Heavy Metals and Hydrocarbon Contamination of Surface water in Azuabie Creek within Bonny Estuary, Nigeria

The aim of this study was to assess some heavy metals (Cr, Ni, Cd, Pb, Zn and Cu) and hydrocarbon concentrations of Azuabie creek using the Okujagu creek as a control location. Seventy two samples were collected from four stations (AZ1, AZ2, AZ3 and OK) in six months (July – December 2016). Samples were analyzed using AAS and GC spectrophotometry while ANOVA and PCA were used for data analysis.The hydrocarbons (THC, 0.3 ± 0.07 – 84.6 ± 28.85 mg/l, TPH,0.07 ± 0.03 - 45.20 ± 13.88 mg/l & PAH, 0.001 ± 0.0003 – 0.384 ± 0.104 mg/l) were generally higher in Azuabie creek and showed increased concentration over time with significant difference (p<0.001) between locations and also between months. The increase in hydrocarbon level is due to oil bunkering and other anthropogenic activities in the study area. The concentration of Cr, Ni, Cd, and Pb generally exceeded WHO and USEPA limits in water while those of Zn and Cu fell below such regulatory limits. Site discrimination by PCA showed AZ1 & AZ2 as most dissimilar stations traceable to higher contaminant levels associated with such sites. In conclusion, the variables within Azuabie creek showed higher contaminant level compared to the control creek. Complete isolation of each site examined indicates dissimilarity in the water quality with respect to contaminant level within the creek hence regular monitoring is needed to detect water quality changes.Keyword: Heavy metals, hydrocarbon, surface water, contaminatio

Cadmium and lead levels in some fish species from Azuabie creek in the Bonny Esturary, Nigeria

The concentrations of cadmium and lead were determined in seven fish species from the Azuabie creek in the upper Bonny estuary of the Niger Delta, which is associated with industrial and abattoir discharges. Cadmium concentrations ranged from 0.01 to 0.06 mg/kg and show no significant difference between species. The concentrations of lead (ranging from 0.104 to 0.310 mg/kg) were significantly higher in Chrysichthys nigrodigitatus and Gobius niger than other species examined. Also,lead was significantly higher than cadmium. The metal concentrations obtained were within values that may be considered safe for human consumption

Accumulation of Pb, Cd and Ni in sediments and root of mangrove plant (Laguncularia sp) from the fringes of the Upper Bonny Estuary, Nigeria

The accumulation of heavy metals in sediments and roots of mangrove plant (Laguncularia sp) in relation to the age of the plant root was evaluated. Composite sediment and root samples were collected from three spots per station at three different locations (St.1: Borikiri, St.2: Bundu-Ama, St3: Eagle Island) of mangrove fringes in the upper Bonny estuary. Heavy metal content of sediment and roots were analyzed using spectrophotometric methods while growth rings/bands was used to estimate age of root. There were variations in the metal content of sediments in space and time. Observed heavy metal range (μg/g) in sediments (N: 0.001 - 2.8, Pb: 0.001 - 4.5, Cd: 0.001 - 0.35) and root (N: 0.001 - 3.3, Pb: 0.001 - 7.1. Cd: 0.001 - 0.5) generally indicated higher values in roots compared to sediments. The age of the plant root examined varied between 2.3 - 5.7 years across sites. ANOVA showed significant difference (p<0.05) in metal concentration in space and time. The concentration of Pb, Cd and Ni in the root of plants fell within and slightly above standard limits of WHO/FAO Pb: 5.0 μg/g; Cd 0.2 μg/g and Ni: 1.5 μg/g).In conclusion, Pb, Cd and Ni in sediment had strong positive linear relationship with those in the plant root but the age of plant root did not give significant relationship with metal accumulation. Laguncularia roots generally accumulated more heavy metals compared to the surrounding sediments which was attributed to discrete exposure of the sites to anthropogenic impacts.Keywords: Heavy metals, Bioaccumulation, Sediment, Mangrove plant, Niger Delt

Bioaccumulation and Consumption Safety of a Sea Food, Gastropod Mollusc (Thais coronata): Polycyclic Aromatic Hydrocarbon (PAH) Perspective

