Levels of Polycyclic Aromatic Hydrocarbons in Water from Nairobi River, Nairobi County-Kenya

Abstract

Nairobi city is the economic and industrial hub for Kenya with increasing industrialization and urbanization. River Nairobi is one of the major rivers in the Nairobi river basin. The river has become a repository for industrial and domestic waste. This has necessitated and environmental issue and more so on its unknown levels of hazardous persistent organic pollutants in particular the polycyclic aromatic hydrocarbons (PAH). Notably, its untreated water from some sections along its course way is used for domestic purposes hence poseshuman health risks that may be attributed to long term exposure and accumulation of PAH. This study analyzed the concentration of 16 US EPA PAHs and compared the levels with US EPA and WHO standards in order assess the potential risks that people using water from this river might be exposed to.The sampling points were chosen based on the various activities such as informal and formal settlements, industrial area andmicro- enterprises ‘Jua kali' activities. PAHs from water samples were extracted, cleaned prior to identification and quantified by GC-MS. The total concentrations of 16 PAHs ranged between 5.19 ng/L and 9.14 ng/L with an overall mean of 10.08 ng/L. Generally, the results show that water from the river was contaminated with PAHs although the levels were below the recommended WHO limit of 50 ng/L. However, it is feared that continuous use of their water by man may result to risk exposure to PAHs. Therefore precaution needs to be taken in the use of untreated water from Nairobi River in fear of body accumulation of PAHs and their dangers.