Subscribe Now Subscribe Today
Research Article

Harazdous Impact of Chromium on Environment and its Appropriate Remediations

Muhammad Faisal and Shahida Hasnain
Facebook Twitter Digg Reddit Linkedin StumbleUpon E-mail

Not available

Related Articles in ASCI
Search in Google Scholar
View Citation
Report Citation

  How to cite this article:

Muhammad Faisal and Shahida Hasnain , 2006. Harazdous Impact of Chromium on Environment and its Appropriate Remediations. Journal of Pharmacology and Toxicology, 1: 248-258.

DOI: 10.3923/jpt.2006.248.258


Chromium, one of the toxic metals is detectable in earth's crust in small quantities associated with other metals, particularly iron. The atomic weight of chromium is 51.996. It melts at 1,875 °C and boils at 2,680 °C. The specific gravity of chromium is 7.19 g cm-3. It forms a number of salts, which are characterized by a variety of colors, solubilities and other properties. The name “chromium” is from the Greek word for color. Most important chromium salts are sodium and potassium chromates and dichromates and the potassium and ammonium chrome alums.

Oxidation States
Chromium can occur under several oxidation states from Cr (0) to Cr (VI). Trivalent chromium Cr (III) occurs naturally in rocks, soil, plants, animals and volcanic emissions (Duffs, 2005). This form is believed by many to play a nutritional or pharmaceutical role in the body, but its exact mechanism of action is unknown. Cr (III) is used industrially as a brick lining for high-temperature industrial furnaces and to make metals, metal alloys and chemical compounds (Barantsevs et al., 2004). Hexavalent chromium, Cr(VI), is produced industrially when Cr(III) is heated in the presence of mineral bases and atmospheric oxygen (for instance, during metal finishing processes). It is the form of chromium that has proven to be of the greatest occupational and environmental health concern. Cr(VI) compounds are emitted into the air, water and soil by a number of different industries. In the air, chromium compounds are present mainly as fine dust particles that eventually settle over the land and water.

Entrance into the Environment
Chromium enters environmental waters from anthropogenic sources such as electroplating factories, leather tanneries, wood preserving, metal processing, chromium plating, alloy preparation, leather tanning, petroleum refining and manufacturing of automobile parts and textile manufacturing facilities (Panov et al., 2003; Huang et al., 2004). Chromium also enters groundwater by leaching from soil. In aqueous environments, however, Cr mainly exists in two oxidation states: Cr(VI) and Cr(III). Aqueous Cr(VI) is present in anionic forms whose compounds are generally soluble over a wide pH range. Hydrolysis of Cr(VI) yields a number of pH-dependent species, that is, H2CrO4, HCrO-4, CrO4-2 and Cr2 O4-2. On the other hand, the main aqueous Cr(III) species are Cr+3, Cr (OH)+2 Cr(OH)+2, Cr(OH)30 and Cr(OH)4¯, while polymeric species such as Cr2 (OH)2+4, Cr3 (OH)4+5 and Cr4 (OH)6+6 are insignificant in natural systems. In the pH range encountered in natural waters, most Cr(III) exists in the least insoluble form of Cr (OH)3 (Smith andGhiassi, 2006).

Industrial Application
It has been estimated that workers in some 80 different professional categories may be exposed to Cr(VI). Various Cr(VI) compounds are used in leather tanning, the production of textiles, dyes, pigments and chrome plating (Cristian et al., 2005). Other sources of chromium emissions include oil and coal combustion, stainless steel welding, steel production, cement plants, industrial paint and coating manufacture and cooling towers, which use Cr(VI) as a rust inhibitor for their submerged moving parts (Potgieter et al., 2003). Occupational exposures to Cr(VI) compounds can be quite acute (Proctor et al., 2004).

Manufacturing of Chromium Salts
Chromium (II) and (III) chemicals are also manufactured but in small amounts as compared to chromium (VI). Chromium dichloride (CrCl2) and chromium sulfate (CrSO4) are examples of the former and chromium trifluoride (CrF3), chromium trichloride (CrCl3) and chromium nitrate (Cr (NO3)3 are examples of the latter. Chromium platers use heated baths of H2Cr2O7 to plate chromium onto pieces of other metals. Under an electric current, the hydrated dichromate ions move toward the positive electrode, which is the metal to be plated. The hydrogen and oxygen gases formed escape the bath forming aqueous acidic chromate laden mists.

Essentiality and Toxicity
Chromium is present in food and feed plants, but the form is not well characterized (Cary, 1982; Das et al., 2005). The likely form is soluble chromium (III) organic compounds such as chromium (III) oxalate in plants (Smith et al., 1989). Chromium is an important micronutrient for animals and humans (Bahijri and Mufti, 2002). Humans must consume organically bound or chelated chromium as part of the proper metabolism of Glucose Tolerance Factor (GTF). Although chromium (VI) can be rapidly absorbed through the intestinal wall, any ingested chromium (VI) is believed to be quickly reduced in the stomach where the pH is around 1 and numerous organic reducing agents can be found.

Chromium plays a key role in the biological life but above critical level it is toxic (Balamurugan et al., 2004; Han et al., 2004;) mutagenic (Gili et al., 2002; Puzon et al., 2002; Wise et al., 2005), carcinogenic (Codd et al., 2003; Reddy et al., 2003; Sato et al., 2003) and teratogenic (Asmatullah et al., 1998). Trivalent form of chromium is more common and its compounds are less soluble and less toxic than hexavalent chromium (Smith andGhiassi, 2006). Trivalent chromium forms stable complex with legends on DNA, proteins and small molecules such as glutathionein (Adach and Cielak-Golonka, 2005). Trivalent chromium bounds to the DNA template cause increased DNA polymerase processivity and decreased DNA replication fidelity. These alterations in DNA function can result in greatly increased bypass of oxidative DNA lesions, which are promutagenic (Adach and Cielak-Golonka, 2005).

