Chromium in US household bleach

Contaminated land: can acute exposure be a significant health risk? Two case studies and associated risk assessment methods

Contaminated land risk assessments generally focus on the chronic health risks, arising from long-term, low-level exposure to the contaminants, and a number of risk assessment tools are in routine use. Situations where significant acute risks might be present are not commonly encountered, and methods for risk assessment are less well established. We present two recent case studies from the northwest of England, the first an area of public open space, and the second an occupied school site, with the associated risk assessments.

Occupational hand dermatitis among cement workers in Taiwan

BACKGROUND/PURPOSE

Occupational dermatitis among cement workers is a major occupational health concern. The two most important occupational hazards for cement workers are irritant and allergic cement contact dermatitis. The objective of this study was to investigate the severity of occupational cement contact dermatitis and the common allergens among cement workers in Taiwan.

METHODS

A total of 97 cement workers from the Cement Workers' Association of Tainan City and County participated in this study. A structured questionnaire was used to evaluate the demographic data and work-related activities of these cement workers. A complete skin examination was conducted, and skin manifestations were assessed by a dermatologist. Allergens from European Standard Tray (Chemotechnique Diagnostic AB, Sweden) with a total of 25 substances were used for patch testing.

RESULTS

Our results showed that 65 out of 97 cement workers were suffering from occupational cement hand contact dermatitis. The most affected skin area was the hand. Thickening of the dorsal surface of the hand, especially around the metacarpophalangeal joint area, and hyperkeratosis of the palm were the major skin manifestations. The results of the patch test showed that 24 out of 97 were allergic to potassium dichromate, nine were allergic to thiuram mix, nine were allergic to fragrance mix and seven were allergic to cobalt chloride. The final diagnosis, based on the results of the skin examination and the patch test, showed that 43 of 97 cement workers had irritant cement contact dermatitis and 22 had allergic cement contact dermatitis.

CONCLUSION

We conclude that occupational cement hand dermatitis among cement workers is an important and severe issue in Taiwan, and the most common allergens among cement workers are potassium dichromate, thiuram mix, fragrance mix and cobalt chloride. The high positive rate of chromium hypersensitivity among cement workers reflects the urgency to regulate the addition of ferrous sulfate to cement in Taiwan.

Dermatological toxicity of hexavalent chromium

Hexavalent chromium causes two types of dermatological toxicities: allergic contact dermatitis (ACD) and skin ulcers. This report reviews the etiology, prevalence, pathology, dose-response, and prognosis of both of these reactions. Reports in the literature indicate that repeated exposure to hexavalent chromium in concentrations of 4-25 ppm can both induce sensitization and elicit chromium ACD. Exposure to 20 ppm hexavalent chromium can cause skin ulcers in nonsensitized people. The prevalence of chromium sensitivity in cement workers, exposed to 10-20 ppm hexavalent chromium for years, is approximately 4-5%. Chromium ACD can be a chronic debilitating disease, perhaps because chromium is ubiquitous in foods and in the environment and is difficult to avoid. Due to the high rates of sensitization in populations chronically exposed to chromium and the chronic nature of chromium ACD, some investigators recommend reducing the hexavalent chromiumconcentrations in consumer products, such as detergents, to less than 5 ppm.

Hexavalent chromium-contaminated soils: options for risk assessment and risk management

Risk assessment involves establishing scientifically defensible dose-response relationships for end points of concern. For Cr(VI)-contaminated soils, this includes conducting dose-response assessments for blood, liver, and kidney toxicity following oral exposure; lung cancer following inhalation exposure; and allergic contact dermatitis following dermal exposure. This dose-response information is then integrated with a site-specific exposure assessment (or default assumptions) in order to develop a site-specific (or generic) soil criterion within the framework of a comprehensive risk characterization. Risk managers develop cleanup standards designed to protect against all possible adverse effects, taking into account these site-specific (or generic) criteria and other factors such as technical feasibility, cost-benefit analyses, and socio-political concerns. Recently a push for cost-benefit analyses of environmental decisions has occurred, further supporting the need for risk assessors to prepare a comprehensive risk characterization, with its attendant uncertainties. These risk assessment and management issues are brought to the forefront by risk assessors and risk managers dealing with Cr(VI)-contaminated soils. This article offers a review and analysis of the risk characterization of Cr(VI)-contaminated soils, showing that the differing toxicities with route of exposures do not necessarily lead to different characterizations or risk. Soil concentrations in the range of 130 to 450 ppm appear to protect against noncancer toxicity from oral exposure, cancer toxicity from inhalation exposure, and allergic contact dermatitis from dermal exposure.

