Evaluating trivalent chromium (CRIII) toxicity on wild terrestrial plants

Elevated chromium levels in soil from mining can impact the environment, including plants. Extensive chromite-ore deposits have been discovered in the Ring of Fire region, thus mining may increase. Chromium toxicity on wild plants is poorly understood. Concentration-response experiments were conducted to evaluate the effects of chromium on terrestrial plants. Using artificial soil, seeds of 32 species were exposed to chromium (CrIII) at concentrations (0-1000 mg/kg) simulating contamination levels. Many plants were not affected at low concentrations, yet higher concentrations were harmful to all species. Secondly, seedbank soils were collected in four habitats near the Ring of Fire and were exposed to chromium at equivalent concentrations as before. More seeds germinated from the lakeshore, with reductions in species/seedlings numbers as chromium increased. This was similar for the upland. This study represents the first step in understanding effects of chromium on plants and could form the basis for risk assessments.