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- Title
Lead toxicity to Lemna minor predicted using a metal speciation chemistry approach.
- Authors
Antunes, Paula M.C.; Kreager, Nancy J.
- Abstract
In the present study, predictive measures for Pb toxicity and Lemna minor were developed from bioassays with 7 surface waters having varied chemistries (0.5-12.5 mg/L dissolved organic carbon, pH of 5.4-8.3, and water hardness of 8-266 mg/L CaCO3). As expected based on water quality, 10%, 20%, and 50% inhibitory concentration (IC10, IC20, and IC50, respectively) values expressed as percent net root elongation (%NRE) varied widely (e.g., IC20s ranging from 306 nM to >6920 nM total dissolved Pb), with unbounded values limited by Pb solubility. In considering chemical speciation, %NRE variability was better explained when both Pb hydroxides and the free lead ion were defined as bioavailable (i.e., f{OH}) and colloidal Fe(III)(OH)3 precipitates were permitted to form and sorb metals (using FeOx as the binding phase). Although cause and effect could not be established because of covariance with alkalinity ( p = 0.08), water hardness correlated strongly ( r2 = 0.998, p < 0.0001) with the concentration of total Pb in true solution ([Pb]T_True solution). Using these correlations as the basis for predictions (i.e., [Pb]T_True solution vs water hardness and %NRE vs f{OH}), IC20 and IC50 values produced were within a factor of 2.9 times and 2.2 times those measured, respectively. The results provide much needed effect data for L. minor and highlight the importance of chemical speciation in Pb-based risk assessments for aquatic macrophytes. Environ Toxicol Chem 2014;33:2225-2233. © 2014 SETAC
- Subjects
LEAD toxicology; LEMNA minor; METALLURGIC chemistry; BIOLOGICAL assay; DISSOLVED organic matter; CHEMICAL speciation; MACROPHYTES
- Publication
Environmental Toxicology & Chemistry, 2014, Vol 33, Issue 10, p2225
- ISSN
0730-7268
- Publication type
Article
- DOI
10.1002/etc.2688