Toxicity Towards Plants
In chromium contaminated sites not only human, animal and microbial life damage but the effects on plants are also equally pronounced. Due to chromium accumulation reduction in plant production along with toxicity in the nutritional contents are also observed (Pandey and Sharma, 2003; Klumpp et al., 2002). Some plants show tolerance against chromium, but some have acquired the ability to accumulate chromium (Tripathi and Chandra, 1991). The root and shoot growth rate and leaf chlorosis could be elicited in hyacinth (Eichornia crassipes) by exposure to chromium and copper for several weeks (Hafeez and Ramzan, 2002). In Triticum aestivum, hexavalent chromium showed adverse effect on the growth parameters and also caused accumulation of chromium in the plants (Faisal et al., 2005). The hexavalent chromium salt has more adverse effect on germination and growth of Helianthus annuus (Faisal and Hasnain, 2005) and Vigna radiata (Hsu and Chou, 1992). The effect of chromium on the cortical cells of meristematic zone was observed in Pisum sativum L. (Gabara et al., 1992). Chromium toxicity on the seed germination and growth of Phaseolus vulgaris was markedly increased with an increase in its concentration (Zeid, 2001). Plants growing in higher concentration of chromium take up more chromium, which accumulate in the plant tissues and via plants enter in the food chain. At a concentration of >0.2 mM Cr(VI), Citrullus plant showed growth depression with chlorosis and loss of turgor of middle leaves (Dube et al., 2003). Growth of mustard (Sorghum bicolor L.) plants decreased by increasing the concentration of Cr(VI) from 50 to 100 μM (Shanker andPathmanabhan, 2004). Lamina minor accumulated Cr(III) in smaller quantities as compared to Cr(VI) which posses more toxic effects on growth parameters as compared to Cr(III). In Brassica juncea Cr(VI) application caused growth retardation, reduces the number of palisade and spongy parenchyma cells in leaves, results in clotted depositions in the vascular bundles of stems and roots and increases the number of vacuoles and electron dense materials along the walls of xylem and phloem vessels (Han et al., 2004). When Vigna radiata plants were treated with Cr(VI), chlorophyll and protein content decreased while activity of catalase, peroxidase, glucose-6-phosphate dehydrogenase and superoxide dimutase increased. Concentration of chlorophyll a and b, soluble protein and grain production decreased significantly in maize plants exposed to Cr(VI) (Sharma et al., 2003).

Toxicity Towards Animals
Chromium also shows toxicity towards different animals (Fatima et al., 2005; Geetha et al., 2005). Exposure of Rana ridibunda to either Cr or a mixture of Cr and Cd caused a decrease in liver GST and P450-MO and renal GST activities (Kostaropoulos et al., 2005). It was observed that treatment of rats with chromium (0.8 mg/100 g body weight/day) for a period of 28 days caused significant increase in chromium content while lowering the body weight along with the organ (kidney, testis, spleen, cerebrum and cerebellum) weight, (Dey et al., 2003). Beside this there was a significant decrease in the DNA and RNA content and in liver, cerebrum and cerebellum significant decreases in total protein content was also observed (Dey et al., 2003). The application of higher dose of chromium in drinking water during embryonic development in mice results in reduced fetal weight, retarded fetal development and higher incidence of dead fetuses (Junaid et al., 1995). Animal studies on the carcinogenicity of various chromium species have generally suggested that water-insoluble species, CaCrO4 in particular (Levy et al., 1986), are the causative agent of respiratory cancers (Gad, 1989). Studies have showed the toxicity of chromium picolinate in renal impairment, skin blisters and pustules, anemia, hemolysis, tissue edema, liver dysfunction; neuronal cell injury, impaired cognitive, perceptual and motor activity; enhanced production of hydroxyl radicals, chromosomal aberration, depletion of antioxidant enzymes and DNA damage in mice (Bagchi et al., 2002). In mice, potassium dichromate treatment (20 mgCr kg-1), as Cr(VI) compound, significantly elevated the level of lipid peroxidation as compared with the control group. This was accompanied by significant decreases in nonprotein sulfhydryls (NPSH) level, superoxide dismutase (SOD) and catalase (CAT) enzyme activities as well as a significant chromium accumulation (Bosgelmez and Güvendik, 2004).

Toxicity Towards Humans
Certain Cr(VI) compounds have been found to be carcinogenic in humans, but the evidence to date indicates that the carcinogenicity is site-specific-limited to the lung and sinonasal cavity and dependent on high exposures, such as might be encountered in an industrial setting (Feng et al., 2003). It has been reported that trivalent chromium salts are poorly absorbed through the gastrointestinal tract. Hexavalent chromium compounds are approximately 1000-fold more cytotoxic and mutagenic than trivalent chromium compounds in cultured diploid human fibroblasts, but both hexavalent and trivalent chromium compounds induce dose-dependent anchorage independence in human diploid fibroblasts (Biedermann and Landolph, 1990). Cr (VI) can cause a wide range of other health effects. Inhaling relatively high concentrations of some forms of Cr(VI) can cause a runny nose, sneezing, itching, nosebleeds, ulcers and holes in the nasal septum (Banerjee et al., 2003). Short-term high-level inhalational exposure can cause adverse effects at the contact site, including ulcers, irritation of the nasal mucosa and holes in the nasal septum (Stohs et al., 2001). Hexavalent chromium compounds induce dose-dependent cytotoxicity and anchorage independence in cultured human diploid fibroblasts (Biedermann and Landolph, 1987). Cr(VI) is one of the most highly allergenic metals, second only to nickel (Bock et al., 2003).

