Determining the Effects of Major Cations (K+, Na+, Ca2+, Mg2+) and pH on Scirpus mariqueter to Assess the Heavy Metal Biotoxicity of a Tidal Flat Ecosystem

ABSTRACT Dong, L.; Li, X.; Liu, X.; He, K., and Jiang, X., 2017. Determining the effects of major cations (K+, Na+, Ca2+, Mg2+) and pH on Scirpus mariqueter to assess the heavy metal biotoxicity of a tidal flat ecosystem. The biotic ligand model (BLM) as a mechanistic bioavailability model has been used to assess the risk of metals on various ecosystems. In this study, the effects of major cations (K+, Na+, Ca2+, Mg2+) and pH on root elongation of the salt marsh plant Scirpus mariqueter were investigated by laboratory experiments, and then a tidal flat sediment–BLM was developed successfully to assess heavy metal biotoxicity on a tidal flat ecosystem for the first time. The results showed that the increase of Na+ activities could decrease Cu2+ toxicity to S. mariqueter. A nonlinear relationship was observed between the median effective concentration (EC50) and H+ activity over the pH range (5.55–8.22). The results indicated that H+ did not compete with Cu2+ for the binding sites within the roots of S. mar...