WRRCTR No.12 Bacterial Pollution of Kaneohe Bay, Oahu (June through August 1967)

Abstract

From June through August 1967, a thorough investigation was made of the presence and numbers of coliform bacteria, fecal streptococci (enterococci), and bacteria capable of growing on peptone-seawater agar at 28°. Six regularly monitored stations and several supplementary stations were established in the middle and southern sections of Kaneohe Bay. The latter receives considerably treated sewage effluent and some untreated sewage. In addition, analysis was made of sewage and sewage effluent from the Kaneohe municipal sewage plant, the Kaneohe Marine Corps Air Station (KMCAS) sewage plant, and Coconut Island. Water from several small streams along the middle sector of the Bay was also tested. The fecal bacteria count was below the maximum set for Class AA water (according to the water quality standards proposed for the State of Hawaii) at all the regular stations on all occasions. The sewage treatment plants did not discharge any significant numbers of living microorganisms into the Bay; actually, the effluent from the Kaneohe municipal plant was found to be sterile after chlorination. The total count of bacteria in the Bay was generally high, but not alarmingly high. No correlation could be found between the bacterial count and the existing weather and tide conditions. In contrast to the low count of fecal bacteria in most parts of the Bay, rather high counts of coliforms, and especially enterococci, were found at several stations in shallow water in the middle sector. The sources of this contamination were found to be several of the small streams emptying into the Bay at this point. The streams from Kahaluu to Molii, as well as the shallow water of the Bay along the corresponding coastline, were all found to meet the proposed standards of Class II fresh water, however. In addition to the study of bacterial pollution of Kaneohe Bay, some data were collected from the sea south of the island of Maui and surrounding the island of Kauai.