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- Speciation of chromium in Algeciras bayPublication . Assefa, Anteneh Taye; Riaño, Dolores GalindoAlgeciras Bay is exposed to contamination from chromium because of the industrial activities carring out around the water, i.e Steel Industry and two Petrol Refineries can be mentioned. More over there are several activities which are being carried out including big ports, fishing and recreational activities. Most of the other trace metals in the water have been studied. Considering the environmental and health effects of this metal, study of its level and speciacion in the bay is necessary for wellbeing of all which are directly or indirectly dependent on this water. Unfiltered samples were used for total chromium determination and filtered samples were used for the other fractions and species of chromium determinations. The samples were collected from five different sampling points and four times between 2007 and 2009. The first and third samplings were done in autumn of 2007 and 2008 respectively. The second and the fourth samplings were done in spring of 2008 and 2009 respectivelly. Total chromium levels in the water from the bay were lower than the maximum guideline level to cause toxicity but it was higher than the background levels indicating artificial introduction of chromium to the water from industrial and/or domestic sources and activities carring out on the water. It is also found that the total and trivalent chromium level in Algeciras bay were higher than that of Mediterranean sea but there were no significant differences (=0.05) between hexavalent chromium levels of the two waters. It is also found that the total chromium, the different fractions and species of chromium in Algeciras Bay is lower than similar water bodies. There were no significant differences among the levels of all chromium forms and species studied during the four seasons but there were significant differences in sampling points for active chromium as well as dissolved chromium. There also were significant differences in the sampling years for particulate chromium as well as dissolved chromium. The correlations among the chromium fractions and species were also studied.
- Evaluation of extraction methods for recovery of fatty acids from marine productsPublication . Xiao, Liping; Mjøs, Svein Are; Grung, BjørnThe extraction efficiency of Soxhlet, acid hydrolysis and Bligh and Dyer were evaluated by using direct methylation on extracts and residues for calculating the mass balance of fatty acids for eight marine powders (fishmeals, krillmeals, cod filet, salmon filet and herring roe). The results show that Soxhlet gave lowest extracted fatty acid content, especially for the samples which contain a high amount of phospholipid. Acid hydrolysis and Bligh and Dyer extract gave comparable extracted fatty acid contents with direct methylation. The mass balance of fatty acids in extract and residue is close to 100% for the three extraction methods which indicate that fatty acid was not lost during the extraction procedures. The difference of extracted fatty acids is mainly due to the different extracting efficiency. The gravimetric lipid has limited correlation with total fatty acids, especially for Soxhlet. Analyses of the fatty acid profiles showed that the Soxhlet extracts were different from the others. Extracts from the acid hydrolysis and Bligh and Dyer methods had similar fatty acid profiles as the direct methylation method. The precision of fatty acid analysis by direct methylation method for marine powders were also validated. The coefficient of variation was 5.11% for solid samples and 1.21% for liquid sample.
- Total analysis and assessement of mobile metal ions in sediments from Algeciras Bay, SpainPublication . Kosore, Charles Mitto; Riano, Maria Dolores Galindo; Isabel Maria Palma Antunes CavacoTotal metal concentrations in surface sediments from seventeen sampling points in Algeciras Bay were determined by total acid decomposition with IR heating technique.