Section headings and selected papers: Preface. Introductory Papers. The Third International Conference on the Protection of the North Sea - review and challenges, D Tromp & R C A Coe;en. Problem Analyses. Regulation of effluents and implications for environmental policy, P A Johnston et al . Modelling. 3-D model and field studies of silt transport in the Dutch coastal zone of the North Sea with emphasis on dump sites, R Spanhoff & J M De Ko;. Sources and Inputs. Pollution of the North Sea by West European rivers, R Hupkes. Monitoring. North Sea Task Force Biological Effects Monitoring Programme, R M Stagg. Contamination with Organic and Inorganic Micropollutants. Fate and effect of detergent chemicals in the marine and estuarine environment, M Stalmans et al . Offshore Pollution and Risk Assessments. Concentrations of alpha- and gamma-hexachlorocyclohexane (Lindane) in the coastal waters of England and Wales, C R Allchin. Wastewater Treatment: Technical Facilities. Water pollution control in Amsterdam: its effect on the North Sea environment and the role of harbour reception facilities, R R Kruize. Wastewater Treatment: Nutrient Removal. High gradient magnetic separation technique for wastewater treatment, A F M Van Velson et al . Eutrophication of the North Sea. Exceptional algal blooms in Dutch North Sea waters, W Zevenboom et al . Perspectives for the Future. Strategy for protecting the North Sea: a chemical industry perspective, J R Lawrence & N C D Cra;g. Posters. Filtration calculations for water development projects: software package, T G Shvachich. Subject Index.