Some observations on the changes of physico-chemical and biological factors in Victoria Harbour and vicinity, Hong Kong, 1988-1996

This study analysed monthly physico-chemical and biological data collected from 18 marine monitoring stations in Victoria Harbour and its vicinity in Hong Kong, from 1988 to 1996, Cluster analysis based on all water quality p arameters measured shows that the 18 monitoring stations can be grouped int o four clusters: Cluster I consists of stations located in the Harbour prop er; Cluster II consists of stations located west of the Harbour and along t he Rambler Channel; Cluster III consists of stations located east of the Ha rbour near Junk Bay and Cluster IV consists of stations located west of the Harbour and near the Ma Wan, Kap Shui Mun and Western Fairways, Factor ana lysis shows high positive loadings for nutrients in the first two factors o f the four clusters. This suggests that effluents from the 11 outfalls of s ewage screening plants influence the water quality of Victoria Harbour and its vicinity, Other factors such as storm water runoff, marine traffic, con struction and industrial activities and the Pearl River discharges also app ear to play an important role in determining local water quality, Five stat ions located along an east-west transect across the Harbour were selected f or trend analysis. The three stations located in the Harbour exhibit an inc reasing trend for temperature and levels of total phosphorus (TP), ortho-ph osphate phosphorous (PO4-P) and faecal bacteria and a decreasing trend for pH and levels of total nitrogen (TN), total kjeldahl-nitrogen (TKN), 5-day biochemical oxygen demand (BOD5) and chlorophyll a. For the station located east of the Harbour, an increasing trend is observed for levels of TP, PO4 -P, but no decreasing trend in TN and TKN is detected, For the station loca ted west of the Harbour, no decreasing trend in TN, TKN and chlorophyll a i s observed. Changes in levels of phosphorus and nitrogen in Victoria Harbou r and the immediate vicinity have led to significant increases in the ratio s of Total Silica (TSi) to TN, as well as a decrease in TN to TP and TSi to TP in most stations, Results of the present study show that Victoria Harbo ur and its immediate vicinity remain polluted. (C) 1999 Elsevier Science Lt d. All rights reserved.