Atmospheric surfactants around lake ecosystem of Tasik Kenyir, Terengganu

Lake ecosystem is a sources of natural organic matter characteristic by humic-like substances (HULIS) believe to have high amount of surface active agents (surfactants) which capable to influence the cloud and climate. This study determined the concentration of anionic surfactants in the atmosphere around lake ecosystems at Kenyir, Terengganu. Aerosols samples were collected by using a High Volume Air Sampler (HVAS) equipped with high volume impactor (to separate between fine and coarse mode aerosols) and glass-fibre filter paper at flow rate of 1.13 m3min-1 for 24 hours. Several possible sources of natural surfactants in the atmosphere for example soils, vegetations and surface water were also collected in order to determine the possible sources and flux of anionic surfactants in the atmosphere. Anionic surfactant was analysed based on colorimetric methods by using methylene blue active substances (MBAS) and UV-visible spectrophotometer at 650 nm. Subsequently, simplified calculations were conducted in estimating the flux of anionic surfactants from various possible sources. The results indicated that the concentration of anionic surfactants in aerosols (coarse and fine mode), soil, vegetation and surface water were 59.17 ± 2.61 μmol/ m3 and 78.10 ± 9.30 μmol/ m3, 0.33 ± 0.17 μmolg-'1, 0.28 ± 0.08 μmolg-1 (dry weight) and 0.01 ± 0.004 μmolL-1, respectively. The overall flux of surfactants signified that soils provide the highest amount of surfactants which is 119.39 Mmolyr-1 in comparison to other possible sources (vegetation = 26.88 Mmolyr-1and surface water = 12.1 x 10-6 Mmolyr-1). Results indicated that soil become a significant natural source of anionic surfactants to the atmosphere which may due to the availability of HULIS. (author)