Formal recycling of e-waste leads to increased exposure to toxic metals: an occupational exposure study from Sweden.

Electrical and electronic waste (e-waste) contains multiple toxic metals. However, there is currently a lack of exposure data for metals on workers in formal recycling plants. The objective of this study was to evaluate workers' exposure to metals, using biomarkers of exposure in combination with monitoring of personal air exposure. We assessed exposure to 20 potentially toxic metals among 55 recycling workers and 10 office workers at three formal e-waste recycling plants in Sweden. Workers at two of the plants were followed-up after 6 months. We collected the inhalable fraction and OFC (37-mm) fraction of particles, using personal samplers, as well as spot samples of blood and urine. We measured metal concentrations in whole blood, plasma, urine, and air filters using inductively coupled plasma-mass spectrometry following acid digestion. The air sampling indicated greater airborne exposure, 10 to 30 times higher, to most metals among the recycling workers handling e-waste than among the office workers. The exposure biomarkers showed significantly higher concentrations of chromium, cobalt, indium, lead, and mercury in blood, urine, and/or plasma of the recycling workers, compared with the office workers. Concentrations of antimony, indium, lead, mercury, and vanadium showed close to linear associations between the inhalable particle fraction and blood, plasma, or urine. In conclusion, our study of formal e-waste recycling shows that workers performing recycling tasks are exposed to multiple toxic metals.

Cobalt skin dose resulting from short and repetitive contact with hard metals.

BACKGROUND: Many daily contacts with metallic items are short and repetitive, and result in metal release; material, sweat, friction and wear may all be important. OBJECTIVES: To study cobalt release and skin deposition as a result of many short and repetitive contacts with two cobalt-containing materials. MATERIALS/METHODS: Study participants (n = 5) handled two types of hard metal disc (Co 6% and Co 15% Cr 0.6%) for 30 min. Deposited cobalt skin doses were measured with acid wipe sampling and chemical analysis. Cobalt release from the hard metal discs in artificial sweat was measured under conditions simulating those present during the handling of discs. RESULTS: Average cobalt skin doses from discs containing 6% Co and 15% Co 0.6% Cr were 1.1 µg/cm(2) [standard deviation (SD) 0.4 µg/cm(2) ] and 0.7 µg/cm(2) (SD 0.5 µg/cm(2) ), respectively. More cobalt was released from hard metal discs containing 6% Co [11.4 µg/cm(2) (SD 1.2 µg/cm(2) )] than from discs containing 15% Co 0.6% Cr [4.8 µg/cm(2) (SD 0.6 µg/cm(2) )]. 10% to 15% of the potentially available cobalt was deposited on the skin during handling. CONCLUSIONS: It is likely that the cobalt deposited as a result of short and repetitive contact with hard metals may cause harm. Research regarding cobalt exposure, metal release and the deposition of skin-sensitizing metals resulting from short and repetitive contact is needed for a better understanding of the allergy risk.

The cobalt spot test--further insights into its performance and use.

BACKGROUND: A spot test was recently developed for easy and rapid testing to detect whether cobalt is available on surfaces in contact with skin. OBJECTIVES: To explore the potential use of the cobalt spot test as a tool for skin dose assessment, and to verify the sensitivity under laboratory conditions. METHODS: A cobalt dilution series (cobalt standards mixed with cobalt spot test reagent solution) was prepared to determine the threshold for colour change. Defined doses of cobalt were applied to the fingers of 5 volunteers. Acid wipe sampling was used to measure the recovery of applied cobalt skin doses on one hand, and cobalt-exposed areas on the other hand were spot tested. RESULTS: A weak colour gradient was visible from approximately 1 to 1.5 µg cobalt/ml in the dilution series. For a skin dose of 0.125 µg cobalt/cm(2) , 80% of the cobalt dose was collected by acid wipe sampling. Spot tests gave positive results in all cases (n = 5). CONCLUSIONS: The cobalt spot test can be used to show cobalt on the skin. More experience is needed to understand and describe the most suitable test conditions.

Nickel deposited on the skin-visualization by DMG test.

