Water quality studies on selected South Pacific lagoons

This report presents the results of studies made on five Pacific lagoons located at Suva, Fiji; Vila, Vanuatu; Tarawa, Kiribati; Tongatapu, Tonga; and Marovo, Western Province, Solomon Islands. Studies were made on water quality by physical, chemical and microbiological analyses. Analyses of shellfish and sediments were also completed for some sites. The results indicate that the major problems in four lagoons were sewage-related. At Marovo, the limited data available indicated that the lagoon is effectively unpolluted except for isolated areas close to large villages. For the SUva, Vila and Tarawa lagoons faecal coliform counts in water and shellfish were frequently high, indicative of potential health problems. These three lagoons plus that in Tongatapu also had relatively high nutrient (nitrate and phosphate) concentrations, sufficient to have detrimental effects on coral growth. No analyses of pesticide residues were completed but possible pollution problems were only anticipated at Suva and Tongatapu.