‘Oyster-watch’ for monitoring coal ash lagoons in an environmentally sensitive area of Hong Kong

Abstract

Deep Bay lies in the western New Territories of Hong Kong. It is an environmentally sensitive area with traditional oyster farming communities and the unique Mai Po Marshes, a nature reserve of international importance. The Bay and its catchment area are faced with many large scale developments, one of which has been the introduction of lagoons for disposal of ash from the recently completed Castle Peak Power Station, one of the World's largest coal fired installations. The paper describes the environmental assessment and planning stages of the lagoon project, highlighting the particular design decisions which were taken from a pollution control point of view. Subsequent operation of the lagoons has been accompanied by a comprehensive monitoring programme including toxic metals analyses of experimental oysters cultivated in the Bay. The rationale behind the choice of methodology is explained and the monitoring data, now available from some three years of surveillance, is discussed both in terms of its primary objective and the wider perspective of Deep Bay developments as a whole.