Improving non-point source pollution model input parameters using substance flux analysis

Abstract

This study investigated Substance Flux Analysis (SFA) as a potential tool to obtain better estimates of phosphorus and cadmium loadings in an on-going comprehensive research effort to model the phosphorus and cadmium transport via., surface runoff to Songkhla Lake in the southern part of Thailand. The lake is a major producer for local fisheries. Because substantial portions of the drainage area are used for agriculture, non-point source pollution loading from the surrounding drainage area to the lake has become a concern, especially since surface runoff is the major transport mechanism for non-point source pollutants. Using SFA it is estimated that approximately 384,289 t of chemical fertilizer were applied throughout the basin in 2004. The major sub-watershed contributing phosphorus and cadmium was the U-Tapao and Eastern Coast Sub Basin 4 Sub-watershed. Changing the fertilizers from 8-24-24, 13-13-21 and 15-15-15 (high cadmium) by 15-15-15 (low cadmium) type led to a significant decrease in cadmium contribution to the lake. © 2009 Asian Network for Scientific Information.