BACKGROUND: Nickel is the most common cause of contact allergy and an important risk factor for hand eczema. Visualization techniques may be powerful in showing exposures. The dimethylglyoxime (DMG) test might be used to establish skin exposure to nickel. OBJECTIVES: To develop and evaluate methods for visualization of nickel on the skin by the DMG test and hand imprints. METHODS: Nickel solutions at different concentrations were applied in duplicate on the hands in healthy subjects (n = 5). The DMG test and acid wipe sampling for quantification were then performed. Hand imprints were taken after manipulation of nickel-releasing tools (n = 1), and in workers performing their normal tasks (n = 7). The imprints were developed by the DMG test. RESULTS: The DMG test on hands gave positive results in all subjects. The lowest concentration giving rise to a colour change was set to 0.13 µg/cm(2) for DMG testing on skin. DMG test-developed imprints worked well except when hands were heavily contaminated by other particles/dust. CONCLUSIONS: The DMG test may be used as a simple and powerful tool for visualization of nickel on skin. DMG test-developed hand imprints may, in the future, be used for semi-quantitative or quantitative exposure assessment.

Occupational hand eczema caused by nickel and evaluated by quantitative exposure assessment.

BACKGROUND: EU legislation has reduced the epidemic of nickel contact allergy affecting the consumer, and shifted the focus towards occupational exposure. The acid wipe sampling technique was developed to quantitatively determine skin exposure to metals. OBJECTIVES: To assess the clinical usefulness of the acid wipe sampling technique as part of the diagnostic investigation for occupational nickel allergy-associated hand dermatitis. PATIENTS AND METHODS: Six patients with vesicular dermatitis on the hands were included. Acid wipe sampling of skin and patch testing with a nickel sulfate dilution series were performed. RESULTS: Nickel was detected in all samples from the hands. In all patients, the nickel content on the hands was higher than on the non-exposed control area. CONCLUSIONS: Occupational exposure to nickel-releasing items raised the nickel content on exposed skin as compared with a non-exposed control site. Nickel-reducing measures led to complete symptom relief in all cases. In cases of a positive nickel patch test reaction and hand eczema, patients should perform the dimethylglyoxime (DMG) test on metallic items at home and at work. The acid wipe sampling technique is useful for the diagnosis of occupational hand eczema following screening with the inexpensive DMG test.

Sensitivity and specificity of the nickel spot (dimethylglyoxime) test.

BACKGROUND: The accuracy of the dimethylglyoxime (DMG) nickel spot test has been questioned because of false negative and positive test reactions. The EN 1811, a European standard reference method developed by the European Committee for Standardization (CEN), is fine-tuned to estimate nickel release around the limit value of the EU Nickel Directive from products intended to come into direct and prolonged skin contact. Because assessments according to EN 1811 are expensive to perform, time consuming, and may destruct the test item, it should be of great value to know the accuracy of the DMG screening test. OBJECTIVES: To evaluate the sensitivity and specificity of the DMG test. METHODS: DMG spot testing, chemical analysis according to the EN 1811 reference method, and X-ray fluorescence spectroscopy (XRF) were performed concomitantly on 96 metallic components from earrings recently purchased in San Francisco. RESULTS: The sensitivity of the DMG test was 59.3% and the specificity was 97.5% based on DMG-test results and nickel release concentrations determined by the EN 1811 reference method. CONCLUSIONS: The DMG test has a high specificity but a modest sensitivity. It may serve well for screening purposes. Past exposure studies may have underestimated nickel release from consumer items.

Skin deposition of nickel, cobalt, and chromium in production of gas turbines and space propulsion components.

Skin exposure to nickel, cobalt, and chromium may cause sensitization and allergic contact dermatitis and it is known that many alloys and platings may release significant amounts of the metals upon contact with skin. Occupational exposure to these sensitizing metals has been studied in different settings with regards to airborne dust and different biological end points, but little is known about deposition on skin from airborne dust and direct contact with materials containing the metals. In this study, skin deposition was studied in 24 workers in an industry for development and manufacturing of gas turbines and space propulsion components. The workers were employed in three departments, representing different exposure scenarios: tools sharpening of hard metal items, production of space propulsion structures, and thermal application of different metal-containing powders. A novel acid wipe sampling technique was used to sample metals from specific skin surfaces on the hands and the forehead of the workers. Total amounts of nickel, cobalt, and chromium were measured by inductively coupled plasma mass spectrometry. The result showed that nickel, cobalt, and chromium could be detected on all skin surfaces sampled. The highest level of nickel was 15 microg cm(-2) h(-1), the highest for cobalt was 4.5 microg cm(-2) h(-1), and for chromium 0.6 microg cm(-2) h(-1). The three departments had different exposures regarding the metals. The highest levels of nickel on the skin of the workers were found in the thermal applications department, cobalt in the tools sharpening department, and chromium in the space propulsion components department. In conclusion, the workers' exposure to the metals was more likely to come from direct skin contact with items, rather than from airborne dust, based on the fact that the levels of metals were much higher on the fingers than on the back side of the hands and the forehead. The skin exposure levels of nickel and cobalt detected are judged capable to induce sensitization and elicit allergic contact dermatitis.

