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Title: Periphyton and abiotic factors influencing arsenic speciation in aquatic environments: Periphyton alters arsenic speciation

Benthic periphytic biofilms are important food sources at the base of aquatic ecosystems. These biofilms also sit at the interface of oxic waters and hypoxic sediments, and can be influenced by or influence trace element speciation. In the present study, we compared arsenic (As) enrichment in periphyton exposed to arsenate (As[V]) or arsenite (As[III]) (20 μg/L, static renewal, 7 d), and we found similar accumulation patterns of total As (101 ± 27 and 88 ± 22mgkg -1 dry wt, respectively). Periphyton As was 6281- and 6684-fold higher than their aqueous exposures and occurred primarily as As(V). When these biofilms were fed to larval mayflies, similar total As tissue concentrations (13.9 and 14.6mgkg -1 dry wt, respectively) were observed, revealing significant biodilution (~10% of their dietary concentrations). Finally, we investigated the influence of aeration and periphyton presence on As speciation in solutions and solid phases treated with As(III). Predominantly As(III) solutions were slowly oxidized over a 7-d time period, in the absence of periphyton, and aeration did not strongly affect oxidation rates. However, in the presence of periphyton, solution and solid-phase analyses (by microscale x-ray absorption spectroscopy) showed rapid As(III) oxidation to As(V) and an increasing proportion of organo-As forming overmore » time. Thus periphyton plays several roles in As environmental behavior: 1) decreasing total dissolved As concentrations via abiotic and biotic accumulation, 2) rapidly oxidizing As(III) to As(V), 3) effluxing organo-As forms into solution, and 4) limiting trophic transfer to aquatic grazers.« less
 [1] ;  [2] ;  [3] ;  [4] ; ORCiD logo [1]
  1. North Carolina State Univ., Raleigh, NC (United States). Dept. of Biological Sciences
  2. Federal Univ. of Vicosa, Vicosa, Minas Gerais (Brazil). Dept. of Soil Science
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
  4. North Carolina State Univ., Raleigh, NC (United States). Dept. of Crop and Soil Sciences
Publication Date:
Grant/Contract Number:
AC02-76SF00515; AC02-98CH10886
Accepted Manuscript
Journal Name:
Environmental Toxicology and Chemistry
Additional Journal Information:
Journal Volume: 37; Journal Issue: 3; Journal ID: ISSN 0730-7268
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; Abiotic transformation; Aquatic plants; Bioconcentration; Biotransformation; Metal speciation; Arsenic
OSTI Identifier: