Bioremediation Mariculture in Zanzibar, Tanzania: A Viability Assessment of Using Bath Sponge and Pearl Oyster Farms to Filter Highly Polluted Waters in the Zanzibar Channel

Abstract

Bioremediation of polluted water off the coastline of the urban center of Zanzibar-Stone Town, Unguja-was assessed through bath sponge and pearl oyster mariculture feasibility. In recent years, scientific analysis has shown a wastewater pollution distribution in conjunction with the water circulation created by the East African Counter Current and its harmful ramifications for the fringing ecosystems. As a proposed mitigation to this issue and in following the experimental examples of bioremediation projects around the world, this study tested facets of the filtration abilities of marine sponges and oysters. Both organisms suggested strong pollution filtration abilities. Phosphate concentrations decreased from an average of 3.93 µg/L (micrograms per liter) to 1.33 and 1.73 µg/L for sponges and oysters, respectively. Unique capabilities of each organism were displayed in the experiments in that the marine sponges visibly eliminated the turbidity level in the 36-hour study period while the marine oysters were suggested to chemically convert the dissolved nitrates through the tested increase in ammonium concentration from an average of 4.01 µg/L in the contaminated water to an average replicate concentration of 21.5 µg/L. The respective mariculture techniques were examined along with management logistics to assess the viability of implementing mariculture for pollution remediation. It was concluded that the mariculture techniques could be feasibly established by carefully collaborating with the nature of the pollution distribution, the consultation and aid of private and governmental organizations and adjacent villages, and further background scientific research.