Soluble Hexavalent Chromium Research Articles

Determination of soluble hexavalent chromium in samples of Portland cement from Brazilian cement manufacturers

Urbanization growing is nowadays highlighted in the big cities. Therefore, it is necessary to increase the production of cement, which is used in several areas of civil construction, to supplement the growing demand. Thus, the objective of this study was to determine the content of hexavalent soluble chromium in Portland cement samples from different cement industries in São Paulo state, Brazil, since this chemical species can cause adverse health effects as well as being a potential human carcinogenic for those who manipulate it. In Brazil, the emission of Cr6+ in the cement has no restrictions, since there is no current Brazilian law that determines the maximum concentration of it, whereas, in Europe, the current law 2003/53/EC establishes a maximum of 2 mg.kg-1. So, the Cr6+ content for different cement samples was determined by spectrophotometry based on the European standard EN196-10/2006. It was found by the analysis that among all types of cement produced in São Paulo, the only one that did not exceed the standard limit was the CP III, probably because this kind of cement has a high concentration of additions in its composition, responsible for diluting thereby chromium content. The other types of cement exceeded the established limit. It was concluded that Brazil urgently needs a law to regulate the hexavalent soluble chromium emission present in Portland cement to minimize the environmental and health effects that the cement out of specification may cause.

Accelerated biocorrosion of stainless steel in marine water via extracellular electron transfer encoding gene phzH of Pseudomonas aeruginosa

Microbiologically influenced corrosion (MIC) constantly occurs in water/wastewater systems, especially in marine water. MIC contributes to billions of dollars in damage to marine industry each year, yet the physiological mechanisms behind this process remain poorly understood. Pseudomonas aeruginosa is a representative marine electro-active bacterium, which has been confirmed to cause severe MIC on carbon steel through extracellular electron transfer (EET). However, little is known about how P. aeruginosa causes corrosion on stainless steel. In this study, the corrosivity of wild-type strain, phzH knockout, phzH complemented, and phzH overexpression P. aeruginosa mutants were evaluated to explore the underlying MIC mechanism. We found the accelerated MIC on 2205 duplex stainless steel (DSS) was due to the secretion of phenazine-1-carboxamide (PCN), which was regulated by the phzH gene. Surface analysis, Mott-Schottky test and H2O2 measurement results showed that PCN damaged the passive film by forming H2O2 to oxidize chromium oxide to soluble hexavalent chromium, leading to more severe pitting corrosion. The normalized corrosion rate per cell followed the same order as the general corrosion rate obtained under each experimental condition, eliminating the influence of the total amount of sessile cells on corrosion. These findings provide new insight and are meaningful for the investigation of MIC mechanisms on stainless steel. The understanding of MIC can improve the sustainability and resilience of infrastructure, leading to huge environmental and economic benefits.

Effects of Alkali on Water Soluble Hexavalent Chromium in Ordinary Portland Cement.

Due to the toxicity and mobility of chromium, the disposal of chromium-containing waste is a pressing issue. Co-processing of chromium-containing waste in a cement kiln is currently one of the most effective methods. However, the presence of water-soluble hexavalent chromium (Cr(VI)) in cement limits the use of this method. In this study, Na2CO3 was used to simulate alkali in industrial raw materials to investigate the pattern of influence of alkali content on water-soluble hexavalent chromium. The mechanisms associated with the oxidation and dissolution of chromium were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma emission spectrometry (ICP-OES). The proportion of Cr(VI) in the clinker detected by XPS increased rapidly with increasing alkali content. In the cement slurry system, alkali promotes more hexavalent chromium leaching by influencing pH and other ion concentrations (Ca2+, SO42−). Therefore, the addition of alkali to either the raw meal or to the cement slurry system will favour an increase in the water-soluble Cr(VI) content. This study may provide theoretical guidance for the preparation and use of clinkers containing chromium.

