only once in 20 or 100 samples respectively, and that would indicate a warning (for example, the need for checking the results and/or for resampling) and then the need for taking remedial action (such as closing the beach until conditions improve and identifying and removing the source of pollution). The bacteriological data in Table 8.8 are presented as two control charts in Figure 8.4, showing the generally poor quality at bathing area A and the greater variability at B, which fails the 90 percentile criterion solely through the high count at the second sampling, even though it is otherwise of good quality.
8.7.6 Technical assessment report
Once the investigation (generally of sanitary conditions and water quality) or monitoring programme is completed, the information is assembled into a comprehensive report. The main body of the report should state the objectives; the manner in which the programme was conducted, with a full description of the recreational area; a historical account of problems and developments; the strategy and reports of inspection, sampling and analysis; significant results obtained; a discussion of the results; and conclusions and recommendations for action. Many of the readers will not have a technical background and therefore an easily readable and accurate “executive summary” should be provided at the front of the report. This gives such readers the main points of the report and invites them to follow-up areas of interest. The report itself should enable the technical reader to understand fully the way in which the study was carried out. Larger bodies of data should be placed in an appendix, so as not to interrupt the flow of the report. A typical report of a sanitary inspection and microbiological analysis includes the following: a description of the survey area(s) and sampling stations, and of any identified hazard(s) and source(s) of pollution (photographs and maps would be useful); the results of the study, including those of the sanitary inspections and microbiological analysis; an in- depth assessment of the risks associated with identified hazards and/or poor water quality; recommendations about the suitability of the area for recreational water use; description and evaluation of various options for improving conditions and thereby for reducing aesthetic and health hazards to users; and recommendations for action, including modifications if necessary, to the monitoring programmes.