In fact, irritation of the skin a most frequently reported human health effect from exposure to Cr(VI), taking the form of skin ulceration (dermatosis) and allergic sensitization (dermatitis) (Hansen et al., 2003). Indeed, dermatosis was the first observed health effect associated with chromium exposure, although improved industrial hygiene practices have greatly reduced its incidence (Refiye et al., 2005). Once absorbed into the blood system there are various antioxidants that act as reducing agents, such as glutathione and ascorbate, which rapidly reduce chromium (VI) to chromium (III). Respiratory cancer is the health effect of most concern and is the basis for the regulation of chromium (VI) (O’Brien et al., 2003). There is also some indication that chromium (VI) may cause cancer of the upper airways and upper gastrointestinal tract, such as the esophagus, larynx, trachea and stomach (Xie et al., 2005). Chromium concentration in the lungs was found to increase with age for both occupationally and environmentally exposed individuals (Xie et al., 2005). The upper lobes tended to have higher concentrations than lower lobes and cancerous portions of lungs showed the highest chromium concentrations. However, large doses of chromium into the blood can result in acute kidney and liver damage (Dey et al., 2003).Research on the carcinogenicity of chromium (VI) has focused on the fact that chromate ions quickly pass through cellular and nuclear membranes, while the trivalent species are many orders of magnitude slower (Pas et al., 2004). Once in the cytoplasm, chromate ions can either pass the nuclear membrane and be reduced to chromium (III) or be reduced in the cytoplasm. Because neither Cr(VI) nor Cr(III) reacts strongly with DNA, it is thought that the reduction of Cr(VI) to Cr(III), either in the cytoplasm, nucleus, or the blood, produces free radicals, which in turn can bind to DNA (Medeiros et al., 2003). Indeed, the DNA-protein crosslinks induced by chromate have been used as a biomarker for chromium exposure (Taioli et al., 1995).

Toxicity Towards Microorganisms
Most microorganisms (protozoa, fungi, algae, bacteria and cyanobacteria) are able to accumulate chromium (Dursun et al., 2003; Pas et al., 2004; Faisal and Hasnain, 2005). In general, toxicity for most microorganisms occurs in the range of 0.05-5 mg Cr L-1 of medium. In Saccharomyces cerevisiae chromium caused oxidative damage to cellular proteins (Sumner et al., 2005). Reduced growth of mycelium in many fungi is due to the toxic effect of hexavalent chromium (Lozovaia et al., 2004). Studies of Shewanella oneidensis showed that the growth was much inhibited even at a low concentration (0.015 mM) of Cr(VI) (Viamajala et al., 2004). Incubation of E. coli cells with 10 mM of hexavalent chromium and 3 mM hydrogen peroxide caused the degradation of double-strand DNA in vivo, which was suppressed by the addition of mannitol (Itoh et al., 1994). Cr(VI) caused decrease in cell size, the structure of cell wall, as well as the redox reaction caused by the exudate or enzyme when the cultures of Chlorella pyrenoidosa, Synechococcus, Spirulina maxima, Spirulina platensis, Selenastrum capriornutum and Scenedesmus quadricauda were grown in chromium solutions (Chen et al., 2003).

Remediation Strategies
To minimize the environmental contamination, much effort has been made to treat hexavalent chromium in wastewater. Developing health-based clean up standard and remediation strategies for chromium-contaminated soils based on the hexavalent forms of this heavy metal is a complex and controversial task.

Conventional Methods
Conventional methods for treatment of contaminated hexavalent chromium include chemical reduction followed by precipitation, ion exchange and adsorption on coal, activated carbon, alum, kaolinite and flyash. However, most of these methods require either high energy or large quantities of chemicals and therefore more practical, cost effective methods are being explored (Ohtake and Silver, 1994).

Abiotic Redution
In some natural system conditions exist where oxidation and reduction of chromium can both occur (Bartlett, 1991). For example, as mentioned above, in aquatic systems chromate ions may be reduced to Cr3+. Manganese dioxide can then oxidize Cr+3 back to chromate. If the water is well aerated and sunlight can penetrate to a sufficient depth, the manganese will be reoxidized, allowing more reduced chromium to be oxidized. Just as manganese can be reoxidized by sunlight and oxygen, iron (III) can also be reduced by sunlight to iron (II), which can then reduce chromium (VI) to (III). Indeed, Kaczynski and Kieber (1993) reported a diurnal variation in the ratio chromium (III)/(VI) in pH neutral lakes caused by indirect action of sunlight on chromium via iron and manganese. The ratio chromium (III)/(VI) may also be affected by the photo disassociation of chromium from organic materials (Kaczynski and Kieber, 1993).

To remediate toxic hexavalent chromium from the contaminated environment, it is necessary first to take up this toxic Cr(VI) and then reduced it in to Cr(III).

Cr Phytoremediation
There are conflicting views concerning the uptake and translocation of chromium (VI) in plants (Citterio et al., 2003; Han et al., 2004). Ramachandran et al. (1980) suggest that CrO4-2 is reduced to chromium (III) at the surface of root cells. Other studies found chromium (VI) in plants, which suggest that dissolved chromium (VI), may be taken up by plants without immediate reduction. For instance, chromate was found in the xylem sap of L. scoparium but not in the soluble plant fraction (Cary et al., 1977). Also, it has been shown that chromium (VI) enters the plant through the root by active transport in barley (Hordeum vulgare L.) (Cary, 1982). Uptake of CrO4-2 by intact barley seedlings was stimulated by Ca+2 but inhibited by SO4-2 and other Group VI anions. Chromate appears to be reduced during passage from culture solutions to plant leaves (Cary et al., 1977). Higher concentrations of chromium have been reported in plants growing in high chromium-containing soils (e.g., soil near ore deposits or chromium-emitting industries and soil fertilized by sewage sludge) compared with plants growing in normal soils. However, most of the increased uptake of chromium results in accumulation in the roots and only a small fraction of the total chromium is translocated to the above-ground part of edible plants (Gardea-Torresdey et al., 2004; Faisal and Hasnain, 2005). Leaves usually contain higher chromium concentrations than grains (Smith et al., 1989). In an attempt to design crop practices that might increase the chromium in food and feed crops, Faisal et al. (2005) also found that plants accumulated chromium from nutrient solutions but retained most of this chromium in the roots. It was found that plant tissues that tend to accumulate iron also accumulate chromium (Burd et al., 1998). Chromium uptake was found to increase with increasing chromate concentration, and most of the chromium accumulated by the roots was present in a soluble, non-particulate form in the plant vacuoles. Although chromium is largely retained in the roots of plants, the oxidation state of chromium, the pH and the presence of humic substances and plant species affect plant uptake and transport (Smith et al., 1989).

