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Tenmile Lake Algae Report July 2019


P.O. BOX L*LAKESIDE, OR 97449 * 541.759.2414

July 18, 2019


Tenmile Lakes water monitoring – July 2019 Update

Tenmile Lakes Basin Partnership is monitoring the Tenmile Lakes waters on a regular basis over this summer with contributions from Coos County through its Coos Health & Wellness Public Health Division and the Oregon Department of State Lands.

Because Blue Green Algae has been present in the lakes for many years, it is important that the toxicity levels of the lakes be monitored to ensure toxin levels remain within safe levels, especially when the lakes are used by the public and their pets for recreational activities such as swimming, boating, and fishing.

The water sampling occurred on July15th, and the results came in on July 18th, 2019 for two different sites:

1. Wulfy Beach swimming area and immediate surroundings (C1)

2. Tenmile Lakes Canal near North Lake RV Resort and Marina swimming area (C2)

The sampling results:

The results at C1 are ABOVE the OHA Recreational Advisory guidelines for Microcystin. The results at C2 are ABOVE the OHA Drinking water- age 5 or younger for Microcystin. It is always recommended for people or pets to not drink the waters of Tenmile Lakes unless properly treated prior to consumption.

Sample Site Collection Date Anatoxin-A (ug/L) Total Microcystin (ugL)

C1 7/15/19 Below detection limit 15.14

C2 7/15/19 Below detection limit 0.38

Oregon Health Authority algae toxin guideline values (2019)

Guidelines Anatoxin –a (ug/L) Microcystin (ug/L)

Recreational Advisory 15 8

Drinking water – Adults 3.0 1.6

Drinking water – age 5 or younger 0.7 0.3

Pets (Informational Guidelines) 0.4 0.2


Due to the patchy nature of blue-green algal blooms it is possible for higher Microcystis and Anabaena densities (and therefore higher microcystin or anatoxin concentrations) to be present in areas not sampled in this survey, particularly along shorelines or during calm conditions of little to no wind. Given the lakes’ demonstrated history of toxic Microcystis and Anabaena blooms and the fact that all areas of the lake cannot be tested at all times, those utilizing the lake for drinking water should always follow Oregon Health Division recommendations for purification. In addition, recreational

users should always avoid contact with water whenever noticeable surface concentrations of algae are evident or when the lake has an obvious green to blue-green appearance. Moreover, because pets or other domestic animals are the most likely to ingest contaminated water, these animals should not be allowed access to the lakeshore whenever either noticeable surface concentrations of algae or an obvious green to blue-green appearance is evident.

Be aware and "avoid visible blooms".

TLBP would like to thank the Coos County Public Health Department, Coos County Commissioners, North Lake Resort, and the Department of State Lands for their help in our toxin monitoring program.

650 W. Easterday Ave., Sault Ste. Marie, MI 49783

Telephone: 906-635-2076 . Fax: 906-635-2266

Superior Analytics

Date: July 18, 2019

To: Richard Litts

Tenmile Lakes Basin Partnership

From: Mr. Benjamin Southwell, Superior Analytics Manager, LSSU

Subject: Data Report for Cyanotoxin Samples Supplied 7/16/2019

Summary: Listed below are the results for the analysis of the supplied samples. An enzyme linked

immunosorbent assay (ELISA) was utilized for the analysis of Anatoxin-a and Microcystin.









C1 7/15/2019 <0.2 15.14

C2 7/15/2019 <0.2 0.38

Assay Limit of Detection 0.2 0.3

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