Contamination and Health Risk Assessment of Suspended Particulate Matter (SPM) in Uyo, Niger Delta, Nigeria

Aims: This study was aimed to assess the level of particulate matter contamination and its associated health risks in Uyo, Niger Delta, Nigeria.
Study Design: The study involved sampling and analysis of suspended particulate matter and assessing the health risk associated with trace metal and anion content using mathematical models.
Place and Duration of Study: This study was conducted at the Uyo metropolis, Nigeria between October, 2012 and May, 2013.
Methodology: Particulate matter samples were collected from five selected locations in Uyo Metropolis and analysed for trace metals using Atomic Absorption Spectrophotometric technique and anions (SO42-, NO3-and PO43-) using UV-Visible Spectrometric technique. Metal Contamination indices were estimated using mathematical models for enrichment factor (EF) and contamination factor (CF). Target Hazard Quotient (THQ) was used to measure the health risk associated with the trace metals.
Results: The order of trace metal concentrations for the five locations were measured as Fe>Cu>Zn>Ni>Cr>Al>Pb>Co>Ti. Pearson correlation analysis indicated strong positive correlations for Fe/Co (r=0.89), Pb/Ni (0.88), Co/Cr (r=0.72), Al/Co (0.70) and Cu/Ti (r=0.60). Mean enrichment factor was highest for Cu (8.2) and lowest for Co (0.1) with moderate and minimal contamination indices of 0.93 and 0.02 respectively for all locations studied. Mean sulphate concentrations ranged between 911.5±1.49 and 1343.5±1.56 mg/kg, phosphates 15.9±2.64 and 98.8±1.52 mg/kg, while nitrate concentration was between 46.7±7.35 and 1371±19.6 mg/kg. Calculated THQ values were highest for Fe (2.30-2.43) and Cu (0.24-0.44).
Conclusion: Findings in the study indicated no significant contamination of particulate matter and no measurable health risk associated with the particulate matter at the time of study. However, there is need for continuous monitoring of these indices due to increased urbanisation and anthropogenic activities in the area.