Microbial Reduction
Microorganisms have the potential to accumulate chromium (Ozdemir et al., 2003) and reduce chromium (VI) to chromium (III) (Desjardin et al., 2003; Camargo et al., 2004; Ramirez-Ramirez et al., 2004). Although high levels of chromium (VI) are toxic to microorganisms (Bartlett, 1991). Chromium is important to yeast metabolism (Coleman, 1988) and sorption of Cr(VI) by several species of yeast has been reported (Rapoport and Muter, 1995; Babyak et al., 2005). Chromium accumulation has been shown to occur in bacteria periphytic to a crab (Helice crassa) carapace and in sewage fungus (Coleman, 1988) and may contribute to the presence of chromium in the food chain.

Bacterial Reduction
Many types of chromium resistant bacteria, which have developed different strategies to overcome heavy metal stress in the environment are now known (Faisal et al., 2005). Bacterial resistance to chromate can be due to chromosomal borne (Peitzsch et al.,1998; Juhnke et al., 2002) or plasmid mediated (Peitzsch et al., 1998) or both (Peitzsch et al.,1998; Juhnke et al., 2002). Some bacterial strains are able to reduce toxic hexavalent chromium to less toxic trivalent chromium (Konovalova et al., 2003; Faisal and Hasnain, 2004; Thacker and Madamwar, 2005). Reduction of hexavalent chromium by microorganisms has been reported under a number of conditions and by a variety of bacterial species (Faisal and Hasnain, 2004: Faisal et al., 2005; Thacker and Madamwar, 2005). Although different genera of bacteria are involved in the reduction of hexavalent chromium to trivalent chromium but E. coli, Bacillus sp, Pseudomonas fluorescens LB300, Desulfovibrio vulgaris, Pseudomonas ambigua G-1 and Alcaligenes eutrophus are most pronounced (Peitzsch et al., 1998).

Cr(VI) is known to be reduced both aerobically and anaerobically in different bacterial systems (Guha et al., 2001; Megharaj et al., 2003; Viera et al., 2003; Faisal and Hasnain, 2004). In anaerobic systems, membrane preparations reduce Cr(VI) and Cr(VI) has been shown to serve as a terminal electron acceptor (Lovley and Phillips, 1994). Aerobic reduction of Cr(VI) has been found to be associated with soluble proteins (Ishibashi et al., 1990). Lovley and Phillips (1994) reported that the sulfate-reducing bacterium Desulfovibrio vulgaris, which was capable of enzymatically reducing Fe (III) and U (VI), could also act as Cr(VI) reducers in the presence of H2 as the electron donor. Although Fude et al., (1994) also found Cr(VI) reduction by a consortium of sulfate-reducing bacteria in a medium containing reducing agents such as ascorbic acid and thioglycolate, the interpretation of the results must be cautioned because those reducing agents might chemically react with Cr(VI), resulting in conversion of Cr(VI) to Cr(III) (Hamilton and Wetterhahn, 1988). Environmental factors, including pH, temperature and other electron acceptor as well as waste characteristics (metal ions, initial Cr(VI) and biomass concentrations) affecting Cr(VI) removal capability were quantified. With the addition of biological inhibitors such as penicillin, cycloserine, or chloramphenicol, the loss of Cr(VI) reduction activity in microbial cells under reducing conditions clearly indicates that Cr(VI) reduction is an enzymatically catalyzed reaction. Such evidence was found with both growing cultures (Wang et al., 1989) and resting cells (Llovera et al., 1993). Other evidence for enzymatic roles in microbial Cr(VI) reduction includes: Cr(VI) was reduced faster with higher cell densities (Chen and Hao, 1996); Cr(VI) reduction occurred only in the presence of cells or cell extracts and electron donors (Lovley and Phillips, 1994); the Cr(VI) activity was lost when the Cr(VI)-reducing cell extracts were heated at 100°C (Ohtake and Hardoyo, 1992); Cr(VI) reduction was incomplete with inadequate acetate concentration (Chen and Hao, 1996); and the highest rates of Cr(VI) reduction all occurred during the exponential growth phase of three different strain cells (Apel and Turick, 1991). All these observations strongly suggest that Cr (VI) reduction in biological systems is directly related to microbial activities. The reduced Cr existed mainly in the medium, forming insoluble Cr as Cr (OH)3 (Shen and Wang, 1994; Faisal and Hasnain, 2004).

Factors Affecting Chromate Reduction
Factors affecting chromate reduction are temperature, pH, gases and organic substance and poisons chemicals. Bacteria can reduce hexavalent chromium under mild conditions. This process may be the best mechanism to assure hexavalent chromium treatment. Commonly used chemical reduction generally occurs only over narrow range of pH. These methods are not only costly but the productions of toxic byproducts are also a problem. Bacterial reduction of hexavalent chromium as a means of bioremediation has several potential advantages.

Reduction occurs under neutral pH.
It requires neither chemical additives nor aeration.
No toxic byproduct is formed.
Anaerobic reduction minimizes excess sludge production in aqueous systems.
The activity is reproducible and reusable.


