Ministry of Health release Turbidity Decision Tree V. 2.

January 2013, Toby Pike, WSABC

The Ministry of Health has released a draft version of the revised  Turbidity Decision Tree – Jan 2013 . The original document was released in April of 2009 and was intended to standardize public health notifications related to turbidity events throughout the province. A summary of the changes made in the revised document can also be downloaded at: Proposed Changes – Turbidity Decision Tree.

New Turbidity draft released

Water suppliers  in the southern interior in 2006 were concerned that a turbidity notification program implemented by the Interior Health Authority was ill-conceived, poorly implemented and actually threatened the health of the public it was intended to serve.

In 2006 the WSA provided the Minister of Health with two briefings on the issue and urged him to review the IH program and provide guidelines for a common province-wide approach to turbidity notifications. The minister committed to reviewing the issue.

The differing health authority interpretation of the health risk associated with turbidity was highlighted in the fall of 2008 when the lower mainland was  subjected to a severe rain event. The storm caused turbidity in the unfiltered Metro Vancouver water system to spike well above the 5 NTU level.

This event would have automatically triggered a Boil Water Notice in the IH region, but  Coastal Health maintained that water sampling in the distribution system showed no increased risk to public health. In support of this decision, CH sited the protected Vancouver watersheds minimized pathogen loading in source water. This is a major difference to the interior of the province, where provincial policy dictates  community watersheds will be open access and subject to multiple-uses.

The subsequent release of the provincial turbidity document in 2009 was welcomed by the water supply industry. This recent release follows an extensive review and consultation with stakeholders. The Ministry of Health is asking for feedback on this new document and the WSA encourages our members to review and provide comment prior to February 15, 2013 to: david.fishwick@gov.bc.ca

Follow these links for for additional information on this subject: Association Papers, External Reports.

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