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Cadmium (Cd) is a toxic heavy metal naturally present in soils and is readily absorbed by edible plants, including cacao, the main ingredient of chocolate foods. High Cd levels in cacao beans pose a public health risk, leading to stringent regulations, particularly in the European Union, which adversely affect small-scale cacao farmers. This study aimed to evaluate the effects of sunflower (Helianthus annuus) and dolomitic lime on Cd levels in one-month-old cacao plants (Theobroma cacao) and the soils they grew in. A greenhouse experiment was conducted, where sunflower and cacao were grown together under two levels of soil Cd exposure, with dolomitic lime added to some treatments. The results indicated that dolomitic lime significantly reduced (P < 0.05) Cd concentrations in cacao, while sunflower presence increased Cd accumulation in cacao, possibly due to the acidic conditions created by sunflower roots. A negative correlation was observed between soil pH and Cd levels in soil. These findings suggest that dolomitic lime may be a viable strategy to mitigate Cd uptake in cacao under low to moderate soil Cd contamination. El cadmio (Cd) es un metal pesado tóxico presente de manera natural en los suelos y es fácilmente absorbido por las plantas comestibles, incluyendo el cacao, el principal ingrediente de los alimentos a base de chocolate. Los altos niveles de Cd en los granos de cacao representan un riesgo para la salud pública, lo que ha llevado a la implementación de estrictas regulaciones, especialmente en la Unión Europea, que afectan negativamente a los pequeños agricultores de cacao. Este estudio tuvo como objetivo evaluar los efectos del girasol (Helianthus annuus) y la cal dolomítica sobre los niveles de Cd en plantas de cacao de un mes (Theobroma cacao) y en los suelos donde crecieron. Se realizó un experimento en invernadero, donde se cultivaron girasol y cacao juntos bajo dos niveles de exposición al Cd en el suelo, con la adición de cal dolomítica en algunos tratamientos. Los resultados indicaron que la cal dolomítica redujo significativamente (P < 0,05) las concentraciones de Cd en el cacao, mientras que la presencia de girasol aumentó la acumulación de Cd en el cacao, posiblemente debido a las condiciones ácidas creadas por las raíces del girasol. Se observó una correlación negativa entre el pH del suelo y los niveles de Cd en el suelo. Estos hallazgos sugieren que la cal dolomítica puede ser una estrategia viable para mitigar la absorción de Cd en el cacao en suelos con niveles bajos a moderados de contaminación por Cd. O cádmio (Cd) é um metal pesado tóxico presente naturalmente nos solos e facilmente absorvido pelas plantas comestíveis, incluindo o cacau — principal ingrediente dos alimentos à base de chocolate. Os altos níveis de Cd nos grãos de cacau representam um risco à saúde pública, o que levou à implementação de regulamentos rigorosos, especialmente na União Europeia, afetando negativamente os pequenos produtores de cacau. Este estudo teve como objetivo avaliar os efeitos do girassol (Helianthus annuus) e da cal dolomítica sobre os níveis de Cd em plantas jovens de cacau de um mês (Theobroma cacao) e nos solos em que cresceram. Foi realizado um experimento em estufa, no qual o girassol e o cacau foram cultivados juntos sob dois níveis de exposição ao Cd no solo, com a adição de cal dolomítica em alguns tratamentos. Os resultados indicaram que a cal dolomítica reduziu significativamente (P < 0,05) as concentrações de Cd no cacau, enquanto a presença do girasol aumentou a acumulação de Cd no cacau, possivelmente devido às condições ácidas criadas pelas raízes do girassol. Observou-se uma correlação negativa entre o pH do solo e os níveis de Cd no solo. Esses achados sugerem que a cal dolomítica pode ser uma estratégia viável para mitigar a absorção de Cd pelo cacau em solos com níveis baixos a moderados de contaminação por cádmio.

