Part 1: Case Histories 1. Trends in Sediment Trace Element Concentrations Around Six Petroleum Drilling Platforms in the Northwestern Gulf of Mexico. 2. The Fate of Oil-based Drilling Muds at Two Artificial Island Sites in the Beaufort Sea. 3. Environmental Effect of Oil-based Mud Drilling in the North Sea. 4. Monitoring in the Vicinity of Oil and Gas Platforms: Results From the Norwegian Sector of the North Sea and Recommended Methods for Fortcoming Surveillance. 5. Patterns of Oil-based Drilling Fluid Utilization and Disposal of Associated Wastes on the Canadian Offshore Frontier Lands. 6. Exposure of Deep Seagrass Beds off the West Coast of Florida to Discharged Drilling Effluents. Part 2: Treatment Practices 7. Options for Treatment and Disposal of Oil-based Mud Cuttings in the Canadian Arctic. 8. Environmental Analysis of a Saline Drilling Waste Disposal Site. 9. Drilling Wastes Management and Closed-Loop Systems. 10. Treatment of Drilling Waste: a Dutch Case History. 11. Feasibility of Land Application as a Waste Management Practice for Disposal of Residual Diesel Invert-based Muds and Cuttings in the Foothills of Alberta. 12. The AGIP Experience in Treatment and Disposal of Wastes on Deep Drilling Sites. 13. Treatment of Salt Contaminated Reserve Pit Material and Drilled Cuttings. 14. Disposal of Salt Water Drilling Mud. 15. Physical/Chemical Fate of Organic and Inorganic Constituents within Waste Freshwater Drilling Fluids. 16. Impact of Heavy Oil Drilling Wastes from Alberta, Canada on Soils and Plants. Part 3: Land Disposal and Effects 17. API Survey Results on 1985 Onshore Wastes Volumes and Disposal Practices within the US Petroleum Exrtraction Industry. 18. The Analytical Methods Utilized and Results from the Analyses of Field Collected Drilling Wastes. 19. Effects of Spent Fr