Posts Tagged ‘cyanotoxins’

December 11, 2017

Real-time Analyses for Emerging Contaminants

Scientists in all areas of life science, including basic research, biotechnology, medicine, forensics, diagnostics, and industry, are utilizing molecular techniques in a wide range of applications.  Real-time or quantitative polymerase chain reaction (qPCR) is a widely used method in many of these areas of science and is the most studied of the new methods for detecting and quantifying microbes (i.e. bacteria, viruses, protozoa, etc.) in water.

This technology has many advantages, which make it attractive for measuring microbes in water.  The qPCR method is very specific to the target organisms being detected. In addition, the qPCR technology is very rapid, with results in about two to three hours (compared to detecting and identifying microbes with cultural methods that require about 24 hours, with some microbes requiring several days or weeks before they appear in culture).

Des Moines Water Works recently purchased qPCR equipment which will allow staff to greatly expand monitoring capabilities, with the ability to look for a multitude of organisms from a small amount of sample utilizing a single instrument.  Specifically, staff will begin analyzing toxic versus non-toxic blooms of cyanobacteria, as well as specific gene targets for toxin production.  Harmful algal blooms (HABs), which are large, rapid-growing populations of cyanobacteria, are caused by excess nutrients from farm fertilizer.

In some instances, cyanobacteria contain genes that allow them to produce toxins, which raise health concerns.  In 2014, the City of Toledo, OH, issued a “do not drink” order for several days to its 500,000 customers.  A toxin released by cyanobacteria in Lake Erie contaminated the water supply.  The toxins produced by cyanobacteria are unregulated and emerging contaminants; however, Des Moines Water Works has embraced the health advisory and protocols, and has invested in new protocols and equipment to monitor proactively.

 

Posted by: Laura Sarcone No Comments
Labels: , , , , Posted in Source Water, Water Quality, Water Treatment December 1, 2015

Reacting to What’s Flowing Down the River

Cyanobacteria, commonly referred to as blue-green algae, are a serious problem in surface water sources in the United States, including Iowa.  Cyanobacteria grow and multiply quickly where there are high nutrients (nitrogen and phosphorus) in warm, calm waters.  Blooms create blue to green murky water, visible surface scum and a foul odor. The blooms can spread across the water but tend to accumulate in shoreline areas.

IMG_5714{Cyanobacteria bloom at Big Creek State Park. Photo courtesy of Iowa Environmental Council

While algae blooms are a nuisance, certain forms of blue-green algae can also produce toxins that can make humans and animals sick.  The Iowa Department of Natural Resources (DNR) monitors state park beaches weekly in the summer for the toxin microcystin that is produced by some forms of blue-green algae common in Iowa. Warnings are posted when microcystin exceeds 20 parts per billion (ppb), a guideline established by the World Health Organization for recreational waters. Contact with water with more than 20 ppb of microcystin represents a risk of cyanotoxin associated illnesses including breathing problems, stomach upset, skin reactions, and even liver damage. Inhaling water droplets containing microcystin can cause runny eyes and nose, cough and sore throat, chest pain, asthma-like symptoms or allergic reactions. Pets and other animals that swim or drink the water can be exposed to deadly levels of microcystin.  This year has been favorable for cyanobacterial blooms, with high nutrients and warm waters. Iowa Department of Natural Resources posted a record 34 warnings at state park beaches with high levels of microcystin.

It is important to note that while DNR monitors state park beaches for this toxin, the problem is not isolated to these lakes. Many other public and private beaches not monitored by DNR are also susceptible to blue-green algae blooms.

Cyanobacteria are also known for causing taste and odor problems in drinking water for utilities that use surface water.  When cyanobacteria counts rise, there is greater potential for the presence of cyanotoxins, which raise health concerns related to the liver, nervous system and gastrointestinal system.  Last year, the City of Toledo, Ohio, issued a “do not drink” order. The municipal ban left approximately 500,000 Toledo and Michigan residents without drinking water for three days, which was contaminated by a toxin produced by an algae bloom in Lake Erie.

Currently there is not a federal standard for blue-green algae or their toxins in drinking water; however, a growing number of states are introducing their own guidelines and the U.S. Environmental Protection Agency (EPA) has named cyanotoxins as a candidate for federal regulation with recently published guidelines.

Historically, Des Moines Water Works had to send cyanotoxin samples to a laboratory in Florida, and wait up to three days for results.  As a result of the events in Toledo, Ohio, recently released EPA guidelines for cyanotoxins, and the increasing occurrence of cyanobacteria blooms in source waters, Des Moines Water Works has begun a more aggressive testing regimen for the presence of harmful cyanotoxins when elevated cyanobacteria levels are present in raw water sources.  Des Moines Water Works recently invested in instrumentation that will allow staff to monitor for microcystin and cylindrospermospin, per EPA recommendations, as well as two additional known cyanotoxins – Anatoxin and Saxitoxin. Des Moines Water Works now routinely samples three times per week during the warmer months of the year, and more frequently when necessary.

With increased monitoring, Des Moines Water Works has detected cyantoxins in our raw water sources.  While the presence of cyanotoxins has been detected in our raw water sources, the treatment processes have adequately prevented the toxins from reaching finished drinking water.  Des Moines Water Works staff treats for unfavorable tastes, odors, and toxins by dispersing powdered activated carbon throughout the water during the presedimentation phase of treatment.  Chlorination of the water also helps remove or destroy bad tastes, odors, and cyanotoxins.

Strategic water treatment, testing, and federal regulation of cyanotoxins are worthy, but a remedy at the source of the contaminant is more urgent. The only viable option to curtail the presence of algae that causes toxins to infiltrate our drinking water is changing upstream land practices, notably industrial agricultural production.

Short of meaningful and measurable water quality improvements in Iowa, Des Moines Water Works, and all Iowans who wish to enjoy water recreation, have no control of algal and cyanotoxins in the Raccoon or Des Moines Rivers, and must react to what flows into the river intakes. The presence of both elevated cyanobacterial levels and related cyanotoxins in Iowa’s lakes and rivers is another reminder of deteriorated water quality in the state of Iowa – forcing water utilities and water recreation enthusiasts to be on alert.

Posted by: Laura Sarcone No Comments
Labels: , , , , , Posted in Source Water, Water Quality