Photodegradation of Neonicotinoids in Rivers Adjacent to Agricultural Intensive Regions: A Novel Water Quality Monitoring Approach

We have completed field sampling at the Elkhorn River and Neuse River sites. All samples have been processed from 2019 and the 2020 samples have been extracted but are awaiting analysis due to COVID19 delays in the Nebraska Water Center. We developed and conducted a portion of the photosimulator experiments to assess direct and indirect photodegradation of thiamethoxam and imidacloprid under synoptic conditions. However, the completion of these experiments were delayed due to COVID19 restrictions. Nebraska Extension Educators developed and deployed virtual opportunities for 3-5 yr olds regarding how contaminants move in rivers. We presented results collected over the past year at 1 international conference (American Society of Agricultural and Biological Engineering) virtually during the summer of 2020. The following specific activities were completed for each research objective: Research Objective 1: Use synoptic field sampling to characterize river reach conditions in terms of light, temperature, and photochemically-important water quality parameters: Nebraska and North Carolina synoptic water quality field sampling sites was completed; Monthly water property and chemistry measurements and grab samples were taken at the two Nebraska sites by a graduate student or PI Messer (COVID restriction dependent); PI Messer''s current PhD student developed protocol for the Langrangian deployment; Data collected from the real time monitoring sites has been downloaded and reviewed to assess differences between site locations and enhance ''static'' experiments in Research Objective 2. Research Objective 2: Simulate spatially ''static'' conditions (i.e., no variation associated with movement), but simulate the effect of changes at one river location through time using laboratory mesocosms and in situ, field mesocosms: PI Messer''s current PhD student completed first portion of the static laboratory mesocosm experiments during spring 2020 to identify indirect vs. direct photodegradation of thiamethoxam and imidacloprid under synoptic conditions Research Objective 3: Measure environmental conditions of a transported water parcel via Lagrangian observations and then recreate those conditions in laboratory mesocosms: Development of methodology and protocol for new Langrangian monitoring system was completed and runs completed in 2017 with Hydrosphere found water particles have very short pulse exposures to photic zones (<10 minutes) rather than sustained periods of exposure. Therefore, these results will guide the future photosimulator experiments. Over the next period of the grant, we plan the following: 1. Analyze remaining synoptic samples at Nebraska water sciences lab (Objective 1) 2. Submit peer reviewed journal article 2 of this project (Objective 1) 3. Conduct remaining static nano pure and river water experiments in photosimulator that were delayed due to COVID 19 (Objective 1) 4. Analyze samples from photo simulator experiments that were delayed due to COVID 19 (Objective 2) 5. Recruit MS student to complete Objective 3 of the project 6. Complete river surveys during high and low flow events that were delayed due to COVID 19 (Objective 3) 7. Conduct Langrangian nano pure and river water experiments in photosimulator (Objective 3) 8. Submit peer reviewed journal article 3 of this project (Objective 2)