Distribution and Risk Assessment of Phthalate Esters in Refuse Dumpsite Soils of Obafemi Awolowo University, Ile-Ife, Nigeria

ABSTRACT

The levels, seasonal variation, and lateral and vertical migration of PAEs in refuse dumpsite soils of Obafemi Awolowo University, Ile-Ife, Nigeria, were investigated in this research. This was done to calculate the health hazards linked to contact with these soils. Soil samples were collected using soil auger during dry and wet seasons at varying soil depths and different intervals of 50, 100, and 117 m between dumpsite and the receiving stream. Microwave extraction method was optimized to extract PAEs from soil samples. Chromatographic quantifications were done using Gas Chromatography connected to a quadrupole Mass Spectrometer. Di(2-ethylhexyl phthalate) possessed the most significant concentration of 49.83 ± 0.49 mg kg⁻¹ in December. The cumulative levels of butylbenzyl phthalate and di (2-ethylhexyl phthalate) accounted for more than 90% of total PAEs in dumpsite soils. Dimethyl phthalate, diethyl phthalate, and dibutyl phthalate had higher levels during wet season as opposed to the high levels of butylbenzyl phthalate and di(2-ethylhexyl phthalate) during dry season. PAEs exhibited a potential to affect groundwater quality based on their vertical distribution. Plastic pollution was identified as the primary source of PAEs in the dumpsite soils. The health risk evaluation indicated that there were no non-carcinogenic and carcinogenic health risks linked to exposure to the aforementioned phthalates.

KEYWORDS:

• Human health
• phthalate esters
• refuse dumpsite
• risk assessment
• soil

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contribution

J. O. Fagbemi: Investigation, Methodology, Data curation, Writing – original draft, Writing – review & editing. J.A.O. Oyekunle: Investigation, Writing – original draft, Writing – review & editing. O.O. Ogunfowokan: Conceptualization, Supervision, Formal analysis, Investigation, Methodology, Writing – review & editing. I. Cheng: Methodology, Supervision, Writing – review & editing. L. Deobald: Methodology, Supervision, Writing – review & editing. Ruth Olubukola A. Adelagun: Writing – review & editing.

Additional information

Funding

The authors did not receive any financial assistance for the study.