A new approach for determination of water soluble hexavalent chromium in real cement and industrial water samples using Ni-Fe layered double hydroxides/urea/glycerol nanocomposite based potentiometric sensor

Hexavalent chromium (Cr (VI)) is considered one of the most toxic elements that directly affects human health and the environment. Therefore, in this study, two sensitive and selective potentiometric sensors are proposed for Cr (VI) detection in various real cement and industrial water samples based on Ni-Fe layer double hydroxides/urea (Ni-Fe LDH/UA) (sensor I) and Ni-Fe LDH/UA/Glycerol (sensor II) nanocomposites using 1,3-didecyl-2-methylimidazolium-Chromate ion-pair (TEGO-Cr) and cetylpyridinium bromide (CPB). Also, the current study discussed the reducing effect of the alkaline sulfur solution on Cr (VI) and other effects on cement properties. The examined sensors presented excellent Nernstian slopes with short response times (<8 s). The fabricated sensors showed a lower detection limit reached 6.0 × 10−8 mol L−1 (3.0 µg L−1) over a wide pH range (4–9). The proposed potentiometric sensors were successfully performed for Cr (VI) determination in real cement and industrial water samples. The present study presented that sulfur solution can be used conveniently to reduce Cr (VI) in the cement industry without any negative effect on the concrete properties of cement.

Enhanced removal of Cr(VI) by reductive sorption with surface-modified Ti3C2Tx MXene nanocomposites

Being one of the most toxic pollutants commonly present in wastewater as soluble hexavalent chromium (Cr(VI)) specie, its concomitant adsorption and chemical reduction to relatively insoluble and less poisonous Cr(III) would be an effective strategy for remediation of Cr-polluted water. As such, a novel MXene-polyelectrolyte nanocomposite was typically synthesized for enhanced Cr(VI) removal. In detail, we applied polyethylenimine (PEI) to modify the Ti3C2Tx surfaces and synthesized Ti3C2Tx/PEI nanocomposites. The as-prepared composites were characterized by various methods such as SEM-EDX, N2 sorption-desorption isotherm, XRD, FTIR, and XPS. Further, the Ti3C2Tx/PEI was used to adsorb Cr(VI) for clarifying the kinetics, isotherms, and the effects of solution pH and coexisting ions on Cr(VI) removal by batch experiments. Our results show that coating of Ti3C2Tx nanosheets with PEI regulates surface charge of the as-synthesized adsorbent and creates it with a three-dimensional network, allowing the fast electrostatic adsorption of Cr(VI) anions to positively charged surface over wide pH range of 1–10 and promoting to achieve improved removal capacity maximum up to 186.5 mg/g. The Cr(VI) adsorption data were well fitted by the pseudo-second-order kinetic and Langmuir isotherm models. In addition, Ti3C2Tx/PEI also exhibits excellent selectivity for Cr(VI) anions over competing ones such as NO3−, Cl−, ClO4−, and SO42−. Time-dependent reaction routes of Ti3C2Tx/PEI nanocomposite toward Cr(VI) was studied by XPS, which confirmed the slow reduction of all sorbed Cr(VI) to Cr(III) in the dozens of hours and final in-situ Cr(III) immobilization, clarifying the sorption-reduction mechanism for Cr(VI) elimination. All these results suggest that Ti3C2Tx/PEI nanocomposite prepared by reported surface-modification approach available for developing other functionalized adsorbents, may be a potential candidate for decontamination of Cr(VI)-polluted wastewater.

Early hydration of blast furnace slag in the presence of sodium chromate

Blast furnace slag (BFS) is a potential candidate for the immobilization of chromium-bearing wastes. This paper investigated the effect of soluble hexavalent chromium (Na2CrO4) on the early hydration behavior of BFS by means of isothermal calorimetry, X-ray diffraction (XRD), thermogravimetry (TG), scanning electron microscopy (SEM) and pH measurement of pore solution. Meanwhile, the compressive strength of BFS pastes in the presence of different dosage of chromate was tested for the structural study. The primary aim was to verify the alkaline activation of Na2CrO4 on the BFS. It was found that the BFS in water had scarcely hydrated in the first 7 days, whereas the addition of Na2CrO4 greatly accelerated the hydration of BFS and promoted the hardening. Increasing the Na2CrO4 dosage could significantly improve the compressive strength, which was sufficient to meet the requirement for immobilization of wastes. The hydration products of BFS in Na2CrO4 solutions were mainly C-(A)-S-H and CrO4-U phase. The CrO4-U phase played a key role in Cr(VI) binding due to its layered structure. During the formation of CrO4-U phase, a large number of alkalis was released, which largely increased the pH of pore solution, thus greatly promoting the BFS hydration. The results indicated that the Na2CrO4 had a strong alkaline activation on blast furnace slag.

