title: Evaluating trivalent chromium toxicity on wild terrestrial and wetland plants.
abstract: Elevated chromium levels in soil from mining can impact the environment, including plants. Mining of chromium is concentrated in South Africa, several Asian countries, and potentially in Northern Ontario, Canada, raising concerns since chromium toxicity to wild plants is poorly understood. In the first experiment, concentration-response tests were conducted to evaluate effects of chromium on terrestrial and wetland plants. Following established guidelines using artificial soil, seeds of 32 species were exposed to chromium (Cr(3+)) at concentrations simulating contamination (0-1000 mg kg(-1)). This study found that low levels of chromium (250 mg kg(-1)) adversely affected the germination of 22% of species (33% of all families), while higher levels (500 and 1000 mg kg(-1)) affected 69% and 94% of species, respectively, from 89% of the families. Secondly, effects on seedbanks were studied using soil collected in Northern Ontario and exposed to Cr(3+) at equivalent concentrations (0-1000 mg kg(-1)). Effects were less severe in the seedbank study with significant differences only observed at 1000 mg kg(-1). Seeds exposed to Cr(3+) during stratification were greatly affected. Seed size was a contributing factor as was possibly the seed coat barrier. This study represents an initial step in understanding Cr(3+) toxicity on wild plants and could form the basis for future risk assessments.
authors.affiliation: Environment and Climate Change Canada, Science and Technology Branch, 1125 Colonel By Drive, Carleton University, Ottawa, ON K1A 0H3, Canada; Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada.
authors.forename: A O
authors.initials: AO
authors.lastname: Lukina
authors.affiliation: Environment and Climate Change Canada, Science and Technology Branch, 1125 Colonel By Drive, Carleton University, Ottawa, ON K1A 0H3, Canada. Electronic address: Celine.Boutin@Canada.ca.
authors.forename: C
authors.initials: C
authors.lastname: Boutin
authors.affiliation: Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada.
authors.forename: O
authors.initials: O
authors.lastname: Rowland
authors.affiliation: Environment and Climate Change Canada, Science and Technology Branch, 1125 Colonel By Drive, Carleton University, Ottawa, ON K1A 0H3, Canada.
authors.forename: D J
authors.initials: DJ
authors.lastname: Carpenter
mesh_terms: D002170:Canada; D002857:Chromium / Q000633:toxicity*; D018525:Germination / Q000187:drug effects*; D010944:Plants / Q000187:drug effects*; D012639:Seeds / Q000187:drug effects* / Q000254:growth & development; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000633:toxicity*; D053833:Wetlands
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002857:Chromium
keywords: Chromium mining; Cr(3+) phytotoxicity; Seed germination; Soil seedbank; Wild plants