The past, present and future of waste management in Wales : a case study of the environmental problems in a small European Region

We review the problems of waste in Wales through a historical sequence of the past, present and future. We define waste as unwanted gaseous, liquid or solid products from domestic and industrial sources, and indicate how problems can arise at the exploitation or manufacturing stages of industrial processes, at the transport stage, and during or after final disposal. Targets for adverse effects from waste include natural ecosystems, and also human socio-economic and environmental systems. Historically, the economic development and exploitation of non-ferrous metals, chemicals, coal and slate have created bulk waste and chemical waste. There are at least 750 sites at which land is contaminated by these materials, although over 8000 ha of colliery spoil have been reclaimed. Among other types of contaminated sites, gasworks and coke ovens are a priority for remedial action, while others are managed mostly by containment. More recently, problems have arisen from fossil fuel combustion (NO x , VOCs, SO 2 , CO 2 ), with discharges liable to continue. Radioactive release to air and water arises from the two power plants and one industrial installation in Wales, with one of the power plants now being decommissioned. Accidentally imported waste from Chernobyl gave rise to unexpected and protracted radioactive contamination of sheep pasture. Solid wastes, of which around 20 million tonnes are produced annually in Wales, is mostly landfilled, but we examine a hierarchy of other strategies involving clean technologies, re-cycling, energy recovery and safe disposal either by incineration or inert landfill. More hazardous wastes in Wales include PCBs and insecticides, which are widespread background contaminants whose ecotoxicological effects are not clearly understood. Disposal by incineration is undertaken, but can lead to local contamination. Freshwater is an important resource in Wales, but 6% of the 4600 km of main river, about half the proportion of English rivers, are of poor or bad quality. Twenty-eight major pollution incidents occurred in Wales during 1992, with many more minor incidents involving slurry, silage, oil and sewage. Chronic discharges include those from abandoned coal mines which create local problems of ochrous deposition. Sewage treatment is being generally upgraded, but sludge volumes will continue to cause problems as disposal to the sea becomes restricted. Marine systems around Wales, although at risk from oil spillages, are affected only locally by excess nutrients and some hazardous chemicals. Beach litter, bacterial contamination of shellfish, and low level radiation from Sellafield also occur.