Single and Joint Action Toxicity Studies of Trace Elements in Binary Mixtures against Clarias gariepinus and Sarotherodon melanotheron

This study investigated the interactions of essential and non-essential trace elements when present in binary mixtures and resultant effects on acute toxicity in fish. The effects of four essential trace elements; Zn, Ni, Co and Cr respectively on the acute toxicities of three non-essential trace elements; Cd, Hg and Pb against Clarias gariepinus and Sarotherodon melanotheron were assessed using laboratory bioassays. The patterns of interaction of the elements affecting toxicity via antagonistic, synergistic or additive reactions were determined using the Synergistic Ratio (RA) and Concentration Addition (CA) joint action toxicity models. Single action toxicity indices showed that Hg was the most toxic element with a 96hr LC50 value of 0.0004 and 0.0003 mmol/l and Co the least toxic element with a 96hr LC50 value of 0.86 and 1.00 mmol/l, against the two fish species respectively. The SR and CA toxicity models showed that the essential trace elements (Zn, Ni, Cr and Co) reduced the toxicity of Pb against C.gariepinus as indicated by SR and RTU values < 1. Both models also showed that Zn reduced the toxicity of Pb and Hg respectively against S.melanotheron. However, the SR model showed that only Co reduced the toxicity of Cd against C.gariepinus. This study has established the possible beneficial interactions among essential trace elements and hazardous non-essential trace elements. Factors influencing such beneficial interactions including physiological processes in fish species, trace element concentrations and physicochemical parameters of exposure medium should be explored in future studies.Keywords: Essential Trace Elements; Non-essential Trace Elements; Antagonism; Toxicit

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

Occurrence of Acetaminophen, Amoxicillin, Diclofenac and Methylparaben in Lagos and Ologe Lagoons, Lagos, Nigeria

The occurrence of acetaminophen, amoxicillin, diclofenac and  methylparaben in Lagos and Ologe Lagoons was investigated by random sampling of the water bodies during rainy and dry seasons. Samples analysis was carried out using high performance liquid chromatography. For the two seasons, the mean environmental concentrations of acetaminophen in Lagos and Ologe Lagoons were 0.075 μg/L and 1.233 μg/L respectively. The mean environmental concentration of amoxicillin in Lagos Lagoon was 0.008 μg/L while 0.003 μg/L was the mean value in Ologe Lagoon. Diclofenac occurrence in Lagos Lagoon had a mean value of 0.136 μg/L while 0.519 μg/L was recorded in Ologe Lagoon. The environmental concentration of methylparaben in Lagos Lagoon was 0.453 μg/L while its means concentration in Ologe Lagoon was 0.089 μg/L. From the results, the environmental concentrations of acetaminophen and diclofenac inOloge Lagoon were higher than their level of occurrence in Lagos Lagoon. However, the levels of occurrence of amoxicillin and methylparaben in Lagos Lagoon were higher than their environmental concentrations in Ologe Lagoon. Methylparaben was the most frequently detected in the water bodies with 87.5% detection frequency. This was followed by diclofenac with 75%. Also, 50% of the water samples analysed contained acetaminophen while amoxicillin had the least (37.5%) frequency of occurrence. The study established that there are active pharmaceuticals compounds and excipients present in the Nigerian aquatic environment which are  micropollutants of emerging environmental concerns and of significant ecological risk. Therefore, there is need for environmental regulators to make concerted efforts towards environmental monitoring of this group of pollutants.Keywords: Acetaminophen, Amoxicillin, Diclofenac, Methylparaben, Environmental Occurrenc

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