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 microg/cm(2)/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.

Release of nickel from coins and deposition onto skin from coin handling--comparing euro coins and SEK.

BACKGROUND: Nickel exposure is the most common cause of contact allergy. The role of contact with nickel-containing coins has been controversial. OBJECTIVES: To compare the release of nickel from 1 and 2 EUR coins (both composed of two alloys: Cu 75%, Zn 20%, Ni 5% and Cu 75%, Ni 25%) and Swedish 1 SEK coin (alloy: Cu 75%, Ni 25%) and to assess the deposition of nickel onto skin by coin handling. METHODS: Nickel release was determined by immersion in artificial sweat (2 min, 1 hr, 24 hr, and 1 week). Deposition of nickel onto the skin was assessed in three subjects after 1-hr handling of 2 EUR and 1 SEK coins. Samples (n = 48) were taken from fingers and palms by acid wipe sampling and analysed by inductively coupled plasma mass spectrometry. RESULTS: Amounts of nickel released by 1 week from 1 SEK, 1 EUR, and 2 EUR coins were 121, 86, and 99 microg/cm(2), respectively. Corresponding 2 min values were 0.11, 0.25, and 0.22 microg/cm(2). Nickel was deposited onto the skin by 1 hr coin handling (range 0.09-4.1 microg/cm(2)), the largest amounts were on fingers; similar amounts of nickel were deposited from 1 SEK and 2 EUR coins. CONCLUSIONS: Nickel is released from 1 and 2 EUR and 1 SEK coins at similar amounts. Nickel is deposited onto skin at substantial and similar amounts by coin handling. Acid wipe sampling is suitable for studies of skin exposure to nickel and in risk assessment.

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 mug/cm(2), range 1.846-5.028 mug/cm(2)) 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.

Large organic aerosols in a dynamic and continuous whole-body exposure chamber tested on humans and on a heated mannequin.

Exposure to large airborne organic aerosols may cause respiratory and skin symptoms. The use of human exposure chambers permits safe mechanistic studies of the effect of inhalation or dermal deposition of such particles. The performance of a dynamic and continuous whole-body human exposure chamber using turbulent air mixing during exposure to these organic aerosols of humans and of a new heated mannequin was evaluated. Variability of temporal and spatial distribution of the airborne particle concentration, and aerodynamic aerosol size distribution of the inhalable fraction, were evaluated. The temporal and spatial distribution of these aerosols close to the breathing zone during an exposure session was typically < or = 10%, which is low for airborne particles of this size. In a larger section around a human, only slightly higher spatial variation was found. Variability between exposure sessions was also low (< 10%). Only limited effect of relative humidity for the organic aerosols was observed. The aerodynamic particle size distribution curves differed slightly, but some were comparable to those in occupational environments. The outcome of the performance tests as measured with the heated mannequin was almost the same as with humans, indicating that the mannequin could be used in preparatory tests in this type of chamber.

Assessment of skin exposure to nickel, chromium and cobalt by acid wipe sampling and ICP-MS.

There is a great need to accurately assess skin exposure to contact allergens. We have developed a technique for assessment of skin exposure to nickel, chromium and cobalt using acid wipe sampling by cellulose wipes with 1% nitric acid. Chemical analysis was performed by inductively coupled plasma mass spectrometry (ICP-MS). The recovery of nickel, chromium and cobalt from arms and palms was 93%. The analytical result is expressed in terms of mass per unit area (microg/cm(2)). The developed acid wipe sampling technique is suitable for determination of nickel, chromium and cobalt deposited on the skin. The technique may be used in workplace studies, in studies of individuals in the general population, in dermatitis patients, in identification of risk groups, as well as in developing preventive strategies and in follow-up after intervention.

