; RNA and DNA processing; and signal transduction. (4) Conclusions: Based on changes in the differences in the leaf protein profiles between treatments, we hypothesize that some proteins associated with signal transduction (Ras-related protein RABA1e), HSPs (heat shock cognate 70 kDa protein 2), growth (actin-7), and cellular development (actin-1) are part of the tolerance response to Cd stress.

A human health risk assessment of methylmercury, arsenic and metals in a tropical river basin impacted by gold mining in the Colombian Pacific region.

The Atrato River basin is one of the most biodiverse areas worldwide, and paradoxically, it is one of the sites in Colombia with the highest environmental impact from gold mining. This study assessed the distribution of Hg, As, Pb, and Cd in 47 fish species (n = 1372) and the accumulative human health risk in inhabitants (n = 2325) from 13 municipalities located along the Atrato River basin. The results revealed that Hg and As in fish present a high potential human health risk based on their mean concentrations. Estimated daily intake (EDI) calculations showed that humans could present detrimental health effects, while that target hazard quotient (THQ) above 1 showed that the exposed population might experience noncarcinogenic health risks, mainly from the accumulative effects of Hg (80.4%) and As (18.2%). The species that would most affect the health of the inhabitants are carnivorous H. malabaricus, A. pardalis, P. schultzi, R. quelen, and C. kraussii, which are among the fourteen most consumed in the region. These species had values of estimated weekly intake (EWI) above the provisional tolerable weekly intake thresholds for MeHg (PTWI of 1.6 and 3.2 µg/kg bw/week for adults and children, respectively) in 7 of the 13 localities evaluated. According to the surveys, the calculated weekly allowable fish amount (MFW) showed that carnivorous fish may generate adverse effects on the consumers because the allowed MeHg is about 2 times higher than the upper reference limit. Other results indicate a significant carcinogenic health risk, mainly from As, in 8 of the 13 localities evaluated. Due to the high rates of unsatisfied basic needs and the monetary poverty in the region, the possibility that inhabitants can replace fish as the principal source of protein is low. Therefore, a food guidance is required to avoid risks, obtain nutritional benefits, and sustain fish populations.

Ethnomedicinal Studies, Chemical Composition, and Antibacterial Activity of the Mammea americana L. Bark in the Municipality of Cértegui, Chocó, Colombia.

Mammea americana L. is a plant with diverse medicinal uses in the municipality of Cértegui, Chocó, Colombia. This research characterized the ethnomedicinal, chemical, and antibacterial activities of the bark of Mammea americana. Through interviews and semistructured surveys with the community, its ethnomedicinal uses were determined. Compounds present in the bark extract were identified and quantified by gas chromatography-coupled to mass spectrometry (GC-MS), and a qualitative analysis was performed by preliminary phytochemistry. Antibacterial activity and minimum inhibitory concentration (MIC) were carried out by agar diffusion and dilution methods, respectively, using ethanolic and aqueous extracts. Ethnomedical data showed that the bark is used to treat 14 conditions, the most representative being gallstones, prostate inflammation, and malaria. Preliminary phytochemical analyses showed the existence of several secondary metabolites such as tannins, alkaloids, flavonoids, triterpenes and/or steroids, quinones, and saponins. A total of 29 compounds were identified; the most abundant were ethyl 5-oxo-4-(p-toluidine)-2,5-dihydro-3-furancarboxylate, phenol, 4,4',4″-ethylidynetris, nerolidol, 19-hydroxy-13-epimanoyl oxide, α-elemene, and δ-cadinene. The results showed remarkable antibacterial activity of the ethanolic extract (20 mg/ml) against Staphylococcus aureus (22.6 mm) and Escherichia coli (19.6 mm) and of the crude water extract (20 mg/ml) against Staphylococcus aureus (18.5 mm) and Escherichia coli (12.4 mm). The strongest MIC was for the ethanolic extract with values of 0.357 and 0.897 mg/ml against S. aureus and E. coli strains, respectively, while in the aqueous extract, S. aureus (3.99 mg/ml) and E. coli (4.3 mg/ml) were recorded. It is assumed that the compounds identified in this study could be responsible for the antibacterial activity of the species, as well as the relationship of the identified compounds and metabolites with the ethnomedical uses given by the community, providing a scientific and traditional basis for its different traditional medical uses.

Assessment of dissolved mercury by diffusive gradients in thin films devices in abandoned ponds impacted by small scale gold mining.

