Cobalt and nickel content of Asian cements

The total cobalt and nickel concentration of 11 brands of Asian cement ranged from 8.1 to 14.2 micrograms/g and 14.9 to 28.5 micrograms/g, respectively. These metals exist mainly as insoluble salts; the water-soluble concentration of cobalt and nickel in the cements ranged from 0.39 to 0.65 micrograms/g and from 0-1.2 micrograms/g, respectively. 1.5% (4/272) of construction workers in a prefabrication construction factory had cobalt sensitivity. All had allergic contact dermatitis from chromate in cement. No worker had isolated cobalt sensitivity and cement dermatitis. It appeared that sensitization to cobalt in cement occurs only secondarily to an existing cement dermatitis. 1.8% (5/272) workers had nickel sensitivity: 2 with allergic contact dermatitis to nickel in their watches, 2 were asymptomatic and 1 had allergic contact dermatitis to chromate and cobalt in cement. The low prevalence of cobalt and nickel sensitivity from cement was probably related to the low concentration of soluble cobalt and nickel salts in the cement. However, these insoluble salts can form soluble complexes with body fluids on eczematous skin and sensitize the skin.     

Chromate allergy: chromate content of Asian cement

The chromate content of 10 different Asian cements is studied. The hexavalent chromate and total chromium concentrations in these cements were analyzed using colorimetric spectrophometry and flame atomic absorption spectrophotometry, respectively. The pH of an aliquot of 20% w/v of cement in water ranged from 11.8 to 12.1. Total chromium content of the 10 brands of cement ranged from 15.9 ug/g to 30.0 ug/g; the hexavalent chromate content ranged from 3.6 ug/g to 25.1 ug/g. These findings were comparable to those reported in Europe and Scandinavia. There was no direct correlation between total chromium and hexavalent chromate content in cement.     

Patch testing with cement containing iron sulfate

Addition of iron sulfate to cement means transformation of water-soluble hexavalent chromium into nonwater-soluble trivalent chromium. This has been the basis for preventive measures concerning sensitization to hexavalent chromium (chromate) in cement. For some years, iron sulfate has been added to cement manufactured in the Scandinavian countries. In the present in vivo study, cements with and without iron sulfate were compared concerning their capacity to elicit allergic patch-test reactions in eight chromate-hypersensitive individuals. No patch-test reactions were obtained from a water extract of cement with iron sulfate when appropriately buffered.     

Change in cement manufacturing process,a cause for decline in chromate allergy?

Hexavalent chromate in cement is the commonest cause of allergic contact dermatitis, especially among construction workers. Over the past decades, there has been a general decline in the prevalence of chromate allergy among construction workers. We suspect that a change in the constituents of cement, resulting in the lowering of the hexavalent chromate, contributed to the decline. Slag (free from hexavalent chromate) from the iron-quenched, blast furnace process has been used as a substitute for clinker (which contains high hexavalent chromate) in manufacturing cement As a result, the slag has diluted the hexavalent chromate content of cement. Our analytical study showed that slag is free from hexavalent chromate and that the hexavalent chromate of clinker ranged from 6–17 μg/g. Substituting slag for clinker resulted in dilution of hexavalent chromate in the cement. The hexavalent chromate content of cement declines proportionately with increasing proportion of slag, e.g., a cement containing 5% slag has a total hexavalent chromate concentration of 17.5 μg/g. whereas increasing the proportion of slag to 60%; reduced the hexavalent chromate content to 7.1 μg/g. in the same cement.     

Effect of processing cement to concrete on hexavalent chromium levels

Hexavalent chromium sensitization is known to occur from exposure to cement. Concrete is a mixture of cement, sand, rock, and water. Admixtures are compounds used to retard or accelerate concrete setting time. Some countries use ferrous sulfate to reduce hexavalent chromium in cement. We evaluated and compared hexavalent chromium levels in cement, rock (aggregate), and wet and dry concrete in samples from Singapore, Ireland, Denmark, Australia, and the United States. Cement from Denmark contains ferrous sulfate. The effect of representative admixtures on hexavalent chromium concentration in concrete was also evaluated, but technical limitations made evaluation difficult. Soluble chromium levels in cement ranged from 0.225 mg/kg in the US sample to 0.036 mg/kg in the Singapore sample. Aggregate chromium levels ranged from 0.083 mg/kg in the Denmark sample to <0.002 mg/kg in the Ireland sample. Fresh US concrete, with 1.27 mg/kg hexavalent chromium, contained the highest level. The Denmark sample, with ferrous sulfate added, was lowest (<0.01 mg/kg). Hardened concrete levels ranged from 0.104 mg/kg from the Ireland sample to 0.002 mg/kg from the Singapore sample. Therefore, hexavalenl chromium levels do appear to be influenced by admixtures and by processing from powdered cement to dry concrete, Ferrous sulfate significantly reduced hexavalent chromium levels in fresh cement.     

