2.8. Dose–response endpoints
The dose–response relationship between nZnO and testing organisms
was studied in terms of the following end-points, namely, root number,
stem length, leaf area, and nutrient solution utilization as a function of
nZnO concentration. By plotting the magnitude of a specific endpoint as
a function of nZnO concentration, the EC value can be calculated using
the computer program, Toxicity Relationship Analysis Program (TRAP),
ver. 1.00 (USEPA, 2002), according to the following logistic equation:
Y ¼ Y0
1 þ e4S X−X50 ð Þ
ð2Þ