A total of 31,673 incidents were reported to the NRA during the year, a 7% increase on 1991. Of these, 23,331 (74%) were substantiated - a 4% increase over the previous year. The most serious "Category 1" incidents also increased slightly to 388.
The NRA has improved its reporting of pollution incidents to include a classification both by pollution source and by pollution type. However, this means that some figures are not directly comparable with data for previous years.
Substantiated incidents were ascribed to one of four source categories: water and sewerage industry, industry, agriculture, and "other". Water and sewerage accounted for 28% of the total, industry 19% and agriculture 12%. However, industry was the major source of Category 1 incidents, accounting for 26%, with water and sewerage and agriculture contributing 20% and 17%, respectively.
Demolition and construction, industrial oil, waste disposal, mining and the chemical industry were all major sources within the industrial group (see figure ). However, only 43% of all industrial incidents could be incorporated into this classification, with the rest either falling into other sectors or being unclassified.
The biggest cause of sewage and water industry pollution was combined sewer overflows, accounting for 30% of all water and sewerage incidents and 42% of Category 1 incidents. Other major causes were sewage works, pumping stations and surface water outfalls. Although serious incidents caused by the industry declined by 18% during 1992, the NRA expresses disappointment that total incidents increased by 1.4% - continuing a trend which has seen the number of water and sewagerelated incidents rise by 50% since 1987.
On the other hand, the report praises farmers for their efforts to reduce water pollution. The number of farm pollution incidents declined by 7% in 1992. The NRA ascribes this to pollution prevention initiatives, dry weather during silage making, and the effect of new regulations on the construction of slurry, silage and fuel oil stores.
Oil and sewage were the most common pollutants, each accounting for 26% of pollution incidents. Oil was also the cause of 18% of serious incidents. The NRA says this supports its demand for regulations on oil storage similar to those already introduced for farm wastes. The Government has promised these repeatedly since the mid-1980s but has yet to deliver.
The report includes a breakdown of enforcement action taken by the NRA. This shows a marked rise in prosecutions of industry, corresponding to the rising number of industrial pollution incidents (see table ). Water industry prosecutions have also increased, while farm prosecutions have declined.
The vast majority of prosecutions brought by the NRA are successful. For pollution incidents in 1992 the NRA brought 297 prosecutions, although a further 176 were outstanding on 1 April this year. All but seven failed. The NRA also issued 250 cautions relating to incidents in 1992.