Five Nitroaromatic Compounds To Guppy Fish Single And Joint Toxic Effects

Guppies (Poecilia reticulata) were exposed to 2,6-dinitrotoluene (2,6-DNT), 2,4-dinitrotoluene (2,4-DNT), 4-nitrotoluene (4-NT), m–dinitrobenzene (m-DNB) and 2,4-dinitroaniline (2,4-DNAn) at one to two weeks aged stages. Assays for individual toxicity, which included acute toxicity in 96h, accumulation toxicity and subacute toxicity in 50 days, and combination toxicity were used. The results of acute toxicity showed that these five compounds had moderate toxicity. The respective 96h median lethal concentrations and 95% confidence intervals contained that 2,6-DNT=25.33(24.78~25.94)mg/L, 2,4-DNT=24.57(23.99~25.12)mg/L, 4-NT=59.81(59.02~60.95)mg/L, m-DNB=19.13(18.20~19.95)mg/L, 2,4-DNAn=13.82(13.21~14.49)mg/L. Their toxicity order is 4-NT<2,4-DNT≈2,6-DNTdays.Toxic unit analysis, toxic unit illustration and additive index were adopted to evaluate combination toxicity. The compounds in mixture conformed to equal toxicity. The results revealed that the combination toxicity of 2,6-DNT and 2,4-DNT was independent or antagonistic effect at 24h, but synergistic effect was observed from 48h to96h; 2,6-DNT and 4-NT showed synergistic effect from 24h to 96h, the same effect also was found in mixture of 2,6-DNT and m-DNB; 2,6-DNT and 2,4-DNAn displayed independent or antagonistic effect from 24h to 96h; at last, 2,6-DNT, 2,4-DNT and 4-NT exhibited synergistic effect from 24h to 96h。...