DOI: 10.57745/rivqed
title: TableS12.csv

description: Estimated values of Time Weighed Mean (TWM) EC50 for specimen of D. magna exposed to lanthanides over 24h or 48h and for both rounds of definitives tests. The TWM EC50 were estimated using equations 4 and 5 in the main text and following the procedure described below.
Column A: symbol of the chemical element.
Column B: atomic mass of each chemical element.
Column C: First ‘1’ or second ‘2’ run of definitive tests.
Column D: Expsoure time (in hours)
Column E: EC50 values (nominal concentrations) for each element, test series (column C) and exposure time (column D).
Column F: Equation number (numbering in the main text) used to estimate the decrease in the exposure concentration over the test duration.
Column G: Estimated losses (%) calculated from the nominal EC50 values (column E) and the relationship between atomic mass and concentration losses (column F).
Column H: Estimated concentrations (%) remaining at the end of the test (100 – values in column G).
Column I: Estimated concentrations (in mg/L) remainig in solution at the end of the test.
Column J: Time Weighed Mean (TWM) concentrations (in mg/L) calculated using equation 2 in the main text (see explanation below for the details).
Column K: Experimentally measured concentrations (filterable 0.45 µm) at t=0h in solution amended with nominal concentrations indicated in column E. This information is available only for series 1 and Time 24h.
Column L: as above, but with measurements at t=24h
Column M: Time Weighed Mean (TWM) concentrations (in mg/L) calculated for the experimentally measured values in columns K and L.

Notes and assumptions:
a) Concentration decreases were experimentally measured in solutions spiked with lanthanides at the correspoding 24 h EC50 for the first round of tests (sections 3.1 and 3.2 of the main text).
b) A relationship existed between atomic mass and percentage concentration decrease after 24 and 48 h for the above EC50 data (equations 4 and 5 in section 3.2 and Figure 3A in the main text).
c1) For the second round of tests, equation 4 was assumed to hold for solutions initially spiked with lanthanides at the corresponding 24 h EC50. No experimental verification was performed for this.
c2) For both rounds of tests, equation 5 was assumed to hold for solutions initially spiked with lanthanides at the corresponding 48 h EC50. No experimental verification was performed for this.

Under assumptions c1 and c2, the TWM EC50 were estimated using a three step procedure. 
An example is provided below using Gd as a model element, for the first round of tests and the 48h EC50.

Step 1. Estimation of the percentage concentration decrease.
The concentration decrease for theoretical solutions initially spiked with LN concentrations equal to the nominal 48h EC50 was estimated using equation 5 (result is given in cell G22 of the CSV file).
Step 2. Estimation of concentration remaining in solution after 48 h.
The percentage concentration remaining in solution after 48h was estimated by the formula '100 - results of step 1' (cell H22 of the CSV file))
The concentration (in mg/L) remaining in solution after 48 h in was calculated by multiplying the results in cell H22 by the nominal EC50 (cell E22) and dividing by 100.
Step 3. The TWM EC50 48h was estimated using formula 2 in the main text.

Here is the example with the corresponding figures:
Nominal 48h EC50 (mg/L) for Gd in the first round of definitive tests: 6.2
Expected % decrease in concentration after 48h 74.1%
Estimated % concentration remaining is solution after 48h: 25.9%
Estimated concentration remaining in solution after 48h: 1.61 mg/L
Estimation of the TWM EC50 at 48h using formula 2 in the main text: 3.40 mg/L.