A Kinetic Study Investigating the Carbothermic Recovery of Chromium from a Stainless-Steel Slag

In 2018, the stainless-steel industry produced > 10 million tons of slag, which for the most part was landfilled because of chromium oxide contamination. Long-term studies indicate a possible formation of soluble hexavalent chromium, which is classified as carcinogenic. Recent research focuses on the development of a treatment technology to recover chromium from the slag into a ferroalloy, producing an oxidic material that can be utilized in the construction industry. To date, there has been no literature dealing with the kinetics of a carbothermic treatment process to result in a model to predict the necessary treatment time. The present article fills this gap by investigating the reduction kinetics of chromium oxide of a process close to practical applications. Based on experimental measurements, a model has been developed to predict the necessary treatment time to reach a specific final chromium concentration as a function of the starting concentration and required process temperature in the range between 1600 °C and 1700 °C. Finally, presented findings can serve as a guideline to develop kinetic models in similar pyrometallurgical recovery processes.

The cytotoxicity and genotoxicity of particulate and soluble hexavalent chromium in leatherback sea turtle lung cells

Hexavalent chromium [Cr(VI)] is a marine pollution of concern as recent studies show it has a global distribution, with some regions showing high Cr concentrations in marine animal tissue, and it is extensively used. Leatherback sea turtles (Dermochelys coriacea) are an endangered marine species that may experience prolonged exposures to environmental contaminants including Cr(VI). Human activities have led to global Cr(VI) contamination of the marine environment. While Cr(VI) has been identified as a known human carcinogen, the health effects in marine species are poorly understood. In this study, we assessed the cytotoxic and genotoxic effects of particulate and soluble Cr(VI) in leatherback sea turtle lung cells. Both particulate and soluble Cr(VI) induced a concentration-dependent increase in cytotoxicity. Next, using a chromosome aberration assay, we assessed the genotoxic effects of Cr(VI) in leatherback sea turtle lung cells. Particulate and soluble Cr(VI) induced a concentration-dependent increase in clastogenicity in leatherback sea turtle lung cells. These data indicate that Cr(VI) may be a health concern for leatherback sea turtles and other long-lived marine species. Additionally, these data provide foundational support to use leatherback sea turtles as a valuable model species for monitoring the health effects of Cr(VI) in the environment and possibly as an indicator species to assess environmental human exposures and effects.

Fluidized-Bed Isobutane Dehydrogenation over Alumina-Supported Ga2O3 and Ga2O3–Cr2O3 Catalysts

Dehydrogenation of isobutane to isobutene over supported gallium oxide microspherical catalysts was investigated in a fluidized-bed reactor. A partially crystallized nanostructured aluminum hydroxide-oxide, which is a product of gibbsite centrifugal thermal activation (CTA) obtained using a CEFLAR technology, was used as a catalyst support. The structural and textural properties of Ga2O3/Al2O3 catalysts were characterized by a range of techniques including XRD, N2-physisorption, TPD of NH3 and CO2, IRS of adsorbed pyridine, and selective adsorption of a series of acid–base indicators. A Ga–Al oxide catalyst exhibited a stable performance close to activity of Cr–Al oxide catalysts not containing soluble hexavalent chromium. Upon addition of Cr2O3 (6 wt % of Cr), in amounts lower than in an industrial chromia/alumina catalyst (10.9% Cr), and 1% ZrO2 to 6%Ga/Al2O3 catalytic activity in isobutane dehydrogenation reaches the performance of the industrial KDM catalyst (“Sintez”, Russia).

Comparative Study of Portland Cement-based and Zeolite-based Concretes in Terms of Hexavalent Chromium Leaching

Abstract The paper presents the results of the leaching study of Portland cement-based and zeolite-based concretes regarding water soluble hexavalent chromium. Three leaching water media (distilled water, rain water, and Britton-Robinson buffer) of various pH values were under investigation. The correlation between pH and leached-out concentrations of chromium was not confirmed. The content of hexavalent water-soluble chromium in leachates of zeolite-based concretes was found to be higher than that in leachates of Portland cement-based samples.

Reduction of Water Soluble Hexavalent Chromium in Hydrated Portland Cement

In this paper, the effect of FeSO4.7H2O and SnCl2.2H2O on Cr(VI) reduction is compared by measuring Cr(VI) content before and after adding of reducing additives in cement samples. The determination of water soluble Cr (VI) from cement samples was precisely conducted by in-house developed method. Also compared the effect of additive’s form (crystalline and powder). The qualitative information regarding reduction of water soluble Cr(VI) in hydrated cement paste and extracted solution was monitored by FTIR and UV-Visible Spectra. It was evidenced that the utmost reduction was found in hydrated cement with SnCl2.2H2O.

