Chromium, its properties, transformation, and impact on humans

Abstract

This review presents current views on the features of сhromium and its compounds, their interconversion, reduction of Cr (VI) by microorganisms, as well as the impact of chromium (VI) on the environment and humans. Chromium can have positive and negative effects on health, according to the dose, exposure time, and oxidation state. The most common forms of this metal in biological systems are trivalent Cr(III) and hexavalent Cr(VI). Hexavalent chromium is mobile, highly toxic to humans, and animals and considered a priority environmental pollutant. He is highly soluble and mobile. On the contrary, Cr(III) has relatively low toxicity and mobility and it is one of the micronutrients needed by humans. Сhromium (III) is an essential nutrient required to promote the action of insulin in body tissues so that the body can use sugars, proteins, and fats. Considerable attention is paid to the issues of interconversion of chromium compounds, reduction of Cr (VI) to Cr (III) by microorganisms, as well as physiological features of their action in humans. The present review discusses on the types of chromate reductases found in different bacteria, their mode of action, and potential applications in the bioremediation of hexavalent chromium. Іn the human body chromium (VI) is rapidly reduced to chromium (III) after penetration of biological membranes and in the gastric environment. The reduction of Cr(VI) to Cr(III) results in the formation of reactive intermediates that together with stress oxidative tissue damage and a cascade of cellular events, contribute to the cytotoxicity, genotoxicity, and carcinogenicity of Cr(VI)-containing compounds.

Microelement imbalance in the rat uterus after short-term heavy metals exposure

“…HM accumulation in the uterus likely perturbs female sex hormone expression and the estrous cycle. It also likely causes blood circulation disorders and dystrophies; inflammation; enzymatic activity inhibition; gene mutations and pathological methylation; perturbed cell integrity, hypoxia, division, and apoptosis; hyper-or hypo-atrophic changes; antioxidant mechanism impairment; increased free radicals production, oxidative stress, lipid peroxidation, and DNA damage [2,5,9,10,[17][18][19][20][21][22]. Unfortunately, the risk of exposure of plants, microorganisms, fish, animals, and humans to HMs and other organic and inorganic elements is significant.…”

Hexavalent chromium adsorption by watermelon peels from tannery wastewater

“…The ability to produce leather with qualities required for high-quality leather, such as good hydrothermal stability, improved dyeing properties, and suppleness, has made chrome tanning the most popular technology in the leather industry globally [10]. However, the method has drawn criticism worldwide for seriously harming the environment and negatively affecting human health and other living things [15].…”

“…Cr(III) is slightly harmful and can be used by the body as a micronutrient [22]. Comparatively more watersoluble than Cr(III), Cr(VI) is a very mobile, toxic, and stable species (Cr(III)) [15]. Because Cr(VI) is 500 times more hazardous than Cr(III), it has been designated as a Class-I human carcinogen [2], [21].…”