Occurrence and distribution of heavy metals in indoor settled particles in Lagos Metropolis, Nigeria

The increased application of technology, industrialization and growing population has resulted in the emission of wastes such as heavy metals that pollute the environment. The occurrence and distribution of heavy metals such as cadmium (Cd), copper (Cu), chromium (Cr), iron (Fe), manganese (Mn), lead (Pb), nickel (Ni) and zinc (Zn) in settled particles (indoor) collected from selected residential in Lagos metropolis over a two- year period (February, 2007 – July, 2008) was therefore investigated. The measurements of heavy metals contents were performed using Atomic Absorption Spectroscopy (AAS). The results showed widespread heavy metals contamination especially Fe and Zn, which were present as the highest concentration while Cd was the lowest in the settled particles (dust). The order of occurrence of heavy metals in settled particles (dust) collected indoor in 2007 and 2008 respectively were as follows, Fe > Zn > Pb > Cu > Cr > Mn > Ni > Cd and Fe > Zn > Mn > Pb > Cr > Cu > Ni > Cd. The outcome of this study implied that dust represent major source of heavy metals around dwelling places in the Lagos metropolis and therefore should be monitored. Additionally, data from this study could stand as a reference point for subsequent monitoring.Keywords: Heavy metals, Settled particle, Indoor, Dust, Lagos metropolis, Dwellin

Urinary 1-hydroxypyrene, haematological and antioxidant status of petrol station attendants in Lagos Metropolis, Nigeria

Background: Workplace polycyclic aromatic hydrocarbons (PAHs) exposure occurs majorly  through inhalation or dermal absorption of volatile compounds or of particles with adsorbed PAHs. PAHs have been found to potentially alter the biochemical, haematologic and antioxidant parameters in humans.Objectives: This study investigated the level of urinary 1-hydroxyperene as a biomarker of PAH exposure, haematological, antioxidant and lipid peroxidation status of petrol station attendants in Surulere area of Lagos Metropolis, Nigeria.Methods: Petrol station attendants (PSA) were randomly selected from different petrol stations in Surulere, Lagos State, Nigeria. Their clinical data and medical history were collected by personal interview via a questionnaire. The participants who met the inclusion criteria and volunteered to continue with the study were selected (n=55). The control subjects were non-smoking students in tertiary school (n=20). The subjects were grouped according to their location within Surulere, Lagos State, Nigeria. Group 1-5 were the petrol station attendants while Group 6 is the control. Group 1 (OO): Oando filling station in Olorunsogo (n=14), Group 2 (MO): MRS filling station in Olorunsogo (n=5), Group 3 (ML): MRS filling station in Lawanson (n=7), Group 4 (OI): Oando filling station in Ishaga (n=19), Group 5 (MI): MRS filling station in Ishaga(n=10) and Group 6 (Control): Tertiary School Students (n=20). All participants in this study willingly volunteered to donate 24-hour urine and blood samples. Urinary 1-hydroxypyrene concentration was assayed for using HPLC while blood samples were used to determine haematological, antioxidants biomarkers including superoxide dismutase (SOD), catalase (CAT) and m alondialdehyde ( M D A ) parameters spectrophotometrically.Results: The concentration of 1-hydroxypyrene in all the PSA groups were significantly (p<0.05) higher than the control. There were variations in the haematological parameters among the PSAalthough they were relatively non-significantly (p<0.05) higher than the control whereas the oxidative stress biomarkers (SOD, CAT and MDA) were significantly (p<0.05) higher than the control.Conclusion: Present study showed that Petrol station attendants are at high risk of PAHs exposure which could lead to detrimental health challenges. The attendants should be encouraged to use safety protective devices in workplace to reduce inhalation of PAHs

Toxicological assessment of four common household surfactants on Clarias gariepinus (Burchell, 1822) and Oreochromis niloticus (Linnaeus, 1758)