Human Skin Cells Are More Sensitive than Human Lung Cells to the Cytotoxic and Cell Cycle Arresting Impacts of Particulate and Soluble Hexavalent Chromium.

Hexavalent chromium Cr(VI) is a known human lung carcinogen, with solubility playing an important role in its carcinogenic potency. Dermal exposure to Cr(VI) is common and has been associated with skin damage; however, no link between chromate exposure and skin cancer has been found. In this study, we compared the cytotoxic and clastogenic effects of Cr(VI) and its impacts on cell cycle progression in human lung and skin fibroblasts. We found human skin cells arrested earlier in their cell cycle and exhibit more cytotoxicity than human lung cells, despite taking up similar amounts of Cr. These outcomes are consistent with a hypothesis that different cellular and molecular responses underlie the differences in carcinogenic outcome in these two tissues.

Abstract 1579: Induction of cytotoxicity by soluble chromium (VI) compounds in cultured C3H/10T1/2 Cl 8 mouse embryo cells effects of ascorbate and dehydroascorbate

Abstract Hexavalent chromium [Cr(VI)]-containing compounds are human carcinogens. They cause cancers in the respiratory system when inhaled, and stomach/other internal cancers when ingested. Soluble and insoluble hexavalent chromium [Cr(VI)] compounds induced base substitution, deletion, addition, and frameshift mutations. Cr(VI) compounds also induce DNA-DNA cross links and DNA-protein cross-links in mammalian cells. We examined the ability of the soluble chromium compounds, sodium chromate (Na2CrO4), calcium chromate (CaCrO4) and potassium chromate (K2CrO4) to induce cytotoxicity and morphological transformation in C3H/10T½ Cl 8 (10T1/2) mouse embryo cells. We tested the hypothesis that the intracellular reductants, ascorbate and dehydroascorbate, can reduce Cr(VI) to Cr(V), Cr(IV), and Cr(III) intracellularly, making it a strong cytotoxin in mammalian cells. Ascorbate is present in serum at concentrations in the mM range under physiological conditions in humans, but is only present in the μM range in mouse embryo cells grown in BME cell culture medium plus 10% fetal calf serum. We hypothesized the relatively weak responses for induction of morphological transformation of mammalian cells by Cr(VI) compounds in culture (dose-dependent but weak induction of foci by lead chromate, and no induction of foci by calcium chromate, potassium chromate, and sodium chromate) is due to the small amounts of ascorbate in cultures of mammalian cells that are insufficient to reduce Cr(VI) to Cr(V), Cr(IV), and Cr(III). Therefore, we investigated the cytotoxic effects of ascorbate on 10T½ mouse embryo cells, and the effects of the highest non-cytotoxic concentrations of ascorbate on Cr(VI)-induced cytotoxicity in 10T½ cells, using reduction in plating efficiency as our cytotoxicity assay. Cell survival data showed that ascorbate itself exerted significant cytotoxic effects at concentrations of 0.00625 mM and higher on 10T½ mouse embryo cells. Furthermore, when 10T½ cells were treated with both Cr(VI) and ascorbate, ascorbate played dual roles. It served as a pro-oxidant (enhancer of the cytotoxicity of chromate) at concentrations up to 0.1 mM, and as an anti-oxidant (reducer of the cytotoxicity of chromate) at concentrations of 0.25 mM and higher. This information is important for our ongoing and future experiments, where we designed a protocol to incorporate ascorbate into our assays assessing the cytotoxicity and cell transforming activity of Cr(VI) compounds. We project that at concentrations of 0.1 mM and lower, ascorbate will enhance the cell transforming activity of Cr(VI) compounds. Supported by undergraduate fellowships from the Provost's Office at the University of Southern California (USC) (P. I., JRL), by funding from the M. S. Program in Molecular Microbiology and Immunology to JRL, by discretionary funding to JRL, and by prior grant ES03341 from NIEHS/NIH (P. I., JRL). Citation Format: Sophia A. Shahin, William Liao, Laureen Tran, Qasim A. Akinwumi, Farn-shuan Tseng, Alyssa Mathew-Joseph, Joseph R. Landolph. Induction of cytotoxicity by soluble chromium (VI) compounds in cultured C3H/10T1/2 Cl 8 mouse embryo cells effects of ascorbate and dehydroascorbate. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1579. doi:10.1158/1538-7445.AM2014-1579

Measurement of soluble and insoluble hexavalent chromium in ambient particulate matter

Background: Hexavalent chromium (Cr(VI)), a pulmonary carcinogen, can present as both soluble and insoluble forms in environment, which may have different toxicities. It is thus important to separa...