In order to fulfil the Minamata Convention on Mercury, it is necessary to monitor the Hg contamination in freshwater ecosystems nearby artisanal and small scale gold mining (ASGM) areas. Since most of these ASGM communities are located in remote areas, a convenient method for sampling, preserving and transporting samples is needed. In this study we evaluated the feasibility of the diffusive gradient in thin-films (DGT) technique to detect and quantify the labile fraction of Hg and other metals (Pb, Cu, Zn, Cd, Ni, Mn and Cr) in a hard-to-reach gold mining district in the state of Chocó, Colombia. We deployed DGT at sampling sites along the Atrato river and abandoned mining ponds (AMPs) which were deserted in different periods since 1997 to 2019 (6-15 years). In average, the labile THg concentrations in AMPs (148.9 ± 43.2 ng L-1) were a 50% higher than in the river water (99.9 ± 37.4 ng L-1). In the ponds, no significant differences were found in labile Hg with respect abandonment period. Labile Ni (0.9-493.1), Mn (1.33-11.48), Cu (0.030-2.233), and Zn (0.67-10.29) (in µg L-1) were found in higher amounts than for the rest of metals. Labile concentrations of metals are related with their downstream proximity to gold mining activities, being higher in devices deployed close to ASGM sites. Moreover, this study demonstrates the feasibility of the DGT technique to sample, transport, storage, and preserve labile Hg from hard-to-reach ASGM areas.

Health Risk Assessment for Human Exposure to Heavy Metals via Food Consumption in Inhabitants of Middle Basin of the Atrato River in the Colombian Pacific.

The Atrato river basin is one of the world's most biodiverse areas; however, it is highly impacted by mercury gold mining, which generates air, water, and soil pollution. (1) Background: The concentrations of persistent heavy metal pollutants, mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As) in the fish, fruits, and vegetables most consumed by the riverside inhabitants of the middle basin of the Atrato river represent a danger to public health; (2) Methods: A total of 154 samples of different fruits and vegetables and 440 samples of fish were analyzed by atomic absorption spectroscopy. A sample of 446 people were surveyed to evaluate food consumption and carcinogenic and non-carcinogenic risk; (4) Conclusions: High concentrations of As, Hg, Pb, and Cd were identified in fish, fruits-tubers, and vegetables-stems commonly consumed by inhabitants of the middle basin of the Atrato River, which exceeded the Codex limits and the limits established by the WHO/FAO, especially for carnivorous fish species. A high carcinogenic and non-carcinogenic risk was evidenced amongst inhabitants of the middle basin of the Atrato River due to the consumption of fish contaminated with high concentrations of As, MeHg, and THg. The risk due to the consumption of vegetables was very low.

Mercury species in fish from a tropical river highly impacted by gold mining at the Colombian Pacific region.

This study was carried out in the Atrato River basin, a tropical ecosystem in northwestern Colombia, highly impacted by gold mining. The aim of this study was to show how these activities have deteriorated the quality of fish species, and how their intensity has influenced the distribution of mercury (Hg) pollution in the Atrato River basin. Results showed that total mercury (THg, n = 842) ranged between 32 ± 53 µg kg-1 (Cyphocharax magdalenae) and 678.5 ± 345 µg kg-1 (Agneiosus pardalis); 38% of the samples exceeded the WHO limit for the protection of populations at risk, and 15% surpassed the WHO maximum limit of THg in fish for human consumption. A significant positive correlation (p < 0.001) was found between THg with total fish length and trophic level, indicating bioaccumulation and biomagnification of mercury in fish, respectively. Using the non-migratory and carnivorous fish species Hoplias malabaricus and Caquetaia kraussii, Hg contamination was found distributed from high mining activity zones (Rio Quito, Medio Atrato, and Murindó & Vigía del Fuerte - upstream zones) to low activity areas (Rio Sucio & Carmen del Darién, and Ciénaga de Ungía & Tumaradó - downstream zones). In the first-ever performed methylmercury (MeHg) measurements in 520 fish muscle samples analyzed from the Atrato River basin, a high MeHg/THg ratio (91% of the THg) in species such as A. pardalis and H. malabaricus were recorded. Results indicated that the environment and the fish species in the Atrato River basin had been greatly affected by gold mining activities practiced on the river and its tributaries. Therefore, environmental authorities must take protection measures for the inhabitants of the area as well as for the environment.

Dataset of concentrations of mercury and methylmercury in fish from a tropical river impacted by gold mining in the Colombian Pacific.

