Effect of anthropogenic land use pattern on nutrient distribution in river surface sediment and catchment topsoil: a study of the lower Chao Phraya watershed | |
| Author | Lhaetee, Husna |
| Call Number | AIT Thesis no.EV-19-03 |
| Subject(s) | Anthropogenic soils--Thailand--Chao Phraya Watershed Nutrient pollution of water--Thailand--Chao Phraya Watershed Water--Nitrogen content--Thailand--Chao Phraya Watershed Water--Phosphorus content--Thailand--Chao Phraya Watershed |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Surface water deterioration is the major problem of many watersheds under the circumstance of urbanization. Excessive discharge of nitrogen (N) and phosphorous (P) breaks the balance of nutrient cycles and causes eutrophication in water bodies, resulting in the deterioration of aquatic ecosystem. Nevertheless, the relationship between watershed development pattern and environmental nutrient loadings remains unclear. The aims of this study were (1) to understand the distribution of nitrogen and phosphorus in river surface sediment and catchment topsoil in lower Chao Phraya watershed, (2) to explore the mechanisms of land use-based anthropogenic impact on watershed nutrient loadings, and (3) to understand the adaptation of ecosystem to development through N cycle analysis in sediment cores. The Flow Injection Analyzer (FIA) was applied to identify the nutrient parameters in surface sediment and topsoil samples and ArcGIS program to create the nutrient concentration contouring maps. Pearson’s correlation and Principle Component Analysis (PCA) is used to identify the relationship between nutrient loading and the development pattern at subwatershed scale in study area. In addition, stable N isotope composition was analyzed using Isotope Ratio Mass Spectrometry (IRMS) in terms to understand the ecosystem adaptation to changed nutrient loadings. The results of nutrient distribution in surface sediment along the watershed demonstrate that TN, NH4+-N, TP, and PO43--P present high concentration at downstream of the watershed distinctly whereas NO3--N was not presented the differentiate concentration at upstream and downstream obviously. The results of topsoil distribution shows that the nutrient concentrations were presented high concentration at downstream of Thachin and Chao Phraya sub-watersheds where urban land present the high concentration of TN, NO3--N, TP, and PO43--P whereas paddy land contributes to high concentration of NH4+-N. The land use-based development pattern classification system identified the development level of three sub-watersheds following the order of Chao Phraya > Thachin > Pasak, which indicates the relatively high anthropogenic impact at Chao Phraya and Thachin whereas Pasak with low to moderate anthropogenic impact. Pearson’s correlation indicates high homogeneity of nutrient sources at highly urbanized sub-watersheds (Chao Phraya and Thachin). Different nutrient loading patterns corresponding to the development levels are identified in the sediment through PCA: agriculture driven nutrient loading at Pasak and urbanization driven nutrient loading at Thachin and Chao Phraya. In terms of soil nutrient loading, PCA indicates that urban land use makes the largest contribution to nutrient especially P discharge in all studied sub-watersheds. While, agriculture makes the primary contribution on nitrogen discharge in each sub-watershed. Comparison of δ15N and 14N isotope composition in sediment core samples reveals high biogeochemical activities at the downstream of Thachin and Chao Phraya indicating the enhanced ecosystem adaptation to increased nitrogen discharge in these areas. However, the ecosystem adaptation is not observed at the downstream of Pasak possibly due to the elevated complexity of the environmental system and pollutant variation in this sub-watershed |
| Year | 2019 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Xue, Wenchao; |
| Examination Committee(s) | Thammarat Koottatep;Shipin, Oleg V. |
| Scholarship Donor(s) | Her Majesty the Queen’s Scholarships (Thailand) ; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2019 |