Speciation of chromium in Algeciras bay

• Autor(a) principal: Assefa, Anteneh Taye
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/10747
• topic: Crómio; Baía de Algeciras; Poluição; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Algeciras 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.