This data article includes information on the impact of gold mining along five zones of a tropical river in the Pacific region of Colombia. The concentrations of total mercury (THg), total length, mertimercury (MeHg) were determined in 16 species of fish. With this information, it was shown as the concentrations of mercury in fish are influenced by the distribution in the contamination along the Atrato River Basin [1]. Further, THg and MeHg concentrations were related with the trophic level to show biomagnification, and with total length to show bioaccumulation, which is important to establish the potential risk to the environment and also to the health of the inhabitants living along the basin from the consumption of fish.

Phytoremediation potential of Cd and Pb-contaminated soils by Paspalum fasciculatum Willd. ex Flüggé.

The phytoremediation capacity of Paspalum fasciculatum Willd. ex Flüggé, was evaluated in soils from a gold mine contaminated with cadmium (Cd) and lead (Pb), using three concentration levels of each metal (15, 30, and 50 mg kg-1). Their ability to assimilate Cd and Pb in its different tissues was evaluated during 90 days of exposure. Plant growth behavior, accumulation of Cd and Pb, and translocation (TF) and bioaccumulation (BAF) factors were also determined. During the first 60 days of exposure, Cd had an inductive effect on the growth of P. fasciculatum; however, after 90 days, this metal had begun to show toxic effects. Plants showed a similar pattern of accumulating Cd and Pb in their tissues with concentrations decreasing in the order roots > leaves > stem. However, the accumulated concentrations of Cd were generally higher than those of Pb with the highest metal uptakes being observed during the first 30 days of exposure. P. fasciculatum was shown to have a phytostabilization effect with regard to Cd, high concentrations of metals in tissues and little translocation, whereas it showed phytoextraction capacity for Pb. In addition, it can increase pH and organic matter in the soil rhizosphere.

Protein Carbonylation As a Biomarker of Heavy Metal, Cd and Pb, Damage in Paspalum fasciculatum Willd. ex Flüggé.

Heavy metal tolerant plants have phytoremediation potential for the recovery of contaminated soils, and the characterization of their metabolic adaptation processes is an important starting point to elucidate their tolerance mechanisms at molecular, biochemical and physiological levels. In this research, the effects of Cd and Pb on growth and protein carbonylation in tissues of Paspalum fasciculatum exposed to 30 and 50 mg·Kg-1 Cd and Pb respectively were determined. P. fasciculatum seedlings exposed to metals grew more than controls until 60 days of cultivation and limited their oxidative effects to a reduced protein group. Carbonyl indexes in leaf and root proteins reached a significant increase concerning their controls in plants exposed 30 days to Cd and 60 days to Pb. From the combined approach of Western Blot with Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and protein analysis by Matrix Asisted Laser Desorption/Ionisation - Time Of Flight (MALDI-TOF/TOF) mass spectrometry, chloroplastic proteins were identified into the main oxidative stress-inducible proteins to Cd and Pb, such as subunits α, γ of ATP synthetase, Chlorophyll CP26 binding protein, fructose-bisphosphate aldolase and long-chain ribulose bisphosphate carboxylase (RuBisCO LSU). Cd generated damage in the photosynthetic machinery of the leaves of P. fasciculatum into the first 30 days of treatment; five of the oxidized proteins are involved in photosynthesis processes. Moreover, there was a proteolytic fragmentation of the RuBisCO LSU. Results showed that intrinsic tolerance of P. fasciculatum to these metals reached 60 days in our conditions, along with the bioaccumulating appreciable quantities of metals in their roots.

Dietary human exposure to mercury in two artisanal small-scale gold mining communities of northwestern Colombia.

Artisanal and small-scale gold mining (ASGM) is the largest anthropogenic source of mercury pollution worldwide, posing a grave threat to human health. The present study identifies current levels of mercury in the human population from mining areas of the Chocó Department, Colombia, through total mercury (THg) and methylmercury (MeHg) measurements in human hair. Mercury exposure of the local population was assessed in two towns affected by ASGM and was related to different variables of interest. Concentrations of THg in human hair ranged from 0.06 to 17.54ppm and the mean value for the subjects under study was 2.48ppm. Men had significantly higher levels than women in both towns (3.29ppm vs. 0.77ppm). Fish consumption was related to a marked increase of THg in hair, with mean values close to five times higher in frequent fish consumers (5-7 times/week) than in non-fish consumers (4.80ppm vs. 0.90ppm). A multiple linear regression model was fitted successfully (R=0.671) and reveals that gender, fish consumption and location of residence were significant indicators of Hg levels in hair, while no significant relationship was found for age. Approximately 60% of subjects tested had THg levels that exceeded the U.S. Environmental Protection Agency reference dose of 1.0ppm, while 25% surpassed that of the World Health Organization (2.2ppm).