Investigation of Different Nutritional Effects of Dietary Chromium in Fish: A Literature Review

Trace metal bioaccumulation in Mytilus galloprovincialis from Essaouira protected coastal area (Atlantic coast of Morocco): Implications for marine ecosystem and human health

This study assessed trace metal pollution in the Essaouira protected coastal area (Atlantic coast of Morocco) using the mussel Mytilus galloprovincialis as a bio-indicator and evaluated potential human health risks from mussel consumption. Samples were collected seasonally at 8:00 am from April 2017 to February 2018, and metal concentrations in mussel tissues were analyzed using ICP-AES. The metals were found in descending order: Fe > Zn > Al > Cu > Pb > Cr > Cd > Ag, with significant spatial and seasonal variations. Cluster analysis indicated different sources for the metals, with Fe, Zn, and Al linked to continental inputs and Cd, Cr, Pb, Cu, and Ag to anthropogenic sources. The pollution gradient, assessed using the Individual Multimetal Bioaccumulation Index (IMBI), showed that the area is less polluted than other Moroccan coasts. The Human health risk assessment revealed no significant risks, confirming the safety of mussel consumption from this region.

Therapeutic Potential of Aloe vera and Aloe vera-Conjugated Silver Nanoparticles on Mice Exposed to Hexavalent Chromium

Hexavalent chromium (Cr (VI)) is a hazardous heavy metal that induces hepatotoxicity and nephrotoxicity. Thus, this study was planned to explore the ameliorating capacity of Aloe vera leaf gel extract (AV) and their conjugated silver nanoparticles (AVNP) against Cr (VI) induced hepatotoxicity and renal toxicity. The organ indices, level of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, malondialdehyde, total protein, and creatinine in blood serum were measured. The histopathological and micrometric analysis of the hepatic and renal tissue sections were studied. The hepatosomatic index was raised significantly (0.098 ± 0.13 g) in Cr treated group. The blood serum level of AST (484 ± 10.7 U/L), ALT (163 ± 5.5 U/L), ALP (336.7 ± 9.5 U/L), MDA (642.3 ± 28.3 U/L), and creatinine (4.0 ± 0.1 mg/dL) were increased significantly, whereas total protein level was declined (2.8 ± 0.3 g/dL) significantly in Cr exposed group. In the histopathological study, necrosis, disturbed hepatic cords, impaired glomeruli, and Bowman's capsule were noted. Micrometric data from the liver and kidney revealed a significant surge in the size of hepatocytes and their nuclei (1188.2 ± 467.7 µ2 and 456.5 ± 205.6 µ2) and CSA of glomeruli and Bowman's capsule (9051.8 ± 249.8 µ2 and 11,835.5 ± 336.7 µ2) in Cr (VI) exposed group, whereas the brush border (10.2 ± 4.0 µ) size declined significantly. The administration of AV and AVNP reduced the oxidative stress induced by Cr (VI).

Assessing Metal Toxicity on Crustaceans in Aquatic Ecosystems: A Comprehensive Review

Residual concentrations of some trace elements and lightweight metals, including cadmium, copper, lead, mercury, silver, zinc, nickel, chromium, arsenic, gallium, indium, gold, cobalt, polonium, and thallium, are widely detected in aquatic ecosystems globally. Although their origin may be natural, human activities significantly elevate their environmental concentrations. Metals, renowned pollutants, threaten various organisms, particularly crustaceans. Due to their feeding habits and habitat, crustaceans are highly exposed to contaminants and are considered a crucial link in xenobiotic transfer through the food chain. Moreover, crustaceans absorb metals via their gills, crucial pathways for metal uptake in water. This review summarises the adverse effects of well-studied metals (Cd, Cu, Pb, Hg, Zn, Ni, Cr, As, Co) and synthesizes knowledge on the toxicity of less-studied metals (Ag, Ga, In, Au, Pl, Tl), their presence in waters, and impact on crustaceans. Bibliometric analysis underscores the significance of this topic. In general, the toxic effects of the examined metals can decrease survival rates by inducing oxidative stress, disrupting biochemical balance, causing histological damage, interfering with endocrine gland function, and inducing cytotoxicity. Metal exposure can also result in genotoxicity, reduced reproduction, and mortality. Despite current toxicity knowledge, there remains a research gap in this field, particularly concerning the toxicity of rare earth metals, presenting a potential future challenge.

Ecotoxicology of hexavalent chromium in fish: An updated review

Chromium (Cr) is prevalently found in trivalent and hexavalent forms. Though the former is toxicologically benign due to its poor cellular permeability, hexavalent chromium i.e. Cr [VI] crosses the biological membrane and induces toxic effects in organisms. While Cr [VI] toxicity in humans is a subject of occupational exposure at industries involved in ferrochrome production, leather tanning, textile dyeing etc., aquatic abundance of Cr [VI] due to discharge of Cr-laden effluents by these industries lead to extensive toxicity in piscine species. The present review aims to discuss the mode of Cr [VI] entry in fish and the several inimical effects that it imparts on fish health. Such effects have been reported in various studies through behavioral, hormonal and hematological alterations. Bio-accumulation of Cr [VI] in vital organs and subsequent perturbation of the oxidative homeostasis leads to organotoxic effects like changes in organo-somatic indices and histo-architecture. At cellular level, Cr [VI] induced genotoxicity is often found to trigger cellular demise including apoptosis. This review also highlights the stress response in fish against Cr [VI] induced toxicity that is mediated through the expressional alteration of a myriad of anti-oxidant and xenobiotic-metabolizing proteins which is, in turn, a function of activated transcription programs including the Nrf2-ARE pathway.