Assessment of the Polycyclic Aromatic Hydrocarbons (PAHs) Concentration in Different Fish Drying Methods
Umudi E. Q.
Apuyor S. E
Clark P. D.
Eresanya O. I.
Onadje F. O.
Chikwe I.S.
Onwugbuta G. C.
Oyagbarha E.
Anyanwu G. C.
Obruche E. K.
Abstract
This study aimed to assess the levels of PAHs that may build up in freshwater fish dried using heat from charcoal, sunlight, ovens, and polythene-assisted drying methods. The exact levels of sixteen PAHs were measured in the fish samples collected from the Otuochas River in Anambra State during October 2024, November 2024, and January 2025, Nigeria. Fish samples were dried, ground, and then subjected to soxhlet extraction with n-hexane, at 60°C for 8 hours. The water content of the extracts was further eliminated using florisil clean-up before GC-MC analysis. The results indicated that sun dried fish had a PAHs level/concentration of 35.7 + 0.2µg/g; oven-dried fish had 47.7 + 0.2µg/g, and charcoal dried fish had 79.53 + 0.2 µg/g, firewood gave in 188.1 + 0.2µg/g. The charcoal combined with polythene led to a PAHs concentration/level of 166.2 + 0.1µg/g, whereas fish dried with firewood and polythene materials had a PAHs level/concentration of 696.3 + 0.2µg/g. Freshwater samples & the undried fish samples (control) showed that the freshwater contained a total PAHs concentration/level of 2.86 + 0.1µg/ml, whereas the fresh fish had 4.97 + 0.2µg/g. The PAHs concentrations in all the dried fish using different drying methods were clearly higher than the control. This is concerning, as even the fish dried in the sun had PAHs levels significantly greater than the control (p<0.05). It is clear that the increase in PAHs likely originated from the PAHs in the environment during the sun drying process. For the other drying methods, where PAHs levels were significantly higher than those of sun-dried fish, it can be concluded that the high amount of PAHs in the dried fish samples were due to the “burning” or drying agents used. A significant increase in PAHs was noted when drying was enhanced with polythene, which is known to produce high levels of PAHs when burned. Therefore, consumers should be cautious about the dried fish they buy from local markets.
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