Beyond the Haze: A Scientific Evaluation of Black Soot and Their Possible Impacts on Human Health

Abstract

Black soot pollution has been a severe environmental and public health challenge in Port Harcourt, Nigeria. Port Harcourt is a metropolitan city in Nigeria and has experienced the hike of release of black soot (PM2.5 and PM10.0) in recent years due the operations of illegal crude oil refining, gas flaring, and industrial emissions other oil exploration activities. There have been frantic efforts by the government and other concerned bodies over time to curb the hazards. Therefore, this study seeks to ascertain the current status of the concentration of black soot particulates in Port Harcourt, with a focus on the chemical composition and associated health risks to the local population. The Met One Aerocet 531S Particle Counter and High-Volume Air Sampler were employed to quantify particulate concentrations in different locations while subsequent laboratory analyses identified the presence of heavy metals and polycyclic aromatic hydrocarbons (PAHs) within the soot samples. The results shows that values of concentrations of particulate matter (PM2.5 and PM10) in the sample locations ranged from 17.60µg/m³ to 46.23µg/m³ and 100.25µg/m³ to 282.32µg/m3 which exceeds the World Health Organization (WHO) safe limits of 15 µg/m³ for PM2.5 and 45 µg/m³ for PM10 (WHO, 2021). Notably, specific areas near industrial zones and illegal oil refining sites exhibited PM10 levels that were three times higher than the safe limits. The analysis of polycyclic aromatic hydrocarbons (PAHs) reveals the presence of Benzo(b)fluoranthene, Benzo(k) Flouranthene, Benzo(a) Pyrene, Indeno(1,2,3-c,d) pyrene and Dibenz(a,h)anthracene, with concentrations varying across different locations. However, the Incremental Lifetime Cancer Risk (ILCR) for both children and adults did not exceed the acceptable risk level of 1 in 1,000,000 mg/kg (10-6).  The study concludes with a call for more regulatory measures to control emissions from industrial and vehicular sources, alongside public awareness campaigns to educate the community about the dangers of black soot pollution.