S. O. Ayoola; C. E. Ejikeme; O. Folami
Abstract
The toxicity effects of crude oil were investigated in the laboratory. Triplicates of (T1) 0.25mg/l, (T2) 1.0mg/l, (T3) 2.25mg/l, (T4) 5.0mg/l and (T5) 7.5mg/l concentration of crude oil exposed to Sarotherodon melanotheron species. The acute toxicity test of crude oil when tested against Sarotherodon ...
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The toxicity effects of crude oil were investigated in the laboratory. Triplicates of (T1) 0.25mg/l, (T2) 1.0mg/l, (T3) 2.25mg/l, (T4) 5.0mg/l and (T5) 7.5mg/l concentration of crude oil exposed to Sarotherodon melanotheron species. The acute toxicity test of crude oil when tested against Sarotherodon melanotheron revealed that the derived toxicity index LC50 was 0.925mg/l. On computing Toxicity Factor (TF), using 96 hours. LC50, crude oil was found to be very toxic to the Sarotherodon melanotheron juvenile. The mean frequencies of micronucleus in S. melanotheron exposed to different concentration of crude oil ranged from 3.01±0.50 – 27.48±2.71. The lowest value was 3.01±0.50 in T0 (control) while the highest value of 27.48 ± 2.71 wasrecorded in fishes exposed to (T5) 7.5mg/l test solutions. The results obtained from micronucleus test showed that T5 had the highest number of micro-nucleated cells followed by T4 while T1, T2, T3, and T0 significantly increased with the concentration across the test chemical. Sarotherodon melanotheron showed various degrees of sensitivity in monitoring genetic damage especially in the normal nucleus (NN). The chromosomal aberrations indicate formation of vacuolated nucleus (VC), micronucleus (MN) and bi-nucleated cells (BN) showed marked increase in occurrence in the following concentrations of occurrences; T1, T2, T3, T4 and T5, respectively. Test solution of concentration T5 (7.5mg/l) was observed to possess fish with highest level of micronucleus frequencies followed by T4 (5.0mg/L). There were significant differences in increasing T5 having the highest number of micro-nucleated cells (MN) with a trend in increasing bi-nucleus cells (BN), polymorphic nucleus (PM), kidney shape nucleus (KN) and bleb nucleus (BLN) cells, respectively, as the concentration of the test chemical increased. The results also showed that there was a significant difference in the effects of the T5 and other test concentrations (T1, T2, T3, T4 and T0). The response of Sarotherodon melanotheron established that is a better model for bioassay test used as a pollution bio indicator. Pollutants even in a very low concentration if present for a long duration may affect the nucleus. Hence, the use of any kind of substances such as crude oil products and synthetic chemicals in aquaculture field should be carefully monitored and used under proper guidance.
S. O. Ayoola; G. T. Olorunsanmi; A. O. Oke
Abstract
Industrial waste discharge has increased the hazard of water pollution. The total hydrocarbon content and bioaccumulation of heavy metals in Sarotherodon melanotheron at Atlas cove area and at Okobaba end of Lagoon Lagos were assessed between November, 2014 and January, 2015. The physicochemical parameters ...
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Industrial waste discharge has increased the hazard of water pollution. The total hydrocarbon content and bioaccumulation of heavy metals in Sarotherodon melanotheron at Atlas cove area and at Okobaba end of Lagoon Lagos were assessed between November, 2014 and January, 2015. The physicochemical parameters were determined according to APHA-AWWA-WEF and heavy metals in the fish species were determined using Atomic Absorption Spectrometer. The total hydrocarbon content (THC) in the fish samples were analysed by using Soxhlet extraction gravimetric methods. The heavy metal values evaluated are Fe, Cr, Pb, Ni and Cu. The concentration of Iron (Fe) in Sarotherodon melanotheron was 72.72 ± 125.95mg/kg, Chromium (Cr)- 10.29 ± 4.61mg/kg; Lead (Pb)- 1.08 ± 0.23mg/kg; Nickel (Ni)- 0.39 ± 0.26mg/kg; and Copper (Cu)- 0.20 ± 0.26mg/kg at Atlas cove area while at Okobaba the concentration were;Fe-115.98±87,Cr-5.25±1.02,Pb-2.04±1.50,Ni-0.78±0.08,and Cu is 0.36±0.15mg/kg. The levels of accumulation of all the heavy metals in Sarotherodon melanotheron were above the WHO permissible limits. The concentration of n- alkanes in Sarotherodon melanotheron at Atlas cove was 164.69 ± 97.04µg/g, polycyclic aromatic hydrocarbon (PAH) was 73.58 ± 72.48µg/g, and total petroleum hydrocarbon was 526.67 ± 214.34µg/g. The average intake of polycyclic aromatic hydrocarbon through fish consumption at Atlas cove area was estimated to be 5039.94 ± 49.2mg/kg; body weight/day. The mean concentration of n-alkanes hydrocarbon in Sarotherodon melanotheron at Okobaba was 152.62±54.11µg/g, the PolycyclicAromatic Hydrocarbon (PAH) was 74.4±50.30 µg/g.The carcinogenic high molecular weight polycyclic aromatic hydrocarbons (HMW-PAH) were of higher concentrations than the lower molecular weight polycyclic aromatic hydrocarbon (LMW-PAH). Therefore, Atlas cove area is more exposed to carcinogenic health risks associated with the consumption of the studied fish than Okobaba end of Lagos Lagoon. This indicates significant carcinogenic health risks associated with the consumption of black jaw Tilapia fish caught from the study areas.