Heavy Metal Burden in Water and Sediment, and Oxidative Stress Responses in the Blue Crab Callinectes amnicola Rochebrune, 1883 from Lagos Lagoon in Southwest Nigerian.
Heavy Metal Burden in Water and Sediment, and Oxidative Stress Responses in the Blue Crab Callinectes amnicola Rochebrune, 1883 from Lagos Lagoon in Southwest Nigerian.
Abstract:
Lagos Lagoon (LL) sustains a diverse array of fish and crustaceans but is vulnerable to anthropogenic activities from the hinterlands. Industrial facilities around the lagoon continuously discharge effluents laden with pollutants such as heavy metals. Assessing indices of oxidative stress can reveal relative ecological risks of pollution to species in their natural habitat. However, this study was designed to determine heavy metal concentrations and oxidative stress responses in Callinectes amnicola from LL habitat.
Monthly samples of surface water, sediment (n=288 each) and crab (n=1750, using circular lift nets mesh 50-76mm) were collected for 24 months from four sampling stations; Mid-lagoon, Makoko, Oko-Baba, and Iddo, Ajah. Cadmium, lead, copper and zinc were analysed in surface water, sediment and crab organs (hepatopancreas, gill, gonad and muscle) samples using Atomic Absorption Spectrophotometer. Activities of oxidative stress enzymes: Superoxide Dismutase Catalase, Glutathione Peroxidase, Reduced Glutathione and Malondialdehyde (Lipid Peroxidation) in crab organs were determined using standard methods. Further assessment of tissue damage was carried out using histopathological method. Data were analysed using descriptive statistics and ANOVA at α 0.05.
Cadmium, lead, copper and zinc concentrations (0.4±0.02, 0.3±0.22, 0.1±0.1, 0.03±0.01mg/L) were lower in surface water than corresponding concentrations in sediment (2.7±1.2, 51.9±45.2, 60.1±53.9, 37.1±27.4 mg/kg) respectively. Heavy metals level in surface water were lower at Mid-lagoon and higher in other stations than respective WHO limits. Concentrations of cadmium, lead, copper and zinc (mg/kg) in organs of crabs from Mid-lagoon were lower and higher at all other station than WHO limits. Levels of SOD, GPx, GSH and Catalase in crab organs were significantly low at the sampling stations; while Malondialdehyde concentrations were significantly higher in crab organs from all sampling stations except those from the Mid-lagoon. Pathological changes including necrosis,vacuolation, detached cuticle were observed in crab organs, in all stations except Mid-lagoon.
The Lagos Lagoon was laden with heavy metals from industrial discharges. This could explain the induced oxidative damage in Callinectes amnicola from the Lagoon.
Monthly samples of surface water, sediment (n=288 each) and crab (n=1750, using circular lift nets mesh 50-76mm) were collected for 24 months from four sampling stations; Mid-lagoon, Makoko, Oko-Baba, and Iddo, Ajah. Cadmium, lead, copper and zinc were analysed in surface water, sediment and crab organs (hepatopancreas, gill, gonad and muscle) samples using Atomic Absorption Spectrophotometer. Activities of oxidative stress enzymes: Superoxide Dismutase Catalase, Glutathione Peroxidase, Reduced Glutathione and Malondialdehyde (Lipid Peroxidation) in crab organs were determined using standard methods. Further assessment of tissue damage was carried out using histopathological method. Data were analysed using descriptive statistics and ANOVA at α 0.05.
Cadmium, lead, copper and zinc concentrations (0.4±0.02, 0.3±0.22, 0.1±0.1, 0.03±0.01mg/L) were lower in surface water than corresponding concentrations in sediment (2.7±1.2, 51.9±45.2, 60.1±53.9, 37.1±27.4 mg/kg) respectively. Heavy metals level in surface water were lower at Mid-lagoon and higher in other stations than respective WHO limits. Concentrations of cadmium, lead, copper and zinc (mg/kg) in organs of crabs from Mid-lagoon were lower and higher at all other station than WHO limits. Levels of SOD, GPx, GSH and Catalase in crab organs were significantly low at the sampling stations; while Malondialdehyde concentrations were significantly higher in crab organs from all sampling stations except those from the Mid-lagoon. Pathological changes including necrosis,vacuolation, detached cuticle were observed in crab organs, in all stations except Mid-lagoon.
The Lagos Lagoon was laden with heavy metals from industrial discharges. This could explain the induced oxidative damage in Callinectes amnicola from the Lagoon.