This review summarizes the current knowledge on the contribution of metals to the development of oxidative stress in fish. Metals are important inducers of oxidative stress in aquatic organisms, promoting formation of reactive oxygen species through two mechanisms. Redox active metals generate reactive oxygen species through redox cycling, while metals without redox potential impair antioxidant defences, especially that of thiol-containing antioxidants and enzymes. Elevated levels of reactive oxygen species lead to oxidative damage including lipid peroxidation, protein and DNA oxidation, and enzyme inactivation. Antioxidant defences include the enzyme system and low molecular weight antioxidants. Metal-binding proteins, such as ferritin, ceruloplasmin and metallothioneins, have special functions in the detoxification of toxic metals and also play a role in the metabolism and homeostasis of essential metals. Recent studies of metallothioneins as biomarkers indicate that quantitative analysis of mRNA expression of metallothionein genes can be appropriate in cases with elevated levels of metals and no evidence of oxidative damage in fish tissue. Components of the antioxidant defence are used as biochemical markers of oxidative stress. These markers may be manifested differently in the field than in results found in laboratory studies. A complex approach should be taken in field studies of metal contamination of the aquatic environment.

In the present paper, the mean effective concentrations (EC50%) of cadmium (Cd+2) and chromium (Cr+6) using postlarvae of the silverside fish Odontesthes (Austromenidia) regia regia were determined. The postlarvae were exposed to different concentrations of the metals, between 0,142 and 1,208 mg.L–1 of cadmium and between 0,53 and 33,74 mg.L–1 of chromium. The mean effective concentrations (EC50%) obtained were 0,648 mg.L–1 of cadmium (at 96 h) and 2,68 mg.L–1 of chromium (at 96 h). Comparatively, cadmium is more toxic than chromium, and silverside is more tolerant than other organisms.

This study covers the bioinorganic chemistry of Cadmium, its biogeochemistry, anthropogenic release into the environment, and speciation in the atmosphere, waters, soils, and sediments.

Desde la entrada en vigencia de la normativa de la Unión Europea en 2019 sobre los límites máximos permitidos de metales pesados, ha aumentado el interés por la cuantificación de estos elementos en el cacao venezolano. En este estudio, se determinó la concentración de cadmio (Cd) en nueve muestras de granos de cacao provenientes de distintas regiones del país, analizando por separado la cáscara y el nib. Se optimizó un proceso de digestión de muestras mediante un diseño factorial y se empleó para la cuantificación espectroscopia de absorción atómica con atomización por llama, utilizando un espectrofotómetro de fuente continua en modo secuencial rápido. La precisión del método se evaluó a través del cálculo del porcentaje de recuperación en determinaciones inter-diarias e intra-diarias. Los resultados arrojaron concentraciones de cadmio en un rango de 1,4 a 7,2 mg kg⁻¹, superando el límite establecido por la normativa europea de 0,6 mg kg⁻¹. Since the European Union regulations on the maximum permissible content of heavy metals came into force in 2019, there has been a growing interest in quantification these metals in Venezuelan cocoa. In the present study, Cd was quantified in nine samples of cocoa beans from different areas of the national territory, analyzing the shell and nib separately. Atomic absorption spectroscopy with flame atomization using a continuous source spectrophotometer in fast sequential mode was utilized. A sample digestion process was optimized through the implementation of a factorial design. Measurements were evaluated by calculating the percentage recovery for inter-day and intra-day precision determination. The cadmium concentration in the samples ranged from 1.4 to 7.2 mg kg−1, exceeding the European Union's established limit of 0.6 mg kg−1.

Phytoplankton constitutes the base of the trophic webs in the marine environment, so it is important to know the possible effects of pollutants on the algal populations. In the present paper the effect of cadmium on the population growth of the diatom Chaetoceros gracilis was assessed. The microalgae were cultured in the a modified “f/2” Guillard medium, and were exposed to different concentrations of cadmium between 50 and 100000 µg.–1, which produced an inhibitory effect from 20% to 99% on the population growth of Chaetoceros gracilis. Based on the dose (cadmium)-response (inhibition) relationship, a mean effective concentration (EC50%) equal to 591 µg.L–1 of cadmium was obtained.

