Planar Optode Technology Research Of Tubificid Bioturbation On The Migration Of Water/Sediment System Based On Copper Ion

Natural sediment is an important part of many aquatic ecosystems such as rivers and lakes,it not only as benthic habitats and food sources,but has the adsorption of pollutants in water.Due to human activities,sewage and industrial waste water emissions,natural water pollution,heavy metal pollutants in sediments accumulated increasingly in with a certain degree of harm to human body,and the heavy metal toxicity in water,the harm to the organism and environment nearby.Bioturbation can affect the migration of heavy metals in sediments and the migration of heavy metals in sediments.At present,there are many methods to measure heavy metals in water and sediment,such as microelectrode method,but lack of real-time detection of heavy metals in sediments in situ.In this paper,tubifex as biological disturbance,the lake surface sediments Changchun South Lake as sampling points,with Cu²⁺ as the representative of heavy metals,using the planar optode technology,with reference to the existing preparation method of Cu²⁺ sensing film with good performance,construction of water / sediment simulation system,to collect the fluorescence image with high resolution camera,two-dimensional distribution of Cu²⁺ heavy metal pollutants real-time monitoring system,to study the water / sediment migration simulation in Cu²⁺ system and transformation of heavy metals.The results show that the maximum excitation wavelength of the Cu²⁺ sensing film is 356 nm and the maximum emission wavelength is by using the fluorescent probe ATA.The response time is short（30 min）and it is stability and accuracy,which can be applied in the experimental system.The image plane technology collected after treatment can render the Cu²⁺ spatial distribution and transformation of the intuitive,after 14 days of continuous monitoring found that compared with no tubifex perturbation of the system,a tubificid bioturbation of water / sediment simulation system,early experiments,Cu²⁺ mainly concentrated in the overlying water and there is a small amount of Cu²⁺ on surface sediments,and Cu²⁺ does not appear in the deep sediments.With the prolonging of tubificid bioturbation time,Cu²⁺ in sediments downward migration slowly.The final bottom Cu²⁺ to the overlying water and surface sediment concentration tends to be uniform.This phenomenon is caused by the disturbance of the tubificid b iological irrigation effect,carrying function and resuspension of physical mixing from the sediment,and tubifex disturbance changed the micro environmental parameters of dissolved oxygen in the system,affect the role of microorganisms in system,therefo re,tubificidae and microorganisms and biochemical factors on the migration of copper ions also have effect.And the greater the density of the earthworm,the lower the migration speed of Cu²⁺,the shorter the time to reach the dynamic equilibrium,the greater the density of the Cu²⁺,the deeper the migration distance of the sediment in the system.The disturbance of tubifex the sediment becomes loose,increased the sediment pore,migration of overlying water high metal concentration in sediments to promote change,and its role The new supersedes the old.Tubifex causes p H and DO system in micro environmental parameters,indirect effects of heavy metal concentration.Tubifex enhanced disturbance in sediments and overlying water at the interface with increasing tubifex density,density increasing,the disturbance is stronger,enhance the disturbance of sediment interface and deep sediments,accelerate the heavy metal migration to sediment.This study is helpful to the study of heavy metal migration in water sediment system.