Micro-Ecosystem for the Estimation of Micro-Pollutants' Behavior in Water Bodies

An open channel was used as a micro-ecosystem. The channel water was circulated by a pump and the head space was covered to be a closed system. Mud was put on the bottom of the channel. RNA coliphage Qbeta was used as model virus in the water-sediment micro-ecosystem to investigate the behavior of viruses in the natural water bodies. 1. The inactivation rate of coliphage Qbeta was lower in the water-sediment ecosystem than in the water ecosystem. The Qbeta concentration decreased by 10^ times in 96 hours in the ecosystem without sediment, while no such decrease of the Qbeta concentration was observed in the water-sediment ecosystem. 2. Viruses in the water-sediment ecosystem could be divided into two categories, free-form viruses and adsorbed viruses. The free-form viruses are suspended viruses in the water phase as individual particles. The adsorbed viruses are attached viruses onto organic or inorganic suspended solids in the water. The concentration of the adsorbed viruses fluctuates with the sedimentation or resuspension of suspended solids. 3. The concentration of adsorbed viruses in the sediment was very high in the water-sediment interface region because of the exchange of solids between the water phase and the sediment. Only 1mm-thick region in the water-sediment interface was turned out to be the high-virus-concentration region under the hydraulic condition of average velocity 11.2cm/s and Reynolds number 1550(turbulent flow). 4. The ratio of the adsorbed Qbeta concentration in the sediment(PFU/g) and the concentration in the bulk water(PFU/ml) was 46.5(ml/g).