Cobalt-containing alloys and their ability to release cobalt and cause dermatitis

Background:  Cobalt, nickel, and chromium are important skin sensitizers. However, knowledge about cobalt exposure and causes of cobalt sensitization is limited.
Objectives:  To study release of cobalt, nickel, and chromium from some cobalt-containing hard metal alloys and to test reactivity to the materials in cobalt-sensitized patients.
Methods:  Discs suitable for patch testing were made of some hard metal alloys. Cobalt, nickel, and chromium release from the materials was determined by immersion in artificial sweat (2 min, 1 hr, 1 day, and 1 week). Patch test reactivity to the discs and to serial dilutions of cobalt and nickel was assessed in previously patch-tested dermatitis patients (19 cobalt positive and 18 cobalt-negative controls).
Results:  All discs released cobalt, nickel, and chromium. Some discs released large amounts of cobalt (highest concentration: 290 μg/cm²/week). Seven discs elicited three or more positive test reactions.
Conclusions:  The concentration of released cobalt was high enough to elicit allergic contact dermatitis in cobalt-sensitized patients. As the materials in the discs are used in wear parts of hard metal tools, individuals with contact allergy to cobalt may develop hand eczema when handling such materials.     

Chromate dermatitis and sodium dithionite

Reduction of hexavalent chromium to the trivalent form is of proven value of chrome sensitive individuals; there can be practical problems in doing this with iron sulphate added to cement. Sulphites such as sodium pyrosulphite and sodium dithionite, applied topically to the skin of cement workers, appear to be effective in the prevention of dermatitis. Sodium dithionite possesses practical advantages in the work-place.     

Deposition of nickel, chromium, and cobalt on the skin in some occupations - assessment by acid wipe sampling

Background:  Nickel, chromium, and cobalt are important skin sensitizers. Better knowledge about skin exposure is needed for more efficient prevention. We have previously developed acid wipe sampling for assessment of skin exposure to metals.
Objectives:  To apply the acid wipe sampling technique in some occupations where intense contact with metallic items occurs and to gather experience for the design of future workplace studies.
Methods:  18 volunteers (carpenters, locksmiths, cashiers, and secretaries as controls) participated. They performed their normal tasks during a job session for exposure. Samples were taken from fingers and palms by acid wipe sampling, and analysis of metals was performed by inductively coupled plasma mass spectrometer.
Results:  The metals were detected in all samples, and the amount of nickel was larger than that of chromium and cobalt. Fingers were more exposed than palms. 8-h exposure to nickel was calculated and was highest in locksmiths (mean 3.784 μg/cm², range 1.846–5.028 μg/cm²) followed by carpenters, cashiers, and secretaries.
Conclusions:  The acid wipe sampling technique is suitable for studies of skin exposure to nickel, chromium, and cobalt in the workplace. The sampling efficiency of acid wipe sampling is high. The amounts of nickel deposited on skin in carpenters, locksmiths, and cashiers are judged capable of eliciting allergic contact dermatitis.     

Occupational dermatoses and allergy to metals in Polish construction workers manufacturing prefabricated building units

The incidence of dermatoses and allergy to metals (Cr, Co, Ni) was determined in 1782 workers exposed to cement, waste fly ash and asbestos cement. They were also exposed to reclaimed (used), mineral oils. Dermatitis was found in 23.6% of the subjects, and oil acne in 11.2%. Allergy to chromium was found in 23% of the subjects; the % of definitely positive patch test results (the total of positive +(+) and strongly positive +(+)+ was, however, 8.6%. Allergy to cobalt was found in 13.4% of the subjects examined (definite in 3.1%). Allergy to nickel was found in 2.7% of the subjects (definite in 1.1%). The risks of occurrence of occupational skin disease and allergy to metals in subjects exposed to ash were found to be lower than in subjects exposed to cement, and were similar to those in subjects exposed to asbestos cement. Overall chromium, cobalt and nickel contents in ash and asbestos were higher than in cement. Soluble chromium compound content in ash was lower than in cement from European countries and similar to that in American cement.     

