Histopathological Biomarkers of Exposure to Monocyclic Aromatic Hydrocarbons in Clarias Ggariepinus (African Catfish)

The pollution of the environment with petroleum products through spills in oil producing countries has resulted in the widespread distribution of benzene, toluene, ethylbenzene and xylene. The aim of this study was to identify histopathological alterations in Clarias gariepinus (catfish) that can be used as biological markers for detection of petroleum hydrocarbon contamination which can be included in monitoring programmes. The toxicological evaluations of benzene, toluene, ethylbenzene and xylene were carried out against Clarias gariepinus. The histopathological effects of benzene, toluene, ethylbenzene and xylene (BTEX) on different organs were investigated in C. gariepinus, Tilapia zillii, and Chrysichthys nigrodigitatus taken from the impacted areas of the Lagos Lagoon. Toxicological evaluations of the monocyclic aromatic components, benzene, toluene, ethylbenzene and xylene on Clarias gariepinus showed that ethylbenzene (0.479 ml/l) was the most toxic compound tested followed by xylene (0.519 ml/l), benzene (0.666 ml/l) and toluene (1.190 ml/l). The results from the histological study identified necrosis and deformation of the gills, inflammations in the liver, and wrinkling of the oocyte membrane in the gonads of fish, as good histopathological biomarkers of hydrocarbon related stressors. The combination of chemical analysis with these identified biomarkers can be used during environmental monitoring programmes for the protection of aquatic ecosystem

Evaluation of Crude Oil Degradation Under a No-Control and Dispersant-Control Settings, Based on Biological and Physical Techniques

The degradation of crude oil under a no-control and dispersant-control setting was evaluated using loss of biological activity test, microbial population growth and measurements of optical transmittance of test media. Comparison of the toxicity of crude oil under the no-control setting to crude oil-dispersant mixture revealed that the mixture was about 2 times more toxic than the crude oil under the no response strategy. Furthermore, the results of the toxicity testing experiments also showed that under the no-control setting, there was a loss in the toxicity of the crude oil from 6.03mL/L - 9.43 mL/L compared to crude oil-dispersant mixture where the toxicity of the crude oil-dispersant mixture was found to remain fairly constant with LC50 value of the mixture ranging from 4.0 mg/L to 4.38 mg/L over the 28 days experimental period. On the basis of the regression coefficient factor (R2), loss of biological activity during the no-control setting was found to be about 3 times more than under the dispersant-control setting. The result of the measurement of optical transmittance of crude oil depicting rate of emulsification under the no-control and dispersantcontrol settings revealed that level of light transmittance under no-control setting ranged from 0% to 84%, while under the dispersant-control setting light transmittance ranged from 0% to 72% over the 28 days of observation. The derived regression factor (R2) however revealed that under the dispersant-control setting, the rate of emulsification and degradation of crude oil was faster (R2 = 0.96) than under the no-control setting (R2 = 0.77). The result of the microbial growth assays also revealed that under the dispersant-control setting, the numbers of microbial colony forming units was about 7 folds higher than the number of colony forming units observed under the no-control setting. The usefulness of the methods for assessing crude oil degradation and its implications for choosing dispersants and making decision on whether or not to deploy dispersants for oil spill control are discussed

Influence of joint application of heavy metals on level of each metal accumulated in the periwinkle Tympanotonus fuscatus (Gastropoda: Potamididae)