The acute toxicity of four common household liquid detergents coded as (FL, ML, MF and LC) was evaluated on two fish species; African Catfish (Clarias gariepinus) and Nile Tilapia (Oreochromis niloticus) fingerlings in a static bioassay. During the exposure period (96 hours), there was a remarkable rise of alkalinity from 22.00 mgL-1 to 62.50 mgL-1 while dissolved oxygen decreased with increased concentration. Behavioral changes such as restlessness, rapid swimming, loss of balance, opercula ventilation, respiratory distress and hemorrhaging of gill filaments were observed before mortality. Based on 96 hr LC50, FL (0.009 ml/L), was the most toxic followed by ML (0.014 ml/L), MF (0.056 ml/L) and LC (0.168 ml/L) against O. niloticus whereas MF (0.021 ml/L) was the most toxic followed by ML (0.033 ml/L), FL (0.038 ml/L) and LC (0.364 ml/L) against C. gariepinus in descending order. In terms of the sensitivity, O. niloticus fingerlings were more susceptible to the detergents than C. gariepinus fingerlings. The use of detergents cannot be discontinued. However, better methods of disposing the ‘after wash' needs to be worked out. At the present rate at which they are manufactured and introduced into the aquatic environment indiscriminately, aquaculture fish species could seriously be threatened.Keywords: Acute toxicity, detergents, Oreochromis niloticus, Clarias gariepinus, behavioral change

Relative toxicity of cigarette butts leachate and usefulness of antioxidant biomarker activity in Nile Tilapia Oreochromis niloticus (Trewavas, 1983)

Relative acute toxicity of cigarette butts leachate, antioxidant biomarkers; superoxide dismutase (SOD), catalase (CAT), gluthathione (GSH)activity and lipid peroxidation (LPO), an index of malondialdehyde (MDA) were evaluated in Nile Tilapia (Oreochromis niloticus) exposed to two selected commonly consumed brand of cigarettes butts in smoked and unsmoked conditions(SCB 1/ 2 and UCB 1/2) respectively. Under laboratory condition acute toxicity was conducted over a period of 96hrs. Antioxidant activity and lipid peroxidation were based on the derived 96h LC50 value over a period of 28days. On the basis of 96hrs LC50 value, SCB 1 was found to be the most toxic (1.346 cigarette butt/l) followed by SCB 2 (2.271cigarette butt/l), UCB 2 (7.313cigarette butt/l) and UCB 1 (5.559cigarette butt/l) against O. niloticus. The results of SOD and CAT activity under the sublethal concentration (1/10th and 1/100th of 96hrs LC50) of cigarette butt leachate showed significantly(P<0.05) decreased activity in liver and gills compared to the control group whereas GSH in the liver and gill was induced significantly (P < 0.05) within 7-14days compared to 21-28days. MDA increased significantly (P< 0.05) in the liver and gill compared to control group. These findings indicate high oxidant activity on the fish, explaining the enormity of the impact of cigarette butt leachates in the environment and the significance of using a set of integrated biomarker in evaluating oxidative stress in aquatic ecosystem.Keywords: Cigarette Butt Leachate, Acute toxicity, Biomarkers, Oxidative stres

Single and joint action toxicity evaluation of insecticide and laundry detergent against Poecilia reticulata

In laboratory bioassays, single action toxicities of an insecticide (Apicide [A]) and two laundry detergents (Persil [P] and Klin [K]) as well as their joint action toxicity studies in binary (1:1; 1:4) and triple (1:1:1) mixtures were evaluated against Poecilia reticulata (Guppy). Joint action toxicity mortality data was analyzed using Synergistic Ratio (SR), Concentration – Addition (RTU) and Isobolograms models. On the basis of 96hr LC50 mortality data from single action studies, showed that A was the most toxic (0.00137mg/l) followed by P (0.773mg/l) and K (28.841mg/l). The joint action toxicity data showed a synergistic effect in mixtures of insecticide and detergents in all ratios (1:1, 1:4, 1:1:1) than when acting alone. In descending order of toxicity it was revealed that Apicide/persil (1:1; 0.00079mg/l)>Apicide/ Persil/Klin (1:1:1; 0.00093mg/l)>Apicide/Klin (1:1; 0.00094mg/l)>Apicide/ Persil (1:1; 0.00098mg/l)>Apicide/ Klin (1:4; 0.00106mg/l). The subjection of the 96h LC50 values of test compound mixtures based SR and RTU showed that interaction of mixtures in various ratios (1:1, 1:4, 1:1:1) tended towards synergisms (SR>1; RTU>1) respectively. Further analysis based on the isobologram model was in conformity with RTU and SR models. The significance of this study showed the relevance of joint action toxicity studies in setting realistic safe limits in order to protect aquatic organisms. Therefore, proper disposal and management strategies for wastes should be enforced.Keywords: Bioassay, Detergent, Insecticide, Toxicity, Poecilia reticulat

