Source characterization of total suspended particulate matter near a riverbed in Central Taiwan

Samples of total suspended particulate (TSP) matter were collected by using TSP samplers from certain areas representing the estuary of the Jhuoshuei River, Taiwan during monsoon and non-monsoon seasons in 2005. A total of 12 elements and nine inorganic ions were identified by inductively coupled plasma atomic emission spectrometry (ICP-AES) and ion chromatography (IC), respectively. Enrichment factors explaining a preponderance of the variance in the data were applied to the data sets. The results show that wind direction significantly affected the concentration of TSP during the monsoon season; moreover, these concentrations were also markedly higher during the monsoon than during the non-monsoon season. Low enrichment factor (EF) values (1.18-2.88) were observed during the monsoon for Ca, Fe, Na, Ba, Cd, Co, Li, Mn, and Sr, reflecting the importance of dust contribution by natural processes. Conversely, the EF values calculated for Ca, K, Ba, Co, Li, and Zn were relatively high (7.03-20.26) when observed during non-monsoon season, a phenomenon suggesting that they are mainly contributed from non-crustal sources. The observations of relatively enhanced EF values during monsoon indicate that the changes in wind direction between monsoon and non-monsoon seasons are associated with the different contribution sources. The high concentration of TSPs observed in the ambient air is believed to be primarily due to surface soil particle emission from the riverbeds.