Scientists in Zulia state, in western Venezuela, are studying the effects on human health of vanadium, a mutagenic metal present in petroleum and in fossil fuel residues. “Vanadium is capable of causing changes in the genetic material of plants, animals and humans,” maintains Víctor Granadillo, of Zulia University. Petroleum has been drilled in the state for the last 90 years.

Granadillo's lab has recorded genetic mutations attributable to vanadium in fish, birds and reptiles. Exposure to the metal can cause changes in blood vessels, arterial pressure and the transport of calcium throughout the human body.

The air in Maracaibo, capital of Zulia, contains 40 to 170 parts of vanadium per billion, while in remote rural areas, the level is just one ppb vanadium.