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Chapter 8*: SANITARY INSPECTION AND MICROBIOLOGICAL WATER QUALITY - page 39 / 52

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  • The sample should be kept in the dark and maintained as cool as possible within a

chilled insulated container and returned to the laboratory promptly after collection. Samples should be analysed as soon as possible and preferably within 8 hours of collection. It is recommended that samples should not be stored for more than 24 hours at 5°C.

  • Additional information should be collected at the time of sampling, including: water

temperature, weather conditions, water transparency, presence of faecal material, abnormal colouration of the water, floating debris, cyanobacterial or algal blooms, flocks of sea birds and any other unusual factors. All information should be recorded on standardised checklists.

  • The minimum microbiological variables that should be investigated are faecal

streptococci or enterococci and thermotolerant coliforms or E. coli. While the former is a recommended indicator for salt water both can be used for freshwater. Additional variables should be investigated if considered relevant and if resources allow.

  • The influence of specific events, such as the influence of rain on the recreational water

use areas, should be established particularly in relation to the duration of the peak contamination period.

  • Extreme events, such as epidemics and natural disasters, may require additional

measures to ensure there is no additional risk associated with recreational water use areas.

  • The procedures to be used for transformation of raw data, to meet the statistical

requirements, should be agreed with the statistical expert prior to analysis. It is usually necessary to transform bacterial counts to logarithms and to convert their approximately log-normal frequency distribution to normality.

  • When unexpectedly high microbiological results are obtained, resampling should be

carried out to determine whether the unexpected results were due to sporadic events or persistent contamination. In the latter case, the source of pollution should be established and appropriate action taken.

8.11 References

Anon 1983 La Qualitat de les Aigües Litorals. Informe. Generalitat de Catalunya, Departament de Sanitat i Seguritat Social, Serie Sanejament Ambiental, Generalitat de Catalunya, Barcelona, 66 pp.

Anon 1996 Proposed amendments to the Hawaii Administrative Rules Chapter 11-54-08, Recreational Waters. In: Water Quality Standards. Department of Health, State of Hawaii, Honolulu, 54-86.

APHA/AWWA/WPCF 1989 Standard Methods for the Examination of Water and Wastewater 17th Edition, American Public Health Association, Washington, D.C.

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