Material flow analysis of pollutants in Taiwan

We present a material flow analysis (MFA) of biological oxygen demand (BOD5) and suspended solids (SS) in estuaries located on the northern and southern coasts of Taiwan. Using data from 1992-2000, we examine human economic activities in each watershed to predict associated pollutant flows. This estimate is compared to data collected at monitoring stations. The ratio allows us to calculate each river system's ability to assimilate and decompose these pollutants, its self-purification capacity. Our results show that over six times as much BOD5 reaches the northern estuary from the urban watershed that in the south. More SS reaches the southern estuary than the north due to more intense land disturbance. Trends for pollutant flows to the northern estuary threaten its capacity to meet sustainability criteria. Trends in the south show a receding threat. We suggest management objectives to enhance prospects for sustaining environmental quality in these two critical regions.