Ecological risk assessment and phthalate ester concentrations in sediment samples from Ilorin metropolis, North Central Nigeria

Abstract

The presence of phthalate esters (PEs) in the environment, common components of plastics and consumer products, is causing increasing anxiety over the prospect of negative effects on ecosystems and human well-being. Ilorin metropolis, situated in north-central Nigeria, is not immune to this environmental challenge. Recognizing the urgent need for a thorough evaluation, this study is dedicated to determining the levels and risk assessment of five PEs (diethyl phthalate (DEP), dibutyl phthalate (DBP), benzylbutyl phthalate (BBP), di-n-octyl phthalate (DnOP), and di-(2-ethylhexyl) phthalate (DEHP)) in seven sediment samples obtained from farms and discharge pipes across Ilorin metropolis. It was observed that the total levels of the five phthalates varied from 1.0126 to 27.7196 ng/g in the sediment. Among them, DBP exhibited the highest concentration in sediment samples, with an average value of 12.87 ng/g, followed by DEHP (average, 10.87 ng/g), DnOP (1.865 ng/g), BBP (1.099 ng/g), and DEP (1.042 ng/g). Significant positive correlations were observed between the concentrations of DBP, DEP, and DEHP and the physico-chemical parameters of the sediments. Ecological risk assessment revealed that only DEP likely posed a minimal risk. While the findings indicate that the phthalates pose minimal or no risk, there is a need for comprehensive phthalate monitoring in these locations to minimize the influx of these substances. This proactive measure is essential to prevent potential disruptions to the delicate equilibrium of the ecosystem, which could result in a catastrophic loss of biodiversity.