Measuring dust on skin with a small vacuuming sampler--a comparison with other sampling techniques.

Airborne skin exposure to allergens and irritants may cause dermatitis. There are few methods for assessing skin exposure to airborne particles. We have modified and tested a vacuuming sampler for removing particles from the skin. The sampler was compared with two other skin and surface exposure sampling techniques. These were based on surrogate skin (a patch sampler-adhesive tape on an optical cover glass) and a tape stripping removal procedure. All three samplers measure the mass of dust on skin. Dust containing starch was deposited onto the skin in a whole-body exposure chamber. Samples were taken from forearms and shoulders and analysed using optical microscopy. With the different sampling techniques small differences in the results were obtained. Agreement between the vacuuming sampler and the tape stripping technique was good. The comparison between patch and tape stripping procedure indicated a slight overestimation for the patch. The three techniques are applicable for assessing skin exposure to particles and for dose-effect studies. The vacuuming method will be further developed and applied in workplace studies. The technique allows for dust sampling from large areas of skin.

Multicentre patch test study of air-oxidized ethoxylated surfactants.

Frequent exposure to water and surfactants is considered to be the main cause of hand eczema from wet work. Ethoxylated surfactants are susceptible to oxidation and some of the oxidation products formed have proved to be contact sensitizers in guinea pigs. The question of human sensitization to oxidized surfactants was addressed in a multicentre study in the Stockholm region. 528 consecutive dermatitis patients were patch tested with widely used ethoxylated surfactants in oxidized and non-oxidized form as well as certain identified oxidation compounds. 61 patients presented with mild, clearly irritant reactions to some of the surfactants tested. 18 patients showed not only erythema but also oedema and/or papules and vesicles, using a morphologic descriptive system for reading the patch test reactions. These reactions occurred mostly to oxidized surfactants and oxidation products. When retesting 9 of these 18 patients only an allergic reaction to acetaldehyde was confirmed. We conclude that oxidized ethoxylated surfactants have increased irritant potential compared to non-oxidized material. Our working hypothesis is that oxidized surfactants of technical quality exert a lower risk of sensitization than do oxidized homologous pure surfactants. Among the potential allergens formed during autoxidation, formaldehyde and acetaldehyde must be considered as a source of unexpected exposure.

Wheat flour exposure results in recruitment of inflammatory cells in the lungs of healthy individuals.

BACKGROUND: Flour dust in bakeries is known to cause allergic as well as nonallergic respiratory symptoms. Fungal alpha-amylase is a commonly used baking additive that has been shown to have allergenic properties. The aim of this study was to investigate any effects on bronchoalveolar lavage (BAL) cells and peripheral blood lymphocytes (PBL) of healthy individuals exposed to airborne wheat flour dust with or without fungal alpha-amylase added. METHODS: Fifteen subjects were exposed during 1 hr in an exposure chamber, ten individuals to wheat flour alone and five with alpha-amylase added. BAL was performed 2-6 weeks before and 1 day after the exposure. BAL cells were differentially counted and flowcytometric analysis of the expression of activation, adhesion, and subset markers on alveolar macrophages (AM) and T cells in BAL fluid and peripheral blood were carried out. RESULTS: Exposure to wheat flour dust increased the total number of cells in BAL fluid from 75.4 (i.q. range 70.4-104.1) to 127.4 (92.1-187.4) cells x 10(6)/L, P < 0.01. There was a significant difference in the change of total BAL cell concentration between the study group exposed to wheat flour only (n = 10; increase with 91.9 x 10(6)/L) and the group exposed to wheat flour with the baking additive fungal alpha-amylase (n = 5; decrease with 5.4 x 10(6)/L). The exposure level of respirable dust was lower in the group that received alpha-amylase and the increase in BAL cell concentration showed a positive correlation with the concentration of respirable dust in the exposure chamber (r = 0.80, P < 0.001). The phenotypic analysis of AM indicated an influx of monocytic cells. CONCLUSIONS: The results indicate that the concentration of respirable dust, but not alpha-amylase, is of importance for the recruitment of inflammatory cells to the peripheral airways in healthy individuals exposed to wheat flour dust.