Fellowship Recipient ' s Name : Erik Olstad Project Title : Spatial distribution and accumulation of nickel in serpentinite soil

Background The ubiquity of nickel in the environment and its common presence in food and water mean that humans are constantly exposed to nickel. Although nickel is not acutely toxic at low levels, it is a carcinogen and has been linked to cellular oxidative stress [1]. Soils that develop on serpentinite, a metamorphic rock type derived from ultramafic igneous rocks (and the state rock of California), are well known for their elevated concentrations of nickel and chromium [2]. The degree of nickel accumulation in serpentinite soil horizons, thus its bioavailability to plants, is controlled by soil characteristics such as pH, amount of organic matter, clay and iron oxide content, and competitive adsorption with other dissolved species [3-7]. These biogeochemical factors are influenced strongly by climate, rainfall, vegetation, and weathering of primary ultramafic minerals. In locations where serpentinite and ultramafic soils have been used for agriculture, nickel transfer to plants has been documented [8], with potential transfer through the food chain to humans.