Analytical chemistry allows an accurate quantification of the total concentrations of a range of chemicals in different media of the ecosystems and contaminated sites, but the numerical values do not have direct relevance to the toxicity of them because the measured concentrations do not represent the active fraction that imposes toxic effects on organisms. It is apparent that an assessment of pollutant concentrations in ecosystems shall be made with new innovation to obtain the organism exposed concentrations so that the subsequent toxicological effects based on these data can provide reliable estimate on toxicity for management decision accordingly. Applied Toxicology, e.g., Ecotoxicology, and Environmental Toxicology, therefore shall have a different scientific framework to adopt the... use of a new concentration term for pollutants to establish a close relationship between the effective concentration in the ecosystem and the toxicity to the organisms to make a meaningful understanding of the ecotoxicology and environmental toxicity. In addition, the choice of the organisms as indicators for chemical toxicity assays is another critical issue and the organism shall be selected with an international consensus to establish a solid baseline for comparable results from different laboratories around the world. Doing this way, the Applied Toxicology can make great advancement and contributes to the society better on a more competitive level based on exact science similar to physical sciences today. A greater opportunity is ahead and effective action needs to be taken collectively and immediately to advance the new knowledge of this research subject.