Field evaluation of a passive sampler for the exposure assessment of 2-methoxyethanol

The development and regulation of occupational exposure limits in Taiwan

The occupational exposure limits (OELs) in Taiwan was promulgated in 1974 and has been revised five times since then. Many of the OELs were adopted from the most recent ACGIH TLVs and US OSHA PELs. A total of 483 chemicals were listed in the current Taiwan OELs Standard. The procedures of OELs development in Taiwan include the IOSH organized a recommended exposure limits (RELs) Committee to select the target chemicals and to recommend the RELs through literature review based on the health effects in the first stage, then, the CLA put policy needs, economical and technical feasibility into consideration and set up the final OELs at the second stage. A standard operation manual of RELs Committee has been developed. Based on our experience, several issues including the participation of representatives from a comprehensive spectrum, communication/education and training/enforcement, continuous collection of the local exposure data and health hazard information, use of health risk assessment, consideration of economic, and technical feasibility, as well as the globalization and information and experience sharing are critical in developing the appropriate OELs. Three examples including benzene, crystalline silica, and 2-methoxy ethanol are given to demonstrate the operation of system.

Passive sampling and/or extraction techniques in environmental analysis: a review

The current state-of-the-art of passive sampling and/or extraction methods for long-term monitoring of pollutants in different environmental compartments is discussed in this review. Passive dosimeters that have been successfully used to monitor organic and inorganic contaminants in air, water, sediments, and soil are presented. The application of new approaches to the determination of pollutants at the sampling stage is discussed. The main milestones in the development of passive techniques for sampling and/or extraction of analytes, and in biomonitors used in environmental analysis, are summarized in this review. Passive samplers and biomonitors are compared.

Evaluation of the protective effectiveness of gloves from occupational exposure to 2-methoxyethanol using the biomarkers of 2-methoxyacetic acid levels in the urine and plasma

AIMS

To evaluate the protective effectiveness of gloves from occupational exposure to 2-methoxyethanol (2-ME); and to examine the association of 2-methoxyacetic acid (MAA) in urine and plasma collected simultaneously from low 2-ME exposure and high 2-ME exposure workers in a semiconductor copper laminate circuit board manufacturing plant.

METHODS

Eight hour time weighted breathing zone monitoring was performed to verify the 2-ME exposure classification between workers in regular and special operations. Urine and plasma samples were simultaneously collected from 74 exposed and 80 non-exposed workers. MAA concentrations in the urine (UMAA) and plasma (PMAA) were measured using previously published methods. Three types of gloves worn by workers (cotton, rubber, and no gloves) were recorded by direct observations in the workplace and validated by person-to-person interview. Protective effectiveness indices (PEI) were used to evaluate the glove effectiveness.

RESULTS

There was no detectable 2-ME/MAA in the air, or in urine and plasma samples in non-exposed workers. The average UMAA and PMAA in special operations were 72.63 mg/g Cr. and 29.72 mg/l, significantly higher than values in regular operations (5.44 mg/g Cr. and 2.58 mg/l, respectively). PMAA showed satisfactory correlation to UMAA in all participants from both regular and special operations. The rubber gloves provided significant reduction in 2-ME uptake, whereas cotton gloves provided little protection with fluctuating effectiveness, based on PEI estimates.

CONCLUSIONS

PMAA, similar to UMAA, could serve as a specific biomarker for 2-ME exposure. Wearing impermeable rubber gloves during high risk tasks can reduce major 2-ME exposure. Other improvements, including engineering control, should be provided to diminish worker exposure to 2-ME in occupational environments.

Hepatic Effects in Workers Exposed to 2-Methoxy Ethanol

The objective of this study was to investigate the effects of 2-ME on hepatic function in exposed workers. Fifty-three impregnation workers from two copper-clad laminate-manufacturing factories using 2-ME as a solvent were recruited as the exposed group. Another group of 121 lamination workers with indirect exposure to 2-ME was recruited as the comparison group. Environmental monitoring of air 2-ME concentrations and biological monitoring of urine 2-methoxy acetic acid concentrations were performed. Venous blood was collected for blood biochemistry analyses. Liver function examination results showed that the aspartate amino transferase, alanine amino transferase, and gamma-glutamyl transferase in the 2-ME-exposed workers were not significantly different from those in the comparison workers. After adjustment for hepatitis carrier status, gender, body mass index, and duration of employment, no difference were found between exposed and comparison groups. We conclude that 2-ME was not a hepatotoxin.

Follow up study of haematological effects in workers exposed to 2-methoxyethanol

AIMS

To examine the association between 2-methoxyethanol (2-ME) exposure and haematological effects, as well as the recovery from these haematological effects with continuous reduction in exposure to 2-ME.

METHODS

Twenty nine exposed and 90 non-exposed workers were recruited. Haematological parameters, eight hour full shift personal exposure to 2-ME, and urinary 2-methoxyacetic acid (MAA) were repeatedly measured in three consecutive surveys within six months.

RESULTS

Results of haematological examination in the first exposure survey showed that haemoglobin, packed cell volume, and red blood cell count in the male exposed workers were significantly lower than those in the comparison workers. The frequency of anaemia in the exposed group (42%) was significantly higher than that in the comparison group (3%). The haematological effects were significantly associated with the urinary MAA of exposed workers. The haematological effects had returned to normal in the first follow up survey 2.5 months later, when a reduction in 2-ME exposure was noted. Haematological results of the second follow up examination six months later remained normal. The mean airborne exposure of 2-ME in the three surveys dropped from 35.7 to 2.65, then to 0.55 ppm. The mean urinary MAA of exposed workers in the three surveys was reduced from 57.7 to 24.6, then to 13.5 mg/g creatinine (n = 29). The reduction in exposure through both inhalation and potential dermal contact with 2-ME might account for the haematological recovery.

CONCLUSION

2-ME is a haematological toxin which leads to anaemia in exposed workers. However, the toxic haematological effects of 2-ME persist for only a short period of time after cessation or reduction of exposure.