Reduced chromium forms insoluble chromium hydroxide at a neutral pH. These chromium compounds are very stable and they are unavailable to living organisms. No microbial activity has been found so for that is able to oxidized reduced chromium. The feasibility of the bioremediation process has been examined in the laboratories and is now proceeding to the developmental stage. So it is postulated that the use of microbes creates the right methods for environmental pollution control.


1:  Adach, A. and M. Cielak-Golonka, 2005. Binary and ternary chromium(III) complexes with cellular reductants and DNA components isolated from redox type systems. Part 3. Chromium(VI)- L-ascorbic acid-adenine (adenosine, ATP). Transition Metal Chem., 30: 323-329.
Direct Link  |  

2:  Asmatulla, S., N. Qureshi and A.R. Shakoori, 1998. Hexavalent chromium induced congenital abnormalities in chick embryos. J. Applied Toxicol., 18: 167-171.
Direct Link  |  

3:  Rekhif, N., A. Atrih and G. Lefevure, 1994. Selection and properties of spontaneous variants of L. monocytogenes ATCC 15313 resistant to different bacteriocins produced by lactic acid bacteria strains. Curr. Microbiol., 28: 237-241.
CrossRef  |  Direct Link  |  

4:  Bagchi, D., S.J. Stohs, B.W. Downs, M.Bagchi and H.G. Preuss, 2002. Cytotoxicity and oxidative mechanisms of different forms of chromium. Toxicology, 180: 5-22.
CrossRef  |  Direct Link  |  

5:  Balamurugan, K., R. Rajaram and T. Ramasami, 2004. Caspase-3: Its potential involvement in Cr(III)-induced apoptosis of lymphocytes. Mol. Cell. Biochem., 259: 43-51.
CrossRef  |  

6:  Banerjee, G., V.J. Iyer and K.M. Cherian, 2003. A rapid in vitro method of identifying contact allergens and irritants. Toxicol. Mechanisms Methods, 13: 103-109.
Direct Link  |  

7:  Bartlett, R.J., 1991. Chromium cycling in soils and water links gaps and methods. Environ. Health Perspective, 92: 17-24.
PubMed  |  Direct Link  |  

8:  Barantseva, S.E.N., M. Bobkova,V.G. Lugin and V.M. Kononovich, 2004. Capacity of granitoid-based glasses for glass ceramics formation. Glass Ceramics, 61: 217-220.
CrossRef  |  

9:  Biedermann, K.A. and J.R. Landolph, 1987. Induction of anchorage independence in human diploid foreskin fibroblasts by carcinogenic metal salts. Cancer Res., 47: 3815-3823.
Direct Link  |  

10:  Biedermann, K.A. and J.R. Landolph, 1990. Role of valence state and solubility of chromium compounds on induction of cytotoxicity mutagenesis and anchorage independence in diploid human fibroblasts. Cancer Res., 50: 7835-7842.
Direct Link  |  

11:  Bosgelmez, I.I. and G. Guvendik, 2004. Effects of taurine on oxidative stress parameters and chromium levels altered by acute hexavalent chromium exposure in mice kidney tissue. Biol. Trace Element Res., 102: 209-225.
Direct Link  |  

12:  Bock, M., A. Schmidt, T. Bruckner and T.L. Diepgen, 2003. Occupational skin disease in the construction industry. Br. J. Dermatol., 149: 1165-1171.
Direct Link  |  

13:  Burd, G.I., D.G. Dixon and B.R. Glick, 1998. A plant growth-promoting bacterium that decreases nickel toxicity in seedlings. Applied Environ. Microbiol., 64: 3663-3668.
Direct Link  |  

14:  Camargo, F.A.O., F.M. Bento, B.C. Okeke and W.T. Frankenberger, 2004. Hexavalent chromium reduction by an actinomycete Arthrobacter crystalopoietes ES 32. Biol. Trace Element Res., 97: 183-194.

15:  Chen, H., G. Pan, H. Yan and Y. Qin, 2003. Toxic effects of hexavalent chromium on the growth of blue-green microalgae. Huan Jing Ke Xue, 24: 13-18.

16:  Chen, J.M. and O.J. Hao, 1996. Environmental factors and modeling in microbial chromium (VI) reduction. Water Environ. Res., 68: 1156-1996.
Direct Link  |  

17:  Citterio, S., A. Santagostino, P. Fumagalli, N. Prato, P. Ranalli and S. Sgorbati, 2003. Heavy metal tolerance and accumulation of Cd, Cr and Ni by Cannabis sativa L. Plant Soil, 256: 243-252.
Direct Link  |  

18:  Codd, R., J.A. Irwin and P.A. Lay, 2003. Sialoglycoprotein and carbohydrate complexes in chromium toxicity. Curr. Opin. Chem. Biol., 7: 213-219.
CrossRef  |  

19:  Coleman, R.N., 1988. Chromium Toxicity Effects on Microorganisms with Special Reference to the Soil Matrix. In: Chromium in the Natural and Human Environments, Nriagu, J.O. and E. Nierboor (Eds.). John Wiley and Sons, New York, pp: 335-368

20:  Cristian, C.A., Y. Renan, G. Jorge, A.R. Maria, B.S.D S. Pedro and S.E. Falabella, 2005. Removal of chromium(III) from tannery effluents using a system of packed columns of zeolite and activated carbon. J. Chem. Technol. Biotechnol., 80: 899-908.

21:  Das, M., S. Dixit and S.K. Khanna, 2005. Justifying the need to prescribe limits for toxic metal contaminants in food-grade silver foils. Food Additives Contaminants, 22: 1219-1223.
Direct Link  |  

22:  Desjardin, V., R. Bayard, P. Lejeune and R. Gourdon, 2003. Utilisation of supernatants of pure cultures of streptomyces thermocarbosydus NH50 to reduce chromium toxicity and mobility in contaminated soils. Water Air Soil Pollut. Focus, 3: 153-156.

