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 in dicate how problems can arise at the exploitation or manufacturing sta ges of industrial processes, at the transport stage, and during or aft er final disposal. Targets for adverse effects from waste include natu ral ecosystems, and also human socio-economic and environmental system s. Historically, the economic development and exploitation of non-ferr ous metals, chemicals, coal and slate have created bulk waste and chem ical 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 mo stly by containment. More recently, problems have arisen from fossil f uel combustion (NO(x), VOCs, SO2, CO2), with discharges liable to cont inue. Radioactive release to air and water arises from the two power p lants and one industrial installation in Wales, with one of the power plants now being decommissioned. Accidentally imported waste from Cher nobyl 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 hi erarchy of other strategies involving clean technologies, re-cycling, energy recovery and safe disposal either by incineration or inert land fill. More hazardous wastes in Wales include PCBs and insecticides, wh ich are widespread background contaminants whose ecotoxicological effe cts are not clearly understood. Disposal by incineration is undertaken , but can lead to local contamination. Freshwater is an important reso urce in Wales, but 6% of the 4600 km of main river, about half the pro portion of English rivers, are of poor or bad quality. Twenty-eight ma jor pollution incidents occurred in Wales during 1992, with many more minor incidents involving slurry, silage, oil and sewage. Chronic disc harges include those from abandoned coal mines which create local prob lems of ochrous deposition. Sewage treatment is being generally upgrad ed, but sludge volumes will continue to cause problems as disposal to the sea becomes restricted. Marine systems around Wales, although at r isk 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. Effect s by one particular form of waste are illustrated by a case study of a cidic deposition in Wales, showing that (i) the sources of waste are p ower plants often outside Wales; (ii) sensitivity can be identified th rough the critical load concept; (iii) targets for adverse effects inc lude dispersed natural ecosystems; (iv) management options are availab le at a range of geographical scales but (v) waste minimization is cos tly in economic terms and will not recover some affected systems, and (vi) symptomatic treatment can be costly in other terms.