Occurrence, Origin, Ecological and Human Health Risks of Organochlorine Pesticides in Soils from Selected Urban, Suburban and Rural Storm Water Reservoirs

ABSTRACT

This study evaluated the occurrence characteristics to trace the origin and associated risks of organochlorine pesticides (OCPs) in soils from urban, suburban, and rural stormwater reservoirs. Samples were collected from the topsoil (0–15 cm) and subsoil (15-30 cm), and quantified for Ʃ₂₀OCPs using a gas chromatography-mass spectrometry (GC-MS) after extraction with n-hexane and dichloromethane. The concentrations of ∑₂₀OCPs ranged from 29.3 to 77.9 ng g⁻¹. The average concentration of Σ₂₀OCPs in the catchments and the isomer compositional pattern is in the order of urban > sub-urban > rural and ∑HCHs > ∑Chlordane > ∑Drins > ∑Endosulfan > ∑DDTs respectively. The HI levels for infants’ exposure were seven-fold that of adults' exposure and were > 1. The human exposure risk is in the order of RiskIng > RiskDerm > RiskInh. The RiskIng and RiskDerm in infants’ exposure were higher than in adults’ exposure, while the RiskInh in adult exposure was higher than that of infants' exposure. The total cancer risk was higher than the acceptable total cancer risk value. The ecological risk indicated a significant biological effect in 56% of the samples. The source apportionment showed that Ʃ₂₀OCPs were of historical and fresh inputs from the non-point and direct origin. Standard clean-up and source-directed mitigation actions should be carried out to assuage the associated risks.

KEYWORDS:

• OCPs
• storm water reservoir
• soil pollution
• risks assessment
• niger delta

Acknowledgments

Special thanks to the laboratory personnel, department of chemistry, Delta State University, Abraka for their technical support.

Conflicts of Interest

The authors declare none

Author Contributions

The conceptualization and design [Onoriode O. Emoyan]. The collection of samples, preparation, and analysis of OCPs [Onoriode O. Emoyan, Beatrice O. Peretiemo-Clarke, Godswill O. Tesi, and Efe Ohwo]. The compilation of results and evaluation of data [Onoriode O. Emoyan and Godswill O. Tesi]. The first draft of the manuscript was written [Beatrice O. Peretiemo-Clarke, Godswill O. Tesi, and Efe Ohwo]. All authors reviewed the previous versions of the manuscript. The final manuscript was reviewed and edited [Onoriode O. Emoyan]. The final manuscript was read and approved by all authors. All authors contributed to the development and completion of this study.