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The health and functioning of coastal ecosystems around Zanzibar Islands is severely affected by a combination of human and natural pressures. These consists of rapid population growth, uncontrolled tourism, overfishing and destructive fishing practices, harvesting of mangroves, dumping of solid waste and untreated wastewater from urban areas, acting on top of climate change related increases in sea temperatures, and sea levels as well as outbreaks of invasive species. Despite a high financial value of the coastal zone related to tourism, fisheries and seaweed production, documentation of the environmental degradation is scarce and clear environmental targets are missing. Through a combination of baseline studies and a literature review, we give an overview of how human and natural pressures have affected the coastal ecosystem health of Zanzibar. We give examples of how well managed marine protected areas can mitigate degradation of coral reefs, and provide suggestions for steps needed to improve management of coastal marine resources.

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The determination of PAH metabolites in fish bile is performed to assess the PAH contamination in fish for environmental monitoring. A growing number of laboratories in Europe use this parameter for national monitoring. However, an international intercomparison between laboratories has not taken place in the last years. Therefore the determination of the PAH metabolite 1-hydroxypyrene was tested in a collaborative trial performed by 10 laboratories from eight countries. Five samples of naturally contaminated fish bile covering different concentration levels were distributed among the participants. The present study was open for different methods: GS/MS, HPLC-fluorescence (HPLC-F), fixed wavelength fluorescence (FWF), and synchronous fluorescence spectrometry (SFS), respectively. The results suggest that all four methods under investigation are suitable for screening purposes, but only three methods have produced comparable results which could be used for a common monitoring database: GC/MS, HPLC-F, and SFS (with conversion factor). Most z-scores were within the acceptance criteria of ±2. The comparability of GC/MS, HPLC-F, and SFS results should be further improved because SFS is a widely used method with a great potential for monitoring. The present study contributes to the quality assurance of results for European marine monitoring.

The possibility of using the pyrene metabolite 1-hydroxypyrene as a biomarker of polycyclic aromatic hydrocarbons (PAHs) exposure was investigated by exposure of the marine polychaete Nereis diversicolor to several PAHs in the laboratory. Animals were exposed to pyrene alone and to five different PAHs - phenanthrene, anthracene, pyrene, benzo[a]pyrene and benzo[k]flouranthene. After five days of exposure the concentrations of parent PAHs and 1-hydroxypyrene were identified using three different analytical methods, high-performance liquid chromatography with fluorescence detection (HPLC/F), synchronous fluorescence spectroscopy (SFS) and gas chromatography with mass spectrometric detection (GC/MS). The SFS measurements of 1-hydroxypyrene were validated by the more sensitive method HPLC/F. The positive correlation between total PAHs and 1-hydroxypyrene concentrations in the polychaete tissues observed in experiments, suggests the feasibility of 1-hydroxypyrene as a suitable biomarker for total PAH exposure assessment. Furthermore, the possibility of employment of the simple and rapid SFS method instead of HPLC/F for biomarker analysis has been confirmed by the positive and significant correlation between results achieved by these two analytical methods.