Chromium in leather footwear-risk assessment of chromium allergy and dermatitis

Heavy metals in contact dermatitis: A review

Contact dermatitis is an inflammatory skin reaction caused by direct contact with chemical substances in the environment and can either be irritant or allergic in nature. The clinical symptoms of contact dermatitis, include local skin rash, itching, redness, swelling, and lesions. Nowadays, 15-20% of people have some degree of contact dermatitis, which can be more or less severe. Immune responses in allergic contact dermatitis (ACD) are due to the effects of cytokines and allergen-specific CD4⁺ and CD8⁺ T cells on the skin. Acids and alkalis such as drain cleaners, plants such as poinsettias, hair colors, and nail polish remover, are all prominent causes of irritant contact dermatitis (ICDs). Heavy metals are metallic elements with a high atomic weight that are hazardous in low quantities and are known to cause dermatitis after systemic or local exposure. Nickel (Ni), chromium (Cr), lead (Pb), and copper (Cu) are among the most common heavy metals used in various industries. Metal allergies may cause ACD and also systemic contact dermatitis (SCD). Contact dermatitis is detected by laboratory tests such as patch testing, lymphocyte stimulation test (LST), and evaluation of cytokine production by primary cultures of peripheral blood mononuclear cells. This article presents an update on the epidemiological and clinical characteristics of ACD and SCD caused by three heavy metals (Cr, Cu, and Pb). Ni is not discussed due to recent coverage. Furthermore, the effects of contact sensitivity to some other heavy metals, such as gold (Au), cobalt (Co), palladium (Pd), and mercury (Hg) are discussed.

Bullous Allergic Contact Dermatitis Caused by Potassium Dichromate

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No immediate effect of regulatory reduction of chromium in leather among adult patients with chromium allergy

BACKGROUND

In March 2014, the European Commission issued a new regulation restricting the content of hexavalent chromium (Cr) in leather to no more than 3 mg/kg. We previously performed a questionnaire study in January 2014 to characterize our patients with Cr contact allergy prior to regulatory intervention.

OBJECTIVES

To assess whether clinical characteristics, self-reported sources of Cr exposure, and burden of disease changed in patients with Cr allergy over time.

METHODS

A questionnaire study was performed among 172 adult dermatitis patients with Cr allergy and 587 age- and sex-matched dermatitis patients without Cr allergy. A questionnaire was sent to all dermatitis patients patch tested from 2003 to 2018 in August 2019.

RESULTS

The overall response rate was 61.2% (759/1241). Patients with Cr allergy were still more commonly affected by current foot dermatitis (odds ratio [OR] 3.82, 95% confidence interval [CI] 2.07-7.08) and hand dermatitis (OR 1.98, 95% CI 1.13-3.49) compared with controls diagnosed during 2013 to 2018. The proportion of patients with Cr allergy reporting dermatitis caused by leather exposure did not change during 2003 to 2012 vs 2013 to 2018 (71.0% vs 66.2%, P = .5). Furthermore, estimates on occupational performance and disease severity (eg, current dermatitis), number of anatomical locations with dermatitis, worst-case dermatitis, and effect on work were similar in patients with Cr allergy for 2003 to 2012 vs 2013 to 2018.

CONCLUSION

No immediate sign of improvement was found in patients with Cr allergy concerning severity of disease and dermatitis from leather exposures 5 years after adoption of the regulation against hexavalent Cr in leather. The regulation may have to be revised for better protection of those already sensitized.

