Leaching of bisphenol A (BPA) to seawater from polycarbonate plastic and its degradation by reactive oxygen species.

In this study, (1) change in the concentration of bisphenol A (BPA) leached from polycarbonate (PC) tube to control water (BPA free), seawater and river water at 20 and 37 °C as a function of time, (2) the fate of BPA caused by addition of H2O2 and Fe3+ to seawater containing BPA leached from PC tube were assessed. BPA leached from PC tube to all water samples increased with the ascendant of temperature and with the passage of time. The BPA leaching velocity in seawater was the fastest in three samples (11 ng/day for seawater, 4.8 ng/day for river water 0.8 ng/day for control water at 37 °C). BPA leaching velocity from PC tube was significantly high at pH 8 (50 mM Na2HPO4) and increased dose-dependently. There was no difference in the velocity of BPA among the 50 mM phosphate-buffers at pH 6.5, 7.0 and 7.5. BPA was leached three times higher by addition of Na+ than K+. However, the higher the K+ concentration, the larger the BPA leached from PC tube. Na+ mixed with PO4− was effective on BPA leaching from PC tube, but not with SO4− or Cl−. The results suggested that BPA leaching from PC tube would be attributed to the concentration of bibasic phosphate such as Na2HPO4 and K2HPO4 in water samples. BPA was degraded in both control water and seawater in the presence of radical oxygen species, but the degradation rate was lower in seawater than in control water, suggesting that anti-oxidative system exists in seawater. Neo-synthesized substance in both control water and seawater in the presence of reactive oxygen species was identified as BPA-quinone by LC–MS.