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PubMedDate not supplied

Occupational exposures to carcinogens in Italy: an update of CAREX database.

To update estimates of the prevalence of occupational exposures to carcinogens in Italy, the 85 CAREX agents were re-assessed. The original exposure estimates in the CAREX database were updated, taking into account changes in exposure patterns and in numbers of employees by industrial class. The 21.8 million employees in Italy, 19.4 in industry and services, 2.4 in agriculture, had 4.2 million exposures. Prevalences of exposures were highest for environmental (passive) tobacco smoke (800,000 exposures), solar radiation (700,000), diesel engine exhaust (500,000), wood dust (280,000), silica (250,000), lead and inorganic lead compounds (230,000), benzene (180 000), hexavalent chromium compounds (160,000), glass wool (140,000), and PAHs (120,000). Exposures to carcinogens at work are still an issue in Italy and do not appear to be controlled as strictly as they should be.

Carcinogens↗
PubMed2002

Low temperature conversion of sludge and shavings from leather industry.

Abstract Brazil has one of the largest herds of cattle in the world, with more than 170 million heads. Over 400 farms have exported more than 2,875 ton (in 1997) of leather to Europe. The wet blue tanning process uses chemicals such as chromium compounds and produces liquid wastes that must be treated by physicochemical and biological systems. About 15,000 ton per month of dewatering sludge with 24% solids content is disposed of into landfills. During the process, pre-tanned skins (wet blue leather) are shaved to the desired thickness and the shavings, like sludge, are among the wastes that must have special attention. The organic content and chromium concentration are high. About 12% of the leather production from cattle hides are shavings, and its chromium concentration ranges from 3.5 to 5.5% of dry matter. The Environmentally friendly leather project, a co-operation between Brazilian and German tanneries, universities and technical schools, is looking for process optimisation, waste minimisation and adequate treatment for solid and liquid wastes from the leather industry. This work presents results of Low Temperature Conversion of chrome-containing sludge and shavings in a laboratory batch reactor, offering a solution for these hazardous wastes, recovering the energy content and transforming metals in insoluble sulphides.

Animals↗
PubMed2001

Mechanisms of chromium toxicity, carcinogenicity and allergenicity: review of the literature from 1985 to 2000.

Laboratory and clinical reports about the pathogenesis of the carcinogenicity and allergenicity of chromium compounds published between 1985 and 2000 have been reviewed as a basis for consideration of the pathogenetic mechanisms involved. There is good evidence from the clinic and the laboratory that Cr[VI] is the ion responsible for most of the toxic actions, although much of the underlying molecular damage may be due to its intracellular reduction to the even more highly reactive and short-lived chemical species Cr[III] and Cr[V]. Exposure to Cr[VI] can result in various point mutations in DNA and to chromosomal damage, as well as to oxidative changes in proteins and to adduct formation. The relative importance of these effects of chromium ions and of the free oxidising radicals they may generate in the body in causing tumours and allergic sensitisation remain to be demonstrated. Biochemical studies of the DNA-damaging effects and of the pathogenesis of the allergic reactions to chromium ions have not kept up with advances in understanding of the molecular basis of the effects of other carcinogens and allergens.

Allergens↗
PubMed1997

Microprobe X-ray absorption spectroscopic determination of the oxidation state of intracellular chromium following exposure of V79 Chinese hamster lung cells to genotoxic chromium complexes.

The oxidation state of intracellular chromium has been determined directly in mammalian lung cells exposed to mutagenic and carcinogenic chromium compounds. Microprobe X-ray absorption spectroscopy (XAS) experiments on single V79 Chinese hamster lung cells showed that Cr(VI) and Cr(V) complexes were reduced completely (>90%) to Cr(III) within 4 h of exposure of the cells. This result provides direct evidence for the hypothesis that these genotoxic oxidants react rapidly with intracellular reductants.

Animals↗
PubMed1995

[Mortality due to bronchopulmonary cancers in workers of 2 foundries].