Analysis of the Chromium Concentrations in Cement Materials

Chromium is an indelible non-volatile trace element of raw materials used in cement clinker production. This work is focused on the study of the content of total chromium and soluble hexavalent chromium in cements. Cements samples of various types (CEM I, CEM II, CEM III and CEM V) were investigated in the experiment. Total chromium content in cements as well as the chemical composition of cement samples was measured by using X-ray fluorescence spectrometry (XRF). The average concentrations of the total chromium in cements vary from 178.5 to 257.3mg per kg of cement. The concentration of the soluble chromium (VI) was measured in cement leachates using colorimetric method. The average concentrations of hexavalent chromium ranged from 0.5 to 2.46mg/kg. The results of chromium (VI) measurements in water leachates confirmed that only a small part of total chromium was extracted from the cement into the water environment. The percentage of water soluble chromium (VI) varied from 0.19 to 1.38%. In addition, X-ray powder diffraction and (XRD) and infrared analysis (FTIR) were used for the cements investigation. Summarizing the results of chromium (VI) monitoring, approximately 75% of investigated cements fulfilled the Slovak eco-labelling requirement.

Reduction of chromium-vi by chromium resistant lactobacilli: A prospective bacterium for bioremediation

Chromium is a toxic heavy metal, which primarily exists in two inorganic forms, Cr (VI) and Cr (III). Highly soluble hexavalent chromium is carcinogenic due to its oxidizing nature. It is well established that the intestinal bacteria including Lactobacilli have regulatory effect on intestinal homeostasis and a breakdown in the relationship between intestinal cells and bacteria results in the manifestation of gastrointestinal (GI) disorders. In this study Cr (VI) resistance was developed in Lactobacillus strains and the reduction of Cr (VI) was evaluated. All resistant strains showed similarities with their respective normal strains and did not acquire resistance to various antibiotics. A complete bacterial reduction of 32ppm Cr (VI) was observed within 6 to 8 hours. The presence of chromate reducing enzyme have also been established following the partial purification (2 to 5 fold) and characterization of chromate reductase in Lactobacillus strains. The chromate reductase of our strains showed optimum activity at pH 6.0 and 30°C. To our knowledge; these strains are fast in Cr (VI) reduction than any other known bacteria. The results suggest that chromate- resistant Lactobacillus strains would be useful for chromium detoxification from GI-tract as well as for bioremediation of hexavalent chromium from contaminated environment.

Leaching Properties of Water-Soluble Hexavalent Chromium by Manufacturing Condition of Cement Clinker

One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The purpose of the present study was to investigate leaching properties of water-soluble hexavalent chromium by different manufacturing conditions of cement clinker. Raw materials were prepared to add different <TEX>$SiO_2$</TEX>, <TEX>$Al_2O_3$</TEX> and <TEX>$Fe_2O_3$</TEX> sources. After the raw materials, such as limestone, sand and clay, iron ore was pulverized and mixed, and the raw meal was burnt at <TEX>$1450^{\circ}C$</TEX> in a furnace with an oxidizing atmosphere. Leaching of soluble hexavalent chromium showed a tendency to decrease with an increasing LSF and IM. However, leaching of soluble hexavalent chromium increased with an increasing S.M. Alkali contents of iron source minerals is closely related to the leaching properties of soluble hexavalent chromium. Green sludge has the highest content of alkali added; leaching of water-soluble hexavalent chromium was mostly high. In order to reduce the water-soluble hexavalent chromium in cement, reducing the alkali content in raw materials is important.

Effects of chromium(VI) reducing agents in cement on corrosion of reinforcing steel

During the production of cement it is necessary to add a reducing agent that converts soluble hexavalent chromium into trivalent chromium. This paper explores effects of iron(II) sulphate reducing agents, namely monosulphate and heptahydrate, as cement admixtures, on corrosion of concrete reinforcement. Accelerated corrosion tests of reinforcing steel have been performed in pore solutions simulating concrete prepared using either CEM I or CEM II type cement, with addition of various concentrations of iron(II) sulphate reducing agent. All of the test results indicate corresponding tendencies and point towards the potential for iron(II) sulphate to foster or accelerate corrosion of the reinforcement. The results of this study indicate an immediate need for a more detailed research, especially in concrete as a more realistic corrosion environment, of the application of iron(II) sulphate as a reducing agent in cement.