Most laboratory assessments of toxicity and bioaccumulation of heavy metals have been concentrated on the accumulation of these metal ions when exposed singly to the test organisms. However, under the natural environmental settings, the metals are never present in isolation and may interact with each other, therefore justifying the need to study the influence of joint application of metals on accumulated levels in exposed animals. In this study, exposure of the periwinkle Tympanotonus fuscatus to sublethal concentrations (equivalent to 0.1 and 0.01 of 96 h LC 50) of heavy metals revealed that they were bioaccumulative varying amounts, depending on the type of metal, exposure period and concentration in the test media. While Zn and Pb ion accumulation increased steadily with exposure time, the amounts of Cu accumulated fluctuated regularly over the 30-day experimental period. The levels of Zn, Cu and Cd bioaccumulated over the 30-day experimental period were reduced by over 2-6 folds (with bioaccumulation ratio values ranging from 0.15 to 0.81) when compared to concentrations of the respective metals accumulated during single bioaccumulation studies. However, Pb concentrations accumulated during the joint action studies increased nearly 2-fold (bioaccumulation ratio range 1.36 to 2.0-fold).La mayoría de los análisis de laboratorio sobre toxicidad y bioacumulación de metales pesados se han concentrado en la acumulación individual de los iones metálicos en los organismos de prueba expuestos a ellos. Sin embargo, bajo condiciones naturales del ambiente, los metales nunca se presentan en forma aislada y deben interactuar unos con otros, justificando así la necesidad de estudiar el efecto de la aplicación conjunta de metales en animales de prueba. En este estudio la exposición de Tympanotonus fuscatus a concentraciones subletales (0.1-0.01 de 96 h LC 50) de metales pesados reveló que la bioacumulación varía según el tipo de metal, el período de exposición y la concentración en el medio de prueba. Mientras los iones de Zn y Pb incrementaron gradualmente su acumulación al pasar el tiempo, las cantidades de Cu fluctuaron regularmente durante los 30 días del experimento. Los niveles de Zn, Cu y Cd bioacumulados durante los 30 días del experimento son de dos a seis veces menores (con un rango de bioacumulación de 0.15-0.81) que los que se obtienen por la exposición a los metales en forma individual. Por el contrario, la acumulación de Pb aumentó al doble (rango de bioacumulación 1.36-2.0)

In vitro cyto-toxic assessment of heavy metals and their binary mixtures on mast cell-like, rat basophilic leukemia (RBL-2H3) cells.

From PubMed via Jisc Publications RouterHistory: received 2018-12-05, revised 2019-02-08, accepted 2019-02-08Publication status: aheadofprintWe investigated the cytotoxicity and mechanisms of cell death induced by salts of Cadmium (Cd ), Lead (Pb ), Arsenic (AsO ) and Chromium (Cr ) on RBL-2H3 cells (a model mast cell line). In addition, cyto-toxic effect on cell viability was assessed to reveal their nature of interaction in binary mixture. The individual cytotoxic characteristics of these metals on RBL-2H3 cell viability showed a concentration-dependent reduction of cell viability. We observed that concentration-dependent cytotoxic potency on RBL-2H3 cells of these metals range in the following order Cd >Cr >As O > Pb with LC values of 0.11 μM, 93.58 μM, 397.9 μM and 485.3 μM respectively. Additive effects were observed with Pb  + Cd , Pb  + AsO , Pb  + Cr and AsO  + Cr . The study revealed that Pb , Cd , AsO and Cr could induce significant (P < 0.01) cell death by apoptosis in RBL-2H3. Highly significant necrotic cell death was observed with Pb and Cr (P < 0.01) than Cd and AsO (P < 0.05). Overall, it can be deduced that several cell death executing pathways may be concomitantly activated on exposure to heavy metals and the predominance of one over others might depend on the type of heavy metal, concentration and the metabolic state of the cell. Eventually, binary mixtures of some of these metals showed less cytotoxicity than would be expected from their individual actions and may depend on the co-exposure of the metal ions and their modes of action. [Abstract copyright: Copyright © 2019 Elsevier Ltd. All rights reserved.

Air Pollution Monitoring Around Residential and Transportation Sector Locations in Lagos Mainland

Background. Industrialization and urbanization, while associated with increased productivity, are also potential causes of increased air pollution. Urban air quality has the potential to affect the health and wellbeing of residents of urban areas. Objectives. The present study investigated the levels of air pollutants around residential areas and transport sector locations (TSLs) in Lagos, Nigeria. Residential areas were defined as areas around inner streets and living quarters, while TSLs included busy roads, dual carriage roads, bus stops and major car parks in the Yaba Local Council Development Area of Lagos Mainland, Lagos, Nigeria. Methods. Air quality parameters were assessed in situ using calibrated hand-held devices at selected residential and TSLs. Each sampling location was geo-referenced and concentrations of the various parameters were used to plot distribution maps. Results. The findings from the monitoring exercise showed that levels of the measured air pollutants: carbon monoxide (CO), particulate matter (PM10 and PM2.5), sulphur dioxide (SO2), noise, temperature and humidity were within the ranges of 1.00 – 6.0 5.97 ppm, 43.345.2 – 127.2159.7 μg/m3, 20.3 23.25 – 69.058.16 μg/m3, 0.0 0 – 0.20.17 ppm, 47.7 50 - 65 70.1 dB, 26.2227.2 – 35.536.7°C and 57.0157.6 – 91.8492.3%, respectively, around residential areas. Values of the measured air pollutants at the TSLs ranged as follows: 2.011.0 – 5.397.7 ppm, 103.3360.7 – 179.77404.0 μg/m3, 50.2832.3 – 91.01184.0 μg/m3, 0.00 – 0.40 ppm, 64.2153.1 – 71.1376.3 dB, 27.1826.2 –27.9332.6°C and 60.3660.0 – 75.0178.0%, respectively. Hydrogen sulphide (H2S), ammonia (NH3), nitrogen oxide (NO2) were below detection limits in both sampling locations while volatile organic carbons (VOCs) ranged from 0.00 – 0.10 ppm in the TSLs. Discussion. Most assessed air quality parameters were significantly higher around bus stops (P < 0.05), except for CO and humidity. In addition, PM10 and PM2.5 were much higher than the World Health Organization (WHO) guidelines. The results indicated that the quality of air (particulate matter) in the study area was poor, especially in the TSLs. Conclusions. The Federal Ministry of Environment, through its relevant agencies, must create policies to address urban air pollution, taking into consideration long term exposures and people that are most vulnerable within the population. Competing Interests. The authors declare no competing financial interests

Genotoxic, Histopathological and Oxidative Stress Responses in Catfish, Clarias gariepinus, Exposed to Two Antifouling Paints

Background. Antifouling paints are enriched with biocides and employed in the maritime industry to protect moving and fixed surfaces from fouling activities of sea dwelling invertebrates. There is limited information on their effect on the non-target African catfish, Clarias gariepinus, a commonly consumed fish in Lagos. Objectives. This study investigated the effects of two commonly used antifouling paints (Berger TBT-free (A/F783 (H)), reddish brown color and Silka Marine lead based paint, pale orange color) on a non-target catfish species, Clarias gariepinus. Methods. The study involved an initial 96-hour acute toxicity assay followed by chronic toxicity evaluation (using 1/10th and 1/100th 96-hour median lethal concentration (LC>50) values) for 28 days to determine the ability of the paints to induce micronucleus and red blood cell abnormalities, and histopathological as well as oxidative stress effects in the catfish.Examined anti-oxidative stress enzyme activities include superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and glutathione-s-transferase (GST). Results. Acute toxicity evaluation results indicated that the Berger paint was 16.1-times more toxic than Silka paint with 96-hour LC50 values of 0.71 mg/L and 11.49 mg/L, respectively. Results from the biochemical assay indicated significantly higher (P<0.05) levels of a lipid peroxidation product, malondialdehyde, in Silka-exposed catfish compared to the control. All enzymes showed significantly higher activities in Berger paint-exposed catfish compared to the control. There was evidence of micronucleated and binucleated cells in the red blood cells of fish exposed to both paints. Histopathological assessment indicated that the exposed fish gills showed evidence of abnormalities such as curved lamellae epithelial necrosis, epithelial lifting and hyperplasia. The liver samples of the catfish showed evidence of portal inflammation as well as mild to severe steatosis, while the gonads showed varying percentages of follicle degeneration. Conclusions. The present study combined an array of biomarkers to determine the negative health impacts of two commonly used antifouling paints on non-target catfish inhabiting Lagos Lagoon. Further in situ studies are recommended to determine the current status of the lagoon fish. Ethics Approval. Ethical approval was obtained from the Department of Zoology, University of Lagos, Post-Graduate Committee. Note that this work commenced before the establishment of the University of Lagos Ethical Committee for the use of animals and humans in scientific studies. The committee does not give retroactive approval but stands by existing approvals before its establishment. However, this study followed the World Medical Association principles on the treatment of animals used in research (https://www.wma.net/policies-post/wma-statement-on-animal-use-in-biomedical-research/), and also American Fisheries Society Guidelines for the Use of Fishes in Research (https://fisheries.org/policy-media/science-guidelines/guidelines-for-the-use-of-fishes-in-research/) Competing Interests. The authors declare no competing financial interest