[Distribution, migration and purifying effect of cadmium in artificial Avicennia marina wetland system]

An artificial mangrove Avicennia marina wetland was set up in a greenhouse, and an irrigation experiment with synthetic wastewater was performed to research the behavior of cadmium in the artificial wetland system. The synthetic wastewater C1 had the characteristics and strength similar to normal municipal sewage, while C5 and C10 had the nutrients and heavy metals as five and ten times as those in C1, respectively. The control was of 15 per thousand salinity. All the test wastewater was quantitatively irrigated weakly for a year. The results showed that the cadmium in the synthetic wastewater discharged into the system was mainly stagnated in soil subsystem (87.67%-96.74%), and only a small portion (0.43%-3.23%) migrated into plants and litters. After a year trial, the Cd content in roots was more than that in stems and leaves. The artificial Avicennia marina wetland system did have a significant effect on purifying cadmium in synthetic wastewater, and the purification rate for C1, C5 and C10 was 90.43%, 97.17% and 97.06%, respectively.