Polycyclic Aromatic Hydrocarbons (PAHs) and Heavy Metal content of Abattoir Wastewater in Bayelsa and Rivers States

Abstract

The polycyclic aromatic hydrocarbons and heavy metals in wastewater generated from abattoir were analyzed. Wastewater samples were collected from four abattoirs in Yenagoa Local Government Area of Bayelsa State and an abattoir in Obio/Akpor Local Government Area of Rivers State, respectively using standard methods. The polycyclic aromatic hydrocarbons (PAHs) were determined using Gas chromatographic method, while the heavy metals were determined using spectrophotometer. Results showed that Acenaphthene, Acenaphthylene and Naphthalene recorded its highest value of 123.77µg/ml, 199.64µg/ml and 6.82µg/ml, respectively in wastewater samples from Opolo, while they were not detected in Rumuokoro samples (0.00µg/ml). Anthracene recorded the highest value in sample from Opolo (4.59 µg/ml) and the least value was in samples from Swale (0.00 µg/ml). Values of Benzo(a)pyrene recorded value of 0.86 µg/ml in Opolo sample. Chrysene value was 66.19µg/ml in Rumuokoro wastewater, 0.03µg/ml in Igbogene wastewater and 0.24 µg/ml in the control while the value was 0.00µg/ml in other abattoir locations. Benzo(b)flouranthene recorded the highest value of 38.79µg/ml at Igbogene and 1.93µg/ml in Tombia while other sampling location recorded 0.00µg/ml. Indenol(1,2,3cd) pyrene highest value of 4.38µg/kg was obtained at Igbogene, Swale, and the control, recorded zero value. Flourene was present in all the abattoir samples but with the highest concentration at Opolo (42.96µg/ml) and the least concentration in Swale (0.17µg/ml). The highest value of 2-methylnaphthalene recorded was 52.65µg/ml at Opolo which was followed by 11.2 µg/ml at Tombia while it was not detected in other locations (0.00µg/ml). Flouranthene recorded its highest concentration of 55.01µg/ml (Rumuokoro) and the least were 0.00µg/ml at Tombia. Rumuokoro and Igbogene had Benzo (k) fluoranthene concentrations of 14.90g/ml and 0.02g/ml, respectively, whereas other locations had zero. Except for Anthracene, Fluoranthene, Pyrene, Chrysene and Benzo(g,h,i)perylene, all the other PAHs were not detected in the control. The decreasing order of total PAHs in wastewater samples is as: Opolo > Tombia > Rumuokoro > Igbogene > Swale > Control. Chromium (Cr) was detected in wastewater from all abattoir locations, while all other heavy metals were undetected. Results from this study shows that the abattoir wastewaters had high pollution strength and thus should be treated before being discharged into the environment. The presence of PAHs that are known carcinogens poses a serious threat to the health and well-being of humans.