Modelling of similarity characteristics of polycyclic aromatic hydrocarbons (PAHs) in Sungai Perak, Malaysia via rough set theory and principal component analysis (PCA).

[Display omitted] • Rough set theory and PCA were applied for environmental data modelling. • The similarity assessment of 16 + 1 US EPA PAHs from Sungai Perak is presented. • LMW PAHs were found to be the most prominent in the water. • Variance were equal to 68.47% (Nap) and 27.63% (carbazole) • The LMW PAHs were likely due to incomplete combustion from vehicles. This paper presents application of rough set theory and PCA for modelling of similarity characteristics of PAHs from Perak River: Tanjung Belanja Bridge (TBB, l 1), Water Treatment Plant Parit (WTPP, l 2), Parit Town Discharge (PTD, l 3), Water Treatment Plant Senin (WTPS, l 4), and Water Treatment Plant Kepayang (WTPK, l 5). The clustering involved PAHs as attributes and sampling stations as objects. The l 1 and l 3 were clustered in Sim deg x , y ≥ 0.8. The Sim deg x , y ≥ 0.7 was observed in all attributes (except l 5) forming two sets of clusters. PCA showed that low molecular weight (LMW) PAHs were prominent with variances of 68.47% (naphthalene, Nap) and 27.63% (carbazole). [ABSTRACT FROM AUTHOR]