Abstract: In the present work, a species sensitivity distribution (SSD) method was used to assess the ecological risk of common heavy metals to marine organisms. The ecological risk was characterized by potentially affected fraction (PAF) of species in relation to concentration of the toxic materials. According to the investigation data obtained at 21 stations in the Jiulongjiang Estuary in May, August and November, the PAFs of seven heavy metals (As, Cd, Cr, Cu, Hg, Pb, and Zn) to marine organisms were calculated. The results showed that As had the highest PAF among the seven heavy metals at each station of the Jiulongjiang Estuary. Spatially, the multi-substance PAF (msPAF) in May was higher than in other months. Temporally, the msPAF of the Stations 1-7 (from the Xixi Stream to the Haimen Isle of the Jiulongjiang Estuary) suffered from heavier pollution. In particular, the pollution status of the Station 2 and Station 5 was the most serious among all the investigated stations.

Key words: P and K fertili-zer, panicle primordium differentiation stage, early rice, low temperature, leaf temperature, physiological characteristics, yield.