When conditions are just right—such as found on warm, sunny days in the summer—small organisms called blue-green algae (or “cyanobacteria”) grow and may multiply rapidly in oceans, lakes, rivers, ponds, and other bodies of water.

As they eat, reproduce, and die, some of these cyanobacteria may produce and release different types of cyanotoxins, which can make people sick if they drink the water. By regularly testing water samples for the presence of these cyanotoxins, water quality specialists can make decisions about treating the water to reduce or remove the toxins or advise the community when it may not be safe to drink or play in the water.

As part of a rigorous water quality monitoring program, skilled City of Salem Public Works employees collect, track, and test water samples from various locations in the watershed, water treatment facility at Geren Island, and water distribution system. Microcystin and Cylindrospermopsin are two types of cyanotoxins caused by blue-green algae (or “cyanobacteria”) that the City can test for at its in-house lab using enzyme-linked immunosorbent assay (ELISA).

A City of Salem certified lab technician prepares water samples for testing using a cyanotoxin automated assay system (CAAS) at its in-house lab. This specialized equipment allows the City to use enzyme-linked immunosorbent assay (ELISA) to test the water for any concentration of cyanotoxins by measuring how much blue light the water will absorb. Results are sent to water quality staff who review, track, and use the data to make decisions about drinking water treatment.

The enzyme-linked immunosorbent assay (ELISA) testing that the City of Salem performs in its in-house lab is the recommended testing method under Oregon’s new rules adopted June 29, 2018, by Oregon Health Authority.

Before water samples can be accurately tested for the presence of cyanotoxins, the samples must be frozen and thawed three times to rupture (or “lyse”) any blue-green algae cells the water may contain. A cryogenic freezer is part of the City of Salem’s ELISA equipment at its in-house lab. By using an in-house lab, the City can receive and share test results as quickly as possible.

A lab technician prepares water samples to test for the presence of any cyanotoxins. As of June 2018, the City of Salem is one of only two organizations in Oregon that have the equipment to run enzyme-linked immunosorbent assay (ELISA) testing.

Carefully labeled samples are loaded into the cyanotoxin automated assay system (CAAS) at the City of Salem lab. The equipment will use an enzyme-linked immunosorbent assay (ELISA) to test the water for any cyanotoxins that may have been produced by blue-green algae that grow during the summer in the North Santiam River and Detroit Lake watersheds.

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Some words explained

Absorb

A verb that means to take in or soak up a substance by chemical or physical action, usually gradually

Assay

A test to determine what or how much something contains or is made of

CAAS

Cyanotoxin automated assay system, lab equipment for running an ELISA test

Cryogenic

Related to very cold temperatures or deep-freezing

Cyanotoxin

A poisonous substance produced by cyanobacteria, also called blue-green algae. Some types of cyanotoxins that ELISA detects are Microcystin and Cylindrospermopsin.

ELISA

Enzyme-linked immunosorbent assay, a method of detecting and measuring cyanotoxins in water

Incubation

To keep at a suitable temperature or in favorable conditions to cause a certain reaction

Lysis

The disintegration of a cell by rupture of the cell wall or membrane

Nanometer

A unit used to measure the visible light spectrum