A study of chromium induced allergic contact dermatitis with 54 volunteers: implications for environmental risk assessment

Over the past 60 years, dose-response patch test studies by various methods have been conducted in an attempt to identify the minimum elicitation threshold (MET) concentration of hexavalent chromium (Cr(VI)) that produces an allergic response in Cr(VI) sensitive subjects. These data are not adequate, however, to provide an accurate estimate of the MET because of the variability in the patch testing techniques and the variability in diagnostic criteria used. Furthermore, the data were not reported in terms of mass of allergen per surface area of skin (mg Cr/cm2-skin), which is necessary for conducting occupational or environmental health risk assessments. Thus the purpose of this study was to determine the MET (mg allergen/cm2) for Cr(VI) and trivalent chromium (Cr(III)) by patch testing techniques. A patch test method that delivers a controlled amount of allergen per surface area of skin was used. A group of 54 Cr(VI) sensitised volunteers were patch tested with serial dilutions of Cr(VI) and Cr(III) to determine the cumulative response rate at several concentrations. The results indicate that the 10% MET for Cr(VI) based on the cumulative response was 0.089 micrograms Cr(VI)/cm2-skin. Only one of the 54 volunteers may have responded to 33 micrograms Cr(III)/cm2-skin, otherwise Cr(III) was unable to produce allergic contact dermatitis in these highly sensitive volunteers. Two supplemental studies were also conducted to assess whether the surface area of the patch and the concentration of Cr(VI) in the patch (related to patch thickness) were likely to influence the results. The data from these studies were used to assess the risk of developing allergic contact dermatitis due to contact with Cr(VI) and Cr(III) in soil. The findings indicated that soil concentrations at least as high as 450 ppm Cr(VI) and 165,000 ppm Cr(III) should not pose an allergic contact dermatitis hazard for at least 99.99% of the people in the community who might be exposed.

Risk assessment of the allergic dermatitis potential of environmental exposure to hexavalent chromium

Although hexavalent chromium, Cr(VI), is a potent sensitizer and inducer of allergic contact dermatitis and is found in many common materials, no standard or guideline currently exists for protection against these effects in environmental exposure. There appears to be a generalized allergenic potential among the various compounds of Cr(VI). Estimates of the prevalence of Cr sensitivity in the population are uncertain, but range from about 2% of the total population in Finland to as high as 20% in U.S. populations with a dermatitis. Based on the thresholds reported for nine separate patch-test studies and statistical analysis of the aggregate dose-response relationship from 72 separate observations from these studies and on studies of allergic responses to bleaches and detergents, the effective threshold for elicitation of allergic contact dermatitis in sensitized populations is about 10 ppm (mg/L) Cr(VI) (as chromium) in solution. Based on evaluation of the literature on cement dermatitis, the threshold concentration of extractable Cr(VI) in solid material may be as low as 10 ppm (microgram/g). For ingestion of Cr(VI), the lowest observed effect level (LOEL) dose for elicitation is 0.26 microgram/kg. In calculating the threshold concentration of Cr(VI) in soil for elicitation of contact dermatitis, extractability must be taken into account.

Nickel, cobalt and chromium in consumer products: a role in allergic contact dermatitis?

In spite of the improved awareness of the potential for nickel, cobalt and chromium to cause skin allergy, the incidence of sensitization to them is generally on the increase, especially for nickel. We review data from the literature and industry on transition metal contamination of consumer products and assess the hazard to man. Consumer products are defined as personal care items and detergent/cleaning products used regularly in domestic work. The analytical data demonstrate that consumer products are a relatively minor source of contact with nickel, cobalt or chromium. The traces found in consumer products will not be the primary cause of sensitization to these metals: levels will be too low and exposure too brief. A person sensitized to these metals has many other more significant sources of daily contact such as earrings, jewelry and metal objects. It is therefore necessary to focus on decreasing the high exposure to these transition metals from other sources rather than on possible trace amounts found in consumer products. Current good manufacturing practice ensures that trace nickel, cobalt and chromium concentrations in consumer products are less than 5 ppm of each metal. It is recommended that this be accepted as a standard for maximum concentrations and that the target should be to achieve concentrations as low as 1 ppm.

Review of the allergic contact dermatitis hazard posed by chromium-contaminated soil: identifying a "safe" concentration

At least 200 sites in the United States contain soil with elevated levels of trivalent and hexavalent chromium [Cr(III) and Cr(VI)]. Although the potential cancer hazard posed by airborne Cr(VI) has been the primary concern for these sites, a soil cleanup standard based on the potential elicitation of allergic contact dermatitis has been proposed for sites in Hudson County, N.J. This paper describes the rationale for identifying a soil concentration of Cr(VI) that should not pose an allergic contact dermatitis hazard-even in sensitized persons. A literature review of eight published patch test studies that evaluated the allergic response to potassium dichromate was conducted. These studies were evaluated for clinical and statistical relevance in establishing a threshold dose of Cr(VI) to which no more than 10% of the subpopulation sensitized to chromium would respond, and that would protect at least 99.84% of the general population. Although each of the studies had certain methodological limitations when evaluated against current test methods, the data set proved useful for deriving an estimated threshold. Using computer data-fitting techniques based on truncated lognormal distributions, a weighted mean 10% threshold of approximately 150 ppm potassium dichromate or 54 ppm Cr(VI) was identified for the eight studies. Due to the types of limitations noted for these studies, this threshold is likely to be somewhat conservative. Test results have shown that between 5 and 10% of the Cr(VI) at concentrations less than about 500 ppm are released from a soil matrix into an isotonic saline solution simulating sweat. Using human sweat as the extractant, it has been shown that only 0.1% of the CR(VI) at concentrations of approximately 1,000 ppm are released from a soil matrix into sweat. Based on 10% solubilization of soil-bound Cr(VI) and the results of our statistical analysis of previous threshold studies, a concentration of approximately 350 to 500 ppm Cr(VI) in soil should be sufficiently low to protect virtually all exposed people, including children, from chromium-induced allergic contact dermatitis.