23:  Dey, S.K., P. Nayak and S. Roy, 2003. Alpha-tocopherol supplementation on chromium toxicity: A study on rat liver and kidney cell membrane. J. Environ. Sci., 15: 356-359.
Direct Link  |  

24:  Dube, B.K., K. Tewari, J. Chatterjee and C. Chatterjee, 2003. Excess chromium alters uptake and translocation of certain nutrients in citrullus. Chemosphere, 53: 1147-1153.
CrossRef  |  Direct Link  |  

25:  Duffus, J.H., 2005. Chemical speciation terminology: Chromium chemistry and cancer. Mineralogical Mag., 69: 557-562.
CrossRef  |  

26:  Dursun, A.Y., G. Uslu, Y. Cuci and Z. Aksu, 2003. Bioaccumulation of copper (II), lead (II) and chromium (VI) by growing Aspergillus niger. Process Biochem., 38: 1647-1651.

27:  Faisal, M. and S. Hasnain, 2004. Comparative study of Cr(VI) reduction in industrial effluent by Ochrobactrum intermedium vs. Bravibacterium sp. Biotechnol. Lett., 26: 1623-1628.

28:  Faisal, M. and S. Hasnain, 2005. Microbial Cr (VI) reduction concurrently improves Helianthus annuus growth. Biotechnol. Lett., 27: 943-947.

29:  Faisal, M., A. Hameed and S. Hasnain, 2005. Chromium resistant bacteria and cyanobacteria: Impact on Cr (VI) reduction potential and plant growth. J. Indus. Microbiol. Biotechnol., 32: 615-621.
Direct Link  |  

30:  Fatima, S., N.A. Arivarasu, A.A. Banday, A.N.K. Yusufi and R. Mahmood, 2005. Effect of potassium dichromate on renal brush border membrane enzymes and phosphate transport in rats. Human Exp. Toxicol., 24: 631-631.
Direct Link  |  

31:  Feng, Z., W. Hu, W.N. Rom, M. Costa and M.S. Tang, 2004. Chromium (VI) exposure enhances polycyclic aromatic hydrocarbon-DNA binding at the p53 gene in human lung cells. Carcinogenesis, 24: 771-778.

32:  Fude, L., B. Harris, M.M. Urrutia and T.J. Beveridge, 1994. Reduction of Cr (VI) by a consortium of sulfate-reducing bacteria (SRB III). Applied Environ. Microbiol., 60: 1525-1531.
PubMed  |  Direct Link  |  

33:  Gabara, B., B. Woj Jyla-Kuchta and N. Tarczynska, 1992. The effect of calcium on DNA synthesis in pea (Pisum sativum L.) roots after treatment with heavy metals. Folia Histochem. Cytobiol., 30: 69-73.

34:  Gad, S.C., 1989. Acute and chronic systemic chromium toxicity. Sci. Total Environ., 86: 149-157.
Direct Link  |  

35:  Gardea-Torresdey, J.L., J.R. Peralta-Videa, M. Montes, G. de la Rosa and B. Corral-Diaz, 2004. Bioaccumulation of cadmium chromium and copper by Convolvulus arvensis L. Impact on plant growth and uptake of nutritional elements. Bioresour. Technol., 92: 229-235.
CrossRef  |  

36:  Geetha, S., V. Singh, M.S. Ram, G. Ilavazhagan, P.K. Banerjee and R.C. Sawhney, 2005. Immunomodulatory effects of seabuckthorn (Hippophae rhamnoides L.) against chromium (VI) induced immunosuppression. Mol. Cell. Biochem., 278: 101-109.
PubMed  |  Direct Link  |  

37:  Gili, P., A. Medros, P.A. Lorenzo-Lorenzo-Luis, E.M. de la Rosa and A. Munoz, 2002. On the interaction of compounds of chromium (VI) with hydrogen peroxide a study of chromium (VI) and (V) peroxides in the acid-basic pH range. Inorganica Chim. Acta, 331: 16-24.
Direct Link  |  

38:  Guha, H., K. Jayachandran and F. Maurrasse, 2001. Kinetics of chromium (VI) reduction by a type strain Shewanella alga under different growth conditions. Environ. Pollut., 115: 209-218.
CrossRef  |  Direct Link  |  

39:  Hamilton, J.W. and K.E. Wetterhahn, 1988. Chromium. In: Handbook on Toxicity of Inorganic Compounds, Seiler, H.G. and H. Sigel (Eds.). Marcel Dekker, New York, pp: 239

40:  Han, F.X., B.B.M. Sridhar, D.L. Monts and Y. Su, 2004. Phytoavailability and toxicity of trivalent and hexavalent chromium to Brassica juncea. New Phytol., 162: 489-499.
Direct Link  |  

41:  Hansen, M.B., J.D. Johansen and T. Menne, 2003. Chromium allergy significance of both Cr(III) and Cr(VI). Contact Dermatitis, 49: 206-212.

42:  Hsu, F. and C.H. Chou, 1992. Inhibitory effect of heavy metals on seeds germination and seedling growth of Miscanthus species. Bot. Bull. Acad. Sci., 33: 335-342.

43:  Huang, K.L., T.M. Holsen, T.C. Chou and M.C. Yang, 2004. The use of air fuel cell cathodes to remove contaminants from spent chromium planting solutions. Environ. Technol., 25: 39-49.

