Alexandro Cezar Florentino

The contamination of water by heavy metals is a great concern for many countries worldwide because of their potential to harm human health and biota. Although bordered by a mosaic of conservation units, the Amapari River (Brazil) is impacted by legal and illegal mineral exploitation. However, data on metal concentrations and related risks remain scarce. This study aimed to evaluate the concentrations of Cr, Cu, Fe, Hg, Ni, Mn, Pb, and Zn in Amapari River water and to assess compliance with environmental and drinking-water standards. We also calculated the Risk Indexes (RI), Chronic Daily Intake (CDI), Risk Quotients (RQ), and Carcinogenic Risk (CR) for ingestion and dermal pathways. Cr, Cu, Fe, Ni, Mn, Pb, and Zn were quantified using flame atomic absorption, and Hg was measured with hydride generation coupled to ICP-MS. Pb, Cu, and Hg exceeded CONAMA 357, and Pb exceeded Ordinance 888. The mean CDI values for ingestion were higher than those for dermal exposure for all analyzed metals. RQ values for ingestion were greater than those for dermal contact. RI was 3.03, showing the potential for adverse noncarcinogenic effects on human health. CR values for Pb and Cr through ingestion were both above 10–4, reflecting a high risk of cancer. CR values for dermal exposure to both metals were also above 10–4. This study demonstrated that the Amapari River is contaminated by multiple metals and poses potential risks to human health. These findings highlight the urgent need for environmental monitoring, regulatory enforcement, and mitigation measures.

Macapá City, located in the Brazilian Amazon, faces critical aquatic pollution challenges due to inadequate sanitation infrastructure, leading to metal contamination in fish within its urban water bodies. Our study evaluated the concentrations of metals (Cu, Cd, Cr, Fe, Mn, Ni, Pb, Zn, and Hg) in muscle tissues of fish from igarapés, ressaca areas, and canals. Samples were collected from six sampling sites to investigate the bioaccumulation of these metals and their potential human health risks. All metals were quantified by atomic absorption spectrometry, except Hg, which was quantified by inductively coupled plasma optical emission spectrometry. Metal concentrations were determined in three carnivorous and seven omnivorous fish species. Cd concentrations exceeded the Brazilian maximum limit established for human consumption in all fish species evaluated. The estimated daily intake (EDI) of Pb and Hg exceeded their reference doses. Our risk assessment, which combined the risk quotient (RQ) for individual metals and the risk index (RI) for metal mixtures, indicated health risks associated with the consumption of fish collected from the study areas. These results demonstrated a worrying exposure to metals (mainly Cd, Pb, and Hg), highlighting the need for environmental management measures and continuous monitoring to protect public health in vulnerable urban areas.

The city of Macapá in the Brazilian Amazon faces critical aquatic pollution challenges due to inadequate sanitation infrastructure, leading to heavy metal contamination in fish within its urban water bodies. This study evaluates concentrations of metals (Cu, Cd, Cr, Fe, Mn, Ni, Pb, Zn, Hg) in muscle tissues of fish from igarapés, floodplain lakes, and canals. Samples were collected from six sites to investigate the bioaccumulation of these metals and their potential human health risks. Using Atomic Absorption Spectrometry and Inductively Coupled Plasma Optical Emission Spectrometry for Hg, metal levels were analyzed in three carnivorous and seven omnivorous fish species. Cd concentrations in several species exceeded safety thresholds for human consumption, while the estimated daily intake (EDI) of Hg also surpassed reference doses. Risk assessment combining the risk quotient (RQ) for individual metals and the risk index (RI) for metal mixtures indicated considerable health risks associated with consuming fish from these contaminated waters. These findings reveal concerning exposure to contaminants, underscoring the need for environmental management and ongoing monitoring to protect public health in vulnerable urban areas.

Mercury contamination in the Amazon arising from both natural sources and intensive mining activities in the region is a significant public health concern. This metal is used to separate Au from sediments. Accordingly, this study aimed to assess the impact of mining on mercury contamination in the animal and human populations of the Amazon. This overall objective was pursued through a systematic review of the existing literature to assess the impact of Hg and identify gaps in geographic coverage arising from this assessment. Herein, we employed PECO and PRISMA-ScR protocols to select articles published between 2017 and 2023 based on projected points on a map within the biogeographic boundaries of the Amazon. We found that mercury concentrations increase with trophic levels, reaching high values of 3.7 µg/g in the muscles of predatory fish and 34.9 µg/g in human hair. The mean level of mercury in human hair in the whole (Amazon) region exceeds 6 µg/g, surpassing tolerance levels. Although mining regions show high concentrations of Hg, the highest incidence was observed among populations with fish-based diets. It was concluded that continuous research and monitoring of fish in the region are required in order to accurately assess the risk associated with Hg contamination, especially since fish are the main source of protein in this region.

