Deteriorating water quality of Kingston Harbour, due primarily to sewage discharge and its effect on nearby Hellshire Coast, has been an issue since the 1970s. The implementation of a new sewage treatment facility in 2007 to receive the harbour’s waste at Soapberry was expected to make a positive difference. Physico-chemical and biological parameters were used to assess water quality to determine the effect of the facility. Eleven stations used in earlier studies (1990 to 1998) were re-sampled to represent Kingston, Hunts Bay and North East Hellshire coastline over a four week sampling regime between May and June 2011. While temperature, salinity, turbidity, dissolved oxygen and pH remained unchanged between the 1990’s and 2011, BOD₅, faecal coliform and nitrate concentrations indicated that the water quality had improved minimally in Kinsgton and Hellshire,and deteriorated significantly in Hunts. Phytoplankton biomass decreased in Kingston (from 3.84 mg m^-3 in 1998 to 2.81 mg m^-3 in 2011) and increased significantly in Hunts (from 14.69 mg m^-3 in 1998 to 24.17 mg m^-3 in 2011). Biomass along Hellshire was similar (2.15 mg m^-3 in 1998; 2.45 mg m^-3 in 2011). In 1998 the nanoplankton biomass (2.7 to 20μm) dominated throughout the Harbour. In 2011 Hunts Bay was dominated by net-plankton (>20μm), indicative of eutrophic waters.

Soapberry; waste water; Kingston Harbour; Hunts Bay; Hellshire; eutrophication