A mortality study was carried out in two factories producing stainless steel in order to assess lung cancer risk among workers employed in coke oven, blast and open hearth furnaces, foundry, electric furnace, hot and cold rolling mills and pickling areas. Occupational exposures of interest were chromium compounds, nickel compounds, polycyclic aromatic hydrocarbons (PAH), silica and asbestos. All male workers having at least one year of employment between 01.01.1960 and 31.12.1990 were followed up for mortality. The vital status was assessed from birth place registries. Complete job histories since date of first employment were abstracted from the company files. The smoking habits of 50% of the cohort members were known from medical records. The observed number of deaths (obs) were compared with the expected ones based on regional rates with adjustment for age, sex and calendar time (Standardized Mortality Ratio, SMR). The cohorts included 6324 (factory 1) and 5270 (factory 2) workers. The overall mortality did not differ markedly from that expected in both factories: SMR = 0.95 (obs = 1540, p = 0.05) in factory 1 and SMR = 1.06 (obs = 916, non-significant) in factory 2. SMRs for lung cancer did not differ from unity, respectively 0.99 (obs = 105) and 1.00 (obs = 54), in whole cohorts. Non-significant lung cancer excesses were observed among workers of some workshops where exposures of interest might have occurred: coke oven (SMR = 2.04), blast furnace (SMR = 1.36), open hearth furnace (SMR = 1.75), hot rolling mills (SMR = 1.29). These processes, however, are no longer involved in the study factories. Furthermore, no lung cancer excess was observed among workers employed in current workshops: electric furnaces and cold rolling mills.

Adult↗
PubMed2000

Enhanced organically bound chromium yeast production.

This paper describes continuous and fed-batch fermentation protocols for enhanced production of organically bound chromium yeast. During continuous fermentation, several inorganic chromium compounds were evaluated. Sodium chromate demonstrated the best chromium incorporation into yeast biomass without any precipitation in the fermentation medium. During fed-batch fermentation, several sodium chromate concentrations were evaluated at 1.1, 3.5, 5.9, 7.1, 8.3, and 10.8 g/L with continuous or single-dose addition. For single-dose addition of sodium chromate, some precipitation was observed for all concentrations, which reduced the available chromium in the fermentation medium. Adapted strain C11-1, obtained during continuous fermentation, produced higher biomass than the wild type but significantly lowered chromium incorporation. Pilot-scale fermentation demonstrated similar total chromium incorporation (2966 ppm) with lower biomass production compared to benchtop fermentation performed at the same sodium chromate addition.

Chromium↗
PubMed1980

Carcinogenicity and mutagenicity of chromium.

Occupational exposure represents the main source of human contamination by chromium. For non-occupationally exposed people the major environmental exposure to chromium occurs as a consequence of its presence in food. Chromium must be considered as an essential element. Its deficiency impairs glucose metabolism. Trivalent chromium salts are poorly absorbed through the gastro-intestinal and respiratory tracts because they do not cross membranes easily. Hexavalent chromium can be absorbed by the oral and pulmonary routes and probably also through the skin. After its absorption, hexavalent chromium is rapidly reduced to the trivalent form which is probably the only form to be found in biological material. Epidemiological studies have shown that some chromium salts (mainly the slightly soluble hexavalent salts) are carcinogens. Lung cancers have, indeed, often been reported among workers in chromate-producing industry and, to a lesser extent, in workers from the chrome-pigment industry. The first attempts to produce cancers in experimental animals by inhalation or parenteral introduction gave negative or equivocal results but, from 1960, positive results have been obtained with various chromium compounds. As for the carcinogenic activity, the mutagenicity of chromium has mainly been found with hexavalent salts. In the majority of assay systems used, trivalent chromium appears inactive. It can be considered as evident, however, that the ultimate mutagen which binds to the genetic material is the trivalent form produced intracellularly from hexavalent chromium, the apparent lack of activity of the trivalent form being due to its poor cellular uptake.

Animals↗
PubMed1984

[Heavy metals--toxicity at low doses in the environment and in the work place].

Ecotoxicity of heavy metals is related to their persistence, accumulation and dispersion tendency. Sources, pathways of exposure and adverse health effects of low doses are reviewed. Environmental and occupational toxicity of lead, cadmium and mercury compounds are discussed and the carcinogenic and sensitizing effects of chromium compounds as an example of a heavy metal which is essential in low doses. High risk groups, most susceptible target organs, early symptoms, signs of subclinical poisoning, numbers of diseases from heavy metals accepted in Austria as occupational diseases and environmental hazards are summarized.

