In occupational settings where rhodium is produced or used, such as the mining industry, refineries and catalytic industries, workers are at risk of being dermally exposed to this metal in either the metallic form or its salt compounds. A considerable amount of contradictory literature has been published with regard to the sensitising abilities of rhodium and no published information is available on the occupational dermal exposure of rhodium as well as its ability to permeate through the skin. Previous studies conducted on the in vitro permeation of metals, such as nickel, cobalt and chromium, have indicated that certain metals undergo oxidation in the presence of sweat and form ions which are able to permeate through skin. For some metals, this ionisation takes place more rapidly in an acidic environment and a decrease in the environmental pH would cause an increase in the release of ions from those metals. Aim: The aim of this study was to determine whether rhodium in the form of rhodium trichloride (RhCl3) would be able to permeate through the skin in vitro, as well as to determine whether any differences exist between the in vitro permeation of rhodium at a pH of 4.5 and a pH of 6.5. Methods: Full thickness abdominal skin was obtained as biological waste after surgery from Caucasian females ranging between 39 and 42 years of age. The Franz diffusion cell method was used in which the experimental cells contained synthetic sweat with RhCl3 and the blanks did not contain any RhCl3 in the donor compartment. All of the cells contained a physiological receptor solution in the receptor compartment. At intervals of 8, 12 and 24 hours, 2 ml of the receptor solution were removed for analysis. The receptor compartment was rinsed with 2 ml receptor solution which was also removed for analysis and 2 ml of fresh receptor solution was added to the compartment. After 24 hours, the receptor and donor solution was removed respectively for analysis and the skin was removed for digestion, prior to analysis. The mass of rhodium in the receptor solutions were determined using Inductively Coupled Plasma Mass Spectrometry. The donor solutions and digested skin solutions were analysed using Inductively Coupled Plasma Optical Emission Spectrometry. Results: At both pH values of 4.5 and 6.5, rhodium was able to permeate through the skin with a cumulative increase in permeation over prolonged exposure time. After 8, 12 and 24 hours, the amount of rhodium that permeated through the skin was higher at pH 4.5 than for pH 6.5. After 12 hours, the permeation of rhodium was statistically significantly higher for pH 4.5 than for pH 6.5 (p = 0.02). At both pH values, the percentage of rhodium that accumulated in the skin was higher than the percentage of rhodium that diffused through the skin and the lag time was less than six hours. Conclusion: At both pH values of 4.5 and 6.5, rhodium was able to permeate through the skin. A decrease in the pH of synthetic sweat led to an increase in the permeation of rhodium and it is recommended that future in vitro permeation studies be conducted at a pH of 4.5, as the skin surface pH of workers are generally considered to be below 5. A higher percentage of rhodium was retained in the skin than the percentage that diffused through, indicating the ability of rhodium to accumulate in the skin, from where it may exert health effects, such as sensitisation. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

In occupational settings where rhodium is produced or used, such as the mining industry, refineries and catalytic industries, workers are at risk of being dermally exposed to this metal in either the metallic form or its salt compounds. A considerable amount of contradictory literature has been published with regard to the sensitising abilities of rhodium and no published information is available on the occupational dermal exposure of rhodium as well as its ability to permeate through the skin. Previous studies conducted on the in vitro permeation of metals, such as nickel, cobalt and chromium, have indicated that certain metals undergo oxidation in the presence of sweat and form ions which are able to permeate through skin. For some metals, this ionisation takes place more rapidly in an acidic environment and a decrease in the environmental pH would cause an increase in the release of ions from those metals. Aim: The aim of this study was to determine whether rhodium in the form of rhodium trichloride (RhCl3) would be able to permeate through the skin in vitro, as well as to determine whether any differences exist between the in vitro permeation of rhodium at a pH of 4.5 and a pH of 6.5. Methods: Full thickness abdominal skin was obtained as biological waste after surgery from Caucasian females ranging between 39 and 42 years of age. The Franz diffusion cell method was used in which the experimental cells contained synthetic sweat with RhCl3 and the blanks did not contain any RhCl3 in the