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Toward Validation of Toxicological Interpretation of Diffusive Gradients in Thin Films in Marine Waters Impacted by Copper
Author(s) -
Strivens Jonathan,
Hayman Nicholas,
Rosen Gunther,
MyersPigg Allison
Publication year - 2020
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.4673
Subject(s) - diffusive gradients in thin films , dissolved organic carbon , mytilus , environmental chemistry , biotic ligand model , genetic algorithm , chemistry , copper , ec50 , water quality , metal , ecology , biology , biochemistry , organic chemistry , in vitro
Abstract Determination of the median effective concentration (EC50) of Cu on Mytilus galloprovincialis larvae by diffusive gradient in thin films (DGT) has been shown to effectively reduce the need to consider dissolved organic carbon (DOC) concentration and quality. A standard toxicity test protocol was used to validate previously modeled protective effects, afforded to highly sensitive marine larvae by ligand competition, in 5 diverse site waters. The results demonstrate significant narrowing of M. galloprovincialis toxicological endpoints, where EC50s ranged from 3.74 to 6.67 μg/L as C DGT Cu versus 8.76 to 26.8 μg/L as dissolved Cu (Cu DISS ) over a DOC range of 0.74 to 3.11 mg/L; Strongylocentrotus purpuratus EC50s were 10.5 to 19.3 μg/L as C DGT Cu versus 22.7 to 67.1 μg/L as Cu DISS over the same DOC range. The quality of DOC was characterized by fluorescence excitation and emission matrices. The results indicate that the heterogeneity of competing Cu binding ligands, in common marine waters, minimizes the need for class determinations toward explaining the degree of protection. Using conservative assumptions, an M. galloprovincialis C DGT Cu EC50 of 3.7 µg/L and corresponding criterion maximum concentration C DGT Cu of 1.8 µg/L, for universal application by regulatory compliance‐monitoring programs, are proposed as a superior approach toward both integration of dynamic water quality over effective exposure periods and quantification of biologically relevant trace Cu speciation. Environ Toxicol Chem 2020;39:873–881. © 2020 SETAC