Environmental Safety

Environmental Fate of Bisphenol A

The vast majority of BPA produced, greater than 99.9%, is consumed at manufacturing sites to make products such as polycarbonate plastic or epoxy resins (Staples et al, 1998). Bisphenol A dust (particulates) is controlled by workplace practices and engineering design and is not a significant contributor to environmental exposures. The relatively small amount of vapor released to the atmosphere is rapidly degraded by sunlight. Low levels may be released to the environment in the effluent water from biological wastewater treatment plants.

The distribution of BPA in the environment can be predicted by its physical properties (Staples et al, 1998). Bisphenol A is a solid with low volatility at ambient temperature conditions, water solubility of 120-300 milligrams per liter and a greater solubility at alkaline pH values. Based on these properties, a simple equilibrium model predicts that about 50% of BPA in the environment has the potential to bind to sediments or soils with the rest remaining in the water column.

Bisphenol A has been shown to be readily biodegradable, meaning that it breaks down rapidly in the environment. A study using guidelines of the Organization for Economic Cooperation and Development demonstrated that bisphenol A meets its criteria for classification as "readily biodegradable."

Biodegradation plays a major role in the removal of BPA from the environment. Recent studies demonstrate that BPA degrades rapidly in surface waters and sediments taken from a wide variety of geographies (including those with no known exposure history), suggesting that microorganisms with the capability to degrade BPA are ubiquitous in the environment (Klecka et al, 2001).

Real world monitoring studies also confirm that BPA is rapidly biodegraded and extensively removed in wastewater treatment systems. For instance, 92-98% removal was reported in the most common type of sewage treatment system, an activated sludge plant (Staples et al, 1998).

The trace amounts of BPA remaining in treated wastewater will continue to biodegrade in receiving waters and downstream of treatment plants (Klecka et al, 2001). Studies using real world surface water samples taken from various geographies demonstrate rapid degradation with a half-life in the range of 1 to 4 days (i.e., time for 50% degradation).