The Impact Of Steelmaking Slag On The Marine Ecology Environment And Exploration Research Of Carbon By Biology

It is an international hotspot by using "iron fertilizer" to increase marine primary productivity, absorbing atmospheric CO2 and reducing the greenhouse effect. The feasibility of slag as the "Iron fertilizer" was explored by studying the effect of steelmaking slag on growth of marine microalage, the water quality and marine life. Firstly, the effect of slag on water quality was studied including metals, nutrients, pH, COD and turbidity. It was revealed that the nutrients had different levels of dissolution, the majority of the metals was absorbed except individual metal but basically reached the first or second water standard; pH was found to increase significantly in small closed water and was greater than the water quality of third or fourth (6.8～8.8); COD was found under the first seawater quality; The turbidity was greater if the slag was smaller and the concentration was greater. But the proportion of slag was generally larger, it can subside faster in water, so in practical application process the transparency of water would not be adversely affected. Secondly, the effect of slag on the marine benthic - Mytilus edulis,the marine bathing life- Penaeus japonicus and Penaeus chinensis. In the range of experimental concentrations, the acute toxicity of slag on Mytilus edulis can be ignored. The growth rate and feeding rate of Mytilus edulis, the number of blood cells was found to be declined with increasing concentrations of slag, but the morphology of blood cell was not significantly changed, so immune function of Mytilus edulis was not impacted obviously. The LC50 of slag on Penaeus japonicus was 1.62g/L, and the LC50 of slag on Penaeus chinensis might be much higher than Penaeus japonicu. Finally, the effect of slag on marine phytoplankton-Heterosigma akashiwo and Skeletonema costatum was studied. Microalgae biomass was found increased significantly compared with the control group by adding slag. It was showed Heterosigma akashiwo biomass got maximum when the concentration of slag was 124～248mg/L, Skeletonema costatum biomass got largest when the concentration was 61～124mg/L. The effect of slag on two kinds of microalgae was same, but it may be different on different kinds of algae, which, the effect on Skeletonema costatum was promoted more significant. The results showed that steelmaking slag could be used as a material to promote the growth of phytoplankton. The increasing of CO2 absord, which was resulted in the addition steelmaking slag, in 1km2 sea areas was estimated on the basis of the experiment in lab.