Urban Watercourses in Peril: Implications of Phthalic Acid Esters on Aquatic Ecosystems Caused by Urban Sprawl

Urban sprawl worldwide warrants the use of large quantities of industrial and household products containing phthalic acid esters (PAEs) resulting in adverse impacts on the quality of aquatic life in urban watercourses. The presence of six PAEs (dimethyl phthalate (DMP), diethyl phthalate (DEP), di(n-butyl) phthalate (DBP), benzyl butyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP), and di(n-octyl) phthalate (DnOP)) in 22 shallow urban watercourses in Colombo and suburbs of Sri Lanka was investigated. The average concentrations of DEP, DBP, BBP, and DEHP in all watercourses varied between 2.5–265.0, 1.0–32.0, 61–108, and 12–165 µg/L, respectively. DMP and DnOP were below the limits of quantification (DMP-0.5 µg/L, DnOP-1.0 µg/L) for all watercourses. DEHP was the most abundant PAE in many watercourses. The significant factors affecting the ubiquitous presence of PAEs in watercourses are the inherent properties of each PAE, presence of industrial and household products with great potential for the migration of PAEs in the sub-catchments, and quality of the receiving water. The contamination levels of PAEs in most of the watercourses are alarmingly high, as evidenced by higher concentrations of DEHP and DBP than those of Canadian permissible levels for the protection of aquatic life (16 and 19 µg/L). This study was the first effort in Sri Lanka to investigate the presence of PAEs in urban watercourses.