Biomanagement of hexavalent chromium: Current trends and promising perspectives

Chromium (Cr) is most widely used heavy metal with vast applications in industrial sectors such as metallurgy, automobile, leather, electroplating, etc. Subsequently, these industries discharge large volumes of toxic Cr containing industrial wastewaters without proper treatment/management into the environment, causing severe damage to human health and ecology. This review gives some novel insights on the existing, successful and promising bio-based approaches for Cr remediation. In lieu of the multiple limitations of the physical and chemical methods for remediation, various biological means have been deciphered, wherein dead and live biomass have shown immense capabilities of removing/reducing and/or remediating Cr from polluted environmental niches. Adsorption of Cr by various agro-based waste and reduction/precipitation by different microbial groups have shown promising results in chromium removal/recovery. Various microbial based agents and aquatic plants like duckweeds are emerging as efficient adsorbents of metals and their role in chromium bioremediation is an effective green technology that needs to be harnessed effectively. The role of iron and sulphur reducing bacteria have shown potential for enhanced Cr remediation. Biosurfactants have revealed immense scope as enhancers of microbial metal bioremediation and have been reported to have potential for use in chromium recovery as well. The authors also explore the combined use of biochar and biosurfactants as a potential strategy for chromium bioremediation for the development of technology worth adopting. Cr is non-renewable and finite resource, therefore its safe removal/recovery from wastes is of major significance for achieving social, economic and environmental sustainability.

Pediatric contact dermatitis: what's new

PURPOSE OF REVIEW

Allergic contact dermatitis (ACD) was once thought to be rare in children but recent studies have demonstrated that the prevalence of ACD is common and appears to be increasing in children. Current trends including toys, hobbies, and personal care products may play a role in potentially new allergen exposure or resurgence of certain allergens, making ACD a moving target in children.

RECENT FINDINGS

ACD and atopic dermatitis can coexist and certain clinical features can help differentiate ACD from endogenous atopic dermatitis in children. It is important to consider ACD in children with recalcitrant atopic dermatitis or dermatitis with atypical distribution. Patch testing has become a more common practice in children. In 2018, the first expert consensus-derived pediatric baseline series consisting of 38 allergens was proposed to aid in the diagnosis of ACD in children. Comparing recent patch testing data in the pediatric population, the top allergens ubiquitously identified were nickel, cobalt, neomycin, Myroxylon pereirae (balsam of Peru), fragrance mix I, fragrance mix II, methylisothiazolinone, methylchloroisothiazolinone/ methylisothiazolinone, formaldehyde, and lanolin.

SUMMARY

ACD is a common problem in children. Detection through patch testing, avoidance of offending allergens, and prevention of common allergens are the main focus of management of ACD in children.

Origins and carriers of Sb, As, Cd, Cl, Cr, Co, Pb, Hg, and Ni in mixed solid waste - A literature-based evaluation

Antimony, arsenic, cadmium, chlorine, chromium, cobalt, lead, mercury, nickel and their compounds are commonly used in the industrial production of various goods. At the end of the product life cycle, these elements enter the waste system as constituents of the products. Mixed municipal and commercial wastes are landfilled, biologically treated, incinerated, and/or processed in mechanical treatment plants to yield solid recovered fuel (SRF). In all these cases, inorganic contaminants that are present in the input waste material play a significant role. In mechanical waste treatment, materials containing high concentrations of these elements (contaminant carriers) can be selectively removed (e.g. by infrared sorters) to improve the output quality, but prior knowledge about the contaminant carriers is required. This paper reviews several waste-related publications in order to identify carriers of Sb, As, Cd, Cl, Cr, Co, Pb, Hg, and Ni in mixed municipal and commercial waste. Identified contaminant carriers are listed alongside ranges for expected concentrations. Furthermore, the data are combined with information on industrial applications and contaminant concentrations in products in order to discuss the reasons for the presence of the respective elements in the carriers. Generally, besides inerts or metals, identified contaminant carriers often include plastics, composite materials, leather products, textiles, rubber, electronic waste, and batteries. Moreover, it is evaluated how individual contaminant carriers are reflected by chemical waste analyses. While the findings of the paper can be applied to different waste treatment options, the discussion focuses on SRF, which is the main output of mechanical treatment plants.

Trend of relevant contact allergens of the feet in Spain over a period of 10 years

INTRODUCTION

Allergic contact dermatitis (ACD) of the feet accounts for approximately 10% of all patch tested patients.