Air Pollution↗
PubMed1993

Mechanisms of chromium carcinogenicity and toxicity.

Chromium, like many transition metal elements, is essential to life at low concentrations yet toxic to many systems at higher concentrations. In addition to the overt symptoms of acute chromium toxicity, delayed manifestations of chromium exposure become apparent by subsequent increases in the incidence of various human cancers. Chromium is widely used in numerous industrial processes, and as a result is a contaminant of many environmental systems. Chromium, in its myriad chemical forms and oxidation states, has been well studied in terms of its general chemistry and its interactions with biological molecules. However, the precise mechanisms by which chromium is both an essential metal and a carcinogen are not yet fully clear. The following review does not seek to embellish upon the proposed mechanisms of the toxic and carcinogenic actions of chromium, but rather provides a comprehensive review of these theories. The chemical nature of chromium compounds and how these properties impact upon the interactions of chromium with cellular and genetic targets, including animal and human hosts, are discussed.

Animals↗
PubMed1984

Effect of chromium(III) on poly(dG-dC) conformation.

The interaction of chromium(III) with poly(dG-dC) inhibits the B to Z transition and results in the condensation of the polymer at high Cr/nucleotide ratios. At low Cr/nucleotide ratios chromium(III) enhanced the ability of ethanol to induce the B to Z transition of poly(dG-dC). The effects of chromium(III) on the conformation of DNA may be related to the carcinogenicity of chromium compounds.

Chromium↗
PubMed1983

Studies on contact sensitivity to chromium in the guinea pig. The role of valence in the formation of the antigenic determinant.

Guinea pigs sensitized with either the trivalent chromium chloride or the hexavalent potassium dichromate are capable of reacting in vivo and in vitro to challenges with both chromium salts. This double reactivity is retained also after repeated restimulations with only 1 of these chromium compounds. From the failure to select lymphocytes directed specifically against a chromium determinant of a particular valence it is concluded that by sensitization with chromium salts of different valences a common determinant or closely related determinants are formed. It is suggested that this determinant is formed by chromium in the trivalent form.

Animals↗
PubMed1991

Lymphocyte proliferation test as a diagnostic aid in chromium contact sensitivity.

We investigated the clinical applicability of the lymphocyte proliferation test (LPT) in chromium contact sensitivity. 6 out of 8 chromium-sensitive patients were positive in the LPT, whereas none of 8 non-chromium-sensitive controls responded in vitro to tri- or hexavalent chromium compounds. LPT thus appeared to offer an additional diagnostic tool in chromium sensitivity. We also studied cellular interactions in 4 of our chromium-sensitive patients. Sensitized T-lymphocytes could be activated to proliferate only in the presence of accessory cells, of which epidermal Langerhans cells (LC) appeared more efficient than blood adherent cells.

Adult↗
PubMed1997

The carcinogenicity of metals in humans.

Epidemiologic evidence on the relation between exposure to metals and cancer is reviewed. Human exposure to metals is common, with wide use in industry and long-term environmental persistence. Historically, the heaviest metal exposures occurred in the workplace or in environmental settings in close proximity to industrial sources. Among the general population, exposure to a number of metals is widespread but generally at substantially lower levels than have been found in industry. The carcinogenicity of arsenic, chromium, and nickel has been established. Occupational and environmental arsenic exposure is linked to increased lung cancer risk in humans, although experimental studies remain inconclusive. Experimental studies clearly demonstrate the malignant potential of hexavalent(VI) chromium compounds, with solubility being an important determining factor. Epidemiologic studies of workers in chromium chemical production and use link exposure to lung and nasal cancer. Experimental and epidemiologic data show that sparingly-soluble nickel compounds and possibly also the soluble compounds are carcinogens linked to lung and nasal cancer in humans. Some experimental and epidemiologic studies suggest that lead may be a human carcinogen, but the evidence is inconclusive. Although epidemiologic data are less extensive for beryllium and cadmium, the findings in humans of excess cancer risk are supported by the clear demonstration of carcinogenicity in experimental studies. Other metals, including antimony and cobalt, may be human carcinogens, but the experimental and epidemiologic data are limited.

