Water Quality Testing

Ministry of Health The Guidelines for Canadian Recreational Water Quality, released by Health Canada in 2012, replace the 1992 version of the guidelines of the same title. The Ministry of Health have reviewed the District of Kelownas resolution, which interprets the guidelines as advising the issuing of a beach water quality advisory after a single sample maximum concentration of 400 E.coli is taken, and determined that the Districts interpretation is inconsistent with the advice in the 2012 Guidelines for Canadian Recreational Water Quality. The 2012 Guideline page 26 reads: Geometric mean concentration minimum of five samples: 200 E. coli100 mL Single-sample maximum concentration: 400 E. coli100 mL Calculation of the geometric mean concentration should be based on a minimum of five samples, collected at times and sites so as to provide representative information on the water quality likely to be encountered by users. Further action should be initiated if either of these guideline values is exceeded. Minimum action should consist of immediate re-sampling of the sites. In addition, a swimming advisory may be issued should the responsible authority identify that the area is not suitable for recreational water use. Page 18 of the 2012 Guidelines also provides the following advice: Most bodies of water used for recreational purposes are not completely homogeneous with respect to their microbiological properties. In recreational water evaluations, the purpose of sampling is to obtain aliquots that are as representative as possible of microbiological quality of the area. A single water sample provides a quantitative estimate of the indicator bacteria present at a particular site and time. Whitman and Nevers 2004 observed that there can be significant variation between samples collected at multiple points along the beach, as well as among samples collected within close proximity to each other at nearly the same time. As the total number of samples increases, the more representative the data will be of the overall water quality. Page 21 advises: Issuing a swimming advisory or a beach closure should be made by the Medical Officer of Health or other appropriate authority in accordance with the statutes existing in each province or territory. This decision should be based on a thorough assessment of the situation with information provided by recreational water monitoring, the Environmental Health and Safety Survey and existing public health surveillance. Given the rationale in the guidelines, it is not anticipated that health authorities would base a closure of a beach on any single sample result, nor would a local government base an entire beach sampling program on a single sample. This approach is consistent with the previous 1992 guidelines which advises that Re-sampling should be performed when any sample exceeds 4000 E.ColiL 400 E.coli100mL. Based on this information, it does not appear that the new guidelines will result in significantly more beach water advisories. The Ministry of Health supports health authorities in adopting the 2012 guidelines.