|Development of a chronic zinc biotic ligand model for Daphnia magna|
Heijerick, D.G.; De Schamphelaere, K.A.C.; Van Sprang, P.A.; Janssen, C.R. (2005). Development of a chronic zinc biotic ligand model for Daphnia magna. Ecotoxicol. Environ. Saf. 62(1): 1-10
In: Ecotoxicology and Environmental Safety. Academic Press/Elsevier: Amsterdam, Netherlands etc.. ISSN 0147-6513, more
100 year floods; Bioavailability; Ecotoxicology; Environment; Heavy metals; Ligands; Models; Risk analysis; Toxicity; Zinc; Arthropoda [WoRMS]; Branchiopoda [WoRMS]; Cladocera [WoRMS]; Crustacea [WoRMS]; Daphnia magna Straus, 1820 [WoRMS]; Invertebrata; Fresh water
|Authors|| || Top |
- Heijerick, D.G., more
- De Schamphelaere, K.A.C.
- Van Sprang, P.A.
- Janssen, C.R., more
The individual effects of the cations Ca2+, Mg2+, Na+, and H+ on the chronic toxicity of Zn to the waterflea Daphnia magna were investigated in different series of univariate experiments, resulting in the development of a chronic Zn biotic ligand model (BLM) for this species. Using the mathematical approach based on a linear relationship between cation activity and metal activity at the ECx level, the following stability constants for binding of competing cations to the biotic ligand (BL) were derived: log KCaBL = 3.22, log KMgBL = 2.69, log KNaBL = 1.90, and log KHBL = 5.77. With the derived constants and a log KZnBL of 5.31, two different BLMs that predict chronic zinc toxicity (EC50, no observed effect concentration (NOEC)) for D. magna as a function of water characteristics were developed. Fractions of binding sites occupied by Zn at the considered effect levels EC50 and NOEC were 0.127 and 0.084, respectively. The NOEC-based model predicts the Zn toxicity within a factor of 2, while the chronic EC50 could be predicted within a factor of 1.5. In the future, these chronic Zn BLMs for D. magna can improve the ecological relevancy of zinc risk assessments by decreasing the bioavailability-related uncertainty of zinc toxicity.