There was a time when it was thought that human exposure to bisphenols comes mainly from canned foods, water and beverage bottles, and dental sealants. This perception has changed rapidly with the realization that thermal paper used at cash registers contains unusually high amounts of monomeric BPA & BPS. It could be a potential source of human exposure and subsequent absorption through the skin and, possibly, muco-cutaneous junctions.
The human exposure of BPA through polycarbonate plastics (pps) appears to be real but minor when compared to certain other sources, such as the cash register receipt. In general, pps are thought to contain small amounts of monomeric and unpolymerized BPA which could migrate to food and other consumables. The process of migration can be facilitated by heating and various methods of sterilization. Large amounts of monomeric BPA are used in the manufacture of thermal and carbonless papers to which humans are routinely exposed. Unlike pps, BPA in the CRS can be rapidly released into the environment and become a significant source of human exposure through dermal contact and absorption.
Thermal papers pose problem to human toxicity not only directly but also through recycling and waste runoff waters. Emerging evidence suggests that BPA is present in the industrial effluents and recycled municipal waters. Thermal paper recycling generates potential environmental and ecological risk to plants, aquatic species and other organisms. Bpa exposure has shown to increase nitrate levels in plants studies have shown that higher amounts of BPA are present in recycled thermal papers than the virgin papers. Based on the urinary levels and BPA exposure studies, the total BPA exposure from the dietary and non-dietary sources exceeds the current tolerable daily intake of 50 mg/kg bw/day. The increased BPA levels in the environment could be due to urbanization and the increased use of thermal and BPA-containing papers. Not only BPA, bps is also is a major concern as they are also found in thermal papers.