OBJECTIVE

To study the clinical profile of patients with feet dermatitis and relevant contact allergens in Spain over a 10-year period.

METHODS

Retrospective observational study of patients with suspected ACD from the GEIDAC (Spanish Research Group on Contact Dermatitis and Cutaneous Allergy) baseline series from eight hospitals in Spain between 2004 and 2014. The clinical data collected from each patient were age, sex, occupation, history of atopic dermatitis, and eczema location.

RESULTS

A total of 450 cases clinically presented dermatitis affecting the feet; of these, 41% of were males and 5.6% were suspected to be of occupational origin. As much as 47% were diagnosed with ACD, 20% with atopic dermatitis/dyshidrotic eczema, and 5% with psoriasis. The "feet group" included statistically significantly more females in the age range of 21 to 60 years. The most frequent relevant contact allergens were potassium dichromate, cobalt(II) chloride, p-tert-butylphenol formaldehyde resin, mercapto mix, and mercaptobenzothiazole.

CONCLUSIONS

ACD is the most frequent clinical diagnosis of feet dermatitis in our series. The most frequent allergens are similar to those published in other series of foot ACD in Europe and the trend has not changed in the studied decade.

Delayed-type hypersensitivity to metals in connective tissue diseases and fibromyalgia

Rheumatic diseases include a group of autoimmune disorders with environmental and genetic etiology that are characterized as a subgroup of connective tissue diseases (CTD). Rheumatoid arthritis (RA) often involves the small joints of the hands in a symmetrical fashion that can lead to loss of joint function, and RA, as well as Sjögren's syndrome (SS) and other rheumatic diseases, are often accompanied by sensitivity to metals. Numerous investigations on metal sensitivity were evaluated in this review. A detailed metal exposure history was collected by different evaluation of studies. In all subjects, the main source of metal exposure was nickel, mercury, gold, palladium, titanium, and chromium. All of SLE (systemic lupus erythematosus), RA and SS patients appeared to have an increased frequency of metal delayed-type hypersensitivity (DTH) (Type IV allergy). As dental restorative materials release minor amounts of their metals (including mercury, gold, and nickel), many adults are commonly exposed to these metal ions by vapor or corrosion into saliva. Metal-related DTH in these patients will induce an inflammatory response. Such inflammations are important factors in CTD progress. It is hypothesized that metal-specific T cell reactivity can act as an etiological agent in the propagation and chronification of rheumatic inflammation. The key responses of metal delayed-type hypersensitivity in autoimmunity are precipitating as an appealing challenge for further investigations.

Prevalence and risk factors of contact dermatitis among clothing manufacturing employees in Beijing: A cross-sectional study

Little is known about the epidemiology of contact dermatitis (CD) in the Chinese clothing industry. This study aimed to investigate the prevalence and some risk factors of contact dermatitis among clothing manufacturing employees in Beijing.This cross-sectional study was conducted by interview using self-administered questionnaires and skin examination between May and August in 2016. Five-hundred twenty-nine employees who had worked at sewing, ironing, and as managers at 12 clothing manufacturing factories were studied.The overall 1-year prevalence of CD among the clothing employees was 28.5% (151/529 employees), with significantly higher prevalence among ironing workers (50%) and sewers (31.7%) compared with managers (12.7%; P < 0.001, n = 529). A significant association was noticed between the 1-year prevalence of CD and types of occupation (sewers and ironing workers versus managers, respectively), exposure to garment materials (leather and feather), dry skin, allergic rhinitis, age, and smoking.Among employees in Chinese clothing industry, sewers and ironing workers had a higher 1-year prevalence of CD than managers. It is noteworthy that exposure to leather and feather materials and the types of manual work are associated with CD, as well as dry skin and allergic rhinitis.

