Field metal mixture toxicity: linking freshwater biota species diversity to chemical speciation and bioavailability

Understanding metal and proton toxicity under field conditions requires
consideration of the complex nature of chemicals in mixtures. We have
previously demonstrated a novel method that relates streamwater concentrations
of cationic metallic species and protons to a field ecological index of
biodiversity (EPT species richness). The model (WHAM-FTOX) has also
been used to assess regional temporal trends involving comparison of modelling
and observations. This presentation communicates a new application of
this model to lake zooplankton species richness. The field indicator used in
this work was the combined richness of Cladocera and Copepoda zooplankton
species. The new modelling has been undertaken with over 1000 data
from surveys of 185 individual lakes in 7 different geographic regions. We
present data for general model fitting and details from individual regions,
including temporal trends.