Melinda Wenner writes in the August issue of Mother Jones about mercury content in high fructose corn syrup. Lye is an ingredient used in making HFCS, it separates corn starch from the kernel. Some chemical companies make lye by pumping salt through vats of mercury. Trace elements of mercury are then passed on to the consumer.
FDA researcher Renee Dufault sent HFCS samples from three manufacturers that used lye to labs for testing. The labs found mercury in most of the samples. When Dufault presented her findings to the FDA's center for food safety she was instructed not to do any more investigations. Not long after that the FDA took her off field investigations and put her behind a desk. She has since retired. The article isn't online yet, Mother Jones doles out content of their current issue piecemeal.
The Ethicurean talked about it back in January.