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Influence of proximity to an urban center in the pattern of contamination by marine debris
2014
Leite, A.S. | Santos, L.L. | Costa, Y. | Hatje, V.
In order to test the relationship between the occurrence of marine debris and the distance from urban areas, nine beaches in the metropolitan area of Salvador, Bahia, Brazil and the adjacent northern coast were studied. Marine debris were collected, sorted in several categories and weighed. It was observed that plastics were numerically the most abundant component of the collected debris. As expected, the beaches closest to Salvador presented the largest density of debris, with the exception of the Porto da Barra beach, which has an efficient public cleaning system and does not have any vegetation, making it difficult toaccumulate solid waste. Linear regression analyses showed significant relationships between the distance from the urban center (Salvador) and the number of marine debris per m2, the total number of debris per beach (abundance), and the diversity of debris types (richness). The results showed that proximity to urban regions was a key factor in the marine debris distribution along the coast.
Show more [+] Less [-]Isolation and characterization of crude oil degrading bacteria from the Persian Gulf (Khorramshahr provenance)
2014
Hassanshahian, Mehdi | Zeynalipour, Mohammad Saleh | Musa, Farzaneh Hosseinzadeh
Fifteen crude oil degrading bacteria were isolated from oil contaminated sites in the Persian Gulf at Khorramshahr provenance. These bacteria were screened with two important factors such as growth rate on crude oil and hydrocarbon biodegradation, and then three strains were selected from 15 isolated strains for further study. One strain (PG-Z) that show the best crude oil biodegradation was selected between all isolates. Nucleotides sequencing of the gene encoding for 16S rRNA show that strain PG-Z belong to Corynebacterium variabile genus. This strain was efficient in degrading of crude oil. This strain was capable to degraded 82% of crude-oil after one week incubation in ONR7a medium. The PG-Z strain had high emulsification activity and biosurfactant production between all isolates. GC–MS analysis shows that C. variabile strain PG-Z can degrade different alkanes in crude oil.
Show more [+] Less [-]Contamination and spatial distribution of heavy metals in topsoil surrounding a mega cement factory
2014
Ogunkunle, Clement Oluseye | Fatoba, Paul Ojo
This study assessed the level of contamination of the topsoil by Pb, Cu, Cr, Cd and Zn and the spatial distribution of these heavy metals around a cement factory. Thirty–eight composite soil samples were collected around the cement factory and subjected to nitric–perchloric acid digestion. Total metal contents of the soil were determined by flame atomic absorption spectrophotometry (FAAS) and the data generated were analyzed statistically. Spatial mapping of the distribution of heavy metals was done through the use of Inverse Distance Weighted technique (IDW) of ArcGIS 10. The results showed that the contamination domain of Cd was in the extreme domain while Pb and Cu levels in the soil were in the severe and moderate contamination domains. Zn and Cr posed no potential environmental hazard because of their low level in the soil. The spatial mapping of the heavy metals indicated Pb and Cu enrichment of the soil not only to come from cement production activities but also from vehicular activities while Cd enrichment of the soil was mainly from the cement production. Mapping of Zn and Cr distribution showed that their enrichments in the soil were from cement production activities. From these findings, it is highly recommended that environmental auditing of the cement production line be carried out to reduce the release of pollutants. It is also important that remediation activities be carried out on the soil to reduce the levels of Cd, Pb and Cu to avert potential ecological disasters.
Show more [+] Less [-]Characterizing metal levels and their speciation in intertidal sediments along Mumbai coast, India
2014
Fernandes, Lina L. | Nayak, G.N.
The present study investigated the concentration, distribution and speciation of metals (Fe, Mn, Cu, Pb, Co, Zn and Cr) in sediments of Mumbai region. Pearson’s correlation matrix and cluster analyses showed good association of metals with grain size and organic matter. Factor analysis applied to the speciation data helped to identify the role of different sediment fractions in metal retention. The environmental risks of metals, evaluated by sediment quality guidelines, revealed some contamination in the region. However, the Individual and Global Contamination Factors and the Risk Assessment Code, suggested low risk to the aquatic environment, except of Mn in the creek sediments.
Show more [+] Less [-]Simulation of the potential effects of CO2 leakage from carbon capture and storage activities on the mobilization and speciation of metals
2014
de Orte, Manoela Romanó | Sarmiento, Aguasanta M. | DelValls, T Ángel | Riba, Inmaculada
One of the main risks associated with carbon capture and storage (CCS) activities is the leakage of the stored CO2, which can result in several effects on the ecosystem. Laboratory-scale experiments were performed to provide data on the possible effects of CO2 leakage from CCS on the mobility of metals previously trapped in sediments. Metal-contaminated sediments were collected and submitted to acidification by means of CO2 injection using different pH treatments. The test lasted 10days, and samples were collected at the beginning and at the end of the experiment for metal analysis. The results revealed increases in the mobility of metals such as Co, Cu, Fe, Pb and Zn due to pH decreases. Geochemical modeling demonstrated that acidification influenced the speciation of the metals, increasing the concentrations of their free forms. These data suggest the possible sediment contamination consequences of accidental CO2 leakage during CCS activities.
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