Las capacidades de los microorganismos de captar metales presentes en ecosistemas acuáticos constituyen una alternativa para la conservación ambiental y de los recursos naturales. En el presente trabajo se evaluó la capacidad de biosorción de cinc y cadmio en soluciones acuosas por cepas de las especies bacterianas Proteus mirabilis y Bacillus subtilis, así como la influencia de diferentes variables, como la edad fisiológica del cultivo, la concentración celular, el pH, el tiempo de contacto y el pretratamiento con métodos físicos y químicos de la biomasa celular en el proceso de remoción. En los estadios fisiológicos evaluados no se observó diferencia en la captura de los metales por los cultivos bacterianos y 2 g.L-1 de biomasa fueron suficientes para alcanzar altos valores de captura. Se determinó que la mayor influencia en el proceso la ejerce el pH empleado, el tiempo de contacto y el efecto de cada tratamiento a la biomasa bacteriana. Los resultados muestran la efectividad de las biomasas microbianas investigadas en la biosorción de cinc y cadmio, y sus potencialidades para el saneamiento ambiental.

Glutathione plays a pivotal role in protecting plants from environmental stresses, oxidative stress, xenobiotics, and some heavy metals. Arabidopsis plants treated with cadmium or copper responded by increasing transcription of the genes for glutathione synthesis, gamma-glutamylcysteine synthetase and glutathione synthetase, as well as glutathione reductase. The response was specific for those metals whose toxicity is thought to be migrated through phytochelatins, and other toxic and nontoxic metals did not alter mRNA levels. Feeding experiments suggested that neither oxidative stress, as results from exposure to H2O2, nor oxidized or reduced glutathione levels were responsible for activating transcription of these genes. Jasmonic acid also activated the same suite of genes, which suggests that it might be involved in the signal transduction pathway for copper and cadmium. Jasmonic acid treatment increased mRNA levels and the capacity for glutathione synthesis but did not alter the glutathione content in unstressed plants, which supports the idea that the glutathione concentration is controlled at multiple levels

El objetivo de este trabajo fue analizar la distribución de los elementos traza (ET) en las fracciones del suelo, en función de los años de riego y su relación con la biodisponibilidad para maíz en el distrito de riego 003, de Tula, Hidalgo. Se muestrearon cuatros zonas con 27, 35, 52 y 102 años de riego, con agua residual, cultivadas con maíz. También se recolectó material vegetal en tres parcelas por cada zona. Se cuantificaron los elementos traza totales, extractables, en la fracciones del suelo y en el material vegetal. La concentración de cadmio total fue mayor a las que se consideran normales en el suelo. Los elementos traza se encuentran en mayor porcentaje en los carbonatos (8% - 31%) y la fracción residual (21% - 72%), con excepción del cobre, que además se asocia con la fracción orgánica (33% - 41%). En tejido vegetal se encontraron concentraciones de zinc (2 – 14 mg kg-1), níquel (0.58 – 1.1 mg kg-1) y plomo (27 – 33 mg kg-1), más altas de las normales, lo que se relacionó al factor de bioconcentración. El manejo del suelo y la concentración de elementos traza determina su biodisponibilidad en suelos áridos.

Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soils. For this reason, determining the chemical form of a metal in soils is important to evaluate its mobility and bioavailability. Sequential extraction was used to fractionate four heavy metals (Cd, Cu, Ni, and Zn) from nine contaminated soils into six operationally defined groups: water soluble, exchangeable, carbonate, Fe-Mn oxide, organic, and residual. The residual fraction was the most abundant pool for all four metals examined. A significant amount (2.4-44%) of Zn was present in the potentially available fraction: nonresidual fraction. A major portion (40-74%) of Cu was associated with the organic, Fe-Mn oxide, and carbonate fractions in most of the soils. Contamination of Cd and Ni in these soils was not as severe as Zn and Cu. Assuming that mobility and bioavailability of these metals are related to their solubility and geochemical forms, and that they decrease in the order of extraction sequence, the apparent mobility and potential bioavailability for these four metals in the soils were: Zn Cu Cd Ni. Metal distributions in different chemical fractions in these soils depended on respective total metal concentrations, except for Zn