donor compartment. All of the cells contained a physiological receptor solution in the receptor compartment. At intervals of 8, 12 and 24 hours, 2 ml of the receptor solution were removed for analysis. The receptor compartment was rinsed with 2 ml receptor solution which was also removed for analysis and 2 ml of fresh receptor solution was added to the compartment. After 24 hours, the receptor and donor solution was removed respectively for analysis and the skin was removed for digestion, prior to analysis. The mass of rhodium in the receptor solutions were determined using Inductively Coupled Plasma Mass Spectrometry. The donor solutions and digested skin solutions were analysed using Inductively Coupled Plasma Optical Emission Spectrometry. Results: At both pH values of 4.5 and 6.5, rhodium was able to permeate through the skin with a cumulative increase in permeation over prolonged exposure time. After 8, 12 and 24 hours, the amount of rhodium that permeated through the skin was higher at pH 4.5 than for pH 6.5. After 12 hours, the permeation of rhodium was statistically significantly higher for pH 4.5 than for pH 6.5 (p = 0.02). At both pH values, the percentage of rhodium that accumulated in the skin was higher than the percentage of rhodium that diffused through the skin and the lag time was less than six hours. Conclusion: At both pH values of 4.5 and 6.5, rhodium was able to permeate through the skin. A decrease in the pH of synthetic sweat led to an increase in the permeation of rhodium and it is recommended that future in vitro permeation studies be conducted at a pH of 4.5, as the skin surface pH of workers are generally considered to be below 5. A higher percentage of rhodium was retained in the skin than the percentage that diffused through, indicating the ability of rhodium to accumulate in the skin, from where it may exert health effects, such as sensitisation. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

Background: Barrier creams are applied to the surface of the skin to form a barrier that aims to prevent the penetration of irritants and allergens through the skin surface. Several inconsistencies and controversies exist in literature regarding the effect that barrier creams may have on skin barrier function. Various skin surface parameters are used to evaluate the effect that the barrier creams have on skin barrier function. These parameters include transepidermal water loss (TEWL), skin hydration and skin surface pH. Total skin thickness may be assessed as a variable on its own. Differences may exist in skin surface parameters when comparing African participants with Caucasian participants. Aim: The specific aim of this research was to evaluate the short-term1 effects of selected barrier creams on skin barrier function. Note 1: The words short-term are used in this study as each barrier cream is only tested over a period of 8 hours and not tested over a long term period of months or years. Method: Forty two non-smoking participants were included and tested in this study, of which 21 were African and the rest Caucasian. TEWL, skin hydration and skin surface pH were used to evaluate the differences in the effect of two different barrier creams (Reinol Solvgard and Momar Chex) on skin barrier function. TEWL was measured by making use of a closed chamber Vapometer (Deflin Technology Ltd., Kuopio, Finland), skin hydration using a Corneometer® CM 825 and skin surface pH using a pH meter probe (Courage and Khazaka Electronic Kӧln, Germany). A micro-pipette was used to drip a standard volume of 20 μl of ultrapure water on the skin surface before the researcher placed the pH meter probe onto the skin surface. Total skin thickness was measured by making use of ultrasound (Ultrascan 22 - TBS0061B) (Courage and Khazaka Electronic Kӧln, Germany). Three consecutive measurements were taken on the mid-forearm and the palm of the experimental arm. After baseline values were measured, 5 ml of the selected barrier cream was applied to the experimental arm. The barrier cream (selected for the day) was reapplied after 2, 4 and 6 hours and measurements were taken every 2, 4, 6 and 8 hours. The total skin thickness was measured at time zero and at 8 hours. Results: TEWL: For both barrier creams, statistical significant differences (p ≤ 0.05) were found between TEWL on the palms of African participants and Caucasian participants. Skin hydration: Statistically significant differences (p ≤ 0.05) were obtained with regard to mid-forearm skin hydration when comparing Reinol Solvgard with Momar Chex (this was applicable to both racial groups). A statistically significant difference (p ≤ 0.05) was obtained with regard to mid-forearm skin hydration when comparing African participants with Caucasian participants (this was only applicable to Reinol Solvgard). Statistical significant differences (p ≤ 0.05) were obtained with regard to skin hydration palm when comparing Reinol Solvgard with Momar Chex (this