A study of anthropogenic, marine and other influences upon water chemistry in Hong Kong rivers

Abstract

A six-year river data water quality set obtained by the Hong Kong Environmental Protection Department (HKEPD) at 82 monitoring sites are used to study, at the regional scale, the spatial controls and influences upon water chemistry in HK rivers. Univariate statistics and factor analysis of the elements have been applied to analyze 27 determinands of surface water quality (pH, water temperature (Temp), flow, Salinity (Sal), Total Solids (TS), Conductivity (COND), Cl, TOC, BOD5, COD, DOmg/L, DO%, NH4, NO2, NO3, TKN, TP, PO4, Al, Fe, Zn, Mn, Pb, Cd, Cr, Cu, Ni). The statistical results show that nutrients, aggregate organics and metals have greater variation than physical parameters which are less influenced by anthropogenic factors. These determinands can also be explained by four principle factors, representing nutrient and organic contamination, marine influences and heavy metal contamination. Finally, the local rivers can be classified into four groups, based on the factor scores derived from the factor analysis. These results may contribute to the improvement of landuse planning and sewerage design in the future.