Forests and surface waters of Sandy Lake & Environs (Bedford, Nova Scotia)

UPDATE 2:35 pm, Thurs Aug 8, 2019: Risk advisory for Sandy Lake lifted

“When an algae bloom is observed, a risk advisory is issued and initial testing is done to determine whether the algae bloom is toxin producing. If the algae bloom is not toxin producing, the risk advisory will be lifted and no further testing is required.

“If the algae bloom is toxin producing, further testing will be carried out and the risk advisory will remain in effect until blooms have disappeared and post-bloom test results indicate water is within safe limits.”

and earlier, from info forwarded by Councillor Tim Outhit, received from Cemeron Deacoff (Water Resources Specialist, Planning and Decelopment, HRM):

We received the lab results late yesterday afternoon that the specimens identified in the lab were principally diatoms (a form of algae), with trace amounts of one species of cyanobacteria that does not produce any toxins. Correspondingly, staff (i.e., P&D Acting Director Eric Lucic) has approved lifting the PSA. Corporate Communications is now drafting that PSA…

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Original post (Aug 6, 2019)

Received this afternoon:

Public Service Announcement
Risk advisory in effect for Sandy Lake due to possible blue-green algae bloom

Wednesday, Aug. 7, 2019 (Halifax, NS) – The Halifax Regional Municipality is advising residents that due to the presence of a possible blue-green algae bloom, a risk advisory is in effect for Sandy Lake in Bedford. Residents are encouraged to avoid swimming in the lake until further notice.

Sandy Lake Beach, which is a supervised beach, will also be closed to swimming until further notice.

Blue-green algae (cyanobacteria) is naturally occurring in freshwater environments and may become visible when weather conditions are calm. These organisms can multiply rapidly during the summer, leading to extensive growth called a bloom. Some types of blue-green algae produce toxins during blooms and when these blooms decay, the toxins may be released into the water, posing a risk to people and pets.

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Revised Dec 17, 2018

Sandy Lake and streams in Dec 13, 2018
Click on image for larger version

On December 13, I repeated a set of observations on pH (a measure of acidity) and EC (electrical conductivity, a measure of salt content) that I had made just over a month ago (Nov 8, 2018) on streams entering Sandy Lake via culverts at the southwest corner.

The lake was frozen solid. I am told it is the first time it has frozen over before January in about 20 years.

Electrical conductivity of Sandy Lake itself has increased over the years:

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