Photodegradation of Butylated Hydroxyanisole in Aqueous Solutions

Butylated hydroxyanisole (BHA) is a synthetic chemical widely used in a variety of foods, cosmetics, pharmaceuticals, and rubber and petroleum products, mainly as an antioxidant. Examples of food products containing BHA as a preservative include cereals, snacks, baked products, meat, and sweets. Its extensive use has allowed the chemical to spread into environments such as sewage and surface water, as well as in human tissues. The chemical is anticipated to be a human carcinogen but its detailed toxicity is still under research. Due to its chemical structure, BHA is susceptible to transformation under exposure to ultraviolet (UV) light. There is limited research on the photodegradation of BHA; however, published data on its photodegradation in aqueous environments, its half-life, and its photoproducts are scarce. In this research, the photodegradation pathways and photoproducts of BHA in simulated aqueous environments were investigated to provide data that could benefit the environmental management and safety assessment of BHA, as well as the development of alternatives to the chemical. BHA (100 μM) in aqueous solution was exposed to UV light using a solar simulator set to an irradiance of 750 w/m², with samples taken at several time points between 0 - 24 hours. Samples were analyzed using high performance liquid chromatography with UV absorbance detection (HPLC-UV). Under these conditions, the photodegradation half-life of BHA was 3.75 hours, and several photoproducts were observed. Ongoing research includes identifying photoproducts, investigating the photodegradation of BHA under different simulated environmental conditions such as different pH and addition of natural organic matter, and extending the methods to study the photodegradation of chemicals that are structurally similar to BHA.