Abstract:
Polycyclic aromatic hydrocarbons (PAHs) are toxic organic compounds causing health 
related risks. They can be present in, air, surface dust and soil having natural and 
anthropogenic sources like incomplete combustion of electronic waste (E-waste). Surface 
dust from electronics and electrical material maintenance shops may contribute organic 
pollutants to the environment due to the E-waste processing activities. These indicate that 
investigating the levels and risk assessments of PAHs associated to such activities is 
crucial. Herein, the levels of selected PAHs, fluorene, naphthalene, and phenanthrene, in 
surface dust collected from selected electronic and electrical materials maintenance 
workshops in Dire Dawa, Harar city, Haramaya University and Haramaya town were 
investigated using an optimized QuEChERS method prior to the HPLC analysis. The 
obtained results showed that the investigated surface dust samples contained high 
concentration of PAHs, 1.50–2.04, ND–1.58, and 1.43–5.2, µg g-1 fluorene, naphthalene, 
and phenanthrene, respectively. The highest concentration of total PAHs (8.33 µg g-1
) was 
found in samples collected from the workshop in Dire Dawa city, followed by Haramaya 
University (4.98 µg g-1
), Haramaya town (4.85 µg g-1
), and Harar city (3.24 µg g-1
). The 
obtained adult daily intake dosage values were in the range of 2.88–7.40 ng kg−1 d−1
, 
suggesting that E-waste processing activities may increase a substantial risk of non dietary PAHs to exposed workers under poor labor protection conditions. The obtained 
hazard quotient ≤2.60 × 10−3 and hazardous Index ≤3.02 × 10−3 values were below 1, 
indicating insignificant non-cancer risk of exposure to the dust-bound PAHs. Even though 
incremental lifetime cancer risk total was estimated at 6.25 × 10−6
–1.6 × 10−5 for adult that 
seems at tolerable levels for lifetime cancer risk, the highest attained of 1.6 × 10−5 is above 
the critical value of 10−5
, which suggest that workplace dusts may pose in cancer risk. The 
correlation results (0.12 ≤ r ≤ 0.74) and one way ANOVA analysis showed that the 
amounts of analytes were significantly different, suggesting that the contaminants share 
same origin. In general, it is recommended to improve the working conditions of workshop 
workers, and inform residents to limit their stay in electronic maintenance workshops