Samples from Salton Sea indicate low levels of harmful toxin
SALTON SEA — Cyanobacteria in the Salton Sea currently is not producing elevated levels of anatoxin-a — also known as “Very Fast Death Factor” — scientists with the State Water Resources Control Board have reported.
Samples from the Salton Sea taken in early July at six different locations underwent analytic biochemistry assay, which is a laboratory analysis of a liquid sample that is able to detect the presence of antigens such as anatoxin-a.
“Their recommendation is that this particular test be able to pick up one microgram per liter, and all of the testing results in all of the areas they tested were lower than that number,” Dr. Stephen Munday, Imperial County Public Health Department health officer, told Imperial Valley Press on Tuesday. “They took a sample of the water and looked at it for a couple of specific things. One is anatoxin, which is a particular toxin that some of these cyanobacteria make.”
Samples were collected at the Salton Sea Boat Launch, Salton Sea Recreational Beach, Bombay Beach, Obsidian Butte, West Shores and Desert Shores. The highest levels of anatoxin-a were found in the samples from the boat launch, Obsidian Butte and West Shores, with the lowest level collected at Desert Shores, according to the official report.
“The testing does not indicate that the levels evaluated are of concern,” Munday said. “It does indicate there is a background level, but that is in virtually every body of water in the world.”
And although not a health concern presently, Munday continued, “that doesn’t mean it couldn’t be in the future.”
ancient and common
Cyanobacteria is a ubiquitous and ancient single-celled organism commonly referred to as blue-green algae.
“These things live all over the world and are some of the oldest living organisms on the face of the Earth,” Munday said. “They are in every continent and in every country — Antarctica, Africa [and] Asia. These things are all around us, just like we’ve got bacteria and fungi that you and I have on our skin and we are inhaling in the air and eating in our food. We are just exposed to these things all of the time. They are part of the environment we live in.”
While cyanobacteria may always produce trace amounts of anatoxin-a, it is not until environmental conditions allow for a rapid increase or accumulation in the population of the organism that a large enough amount of the toxin may be present to harm biological organisms. These types of growth are called harmful algal blooms, which can lead to fish die-offs and other adverse biological effects.
“Like everything else, the dose is what makes the poison,” Munday said. “All things are poisonous, it is just in the amount.”
Factors contributing to cyanobacterial bloom formation and persistence include light intensity and total sunlight duration; the availability of phosphorus, which is present in agriculture runoff; water temperature; pH balance; water flow and water column stability, according to the U.S. Environmental Protection Agency.
Although bloom conditions in much of the United States are more favorable during the late summer, the interrelationship of these factors causes large seasonal and year-to-year fluctuations in the cyanobacteria levels.
“You have to take into account not only how much sun exposure is received, but how warm the water is and how much food there is available to them,” Munday said. “The bottom line is things vary, and the Salton Sea is a big body of water so you can’t overly generalize because what is going on at one shore is not necessarily going to be on the other shore at the same time.”
Symptoms
When high levels of toxins generated by algae bloom are present in a body of water, it can lead to adverse health effects in humans.
Exposure to toxins can be made through direct contact, inhalation or ingestion of the water during recreational activities, according to EPA. Exposure can result in a wide range of symptoms in humans including fever, headaches, muscle and joint pain, blisters, stomach cramps, diarrhea, vomiting, mouth ulcers and allergic reactions. Such effects can occur within minutes to days after exposure. In severe cases, seizures, liver failure, respiratory arrest and rarely death may occur.
State monitoring
Since 2005, the State Water Resources Control Board has been working to identify and respond to harmful algal blooms in both fresh and saltwater areas. At that time, the board formed the California Cyanobacteria Harmful Algal Bloom Network. Since then, staff at both the state and regional water boards have worked to coordinate monitoring of fresh and saltwater bodies, including the Salton Sea, and follow up when algal blooms are detected.
“In general, there have been limited areas of bloom in the past, and when that occurs we automatically tell people to avoid those areas,” Munday said.