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Abstrak :
The measurement of susoended sediment, particularly in field settings, is important in the documentation of sediment transport and deposition. Many measurement techniques have been used euth varying degrees of success.

Abstrak :
Preceding monitoring reports indicated that di (2-ethylhexyl) phthalate (DEHP), a common plasticizer, was found in the samples of suspended sediment and water collected from the lower part of Chao Phraya River. In this continuing study, the suspended sediment and water samples from the Chao Phraya Delta were collected twice a year in January and July during January 201 1 - July 2013. The analyses were performed for both DEHP and Diethyl Phthalate (DEP). Overall results showed that concentrations of both DEHP and DEP in the water samples were relatively higher than those in the suspended sediment samples. The concentrations of DEHP and DEP from all sampling periods in the water samples ranged from 1.58 - 27.55 pg/L and from 0.64 - 2.59 ug/L, respectively, whereas the concentrations of DEHP and DEP from all sampling periods in the suspended sediment samples ranged from 0.01 - 26.82 mg/g and from 0.01 - 1.93 mg/g, respectively. The concentrations of both DEHP and DEP in both suspended sediment and water samples were relatively higher in the samples collected during lower discharge period of the Chao Phraya River in July. The results indicated that sediment transport system could play an important role in the dispersion of both DEHP and DEP. The ecological risk assessment indicated that for the current level of contaminations the risk did not exceed the acceptable level.

Abstrak :
Soil loss and its transport processes were coupled with an existing distributed hydrological model to assess the effects of land use change on stream flow and suspended sediment load in the Chao Phraya River basin, Thailand. The simulation period spanned from 2001 to 2010. The results indicate that the Nash-Sutcliffe efficiency of upper sub-basins fluctuated in the range 0.51- 0.72, indicating the applicability of the model for longterm simulation at the monthly scale. Land use change during 200l-2010 caused a 1.6% increase in suspended sediment load based on the present trend. The changes were particularly pronounced in the Wang River basin, where the delivery ratio was highest. Moreover, the urbanization and conversion of farm land from paddy fields exerted negative effects on sediment runoff in Chao Phraya River basin. The proposed model has the ability to quantitatively evaluate the heterogeneity of sediment runoff in the basin, demonstrating the benefits and trade-offs of each land use change class. The results of this study can support basin and local land development policy to control sediment losses during development.