44:  Ishibashi, Y., C. Cervantes and S. Silver, 1990. Chromium reduction in Pseudomonas putida. Applied Environ. Microbiol., 56: 2268-2270.
Direct Link  |  

45:  Itoh, M., M. Nakamura, T. Suzuki, K. Kawai, H. Horitsu and K. Takamizawa, 1994. Mechanism of chromium (VI) toxicity in E. coli is hydrogen peroxide is essential in Cr (VI) toxoity. J. Biochem., 117: 780-786.

46:  Juhnke, S., N. Peitzsch, N. Hubener, C. Grosse and D.H. Nies, 2002. New genes involved in chromate resistance in Ralstonia metallidurans strain CH34. Arch. Microbiol., 179: 15-25.
CrossRef  |  

47:  Junaid, M., R.C. Murty and D.K. Saxana, 1995. Embryotoxicity of orally adminstered chromium in mice exposure during the period of organogenesis. Toxicol. Lett., 84: 143-148.
CrossRef  |  

48:  Kaczynski, S.E. and R.J. Kieber, 1993. Aqueous trivalent chromium photoproduction in natural waters. Environ. Sci. Technol., 27: 1572-1576.
CrossRef  |  

49:  Hafez, M.B. and Y.S. Ramadan, 2002. Treatment of radioactive and industrial liquid wastes by Eichornia crassipes. J. Radioanalytical Nuclear Chem., 252: 537-540.
CrossRef  |  

50:  Klumpp, A., K. Bauer, C. Franz-Gerstein and M. de Menezes, 2002. Variation of nutrient and metal concentrations in aquatic macrophytes along the Rio Cachoeira in Bahia (Brazil). Environ. Int., 28: 165-171.
CrossRef  |  

51:  Konovalova, V.V., G.M. Dmytrenko, R.R. Nigmatullin, M.T. Bryk and P.I. Gvozdyak, 2003. Chromium (VI) reduction in a membrane bioreactor with immobilized pseudomonas cells. Enzy. Microbial. Technol., 33: 899-907.
Direct Link  |  

52:  Kostaropoulos, I., D. Kalmanti, B. Theodoropoulou and N. Loumbourdis, 2005. Effects of exposure to a mixture of cadmium and chromium on detoxification enzyme (GST, P450-MO) activities in the frog Rana ridibunda. Ecotoxicology, 14: 439-447.
PubMed  |  Direct Link  |  

53:  Levy, L.S., P.A. Martin and P.L. Bidstrup, 1986. Investigation of the potential carcinogenicity of a range of chromium containing materials on rat lungs. Br. J. Indust. Med., 43: 243-256.
PubMed  |  

54:  Llovera, S., R. Bonet, M.D. Simon-Pujol and F. Congregado, 1993. Chromate reduction by resting cells of Agrobacterium radiobacter EPS-916. Applied Environ. Microbiol., 59: 3516-3518.
PubMed  |  Direct Link  |  

55:  Lovely, D.R. and E.J.P. Phillips, 1994. Reduction of chromate by Desulfovibrio vulgaris and its c3 cythochrome. Applied Environ. Microbiol., 60: 726-728.
Direct Link  |  

56:  Dar, G.H., 1999. Effect of chromium (VI) on carbon and nitrogen mineralization in sewage sludge amended and unamended soils. Applied Biol. Res., 1: 29-34.

57:  Medeiros, M.G., A.S. Rodrigues, M.C. Batoreu, A. Laires, J. Rueff and A. Zhitkovich, 2003. Elevated levels of DNA-protein crosslinks and micronuclei in peripheral lymphocytes of tannery workers exposed to trivalent chromium. Mutagenesis, 18: 19-24.
Direct Link  |  

58:  Megharaj, M., S. Avudainayagam and R. Naidu, 2003. Toxicity of hexavalent chromium and its reduction by bacteria isolated from soil contaminated with tannery waste. Curr. Microbiol., 47: 51-54.
CrossRef  |  Direct Link  |  

59:  O'Brien, T.J., S. Ceryak and S.R. Patierno, 2003. Complexities of chromium carcinogenesis: Role of cellular response, repair and recovery mechanisms. Mutat. Res./Fundam. Mol. Mech. Mutagen., 533: 3-36.
CrossRef  |  PubMed  |  Direct Link  |  

60:  Ohtake, H. and J.K. Hardoyo, 1992. New biological method for detoxification and removal of hexavalent chromium. Water Sci. Technol., 25: 395-402.
Direct Link  |  

61:  Ohtake, H. and S. Silver, 1994. Bacterial Detoxification of Toxic Chromate. In: Biological Degradation and Bioremediation of Toxic Chemicals, Chaudhry, G.R. (Ed.). Dioscorides Press, Portland, pp: 403-415

62:  Pandey, N. and C.P. Sharma, 2003. Chromium interference in iron nutrition and water relations of cabbage. Environ. Exp. Bot., 49: 195-200.

63:  Ozdemir, G., T. Ozturk, N. Ceyhan, R. Isler and T. Cosar, 2003. Heavy metal biosorption by biomass of Ochrobactrum anthropi producing exopolysaccharide in activated sludge. Bioresour. Technol., 90: 71-74.

64:  Panov, V.P., K. Gyul, E.E. Yan and A.S. Pakshver, 2003. Regeneration of exhausted chrome tanning solutions from leather production as a method preventing environmental pollution with chromium. Russian J. Applied Chem., 76: 1476-1478.

65:  Pas, M., R. Milacic, K. Drasar, N. Pollak and P. Raspor, 2004. Uptake of chromium (III) and chromium (VI) compounds in the yeast cell structure. Biometals, 17: 25-33.

66:  Peitzsch, N., G. Eberz and D.H. Nies, 1998. Alcaligenes eutrophus as a bacterial chromate sensor. Applied Environ. Microbiol., 64: 453-458.

67:  Potgieter, S.S., N. Panichev, J.H. Potgieter and S. Panicheva, 2003. Determination of hexavalent chromium in South African cements and cement-related materials with electrothermal atomic absorption spectrometry. Cement Concrete Res., 33: 1589-1593.