was applicable to both racial groups). Statistically significant differences (p ≤ 0.05) were obtained with regards to skin hydration palm when comparing African participants with Caucasian participants (this was applicable to both barrier creams). Skin surface pH: A statistically significant difference (p ≤ 0.05) was obtained with regard to pH of the mid-forearm when comparing Reinol Solvgard with Momar Chex (this was applicable to only the African participants). A statistical significance (p ≤ 0.05) was obtained with regards to skin surface pH mid-forearm when comparing African participants with Caucasian participants (this was applicable to Momar Chex barrier cream only). A statistically significant difference (p ≤ 0.05) was obtained with regards to the pH of the palm when comparing Reinol Solvgard with Momar Chex (this was only applicable to the African racial group). Conclusion: Using skin surface parameters, it can be concluded that Momar Chex barrier cream elicited more positive effects on skin barrier function than Reinol Solvgard barrier cream. This may be ascribed to the fact that both barrier creams lowered TEWL (positive effect), Reinol Solvgard lowered skin hydration (negative effect) whereas, Momar Chex increased the skin hydration (positive effect) and both barrier creams increased skin surface pH (negative effect). Furthermore, the objectives of this study were reached as (a) short-term effects on skin surface parameters were identified between African versus Caucasian participants, (b) significances were observed between the two barrier creams (Momar Chex and Reinol Solvgard) by making use of skin surface parameters and (c) general increases and or decreases were observed in skin surface parameters over a short term period of 8 hours. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2015

Nickel is one of the most commonly known sensitisers and has been classified by the International Agency for Research on Cancer (IARC) as a possible carcinogen to humans (group 2B). Workers at a South African base metal refinery packaging area are potentially exposed to many hazardous chemicals that include nickel. Aims and Objectives: The aim and objectives of this study were to assess dermal and respiratory exposure of workers exposed to nickel in a packaging section at a South African base metal refinery and to assess the change in skin barrier function during a work shift by measuring percentage change in trans epidermal water loss (TEWL), skin hydration and skin surface pH. Skin health was established with a skin questionnaire. Surfaces that workers may come into contact with were also assessed. Method: Respiratory and dermal exposure assessment was done concurrently. Respiratory exposure was assessed and analysed by using the National Institute for Occupational Safety and Health (NIOSH) method 7300. The Institute of Occupational Medicine (IOM) inhalable aerosol sampler was used for personal air sampling. The TEWL index, skin hydration and skin surface pH of the index finger, palm, forearm and forehead were measured before and at the end of the shift with a Derma Measurement Unit, EDS 12 and Skin-pH-Meter® pH 905. These measurements were reported as percentage change in skin barrier function during the shift. Dermal exposure samples were collected with Ghostwipes™ from the index finger and palm of the dominant hand before, during and at the end of the shift, while samples from the forearm and forehead were only collected before and after the shift. Surface sampling was collected and all wipes were analysed for nickel according the NIOSH method 9102, using inductively coupled plasma-atomic emission spectrometry. Results: Respiratory exposure for the whole group of workers in a packaging section was well below the eight hour Time Weighted Average (TWA) respiratory Occupational Exposure Limit (OEL) of 0.5 mg m-3 for nickel. Dermal nickel loading was detected for all the job categories on all the anatomical areas even before the shift had commenced. During the shift more nickel was detected on the index finger and palm of the hand. Levels on the forearm and forehead were much lower in comparison with the index finger and the palm of the hand. Workplace surfaces, which workers may come into contact with on a daily basis, were also contaminated with nickel. Forklift drivers showed high exposure on the index finger and palm of their hands, and this can be attributed to them not wearing any gloves for hand protection. An increase in percentage change for TEWL was seen for most of the job categories on all anatomical areas measured during the shift. Percentage change in skin surface pH and skin hydration varied among job categories. Conclusion: The research addressed the problem statement, with the stated objectives. It was hypothesised that workers at a packaging section of a base metal refinery are exposed to quantifiable levels of nickel through the dermal exposure route. The hypothesis was