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Preparation and characterization of nickel‐spiked freshwater sediments for toxicity tests: Toward more environmentally realistic nickel partitioning
Author(s) -
Brumbaugh William G.,
Besser John M.,
Ingersoll Christopher G.,
May Thomas W.,
Ivey Chris D.,
Schlekat Christian E.,
Garman Emily Rogevich
Publication year - 2013
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.2272
Subject(s) - nickel , environmental chemistry , environmental science , nickel compounds , characterization (materials science) , toxicity , chemistry , materials science , nanotechnology , organic chemistry
Two spiking methods were compared and nickel (Ni) partitioning was evaluated during a series of toxicity tests with 8 different freshwater sediments having a range of physicochemical characteristics. A 2‐step spiking approach with immediate pH adjustment by addition of NaOH at a 2:1 molar ratio to the spiked Ni was effective in producing consistent pH and other chemical characteristics across a range of Ni spiking levels. When Ni was spiked into sediment having a high acid‐volatile sulfide and organic matter content, a total equilibration period of at least 10 wk was needed to stabilize Ni partitioning. However, highest spiking levels evidently exceeded sediment binding capacities; therefore, a 7‐d equilibration in toxicity test chambers and 8 volume‐additions/d of aerobic overlying water were used to avoid unrealistic Ni partitioning during toxicity testing. The 7‐d pretest equilibration allowed excess spiked Ni and other ions from pH adjustment to diffuse from sediment porewater and promoted development of an environmentally relevant, 0.5‐ to 1‐cm oxic/suboxic sediment layer in the test chambers. Among the 8 different spiked sediments, the logarithm of sediment/porewater distribution coefficient values (log K d ) for Ni during the toxicity tests ranged from 3.5 to 4.5. These K d values closely match the range of values reported for various field Ni‐contaminated sediments, indicating that testing conditions with our spiked sediments were environmentally realistic. Environ Toxicol Chem 2013;32:2482–2494. © 2013 SETAC