Seafood and other environmental matrices are major entry route of harmful pollutants into humans due to constant contamination of the aquatic environment hence requires monitoring. This study scientifically explored the hypothesis that benthic gastropods bioaccumulate harmful pollutants that pose health risk to consumers of the sea food. Fifty samples of Thais coronata were collected per site from major regional fish landings. Two hundred samples were collected monthly for eight months to determine the concentrations of polycyclic aromatic hydrocarbon-PAH and possible health risks due to consumption using regulatory limits for guidance. Total PAH concentrations (μg/kg) varied between 65.68–173.52 suggesting differences in consumed concentrations at different times. The concentration of individual PAH congeners (1.376 ± 0.07-40.356±2.21 μg/kg) and PAH4 were below the European Union maximum limits. The Daily Dietary Intake values ranged from 0.075-2.212 μg/kg for individual PAH congeners while that of PAH4 was 1.359 μg/kg and were all below their respective reference oral doses. The carcinogenic potencies of the PAH congeners ranged from 0.001-143.389, the carcinogenic toxic equivalents (TEQs) of all PAH congeners was 0.1522 while that of PAH4 was 0.0044. The Excess cancer risk (ECR) value (10-8–10-5) was within USEPA guideline of 10-6 while the margin of exposure (MOE) of individual PAHs and PAH4 were higher than critical border line of 10,000 given by European Food Safety Authority but diagnostic ratio suggested PAH sources of pyrogenic origin in samples monitored. The study concluded low health risk for consumers of the shellfish (Thais coronata) in the study region but with recommendation advisory for regular monitoring to observe changes

Protective effects of a compound herbal extract (Tong Xin Luo) on free fatty acid induced endothelial injury: Implications of antioxidant system

<p>Abstract</p> <p>Background</p> <p>Tong-Xin-Luo (TXL) – a mixture of herbal extracts, has been used in Chinese medicine with established therapeutic efficacy in patients with coronary artery disease.</p> <p>Methods</p> <p>We investigated the protective role of TXL extracts on endothelial cells injured by a known risk factor – palmitic acid (PA), which is elevated in metabolic syndrome and associated with cardiovascular complications. Human aortic endothelial cells (HAECs) were preconditioned with TXL extracts before exposed to PA for 24 hours.</p> <p>Results</p> <p>We found that PA (0.5 mM) exposure induced 73% apoptosis in endothelial cells. However, when HAECs were preconditioned with ethanol extracted TXL (100 μg/ml), PA induced only 7% of the endothelial cells into apoptosis. Using antibody-based protein microarray, we found that TXL attenuated PA-induced activation of p38-MAPK stress pathway. To investigate the mechanisms involved in TXL's protective effects, we found that TXL reduced PA-induced intracellular oxidative stress. Through AMPK pathway, TXL restored the intracellular antioxidant system, which was depressed by the PA treatment, with an increased expression of thioredoxin and a decreased expression of the thioredoxin interacting protein.</p> <p>Conclusion</p> <p>In summary, our study demonstrates that TXL protects endothelial cells from PA-induced injury. This protection is likely mediated by boosting intracellular antioxidant capacity through AMPK pathway, which may account for the therapeutic efficacy in TXL-mediated cardiovascular protection.</p

Macrophage Replication Screen Identifies a Novel Francisella Hydroperoxide Resistance Protein Involved in Virulence

Francisella tularensis is a Gram-negative facultative intracellular pathogen and the causative agent of tularemia. Recently, genome-wide screens have identified Francisella genes required for virulence in mice. However, the mechanisms by which most of the corresponding proteins contribute to pathogenesis are still largely unknown. To further elucidate the roles of these virulence determinants in Francisella pathogenesis, we tested whether each gene was required for replication of the model pathogen F. novicida within macrophages, an important virulence trait. Fifty-three of the 224 genes tested were involved in intracellular replication, including many of those within the Francisella pathogenicity island (FPI), validating our results. Interestingly, over one third of the genes identified are annotated as hypothetical, indicating that F. novicida likely utilizes novel virulence factors for intracellular replication. To further characterize these virulence determinants, we selected two hypothetical genes to study in more detail. As predicted by our screen, deletion mutants of FTN_0096 and FTN_1133 were attenuated for replication in macrophages. The mutants displayed differing levels of attenuation in vivo, with the FTN_1133 mutant being the most attenuated. FTN_1133 has sequence similarity to the organic hydroperoxide resistance protein Ohr, an enzyme involved in the bacterial response to oxidative stress. We show that FTN_1133 is required for F. novicida resistance to, and degradation of, organic hydroperoxides as well as resistance to the action of the NADPH oxidase both in macrophages and mice. Furthermore, we demonstrate that F. holarctica LVS, a strain derived from a highly virulent human pathogenic species of Francisella, also requires this protein for organic hydroperoxide resistance as well as replication in macrophages and mice. This study expands our knowledge of Francisella's largely uncharacterized intracellular lifecycle and demonstrates that FTN_1133 is an important novel mediator of oxidative stress resistance