accepted and control measures together with future studies were recommended. The results confirmed that all workers at a base metal refinery are exposed to quantifiable levels of nickel through the dermal exposure route. Dermal exposure was evident on all anatomical areas for all job categories before the shift had commenced. Personal protective equipment was provided to all employees, but forklift drivers did not wear gloves when operating the forklift. Respirable exposure to nickel was below the OEL. Changes in TEWL and to a lesser extent skin hydration, suggest a deterioration in skin barrier function during the shift. Forklift drivers as well as plate washers may be the highest risk job categories in developing allergic contact dermatitis. Several measures to lower respiratory and dermal exposure to nickel are also recommended. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

Copper exposure is known to be a rare cause of skin irritation and allergic reactions and according to our knowledge occupational dermal exposure to copper sulphate has not yet been characterised. As a result, the objectives of this study were to assess the dermal exposure of workers at a chemical industry to copper sulphate and to characterise the change in the their skin barrier function from before to the end of the work shift, as the skin’s barrier function can greatly influence the permeation of chemical substances. Methods: The change in skin barrier function of reactor workers, crystal and powder packaging workers at the chemical industry were assessed by measuring their dominant hand’s palm, back and wrist as well as their foreheads’ skin hydration, transepidermal water loss (TEWL) and skin surface pH before and at the end of the work shift. Commercial GhostwipesTM were used to collect dermal exposure samples from the same four anatomical areas before and at the end of the shift. Additional dermal exposure samples were collected from the palm and back of hand, prior to breaks 1 and 2. Surface wipe sampling was also conducted at several work and recreational areas of the chemical industry. Wipe samples were analysed by an accredited analytical laboratory, according to NIOSH method 9102 by means of Inductively Coupled Plasma-Atomic Emission Spectrometry. Results: Changes in skin hydration of the workers and anatomical areas at the end of the work shift were highly variable, while in general TEWL increased and skin surface pH decreased. Copper was collected from the skin of all workers before the shift commenced, and dermal exposure increased throughout the work shift. All of the work and recreational areas from which surface samples were taken, were contaminated with copper. Conclusion: As a result of intermittent use of inadequate protective gloves and secondary skin contact with contaminated surfaces and work clothing, workers at the chemical industry are exposed to copper sulphate via the dermal exposure route. The decrease in the workers’ skin barrier function (increased TEWL) and skin surface pH is most likely the result of their dermal exposure to sulphuric acid, and may lead to enhanced dermal penetration. The low account of skin irritation or reaction incidences among these workers is contributed to their ethnicity as well as to the low sensitisation potential of copper. Recommendations on how to lower dermal exposure and improve workers’ skin barrier function are made. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

Background: Barrier creams are applied to the surface of the skin to form a barrier that aims to prevent the penetration of irritants and allergens through the skin surface. Several inconsistencies and controversies exist in literature regarding the effect that barrier creams may have on skin barrier function. Various skin surface parameters are used to evaluate the effect that the barrier creams have on skin barrier function. These parameters include transepidermal water loss (TEWL), skin hydration and skin surface pH. Total skin thickness may be assessed as a variable on its own. Differences may exist in skin surface parameters when comparing African participants with Caucasian participants. Aim: The specific aim of this research was to evaluate the short-term1 effects of selected barrier creams on skin barrier function. Note 1: The words short-term are used in this study as each barrier cream is only tested over a period of 8 hours and not tested over a long term period of months or years. Method: Forty two non-smoking participants were included and tested in this study, of which 21 were African and the rest Caucasian. TEWL, skin hydration and skin surface pH were used to evaluate the differences in the effect of two different barrier creams (Reinol Solvgard and Momar Chex) on skin barrier function. TEWL was measured by making use of a closed chamber Vapometer (Deflin Technology Ltd., Kuopio, Finland), skin hydration using a Corneometer® CM 825 and skin surface pH using a pH meter probe (Courage and Khazaka Electronic Kӧln, Germany). A micro-pipette was used to drip a standard volume of 20 μl of ultrapure water on the skin surface before the researcher placed the pH meter probe onto the skin surface. Total skin thickness was measured by making use of ultrasound (Ultrascan 22 - TBS0061B) (Courage and Khazaka Electronic Kӧln, Germany). Three consecutive measurements were taken on the mid-forearm and the palm of the experimental arm. After baseline values were measured, 5 ml of the selected barrier cream was applied to the experimental arm. The barrier cream (selected for the day) was reapplied after 2, 4 and 6 hours and measurements were taken every 2, 4, 6 and 8 hours. The total skin thickness was measured at time zero and at 8 hours. Results: TEWL: For both barrier creams, statistical significant differences (p ≤ 0.05) were found between TEWL on the palms of African participants and Caucasian participants. Skin hydration: Statistically significant differences (p ≤ 0.05) were obtained with regard to mid-forearm skin hydration when comparing Reinol Solvgard with Momar Chex (this was applicable to both racial groups). A statistically significant difference (p ≤ 0.05) was obtained with regard to mid-forearm skin hydration when comparing African participants with Caucasian participants (this was only applicable to Reinol Solvgard). Statistical significant differences (p ≤ 0.05) were obtained with regard to skin hydration palm when comparing Reinol Solvgard with Momar Chex (this was applicable to both racial groups). Statistically significant differences (p ≤ 0.05) were obtained with regards to skin hydration palm when comparing African participants with Caucasian participants (this was applicable to both barrier creams). Skin surface pH: A statistically significant difference (p ≤ 0.05) was obtained with regard to pH of the mid-forearm when comparing Reinol Solvgard with Momar Chex (this was applicable to only the African participants). A statistical significance (p ≤ 0.05) was obtained with regards to skin surface pH mid-forearm when comparing African participants with Caucasian participants (this was applicable to Momar Chex barrier cream only). A statistically significant difference (p ≤ 0.05) was obtained with regards to the pH of the palm when comparing Reinol Solvgard with Momar Chex (this was only applicable to the African racial group). Conclusion: Using skin surface parameters, it can be concluded that Momar Chex barrier cream elicited more positive effects on skin barrier function than Reinol Solvgard barrier cream. This may be ascribed to the fact that both barrier creams lowered TEWL (positive effect), Reinol Solvgard lowered skin hydration (negative effect) whereas, Momar Chex increased the skin hydration (positive effect) and both barrier creams increased skin surface pH (negative effect). Furthermore, the objectives of this study were reached as (a) short-term effects on skin surface parameters were identified between African versus Caucasian participants, (b) significances were observed between the two barrier creams (Momar Chex and Reinol Solvgard) by making use of skin surface parameters and (c) general increases and or decreases were observed in skin surface parameters over a short term period of 8 hours. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2015

Nickel is one of the most commonly known sensitisers and has been classified by the International Agency for Research on Cancer (IARC) as a possible carcinogen to humans (group 2B). Workers at a South African base metal refinery packaging area are potentially exposed to many hazardous chemicals that include nickel. Aims and Objectives: The aim and objectives of this study were to assess dermal and respiratory exposure of workers exposed to nickel in a packaging section at a South African base metal refinery and to assess the change in skin barrier function during a work shift by measuring percentage change in trans epidermal water loss (TEWL), skin hydration and skin surface pH. Skin health was established with a skin questionnaire. Surfaces that workers may come into contact with were also assessed. Method: Respiratory and dermal exposure assessment was done concurrently. Respiratory exposure was assessed and analysed by using the National Institute for Occupational Safety and Health (NIOSH) method 7300. The Institute of Occupational Medicine (IOM) inhalable aerosol sampler was used for personal air sampling. The TEWL index, skin hydration and skin surface pH of the index finger, palm, forearm and forehead were measured before and at the end of the shift with a Derma Measurement Unit, EDS 12 and Skin-pH-Meter® pH 905. These measurements were reported as percentage change in skin barrier function during the shift. Dermal exposure samples were collected with Ghostwipes™ from the index finger and palm of the dominant hand before, during and at the end of the shift, while samples from the forearm and forehead were