Water Pollution Impact on Organic Matter Export and Greenhouse Gas Emission From Asian River Systems
Inland waters play an important role not only in the biosphere by providing various ecosystem services but also in the global biogeochemical cycles byconnecting the terrestrial and oceanic pools. Despite of significant impact on the global biogeochemistry, changesin the riverine organic matter (OM) flux and quality derived from anthropogenic pollution such as untreated sewage and industrial wastewaterhaverarelybeen explored in the rapidly urbanizing watersheds across Asia. A collaborative project was initiated to conduct a regional monitoring of OM flux and quality and greenhouse gas (GHG) emission in the three major Asian rivers- Ganges-Brahmaputra, Mekong and Yellow River. The project aims to bring together regional experts on riverine biogeochemistry to develop standard monitoring techniques, conduct field expedition andsynthesize data into a regional database. In order to explore the anthropogenic impact on the OM flux and quality, water and dissolved gas samples from the downstream reach, urban tributary, and pollution sources were compared with the unpolluted upstream samples. Preliminary results showed higher dissolved organic carbon (DOC)and dissolved GHG concentration at the downstream sites compared to the upstream sites, indicating the contribution from the urban tributary discharge and/or pollution sources in the Ganges-Brahmaputra and the Mekong River. More inclusive sampling from these rivers at heavily urbanized reaches across Asia will be coupled with molecular level analysis using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to examinethe anthropogenic alterations of OM flux and quality and GHG emission from major Asian rivers.
Index Terms - Anthropogenic impacts, Asian Rivers, organic matter, riverine biogeochemistry.