Water treatment plants increasingly use methods to oxidize undesirable constituents and convert them into presumably less harmful chemicals called transformation products. Past research has examined byproducts of chlorination but little is known about the products formed during oxidation with hydrogen peroxide and UV light, which are especially relevant in water reuse.

The water quality and health implications of phenol transformation products were studied by researchers from Oxidation processes convert commonly used chemicals into harmful compounds that affect cellular function and metabolism.Johns Hopkins University and the University of California, Berkeley. Phenols were first oxidized using peroxide radicals, a process often used by water treatment plants. Amino acids and proteins were then added to the mix, and depending on what chemical reactions took place, the team could do some backwards calculation to determine what compounds the phenols must have turned into in the earlier step.

Transformation products identified included 2-butene-1,4-dial, a compound that is known to induce DNA damage and other adverse effects on human cells. Furan, a toxic compound in cigarette smoke and car exhaust, is also converted into 2-butene-1,4-dial in the body, and it may be this conversion that's responsible for the toxicity of those fumes.

The researchers observed 37 different protein targets which are involved in a range of biological processes, from energy metabolism to protein and steroid synthesis, were affected after mouse liver proteins were exposed to the compound. One enzyme that 2-butene-1,4-dial was shown to bind is critical in apoptosis, or "cell suicide." Inhibiting this compound in a living organism might lead to unchecked cell proliferation, or cancer growth. Other compounds that 2-butene-1,4-dial interferes with play key roles in metabolism.

The researchers plan to expand these methods to the screening of other types of compounds and multiple chemicals. The study is published in the Proceedings of the National Academy of Sciences.