only collected before and after the shift. Surface sampling was collected and all wipes were analysed for nickel according the NIOSH method 9102, using inductively coupled plasma-atomic emission spectrometry. Results: Respiratory exposure for the whole group of workers in a packaging section was well below the eight hour Time Weighted Average (TWA) respiratory Occupational Exposure Limit (OEL) of 0.5 mg m-3 for nickel. Dermal nickel loading was detected for all the job categories on all the anatomical areas even before the shift had commenced. During the shift more nickel was detected on the index finger and palm of the hand. Levels on the forearm and forehead were much lower in comparison with the index finger and the palm of the hand. Workplace surfaces, which workers may come into contact with on a daily basis, were also contaminated with nickel. Forklift drivers showed high exposure on the index finger and palm of their hands, and this can be attributed to them not wearing any gloves for hand protection. An increase in percentage change for TEWL was seen for most of the job categories on all anatomical areas measured during the shift. Percentage change in skin surface pH and skin hydration varied among job categories. Conclusion: The research addressed the problem statement, with the stated objectives. It was hypothesised that workers at a packaging section of a base metal refinery are exposed to quantifiable levels of nickel through the dermal exposure route. The hypothesis was accepted and control measures together with future studies were recommended. The results confirmed that all workers at a base metal refinery are exposed to quantifiable levels of nickel through the dermal exposure route. Dermal exposure was evident on all anatomical areas for all job categories before the shift had commenced. Personal protective equipment was provided to all employees, but forklift drivers did not wear gloves when operating the forklift. Respirable exposure to nickel was below the OEL. Changes in TEWL and to a lesser extent skin hydration, suggest a deterioration in skin barrier function during the shift. Forklift drivers as well as plate washers may be the highest risk job categories in developing allergic contact dermatitis. Several measures to lower respiratory and dermal exposure to nickel are also recommended. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

Copper exposure is known to be a rare cause of skin irritation and allergic reactions and according to our knowledge occupational dermal exposure to copper sulphate has not yet been characterised. As a result, the objectives of this study were to assess the dermal exposure of workers at a chemical industry to copper sulphate and to characterise the change in the their skin barrier function from before to the end of the work shift, as the skin’s barrier function can greatly influence the permeation of chemical substances. Methods: The change in skin barrier function of reactor workers, crystal and powder packaging workers at the chemical industry were assessed by measuring their dominant hand’s palm, back and wrist as well as their foreheads’ skin hydration, transepidermal water loss (TEWL) and skin surface pH before and at the end of the work shift. Commercial GhostwipesTM were used to collect dermal exposure samples from the same four anatomical areas before and at the end of the shift. Additional dermal exposure samples were collected from the palm and back of hand, prior to breaks 1 and 2. Surface wipe sampling was also conducted at several work and recreational areas of the chemical industry. Wipe samples were analysed by an accredited analytical laboratory, according to NIOSH method 9102 by means of Inductively Coupled Plasma-Atomic Emission Spectrometry. Results: Changes in skin hydration of the workers and anatomical areas at the end of the work shift were highly variable, while in general TEWL increased and skin surface pH decreased. Copper was collected from the skin of all workers before the shift commenced, and dermal exposure increased throughout the work shift. All of the work and recreational areas from which surface samples were taken, were contaminated with copper. Conclusion: As a result of intermittent use of inadequate protective gloves and secondary skin contact with contaminated surfaces and work clothing, workers at the chemical industry are exposed to copper sulphate via the dermal exposure route. The decrease in the workers’ skin barrier function (increased TEWL) and skin surface pH is most likely the result of their dermal exposure to sulphuric acid, and may lead to enhanced dermal penetration. The low account of skin irritation or reaction incidences among these workers is contributed to their ethnicity as well as to the low sensitisation potential of copper. Recommendations on how to lower dermal exposure and improve workers’ skin barrier function are made. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014