Chromium(III) oxide nanoparticles induced remarkable oxidative stress and apoptosis on culture cells

Chromium(III) oxide (Cr(2)O(3)) is used for industrial applications such as catalysts and pigments. In the classical form, namely the fine particle, Cr(2)O(3) is insoluble and chemically stable. It is classified as a low-toxicity chromium compound. Recently, industrial application of nanoparticles (a new form composed of small particles with a diameter of ≤100 nm, in at least one dimension) has been increasing. Cellular effects induced by Cr(2)O(3) nanoparticles are not known. To shed light upon this, the release of soluble chromium from Cr(2)O(3) nano- and fine-particles in culture medium was compared. Fine Cr(2)O(3) particles were insoluble in the culture medium; on the contrary, Cr(2)O(3) nanoparticles released soluble hexavalent chromium into the culture medium. Cr(2)O(3) nanoparticles showed severe cytotoxicity. The effect of Cr(2)O(3) nanoparticles on cell viability was higher than that of fine particles. Cr(2)O(3) nanoparticles showed cytotoxicity equal to that of hexavalent chromium (K(2)Cr(2)O(7)). Human lung carcinoma A549 cells and human keratinocyte HaCaT cells showed an increase in intracellular reactive oxygen species (ROS) level and activation of antioxidant defense systems on exposure to Cr(2)O(3) nanoparticles. Exposure of Cr(2)O(3) nanoparticles led to caspase-3 activation, showing that the decrease in cell viability by exposure to Cr(2)O(3) nanoparticles was caused by apoptosis. Cellular responses were stronger in the Cr(2)O(3) nanoparticles-exposed cells than in fine Cr(2)O(3) - and CrCl(3) -exposed cells. Cellular uptake of Cr(2)O(3) particles were observed in nano- and fine-particles. The cellular influence of the extracellular soluble trivalent chromium was lower than that of Cr(2)O(3) nanoparticles. Cr(2)O(3) nanoparticles showed cytotoxicity by hexavalent chromium released at outside and inside of cells. The cellular influences of Cr(2)O(3) nanoparticles matched those of hexavalent chromium. In conclusion, Cr(2)O(3) nanoparticles have a high cytotoxic potential.

Potassium Dichromate Induced Cytotoxicity, Genotoxicity and Oxidative Stress in Human Liver Carcinoma (HepG2) Cells

Chromium is a widespread industrial waste. The soluble hexavalent chromium Cr (VI) is an environmental contaminant widely recognized to act as a carcinogen, mutagen and teratogen towards humans and animals. The fate of chromium in the environment is dependent on its oxidation state. Hexavalent chromium primarily enters the cells and undergoes metabolic reduction to trivalent chromium, resulting in the formation of reactive oxygen species together with oxidative tissue damage and a cascade of cellular events. However, the results from in vitro studies are often conflicting. The aim of this study was to develop a model to establish relationships between cytotoxicity, genotoxicity and oxidative stress, in human liver carcinoma [HepG2] cells exposed to potassium dichromate. HepG2 cells were cultured following standard protocols and exposed to various concentrations [0–50 μM] of potassium dichromate [K2Cr2O7]. Following exposure to the toxic metal, the MTT assay was performed to assess the cytotoxicity, the thiobarbituric acid test to evaluate the degree of lipid peroxidation as an indicator of oxidative stress and the alkaline comet assay was used to assess DNA damage to study genotoxicity. The results of the study indicated that potassium dichromate was cytotoxic to HepG2 cells. The LD50 values of 8.83 ± 0.89 μg/ml, 6.76 ± 0.99 μg/ml, respectively, for cell mortality at 24 and 48 hrs were observed, indicating a dose- and time-dependent response with regard to the cytotoxic effects of potassium dichromate. A statistically significant increase in the concentration of malondialdehyde [MDA], an indicator of lipid peroxidation, was recorded in exposed cells [15.9 – 69.9 μM] compared to control [13 μM]. Similarly, a strong dose-response relationship (p<0.05) was also obtained with respect to potassium dichromate induced DNA damage (comet assay) in HepG2 cells exposed [3.16 ± 0.70 – 24.84 ± 1.86 microns – mean comet tail length]; [12.4 ± 1.45% – 76 ± 1.49% – % tail DNA] to potassium dichromate than control [3.07 ± 0.26 microns – mean comet tail length]; [2.69 + 0.19% – % Tail DNA], respectively. The results demonstrated that potassium dichromate was highly cytotoxic to HepG2 cells, and its cytotoxicity seems to be mediated by oxidative stress and DNA damage.