Concurrent sensitization to metals and occupation

Background. Cosensitization to nickel, cobalt and chromium occurs in the general population and in some occupational groups. Objectives. To estimate the isolated and concurrent occurrence of nickel, cobalt and chromium contact sensitization and their association with individual and occupational risk factors. Patients/methods. Twelve thousand four hundred and ninety‐two patients were patch tested with the European baseline series between 1997 and 2004 in north‐eastern Italy. The associations between patch test results and patient characteristics and occupations were investigated by means of multinomial logistic regression analysis. Results. Of the patients, 34.7% (4334 patients) had one or more positive patch test reactions to metals. As compared with those with negative reactions to all three metals, nickel sensitization was significantly higher in females than in males, not only as monosensitization, but also as cosensitization with cobalt, with chromium, or with both metals. Building and related trades workers showed positive reactions to chromium + nickel [odds ratio (OR) 1.99; 95% confidence interval (CI) 1.05–3.76) and chromium + cobalt (OR 2.61; 95% CI 1.46–4.67]. Cleaning workers showed a high prevalence of nickel, chromium, nickel + chromium and nickel + cobalt + chromium cosensitization (ORs 1.29, 1.66, 2.11, and 1.79, respectively). An excess risk for cosensitization to all three metals was found in textile and leather workers (OR 2.19; 95% CI 1.10–4.33), and in bartenders (OR 2.10; 95% CI 1.03–4.26). Conclusions. Some occupational groups are more likely to develop nickel, cobalt and chromium cosensitization.     

Influence of detergent washing powders on minimal eliciting patch test concentrations of nickel and chromium

Minimum eliciting levels of nickel have been estimated in 25 nickel-sensitive subjects, and of chromium in 14 chromium-sensitive subjects by patch tests with aqueous solutions of the respective metals. The minimum level of each metal required to provoke a patch test reaction was considerably greater than that found in fabric washing powder solutions and was in the majority of patients tested of the order of 112 ppm nickel (0.05% nickel sulphate) or 885 ppm hexavalent chromium (0.25% potassium dichromate). One nickel-sensitive subject and one chromium-sensitive subject reacted to 1 ppm of the respective metal. Fabric washing powder did not significantly alter the patch test reaction to nickel sulphate or provoke reactions in nickel- or chromium-sensitive subjects. EDTA significantly reduced the number and severity of patch test reactions to nickel sulphate but not those to potassium dichromate or trivalent chromium.     

Nickel,chromium and cobalt sensitization in a patch test population in north‐eastern Italy (1996–2010)

Background. Sensitization to nickel, cobalt and chromium is frequent in patch test populations. The prevalence is affected by geographical and socio‐cultural factors. Objectives. To investigate the temporal trend of nickel, cobalt and chromium contact sensitization between 1996 and 2010 in north‐eastern Italy. Patients/methods. Nineteen thousand and eighty‐eight patients (67.2% women and 32.8% men) with suspected allergic dermatitis underwent patch testing with the European baseline series. The associations between nickel, cobalt and chromium sensitization and patient age (in quintiles) and year of patch testing were investigated by means of multivariate logistic regression analysis. Results. The prevalence of nickel sensitization decreased significantly among younger women (≤26 years), from 38.3% (1996–1998) to 31.9% (2002–2004), 28.3% (2005–2007) and 29.0% (2008–2010), whereas an increase was observed in the 36–45‐year and 46–58‐year age groups. The overall prevalence of chromium sensitization dropped from 10.2% (1996–1998) to 4.6% (2008–2010) among women, and from 11.3% (1996–1998) to 5.9% (2008–2010) among men. The prevalence of cobalt sensitization increased among younger men (≤26 years), from 2.7% (1996–1998) to 7.3% (1999–2001), 9.6% (2002–2004), and 6.6% (2005–2007). Conclusions. Our study showed a decreasing trend of nickel sensitization (only among younger women) and of chromium sensitization in both sexes.     

Chromium content in human skin after in vitro application of ordinary cement and ferrous-sulphate-reduced cement

The amount of chromium found in human skin after in vitro application of cement suspensions on full-thickness human skin in diffusion cells was investigated. Cement suspensions made from ordinary Portland cement or Portland cement with the Chromate reduced with added ferrous sulphate were used. The cement suspensions were either applied on the skin surface under occlusion for 48 h or applied repeatedly every 24 h for 96 h. No statistically significant difference in chromium content of skin layers between skin exposed to ordinary Portland cement, skin exposed to cement with added ferrous sulphate and unexposed skin was observed, despite a more permeable skin barrier at the alkaline pH of the cement suspensions, i.e., pH 12.5. Increased chromium levels, in epidermis and dermis were seen when ordinary Portland cement was applied as a suspension with added sodium sulphate (20%) on the skin surface for 96 h. The content of water-soluble chromium in ordinary Portland cement may vary due to the alkali sulphate content of the cement.     