Rapid detection of Cr(VI) ions based on cobalt(II)-doped carbon dots

A new type of cobalt(II)-doped carbon dots (CCDs) have been fabricated and used successfully for sensing Cr(VI) ions on the basis of photoluminescence quenching. The structural characterization of as-obtained CCDs was thoroughly performed by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and X-ray photoelectron (XPS) spectroscopy. The optical properties were also determined by absorption and fluorescence spectra. By recording 3D fluorescence spectrum, a unique intra-particle Förster resonance energy transfer (FRET) system was investigated. In addition, fluorescence quenching of CCDs was observed in the presence of Cr(VI) ions due to inner filter effect. A good linear relationship between the concentration of Cr(VI) ions and fluorescent intensity was obtained in the range from 5μM to 125μM (R²=0.99), and the limit of detection was calculated as 1.17μM (0.12ppm for Cr(VI)). Importantly, this method was capable of rapidly detecting Cr(VI) ions in tap water and fish samples, which may be helpful in risk reduction of intake Cr(VI) contamination from water and seafood.

Chromium(III) and chromium(VI) release from leather during 8 months of simulated use

BACKGROUND

Chromium (Cr) release from Cr-tanned leather articles is a major cause of Cr contact dermatitis. It has been suggested that Cr(VI) release from leather is not necessarily an intrinsic property of the leather, but is strongly dependent on environmental conditions.

OBJECTIVES

To test this hypothesis for long-term (8 months) simulated use.

MATERIALS AND METHODS

The release of total Cr and Cr(VI) from Cr-tanned, unfinished leather was analysed in subsequent phosphate buffer (pH 8.0) immersions for a period of 7.5 months. The effect of combined ultraviolet treatment and alkaline solution (pH 12.1) was tested. Dry storage [20% relative humidity (RH)] was maintained between immersions. Atomic absorption spectroscopy, X-ray fluorescence and diphenylcarbazide tests were used.

RESULTS

Cr(VI) release was dependent on previous dry storage or alkaline treatment, but not on duration or number of previous immersions. Cr(III) release decreased with time. Fifty-two percent of the total Cr released during the last immersion period was Cr(VI). Cr(VI) release exceeded 9 mg/kg in all immersion periods except in the first 10-day immersion (2.6 mg/kg).

CONCLUSIONS

Cr(VI) release is primarily determined by environmental factors (RH prior to immersion, solution pH, and antioxidant content). The RH should be kept low prior to testing Cr(VI) release from leather.

Hexavalent and trivalent chromium in leather: What should be done?

Trivalent chromium compounds are used for leather tanning, and chromium may be released during use of leather goods. In certain instances, small amounts of hexavalent chromium can be formed and released. Both trivalent and hexavalent chromium can elicit allergic skin reaction in chromium sensitised subjects, the latter being significantly more potent. Induction of sensitisation only occurs after exposure to hexavalent chromium. A minority of subjects are sensitised to chromium, and in a fraction of these subjects allergic skin reaction have been described after wearing leather shoes or, less frequently, other leather goods. The evidence that in all these cases the reaction is related to hexavalent chromium is not always strong. The content of hexavalent chromium in leather is regulated in European Union, but rate of release rather than content is relevant for allergic skin reaction. The role of trivalent chromium appear much less relevant if at all. Modern tanning procedure do not pose significant risk due to either hexavalent or trivalent chromium. Dismissing bad quality and worn-off leather goods is relevant in reducing or eliminating the skin reaction. It should also be pointed out that shoe components or substances other than chromium in leather may cause allergic/irritative skin reactions.

Chromium released from leather - I: exposure conditions that govern the release of chromium(III) and chromium(VI)

Background

Approximately 1–3% of the adult population in Europe is allergic to chromium (Cr). A new restriction in REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) based on the ISO 17075 standard has recently been adopted in the EU to limit Cr(VI) in consumer and occupational leather products.

Objectives

The aim of this study was to critically assess key experimental parameters in this standard on the release of Cr(III) and Cr(VI) and their relevance for skin exposure.

