Study On Setting Occupational Exposure Limit For Bisphenol A

Bisphenol A (BPA), a widely used compound, is used in the production of phenol resins, polyacrylates, and polyesters, and especially in epoxy resins and polycarbonate plastics, and is known as a weak environmental estrogen. BPA has been tested in oral toxicity studies using rats, mice, dogs and non-human primates. Those experiments exhibited a decreased body weight, early puberty, abnormal developments of reproductive organs, especially effect to the brain development, emotion, memory, Sexual Dimorphism behavior of the offspring with the exposure during pregnancy lactation period. The majorl effect was slight upper respiratory tract epithelium inflammation in the inhalation studies. Epidemiological studies indicate that BPA exposure may have a relationship with obesity, diabetes, heart disease, hormone level in the body, precocious puberty and abnormal behavior of the children.People are widely exposed to BPA through many known and unknown pathways. Biomonitoring studies reveal that more than90%of urine is BPA detectable in USA and Canada, while about50%in China. Human exposure to bisphenol A may be occupational, with a higher exposure, which means a higher health risk. Inhalation in the form of dust is the most relevant pathway. Germany and Holand set an occupational limit,5mg/m3, in1997and1999respectively. While more and more studies focus on BPA, the Scientific Committee on Occupational Exposure Limits (SCOEL) gave a recommended limit,10mg/m3, in2004. In2010, Germany confirmed the limit set in1997. There is no occupational exposure limit for BPA in China, which is necessary to protect the workers.In this study, literature overview, environmental monitoring, the urinary BPA concentration determination and data analysis of occupational physical examination data in an epoxy resin factory (choosing a water plant as a control) were carried out, to validate the occupational limit (TWAs) for BPA,5mg/m3, and a method to determine the BPA concentration in the air.The study gave a method to determine the air BPA concentration by HPLC-UV/FLD, preferring to fluorescence detector (FLD), with a second choice of uv dectector (UV) if FLD was absent. This method have a low limit of dectection (LOD),5μg/L, converted to air concentration as10ng/m3based air sampling volume of960L. It has a wide linear range of0.02～20ng/m3, allowing to measure the wide concentration range. It is convenience to use because of the multiple choices of the detectors and temperature.The study showed that the median short-time exposure level of the workers was4.07μg/m3, with a range of0.03～3185.12μg/m3; the median level of TWA8is2.2μg/m3, which was much higher than the general population, with a range of0.01～6270.13μg/m3, and the95%upper bound was about1mg/m3。Compare to the control (The median of creatinine-adjusted urinary BPA levels are2.96μg/L,2.56μg/L pre-and post-shift), the workers in the resin had a higher BPA exposure level (The median of creatinine-adjusted urinary BPA levels are11.31μg/L,16.17μg/L). The median urinary level of the resin workers was higher than the75%upper bound of the control. Inhaling the air containing a high level of BPA was the main source of the high urinary BPA level of the resin workers。There was no observed health problem related to the BPA exposure, after analyzing the occupational physical examination data in the resin factory and the water plant. The different morbidity between the two group was not significant(p>0.05), considering BPA can causue upper respiratory tract epithelium inflammation. The different abnormal rate of the ECG and fasting blood glucose between the two group was not significant(p>0.05), considering BPA may be related to the heart disease and diabetes.Up to now, Germany and Holand have set an occupational limit for BPA,5mg/m3. In2004, SCOEL gave a recommended limit,10mg/m3. In the study, in view of no observed health problem related to the BPA exposure at the current exposure level, Also based on the overview of the toxicity and epidemiology study, metabolic kinetics estimating and the limits of Germany and Holand, it recommend that the of BPA in the workplace air is5mg/m3in China.