Mercury contamination in the Amazon is a significant public health concern arising from both natural sources and intensive mining activities in the region. This metal is used to separate Au from sediments, forming an amalgam that facilitates the extraction of precious metals. Accordingly, this study aimed to address the following question: What is the impact of mining on mercury contamination in the animal and human populations of the Amazon? The overall objective of this study was to conduct a systematic review of the existing literature to identify gaps in geographic coverage and assess the impact of Hg contamination on human and animal populations in the Amazon region. Our hypothesis was that higher mercury concentrations in tissue samples would be found closer to the mining areas. We employed the PECO and PRISMA-ScR protocols to collect articles published between 2017 and 2023, selected based on criteria representing projected points on a map within the biogeographic boundaries of the Amazon. Mercury concentrations increase with trophic levels, reaching high values of 3.7 µg/g in the muscles of predatory fish and 34.9 µg/g in human hair. The average level of mercury in humans exceeds 6 µg/g, surpassing tolerance levels. Although mining regions show high concentrations of Hg, the highest incidence was observed among populations with fish-based diets. Research on fish is crucial for assessing the risk to human health, given that fish are the main source of protein in the region.

The objective was to determine the phytochemical composition and evaluate the in silico and in vivo biocidal activity of the essential oil of Cymbopogon citratus (DC.) Stapf in an Aedes aegypti model. The phytochemical composition was analyzed using Gas Chromatography coupled to the Mass Spectrometer, while molecular docking was used to evaluate the potential for inhibition of Acetylcholinesterase. The ovicidal, larvicidal, and adulticidal activities were investigated to evaluate the capacity of the essential oil to inhibit egg hatching and to cause mortality in larvae and adults of A. aegypti. The phytochemical analysis revealed the presence of 11 different compounds, with emphasis on β-myrcene (24.03%), β-citral (27.45%), and Neral (35.36%). In molecular docking, the compounds Geraniol (3.96%) and Linalool (2.77%) proved to be the best inhibitors. As for insecticidal activities, the essential oil of C. citratus was effective in inhibiting the hatching of A. aegypti eggs and was highly toxic to larvae. However, toxicity in adults of A. aegypti was incipient. These results indicate that the essential oil of C. citratus has potential as a candidate for the development of new insecticides aimed at controlling the immature stages of A. aegypti, possibly due to the inhibition of the enzyme acetylcholinesterase.

In this bioremediation study, the fungus Penicillium sp. isolated from kefir grains was evaluated for its resistance to copper in the culture medium. Penicillium sp. was cultivated in liquid medium prepared using 2% malt-agar at pH 7.0. Biomass of the fungus was significantly reduced, but only when 800 mg·L⁻¹ of Cu(NO₃)₂ copper nitrate was used. The effect on radial growth of the fungus in experiments combining different pH values and the inorganic contaminant showed an inhibition of 73% at pH 4.0, 75% at pH 7.0 and 77% at pH 9.0 in liquid medium. Thus, even though the growth of Penicillium sp. could be inhibited with relatively high doses of copper nitrate, images obtained with scanning electron microscopy showed the preservation of fungal cell integrity. Therefore, it can be concluded that Penicillium sp. isolated from kefir grains can survive while performing bioremediation to minimize the negative effects of copper on the environment through biosorption.

This work aimed to carry out a bioremediation study to evaluate the resistance of Penicillium sp. isolated from kefir grains for the treatment of copper. The fungal culture medium was prepared using a 2% malt-agar medium at pH 7.0 in which Penicillium sp. was inoculated. Penicillium sp. growing in a liquid medium showed a decrease in biomass in presence of Cu(NO3)2 (800 mg.L-1), suggesting that the metal impacts the growth rate of the fungus. Moreover, the combined factors of pH and the presence of the inorganic contaminant impacted the radial growth of the fungus, causing inhibition of 73% at pH 4.0, 75% at pH 7.0, and 77% at pH 9.0 in liquid medium compared to control. However, images obtained with scanning electron microscopy showed the integrity of the fungus cell, even at high doses of copper in the medium. Therefore, it can be concluded that Penicillium sp. isolated from kefir grain can bioremediate the environment and that the harmful effects of heavy metals can be minimized as a result biosorption. Although the growth of Penicillium sp. is inhibited, such retardation requires high doses of copper nitrate, thus ensuring the use of this microorganism for protection against the harmful effects of non-essential copper in the environment.

Lipases (EC 3.1.1.3) are hydrolases that catalyze triglycerides hydrolysis in free fatty acids and glycerol. Among the microorganisms that produce lipolytic enzymes, the entophytic fungi stand out. We evaluated 32 fungi of different genera, Pestalotiopsis, Aspergillus, Trichoderma, Penicillium, Fusarium, Colletotrichum, Chaetomium, Mucor, Botryodiplodia, Xylaria, Curvularia, Neocosmospora and Verticillium, isolated from Euterpe oleracea Mart. (Açaizeiro) from the Brazilian Amazon for lipase activity. The presence of lipase was evidenced by the deposition of calcium crystals. The endophytic Pestalotiopsis sp. (31) and Aspergillus sp. (24) with Pz 0.237 (++++) and 0.5 (++++), respectively, were the ones that showed the highest lipolytic activity in a solid medium. Lipase activity was rated in liquid medium, in a different range of temperatures (°C), pH and time (days). The values obtained in the production of lipase by the endophytic fungi were 94% for Pestalotiopsis sp. (31) and 93.87% for Aspergillus sp. (24). Therefore, it is emphasized that the endophytic fungus isolated the E. oleracea palm may be a potential candidate to produce enzymes of global commercial interest.