Quantitative Evaluation of Phthalate Esters in Three Tributaries of Asa River, Ilorin, Nigeria

This paper focuses on the determination of both the presence and concentration of phthalate esters in three tributaries of Asa River in Kwara State, Nigeria.Water samples were collected at different points from each of the three tributaries (Unity, Osere and Yidi streams) and a total number of 18 samples were collected and the concentration of the prevailing phthalates was determined using GC-MS. Seven different phthalates were found present in the samples and they are: DMP, BBP, DEHP, DNOP, DEP, DBP, and DNHP. The concentration of DMP in the 18 samples ranged from 0.114 -0.525 μg/L, BBP (0.266-0.697 μg/L), DEHP (0.086- 0.198 μg/L), DNOP (0.062- 0.456 μg/L), DEP (0.162- 0.679 μg/L), DBP (0.168- 0.399 μg/L), and DNHP (0.010-0.064 μg/L). The total phthalate concentration in the three tributaries was lower than the USEPA limit of 3 μg/L for fishes and aquatic lives except for Unity stream where the total was 3.018 μg/L. This study was carried out during the rainy season and the result obtained here could be used as a reference for a further study during dry season to compare the impact of seasonal variation on the distribution and concentration of phthalate esters in the selected tributaries.