Material and methods

Four differently tanned, unfinished, leather samples were systematically investigated for their release of Cr(III) and Cr(VI) in relation to surface area, key exposure parameters, temperature, ultraviolet irradiation, and time.

Results

Although the total release of Cr was largely unaffected by all investigated parameters, except exposure duration and temperature, the Cr oxidation state was highly dynamic, with reduced amounts of released Cr(VI) with time, owing to the simultaneous release of reducing agents from the leather. Significantly more Cr(III) than Cr(VI) was released from the Cr-tanned leather for all conditions tested, and it continued to be released in artificial sweat up to at least 1 week of exposure.

Conclusions

Several parameters were identified that influenced the outcome of the ISO 17075 test.

Chromium released from leather - II: the importance of environmental parameters

BACKGROUND

Approximately 1-3% of the adult population in Europe are allergic to chromium (Cr). A new restriction in Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) based on the ISO 17075 standard has recently been adopted in the EU to limit Cr(VI) in consumer and occupational leather products to < 3 mg/kg.

OBJECTIVES

To investigate the influence of storage conditions [relative humidity, temperature, ultraviolet (UV) irradiation, and duration] on Cr release, and to assess several parameters relevant for occupational exposure (repeated exposure, wear, alkaline solutions, and sequential wet and dry exposures).

MATERIAL AND METHODS

A leather of relevance for work gloves was investigated for its release of Cr(III) and Cr(VI) under these different experimental conditions.

RESULTS

Relative humidity (water content in leather) during storage prior to Cr extraction was the single most important parameter. Cr(VI) levels could vary from non-detectable to levels significantly exceeding the restriction limit, depending on the relative humidity. Leather contact with alkaline solution and UV irradiation during storage could increase the Cr(VI) levels in subsequent extractions.

CONCLUSIONS

The amount of Cr(VI) in leather is not an intrinsic property, but is influenced by environmental conditions of relevance for occupations and skin exposure.

Correlation between bulk- and surface chemistry of Cr-tanned leather and the release of Cr(III) and Cr(VI)

About 1-3% of the adult general population in Europe is allergic to chromium (Cr). The assessment of the potential release of Cr(III) and Cr(VI) from leather is hence important from a human health and environmental risk perspective. The Cr(VI) content in leather was recently restricted in the European Union. The aim of this study was to assess possible correlations between the bulk and surface chemistry of leather, released Cr(III) and Cr(VI), and capacities of co-released leather specific species to reduce and complex released Cr. Four differently tanned leathers were characterized by scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and the diphenylcarbazide colorimetric method. Their characteristics were compared with results on Cr(III) and Cr(VI) release into artificial sweat (ASW, pH<6.5) and phosphate buffer (PB, pH 7.5-8.0), measured by means of spectrophotometry and atomic absorption spectroscopy. Co-released leather-specific species were shown to reduce Cr(VI), both in ASW and in PB. Their reduction capacities correlated with findings of the surface content of Cr and of released Cr. Leather samples without this capacity, and with less aromatic surface groups visible by ATR-FTIR, revealed Cr(VI) both at the surface and in solution (PB).

Use of Ethylenediaminetetraacetic Acid as a Scavenger for Chromium from “Wet Blue” Leather Waste: Thermodynamic and Kinetics Parameters

One serious consequence of the current consumer society is the transformation of the environment into a waste receptacle arising from human activities. Because of the potential toxic effects of chromium solid waste containing this metal there are grounds for serious concern for the tanning and leather processing industry. The application of tannery waste as organic fertilizer has led to extensive contamination by chromium in agricultural areas and may cause the accumulation of this metal in soils and plants. This work evaluated the extraction of Cr+3and Cr+6contained in solid waste from the leather industry through density functional theory (DFT) calculations. The Gibbs free energy calculations reveal that the chelator ethylenediaminetetraacetic acid (EDTA) forms more stable complexes with metal ions of chromium compared with the structures of the complexes [Cr(NTA)(H2O)2] and [Cr-collagen], the latter used to simulate the protein bound chrome leather.