Addition of ferrous sulfate to cement and risk of chromium dermatitis among construction workers

Lowering the water-soluble chromium content of cement to < 2 ppm has been suggested to diminish tile risk of allergic hand dermatitis caused by chromium among construction workers. The prevalence of chromium dermatitis was determined for a representative sample of 913 house construction workers and 707 concrete element prefabrications workers, with a questionnaire and clinical examination, before the use of cement with such H low content of water-soluble chromium was Lined on Finnish construction sites in 1987. The prevalence of allergic contact dermatitis caused by water-soluble chromium, diagnoses confirmed with patch tests among the workers with hand dermatitis, was 9/ 117 (7.7%). 4 of them were new 4/105 (4%) and 5 had been diagnosed earlier. In 1997, the prevalence of work-related hand dermatitis (allergic and irritant together) was 6.8% among the construction workers and 8.9% among the concrete element prefabrication workers. The Finnish Register of Occupational Diseases was checked for reports of chromium dermatitis and other forms of hand dermatitis from 1978 to 1992. The results indicated that, after 1987, the occurrence of allergic contact dermatitis caused by chromium decreased to less than 1/3 the previous level, whereas the occurrence of irritant contact dermatitis remained stable throughout the observation period. Regardless of some potential confounders, the addition of ferrous sulfate to cement during the production process may have reduced the number of cases of allergic contact dermatitis among construction and concrete element prefabrication workers. Our results agree with the results of Danish studies and Swedish observations.     

Occupational dermatitis related to chromium and cobalt: experience of dermatologists (EPIDERM) and occupational physicians (OPRA) in the U.K. over an 11-year period (1993-2004)

BACKGROUND: Chromium and cobalt (and their compounds) are well recognized as being important causes of occupational contact dermatitis (OCD), particularly of the hands, although their exact contribution to occupational hand dermatitis varies between different studies. In some European studies, cases of chromium-related dermatitis have decreased following the addition of ferrous sulphate to cement to reduce the amount of available chromium. OBJECTIVES: To examine, using data from the U.K. occupational skin surveillance schemes, the proportionate reported incidence and changing trends in OCD considered to be related to chromium and cobalt for the 11-year period from February 1993 to December 2004. METHODS: Surveillance data collected by the two British occupational health surveillance schemes, EPIDERM and OPRA, from February 1993 to December 2004 were studied. These are occupational health surveillance schemes in the U.K. to which physicians voluntarily and anonymously report new cases of skin disease suspected to be work related. RESULTS: Over the 11-year period, dermatologists reported 22 184 cases of OCD, comprising 77% of all types of occupational skin diseases that were disclosed. Chromium was recorded as being thought to play a role in 1226 (6%) of these, with cobalt identified as being likely to be implicated in 823 (4%). The numbers fluctuated on a year-on-year basis but there were no overall trends during the period of study. The male/female ratio was 5 : 1 for chromium and 1 : 1 for cobalt. Overall, the male/female ratio for OCD was 1.4 : 1. The rates of dermatitis believed to be related to both metals generally increased with age. In women, the highest rate for chromium was seen in the > 60 years age group, whereas conversely, for cobalt the rate decreased with age. For chromium-related OCD the most common occupations were builders and building contractors, bricklayers, construction workers and plasterers. For cobalt-related OCD, the commonest occupations were hairdressers/barbers, builders/building contractors, retail cash/checkout operators, machine operatives and domestic cleaners. Occupational physicians reported 15 016 cases of OCD (82% of all occupational skin diseases reported by them) for the period May 1994-December 2004. Of these, only 38 cases were thought to be related to chromium and 30 to cobalt (25 of the latter were processing labourers). CONCLUSIONS: In this series, chromium was reported by dermatologists as potentially being involved in 6% of all cases of OCD in the U.K., and cobalt in 4%. Our data support the view that chromium-related dermatitis has an onset in later working life and often affects those in the building trades, whereas cobalt-related dermatitis seems to have an earlier onset and may affect a wide range of employments.     

