Evaluating trivalent chromium toxicity on wild terrestrial and wetland plants. (November 2016)

• Record Type: Journal Article
• Authors: Lukina, A.O.; Boutin, C.; Rowland, O.; Carpenter, D.J.
• Is Part Of: Chemosphere. Volume 162(2016)
• Page Start: 355
• Page End: 364
• Publication Date: 2016-11
• Subjects: Chromium mining -- Cr3+ phytotoxicity -- Wild plants -- Soil seedbank -- Seed germination; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2016.07.055
• Languages: English
• ISSNs: 0045-6535

Abstract

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. Graphical abstract: Species sensitivity ranks using EC25s for the tested wild species, crops [bold], and trees [underlined] exposed to Cr 3+ in artificial soil during the concentration-response experiments. Of the 32 species tested, nine species required stratification and were thus initially exposed to chromium either immediately after stratification [A] or during stratification [B]. Only species exhibiting effects are included. Highlights: Cr 3+ affected many of the 32 terrestrial and wetland plant species growing in soil. Lowest dose tested (250 mg kg −1 ) affected 22% plant species from 33% of families. Highest dose tested (1000 mg kg −1 ) affected 69% plant species from 89% of families. Seeds in seedbank of natural soils were only affected at 1000 mg kg −1 . Toxicity level to seeds exposed to Cr 3+ during stratification increased.