Composition and possible sources of anionic surfactants from urban and semi-urban street dust

This study was carried out to determine the distribution of anionic surfactants in street dust samples from urban and semi-urban areas of Malaysia. The dust was collected from streets experiencing heavy traffic in both Kuala Lumpur, an urban location, and Bangi, a semi-urban location. The samples were separated into three particle size fractions (μm) using a laboratory test sieve, namely: fraction A (125 > X ≥ 63), fraction B (63 > X ≥ 45) and fraction C (X < 45). Anionic surfactants as Methylene Blue Active Substance (MBAS) were determined by the Colorimetric Method using a UV-Vis Spectrophotometer. Results indicated that anionic surfactants (MBAS) from fraction C showed the highest concentration (Kuala Lumpur 0.53 ± 0.04 μmolg−1 and Bangi 0.49 ± 0.03 μmolg−1), followed by larger particles (fractions B and A). The cations detected followed the trend of Ca2+ > K+ > Na+ > NH4− > Mg2+, whereas for anions, the trend was SO42− > Cl− > NO3− > F−, respectively. Results from principal component analysis and the multiple linear regression (PCA-MLR) of ionic compositions, clearly revealed that surfactants from the street dust at both sampling stations were primarily derived from anthropogenic sources. Examples of these sources include construction/industrial activity and vehicular emissions/biomass burning.