Heavy metals and polycyclic aromatic hydrocarbon content of cultured Clarias gariepinus (Cat Fish) muscle and pond water in Lagos Metropolis, Nigeria

Background: The quest to meet growing demand for fish and economic sustenance has led to increased number of aquaculture farms in Nigeria with little consideration on the biochemical and environmental status of the fishes. Objective: This study investigated the heavy metals, polycyclic aromatic hydrocarbons (PAHs) haematological, antioxidant and biochemical status of cultured Clarias gariepinusand its pond water. Methods: Muscle tissues excised from C. gariepinus and pond water samples obtained from commercial fish ponds across five locations (Akoka, Surulere, Ejigbo, Iyana Ipaja and Badagry) within Lagos State, Nigeria were evaluated for heavy metals, polycyclic aromatic hydrocarbons (PAHs), and antioxidants content using Atomic Absorption Spectrophotometer, Gas Chromatography, and  spectrophotometric methods respectively. Haematological and some biochemical parameters were determined in blood samples collected from the fishes. Results: Heavy metals and PAHs detected in the fish muscle and pond water samples were at concentrations significantly (p<0.05) above standard permissible limits. The order of prevalence of heavy metals in the C. gariepinus muscle and pond water was Ni > Pb > Cr > Cd. Significant (p<0.01) positive associations exist between antioxidant biomarkers (SOD, CAT and GSH) and lipid peroxidation biomarker (MDA). However, there was no significant (p>0.05) difference in the levels of haematological, lipid profile and kidney function biomarkers of the C. gariepinus cultivated across all the five locations. Conclusion: Present study show evidence of pollutants in the fish muscle and therefore call for adequate monitoring to ensure the safety of the food chain especially with the up springing of local fish farms across Lagos, Nigeria. Keywords: Biosafety, Clarias gariepinus, Food chain, Heavy metals, Polycyclic aromatic hydrocarbon

Physiological, endocrinological and environmental determinants of female infertility in Lagos, Nigeria

Background: Female infertility has become a fundamental health and social issue globally. A number of factors have been reported to contribute to this condition. In-vitro fertilization (IVF), a major technique used in tackling infertility has experienced relatively low success rate. Objectives: This study investigated the relationship between physiological, endocrinological, environmental factor and infertility among Nigerian infertile women. Methods: Infertile women (n=190) from five fertility  clinics in Lagos, Nigeria were recruited. Structured  self-administered questionnaires were  distributed to  the participants to obtain their physiological parameters such as age, blood group, rhesus factor  and genotype. Blood samples of the participants were collected and analyzed for the levels of follicle stimulating hormone (FSH), luteinising hormone (LH) and prolactin (PRL) using enzyme-linked immune sorbent assay (ELISA). The heavy metals levels in the blood samples were determined using atomic absorption spectrometry (AAS). Results: Participants of the oldest age group (51 – 55 years) had elevated levels of the reproductive hormones compared to other age groups while participants with blood group A showed higher level of PRLcompared to other blood groups, whereas the levels of FSH and LH were higher in blood group O compared to other groups. Participants with the heterozygous genotype AS had higher basal level of PRLand LH, while participants with the homozygous genotype AA showed a higher basal level of FSH. The basal levels of the three reproductive hormones (FSH, LH and PRL) were higher in participants with rhesus negative when compared to those with rhesus positive. However, the variation in the hormone levels, blood groups and Rhesus factor were not significantly different (p<0.05) among the various participant groups. Nevertheless, heavy metals which include lead, cadmium, chromium and mercury were detected in blood samples of the participants. Conclusion: Therefore, present study showed no association between blood group, genotype, Rhesus factor and infertility nor possible IVF outcome but it established that age and heavy metals may affect fertility via an imbalance in the basal levels of reproductive hormones