Accumulation and persistence of fecal pollution in the coastal area of Rovinj

Paliaga, Paolo (2015) Accumulation and persistence of fecal pollution in the coastal area of Rovinj. Doctoral thesis, Faculty of Science > Department of Geology.

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Abstract

Fecal contamination represents an important problem for coastal areas that affects the ecosystem and poses a threat to human health. The accumulation and persistence of fecal pollution was analyzed in the sediments and waters along the coast of Rovinj from 3 bays exposed to different types and amounts of sewage effluents. The level of sewage contamination was quantified using fecal indicator bacteria and fecal sterols. The distribution of waste waters around the main sewage outfall in Cuvi bay depended on the distance from the outfall, the volume discharged, the momentary currents and the presence of the thermocline. Fecal indicator bacteria and sterols were strongly correlated but their relation changed from season to season. Fecal contamination was detected in a radius of 300 m from the outfall. Seasonal changes of the abundance and production of heterotrophic bacteria were very similar in the contaminated and uncontaminated areas with a limited increase in the abundance and production close to the outfall. In the bay of Valdibora, influenced by a fish cannery effluent around 10 times smaller than the outfall in Cuvi bay the levels of contamination were comparable. The abundance of heterotrophic bacteria was the largest around the industrial outfall, while the specific rate of replication was very low. The grainsize composition of surface sediment (0-5cm) was altered in comparison to the less contaminated deeper sediment (5-10 cm) in a radius of 300 m around the main sewage outfall. At the sewage disposal site, coprostanol was predominantly associated with very fine sand. The fish cannery effluent, created highly anoxic conditions in the sediment that favored the diagenetic formation of coprostanol. The sediments from the southern harbor, exposed only to boat and yacht effluents displayed very low levels of fecal contamination.

Item Type: Thesis (Doctoral thesis)
Keywords: sewage outfalls, fecal sterols, fecal indicator bacteria, water column, marine sediment, northern Adriatic
Supervisor: Najdek Dragić, Mirjana and Fuks, Dragica
Date: 2015
Number of Pages: 94
Subjects: NATURAL SCIENCES > Geology > Geology and Paleontology
Divisions: Faculty of Science > Department of Geology
Depositing User: Danica Vujičić
Date Deposited: 13 Jul 2015 12:11
Last Modified: 13 Jul 2015 12:11
URI: http://digre.pmf.unizg.hr/id/eprint/4119

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