Abstract: 1,4-Dinitrobenzene(1,4-DNB) is one of the preferential toxicants stipulated by OECD and EPA of USA.With Oryzias latipes, which were chosen as the acceptors according to the international standard, the acute,subacute and accumulative toxicity experiments were conducted.The threshold mass concentration of O.latipes was 1.360 mg/L.The subacute experiment showed that O.latipes were hardly affected when the mass concentration of 1,4-DNB was 0.0292 mg/L, but were significantly affected when the mass concentration of 1,4-DNB was 0.0420, 0.0608 or 0.0875 mg/L in contrast to the control sample(P＜0.05).The accumulative rate(K) was 1.21.This shows that there are significant accumulative actions of 1,4-DNB in fish.When the mass concentration of 1,4-DNB is in the range of 0.032-0.320 mg/L, the higher the 1,4-DNB concentration, the more strongly the Na⁺/K⁺-ATPase is inhibited.The calculated IC50 values in gill, kidney and liver of O.latipes are 0.128, 0.132 and 0.428 mg/L, respectively.

Key words: 1,4-Dinitrobenzene (1,4-DNB), Oryzias latipes, Toxicity, Na⁺/K⁺-ATPase activity