Isolated and concurrent prevalence of sensitization to transition metals in a Spanish population

Background Positive patch test results to transition metals (nickel sulphate, palladium chloride, cobalt chloride and potassium dichromate) alone and in combinations with one another are well known. Numerous factors may play a role in isolated and concurrent sensitization to these allergens. Objetive This study aims to describe the isolated and concurrent prevalence of sensitization to transition metals in a Spanish Dermatology Department, between 2000 and 2005, and to determine the prevalence of concomitant positive patch test reactions to different transitional metals. Patients/methods Patients (N= 1092) were tested with the standard series of our Allergic Contact Unity, using a standardized technique. Data from these patients were recorded on a computer entry form and analysed. Statistical analyses to evaluated associations of metal contact allergy were performed, and we evaluated the concordance among these associations of transition metals. Results Three hundred twenty (29.3%) patients reacted positively to nickel, 128 (11.7%) to palladium, 118 (10.8%) to cobalt and 82 (7.5%) to chromium. The prevalence of positive reactions to metals was 32.4%. The association of palladium–nickel was the most frequent, with an acceptable concordance (k= 0.46). Conclusion This study illustrates that concomitant positive patch test reactions to different transitional metals are frequently seen in patients with allergic contact dermatitis. Our results reflect the high prevalence of sensitization to nickel in Spain.     

Reduction of chromate in cement by iron sulfate

Cement dermatitis is connected with chromate sensitivity. It can therefore be expected that "elimination" of chromate in cement would decrease the number of cases of cement dermatitis. Iron sulfate added to cement reduces the chromate completely and the 3-valent chromium is precipitated. An amount of 0.35% (w/w) iron sulfate, FeSO4 . 7H2O, is enough to reduce 20 microgram Cr6+/g cement. There is no technical side effect to the concrete. The iron sulfate is preferably added to cement when there is an intimate contact with skin, e.g. at floor laying, repairs and hand-made casting.     

Waste volatile ashes, a new source of hypersensitivity to metals

Dermatological examination was done and patch tests were performed in 393 workers employed in contact with waste volatile ashes in electric power stations, and workers employed in construction material industry producing prefabricated construction blocks from these ashes. All studied workers were exposed also additionally to mineral oils. Eczema was found in 17.8% of cases, and oil acne in 8.1%. Chromium hypersensitivity was noted in 21.4% of workers, cobalt hypersensitivity in 12.2% and nickel hypersensitivity in 5.3%. Using the method of atomic absorption spectrophotometry the levels were assessed of chromium, cobalt and nickel in these ashes comparing them with the levels in cement. In the ashes the content of chromium and cobalt exceeded three times their content in cement. The content of soluble chromium compounds in the ashes was lower than in cement from European countries and approached that in American cement.     

Serum and urine nickel in nickel-sensitized women: effects of oral challenge with the metal

15 women with a positive patch test only to nickel (Ni) and without atopy and 10 control women were selected for the study. Blood and urine specimens were collected with a standard procedure either before (at 8 a.m.) or 4 and 24 h after the ingestion of 10 mg of Ni (as Ni sulfate). 7 of the Ni-sensitized patients showed a flare-up of eczema and/or urticaria during the test, while the other women were non-symptomatic. Serum and urine Ni of controls and Ni-sensitized women did not significantly differ. Serum and urine Ni levels determined before the oral Ni challenge were in the range of reference values recently reported by other authors (0.2–2.0 μg/l of serum or urine). Ni was greatly augmented in urine and serum 4 h after the challenge (25th–75th percentiles: 43–264 μg/l urine Ni and 15–52 μg/l serum Ni). 24 h after Ni ingestion, urine Ni was 41–153 μg/l and serum Ni 4–17 μg/l. Our study confirms a previous investigation showing similar levels of serum and urine Ni following ingestion of the metal in control and Ni-sensitized women without atopy.     

Routine patch testing with cadmium chloride

During a 22-month period, 2.0% cadmium chloride in distilled water was included in our routine patch test series. Twenty-five of 1502 eczema patients showed reactions (1.7 %), but none had any relevant history. At serial dilution test only one patient reacted to 1.0 % cadmium; all the other dilutions applied gave negative reactions. Analysis by atomic absorption spectrophotometry of the cadmium chloride used for patch testing showed that it contained less than 1 μg/g of chromium, copper, cobalt and nickel. The conclusion is that no certain case of contact allergy to cadmium chloride has been revealed. An experimental study using the guinea pig maximization test is in progress.