Pii: S0025-326x(99)00014-4

Recent advances in pollution control and monitoring technologies, improved analytical capability, changes in government priorities and results of scienti®c studies have substantially changed our views and perceptions towards marine pollution in the last two decades. Globally, the problems caused by eutrophication, water borne pathogens and xenobiotic compounds are likely to be exacerbated and pose signi®cant ecological and/or public health risks in the coming years, especially in developing countries. The large amount of anthropogenic input of nutrients has caused major changes in the structure and function of phytoplankton, zooplankton, benthic and ®sh communities over large areas, and such a trend is likely to continue in many coastal waters. Escalated public health risks associated with the increases in frequency and severity of toxic algal blooms are also of growing concern. Reduction of nutrient input through changes in land-use and farming practises, and the development of cost-e€ective methods for nutrient removal are required. Water borne pathogens a€ect large numbers of people through consumption of contaminated seafood and direct contact with contaminated water, and such problems are much more serious in developing countries. Current techniques in monitoring bacterial indicators in water and shell®sh have clear limitations and cannot a€ord adequate protection to safeguard public health. Emerging molecular techniques, such as multiplex PCR and speci®c gene probes, are likely to provide new and cost e€ective tools for monitoring water borne pathogens in the coming years. Nowadays, xenobiotic compounds can be found almost everywhere in any marine ecosystems. Although these compounds normally occur at very low concentrations and their e€ects are not well understood, there is growing concern about the chronic exposure and bioconcentration/biomagni®cation of xenobiotic compounds. In particular, endocrine disrupters which may cause reproductive dysfunction and threaten species survival, are of growing concern. At present, most of our knowledge on toxic e€ects of xenobiotic compounds is derived from short-term exposure of a single species to high (environmentally unrealistic) and uniform concentrations under laboratory conditions. Data so derived are largely inadequate in predicting ecological e€ects in the ®eld, in which multi-species are being exposed to varying, low concentrations under an interacting and complex environment. NOEC and LOEC for population/community/ecosystem, as well as the time required for population/community/ecosystems to recover after toxicant insult, are poorly known. These important topics will become the major endeavours for ecotoxicologists in the years to come. Ó 1999 Elsevier Science Ltd. All rights reserved.