Determination of Bisphenol a Bpa in Thermal Papers, Selected Soil Samples and the Effect of Temperature and Humidity on Its Concentration

Abstract

Exposure to Bisphenol A (BPA) is associated with various health complications globally. Whereas various research have been conducted in Asia, North America and Europe, limited work has been conducted inAfrica on BPA . The aim of the research was to quantify the amount of BPA in thermal paper and soil samples, and study the effect of temperature and humidity on the concentration of BPA in thermal papers. Soil samples were collected from Dandora Dumpsite where some of the wastes containing BPA get deposited and TUK-garden which was the control site. Thermal paper samples were collected from selected supermarkets and ATM Lobby points within the Central Business District (CBD) of Nairobi City County, in March 2017. Sample analysis was done using GC/MS method after extraction in organic solvent. The method LOD was 0.16 mg/g, while the percentage recoveries were 86% and 83% for thermal paper and soil samples, respectively. The highest concentration of BPA in the bank thermal papers was 3.59±0.24 mg/g, while the lowest concentration was 1.94±0.25 mg/g. The lowest BPA concentration from the supermarket thermal papers was 1.08±0.06 mg/g while the highest BPA concentration was 2.75±0.14 mg/g. The unused thermal papers bought locally had a BPA concentration of 1.74±0.89 mg/g, while both unprinted and printed non-thermal papers did not show any trace of BPA. The soil samples from Dandora Dumpsite site 20 had the highest BPA concentration at 154.82±12.72 mg/g while TUK-garden soil had the lowest BPA concentration at 0.49±0.12 mg/g. The results showed that thermal paper samples collected from the bank’s ATM Lobbies had higher concentration of BPA than the thermal papers from the supermarkets. Investigation of the effect of temperature temperature and humidity on BPA extraction showed higher BPA concentrations in the thermal papers at higher temperature and humidity, suggesting that an increased temperature and humidity increased availability of BPA on extraction leading to higher recoveries.