Polycyclic aromatic hydrocarbons in giant African snails Archachatina marginata (Swainson, 1821) (Gastropoda: Pulmonata Achatinidae) from southern Nigeria

Abstract

Giant African snails were collected from different zones in southern Nigeria, and analyzed for their polycyclic aromatic hydrocarbon (PAH) content. The purpose was to provide information on the health risk arising from exposure to PAHs through consumption of these snails. A mixture of acetone/dichloromethane/n-hexane was used for the Soxhlet extraction of PAHs from the snail samples, and the resulting extracts were assayed by gas chromatography-mass spectrometry (GC-MS). The concentrations of the Ʃ17 PAH concentrations varied from 290 to 4180, 48–4150, 23–1560, 303–2970, and 2230–2880 µg kg−1 for snails purchased in Warri, Port Harcourt, Calabar, Onitsha, and Benin City zones respectively. The benzo(a)pyrene (BaP) concentrations in 53% of these snails exceeded the permissible limit of 6.0 µg BaP kg−1 in molluscs meant for consumption by humans. The PAH4 concentrations in 42% of these snail samples exceeded the specified limit of 35 µg kg−1 for molluscs. The hazard index (HI) from consumption of snails from these zones was less than one, while the total cancer risk relating to the consumption of snails from these zones by adults and children was of the order of 10−4 and 10−6, respectively. There is a need for caution in the consumption of snails from these regions because higher intake values than those assumed in this work could pose considerable carcinogenic risks to the consumers. The source analyses indicated PAHs in these snail samples originated from oil spills, biomass combustion, traffic emissions, and gas flaring.