Animals↗
PubMed2006

[Exposure to metal compounds in occupational galvanic processes].

BACKGROUND: Occupational galvanic processes are provided in more than 600 small and medium enterprises in Poland. Workers who deal with galvanic coating are exposed to heavy metal compounds: tin, silver, copper and zinc. Some of them are carcinogenic, for example, hexavalent chromium compounds, nickel and cadmium compounds. MATERIAL AND METHODS: Research covered several tens of workstations involved in chrome, nickel, zinc, tin, silver, copper and cadmium plating. Compounds of metals present in the air were determined: Cr, Ni, Cd, Sn, Ag--by atomic absorption spectrometry with electrothermal atomization (ET-AAS) and Zn--by atomic absorption spectrometry with flame atomization (F-AAS). RESULTS: The biggest metal concentrations--of silver and copper--were found at workstations of copper, brass, cadmium, nickel and chrome plating, conducted at the same time. Significant concentrations of copper were found at workstations of maintenance bathing and neutralizing of sewage. The concentrations of metals did not exceed Polish MAC values. MAC values were not exceeded for carcinogenic chromium(VI), nickel or cadmium, either. CONCLUSIONS: In galvanic processes there was no hazard related to single metals or their compounds, even carcinogenic ones. Combined exposure indicators for metals at each workstation did not exceed 1, either. However, if there are even small quantities of carcinogenic agents, health results should always be taken into consideration.

Air Pollutants, Occupational↗
PubMedDate not supplied

An assessment of the tumorigenic properties of a Hudson County soil sample heavily contaminated with hexavalent chromium.

During much of this century, Hudson County, New Jersey, was a major center for the processing of chromium ore. Some of the residue from this processing was used in landfills and in construction materials throughout the county and, in some cases, in highly populated areas. Given that it is widely accepted that exposure to hexavalent chromium compounds poses a risk for the development of respiratory-tract cancer, concerns were raised that individuals who worked or resided in chromium-contaminated areas might be at increased risk for the development of respiratory cancer. To address these concerns, we evaluated a Hudson County soil sample-heavily contaminated with chromium ore residue (Cr(+6) concentration at 5 895 mg/kg)-with respect to its carcinogenic potential to the respiratory tract of Sprague-Dawley rats. Groups of animals were given repeated intratracheal exposures to one of four materials: (1) Hudson County chromium-contaminated soil (CCS), (2) CCS augmented with calcium chromate (CaCrO4), (3) CaCrO4 alone, or (4) control soil. Nominal total doses of Cr(+6) for each respective group were 324 microg/kg, 7,975 microg/kg, 8,700 microg/kg, and 0.02 microg/kg. Incidences of malignant tumors and nephritis were not elevated in any group. Four primary lung tumors appeared in animals that received CCS + CaCrO4, and one primary lung tumor appeared in the group treated with CaCrO4 alone. These incidences were not significant statistically, but the rare spontaneous occurrence of these tumors in Sprague-Dawley rats suggested that they were treatment related. No primary lung tumors appeared in the control or CCS-treated groups.

Animals↗
PubMed2002

Essential elements as early indicators of hexavalent chromium nephrotoxicity.

The kidney is the appropriate critical organ for indicating chronic exposure to chromium compounds. The present work investigates the effect of dose-dependent hexavalent chromium concentration in various tissues of rats, the disturbances in metabolism of zinc and copper in liver and kidney, and histopathological changes in kidneys. White Wistar rats were used. Animals were injected intraperitoneally at a dose of 0.5 and 5 mg Cr/kg as K2CrO4. The animals were sacrificed after single and repeated doses at 24 h after the last injection. Disturbances in the metabolism of zinc and copper in the kidney of rats occur when the concentration of chromium in this organ attains about 30 microg Cr/g. An increase in urinary output of these essential metals is a more sensitive indicator of nephrotoxicity than ultrastructural damage of kidney.

Animals↗