68:  Proctor, D., J. Panko, E. Liebig and D. Paustenbach, 2004. Estimating historical occupational exposure to airborne hexavalent chromium in a chromate production plant. 1940-1972. J. Occupational Environ. Hygiene, 1: 752-767.

69:  Puzon, G.J., J.N. Petersen, A.G. Roberts, D.M. Kramer and L. Xun, 2002. A bacterial flavin reductase system reduces chromate to a soluble chromium(III)-NAD+ complex. Biochem. Biophys. Res. Commun., 294: 76-81.
CrossRef  |  Direct Link  |  

70:  Ramachandran, V., T.J. DSouza and K.B. Mistry, 1980. Uptake and transport of chromium in plants. J. Nuclear Agric. Biol., 9: 126-126.

71:  Ramirez-Ramirez, R., C. Calvo-Mendez, M. Avila-Rodriguez, P. Lappe and M. Ulloa et al., 2004. Cr(VI) reduction in a chromate-resistant strain of Candida maltosa isolated from the leather industry. Antonie Van Leeuwenhoek, 85: 63-68.

72:  Rapoport, A.I. and O.A. Muter, 1995. Biosorption of hexavalent chromium by yeasts. Process Biochem., 30: 145-149.

73:  Reddy, B.M., J. Charles, G.J. Naga, V. Raju, B. Vijayan, S. Reddy, M.R. Kumar and B. Sundareswar, 2003. Trace elemental analysis of carcinoma kidney and stomach by PIXE method nuclear instruments and methods in physics research secton B. Beam Interact. Mater. Atoms, 207: 345-355.

74:  Refiye, Y., P. Aysegul. Y. Bihter, D.M. Mutluhan and I. Arisan-Atac, 2005. Effects of a combination of niacin and chromium (III)-chloride on the skin and lungs of hyperlipemic rats. Biol. Trace Element Res., 103: 249-260.

75:  Sato, H., K. Murai, T. Kanda, R. Mimura and Y. Hiratsuka, 2003. Association of chromium exposure with multiple primary cancers in the nasal cavity Auris nasus Larynx. Mineralogical Maga., 30: 93-96.

76:  Sharma, D.M., C.P. Sharma and R.D. Tripathi, 2003. Phytotoxic lesions of chromium in maize. Chemosphere, 51: 63-68.
Direct Link  |  

77:  Shanker, A. and G. Pathmanabhan, 2004. Speciation dependant antioxidative response in roots and leaves of sorghum Sorghum bicolor (L.) Moench cv CO 27) under Cr(III) and Cr(VI) stress. Plant Soil, 265: 141-151.
CrossRef  |  Direct Link  |  

78:  Shen, H. and Y.T. Wang, 1994. Biological Reduction of chromium by E. coli. J. Environ. Eng., 120: 560-560.

79:  Smith, E. and K. Ghiassi, 2006. Chromate removal by an iron sorbent mechanism and modeling. Water Environ. Res., 78: 84-93.

80:  Smith, S., P.J. Petersen and K.H.M. Kwan, 1989. Chromium accumulation transport and toxicity in plants. Toxicol. Environ. Chem., 24: 241-251.

81:  Stohs, S.J., D. Bagchi, E. Hassoun and M. Bagchi, 2001. Oxidative mechanisms in the toxicity of chromium and cadmium ions. J. Environ. Pathol. Toxicol. Oncol., 20: 77-88.
PubMed  |  Direct Link  |  

82:  Sumner, E.R., A. Shanmuganathan, T.C. Sideri, S.A. Willetts, J.E. Houghton and S.V. Avery, 2005. Oxidative protein damage causes chromium toxicity in yeast. Microbiology, 151: 1939-1948.

83:  Taioli, E., A. Zhitkovich, P. Kinney, I. Udasin, P. Toniolo and M. Costa, 1995. Increased DNA-protein crosslinks in lymphocytes of residents living in chromium-contaminated areas. Biol. Trace Element Res., 50: 175-175.

84:  Tripathi, R.D. and P. Chandra, 1991. Chromium uptake by Spirodela polyrrhiza L. Schleiden in relation to metal chelators and pH. Bull. Environ. Contamination Toxicol., 47: 764-769.

85:  Viamajala, S., B.M. Peyton, R.K. Sani, W.A. Apel and J.N. Petersen, 2004. Toxic effects of chromium(VI) on anaerobic and aerobic growth of Shewanella oneidensis MR-1. Biotechnol. Progress, 20: 87-95.

86:  Viera, M., G. Curutchet and E. Donati, 2003. A combined bacterial process for the reduction and immobiliztion of chromium. Int. Biodeterior. Biodegrad., 52: 31-34.

87:  Wang, P., T. Mori, K. Kamori, M. Sesatu, K. Toda and H. Obtake, 1989. Isolation and characterization of an Enterobacter cloacae strain that reduces hexavalent chromium under anaerobic conditions. Applied Environ. Microbiol., 55: 1665-1669.

88:  Wise, S., A. Holmes, J. Moreland, H. Xie and S. Sandwick et al., 2005. Human lung cell growth is not stimulated by lead ions after lead chromate-induced genotoxicity. Mol. Cell. Biochem., 297: 75-84.

89:  Xie, H., S.S. Wise, A.L. Holmes, B. Xu, T.P. Wakeman, S.C. Pelsue, N.P. Singh and J.P. Wise, 2005. Carcinogenic lead chromate induces DNA double-strand breaks in human lung cells. Mutation Res., 586: 160-172.

90:  Zeid, I.M., 2001. Responses of Phaseolus vulgaris chromium and cobalt treatments. Biol. Plant., 44: 111-115.
CrossRef  |  

©  2022 Science Alert. All Rights Reserved