Die monitering van werkerblootstelling aan palladium in 'n metaalaffineerdery

Abstract

The refinement of the Platinum Group Metals is a complicated chemical process requiring specialized workers and technologists. Much is known about the health effects of Platinum, but little is known about the effect of metals like Palladium and Iridium on the body. There is no Threshold Limit Value for Palladium. Concerns have been raised by many about the effect of Palladium on the health of the public due to the auto-catalyst emissions. Cases of dermatitis and asthma due to dental castings and glass frames have also been reported. These reports raised concerns at Impala Platinum Refinery: how healthy and safe are the workers working with Palladium-salts? What is the best occupational hygiene monitoring technique to quantify the Palladium levels and which medical monitoring techniques should be conducted on the workers of the Palladium-area? The aim of the study was the following: to determine the levels of exposure to Palladium, to determine if an immunologic reaction will occur due to Palladium exposure and to identify a suitable monitoring technique for Palladium. To achieve these goals three groups were chosen on the grounds of possible exposure. A group of ten unexposed workers at the clinic were chosen as the control group. These workers are not employed at the plant so it is assumed that they are not exposed to Palladium. The second group was ten workers in the plant that don't physically come in contact with Palladium. The third group consisted of four workers working with Palladium every day. The results found from the workers of the Palladium-area could be compared to the results of an unexposed group (clinic) and a group that could be possibly exposed (plant). The medical monitoring methods that were used for this study were lung function tests, skin tests (skin prick test and patch testing) and biological monitoring (urine and blood samples). No Biological Exposure Index exists for Palladium in urine.

The occupational hygiene methods that were used were personal, static and high volume sampling as well as swab samples. The Occupational Exposure Limit for Platinum (2 µg/m3 ) as given by the Regulations for Hazardous Chemical Substances, 1995, of the Occupational Health and Safety Act, 85 of 1993 was used to interpret the results for Palladium monitoring. By means of the occupational hygiene monitoring techniques it were determined that all three the groups were exposed to Palladium. The workers of the Palladium area are exposed to the highest levels of Palladium as was expected. By means of personal monitoring it was determined that these workers are exposed to levels high above the standard of 2 µg/m3 used during this study. The swab samples showed that very high levels of Palladium consist in the area, on the skin and on the clothes. This means that the workers are exposed via the skin and the respiratory route. The results for the medical monitoring techniques were somewhat controversial. With the lung function tests it were found that the workers of the clinic had the best lung functions. The workers of the plant showed the weakest lung functions and the workers of the Palladium area had the second best lung functions. When these results are compared to the results from the pre-employment screening, it can be seen that the workers of the plant had the weakest lung functions since employment. A definite decline in the lung functions for all the workers were found, but it can be partially explained by the fact that there was an increase in the Body Mass Index and an increase in the age of the workers. A very good result was that the FEV1 which is the most important indicator for asthma, showed a very small decline and it was still above 7 5 %, which is the standard of the clinic. The skin prick test that tests for Type I sensitivity and die patch test that tests for Type IV sensitivity were both negative on the workers. This means that the Palladium concentrations used for this study didn't elicit an immunologic reaction. The urine and blood results were controversial. The workers of the clinic showed the lowest level of Palladium in the urine. The average value of 3 ,4 µg/L for this group is much higher than values like 0,1 - 0,7 µg/L found during other studies in Italy. The workers of the plant and the Palladium-area showed the same concentrations (3 ,7

µg/L). One can conclude that there is no correlation between exposure and the urine levels as the workers of the Palladium-area are exposed to the highest levels but show the same concentration as the workers of the plant. The workers of the plant showed the lowest IgE-levels (15,92 IU), which are unexpected as they are exposed to a variety of chemicals, which can increase the lgE-levels. The workers of the clinic (104,46 IU) and the Palladium-area (294,93 IU) showed values above the normal of 25 IU. In each of these groups was a person with exceptionally high values that influenced the average. The interpretation of the IgE-results is complicated, as factors like diseases, seasons and life-styles influence the levels. This study shows that all three the groups are exposed to Palladium. The workers of the Palladium-area are exposed to levels that can influence the health of the workers in a negative way. More attention must be paid to housekeeping, personal hygiene and supervising for the sake of the health of the workers. It can be said that the workers of the Palladium-area currently show a positive health image. The conclusion can be made that the goal of the study has been reached. The levels of exposure for all three the groups were determined. No immunologic reaction occurred due to the negative skin tests and no sign of asthma was detected. A good monitoring technique would be the standard occupational hygiene methods ( especially personal sampling) as well as lung function tests and urine samples.