[SYSTEM] You are answering a single information-extraction question. Use ONLY the supplied source material. Do not use prior knowledge. Give a clear, concrete answer with the specific number, name, year, or value asked for. [USER] --- SOURCE ARTIFACT (M3-L4) --- # Table 135 — No caption detected. PDF page: 584 ```csv Ratio of concentrations of heavy metals used in the mixture (Chiral sta n the mixture (Chiral sta.,r rt r Artemia,Synergism.\ ia \ Acartia 120,II,II LEBaL,20,be) T2205 0k,35,8 25:1,32,5 5OuE,22,12 100:1,18,16 400:1,26,14 ``` --- END ARTIFACT --- Question: What would you report as the table-based survival estimate for Artemia at 250:1? Answer concisely. Cite the row/cell/section you used. State your final numerical answer clearly.