Toxicity of phenolic compounds in relation to the size of a freshwater fish, Notopterus notopterus (Pallas).

Fish, Notopterus notopterus, in four sizes (4.5 +/- 1.0, 9.0 +/- 1.0, 14.5 +/- 1.2, and 22.6 +/- 1.8 cm in length) were exposed to phenol (P), 2,4-dinitrophenol (DNP), and pentachlorophenol (PCP) separately, and also to their three combinations (PCP + DNP)/P (highly antagonistic), (DNP + P)/PCP (additive), and (P + DNP)/PCP (highly synergistic) to evaluate the effect of fish size on the toxicity of these chemicals separately and in combination. The results reveal that with increased fish size (from 4.5 + 1.0 to 14.5 + 12 cm in length) toxicity of phenolic compounds decreased. On the contrary, the larger size fish (22.6 +/- 1.8 cm in length) was comparatively more susceptible. This indicates that change in fish size does influence the toxicity of phenolic compounds.