Learn how scientists predict the spread of toxic algae blooms
Algae toxic enough to cause skin rashes and itching are showing up at Lake Wateree, and state regulators are warning swimmers to stay out of areas where the greenish, scummy material is visible in the water.
Lake Wateree, a recreation hot spot north of Columbia, is the only lake in South Carolina known to have toxic levels of algae, a resilient plant that some suspect is growing because of pollution and blistering summer weather.
While there is no blanket advisory against swimming, DHEC is discouraging people from taking a dip in any spot where they see or know about algae. One scientist said toxic algae could affect miles of shoreline at Lake Wateree, a 13,000-acre lake about a half hour’s drive north of Columbia.
The toxic algae outbreak in Lake Wateree has some homeowners and lake users nervous as scientists study the causes and public health threats.
A major concern is not only how the algae affect people, but dogs that might venture into the water. Recent reports attributed the deaths of some dogs to exposure to algae in North Carolina and Georgia lakes. DHEC says it has no information any dogs have died as a result of exposure to algae in South Carolina lakes.
“It’s advised that people and animals not enter water where there is a visible algae bloom,’’ DHEC spokeswoman Laura Renwick said in an email this week. “Lake Wateree, like any natural water body, isn’t a sterile environment and the presence of harmful bacteria, viruses and other organisms that can cause illness is always a possibility.’’
Key questions are what’s causing the algae outbreak and why Lake Wateree is the only major recreational lake in South Carolina with known blooms of harmful algae. DHEC has not found toxic algae in Lake Murray, the Columbia area’s other major recreational lake, officials said. The agency said toxic algae at Lake Wateree were first noticed in 2014.
So far, major water utilities that draw from Lake Wateree have not reported any problems with algae. But “everybody’s got their eye on it,’’ said Michael Hancock, general manager at the Lugoff Elgin Water Authority.
Some people who live on Lake Wateree say they began hearing about harmful algae in the past three to four years, but would like to know more.
Bill Stroup, chairman of the 1,000-member Lake Wateree Association advocacy group, said he stepped in the algae about two years ago while cleaning debris from a cove near his home in the Dutchman’s Creek area. Stroup said he didn’t think much about wading in the water at the time, but his leg later developed a small, uncomfortable rash that he suspects was caused by the algae exposure.
“Over the next couple of hours, I started to have some itching on my leg,’’ he said. “There was a little bit of a rash. Itching and a little bit of pain.’’
Stroup said the itching eventually went away, but he hasn’t forgotten the experience.
“I am careful not to go in that cove now,’’ Stroup said.
Jim Rex, a long-time Lake Wateree homeowner, said he hasn’t noticed the algae in deep parts of the lake, but it is an issue in coves — and that is unsettling. Some people are aware of the algae, but there is not widespread public awareness of the problem at Lake Wateree, he said. He favors posting signs at some problem spots warning of the toxic algae.
“I think a lot of people do not know about it,’’ he said.
The algae, a strain known as lyngbya, attach to the bottom of the lake, and at times, can float to the surface. The algae are unsightly, with a foul odor that people may notice when they get close, said John Ferry, a scientist at the University of South Carolina. Resembling strands of hair, lyngbya algae have clogged the motors of boats that have ventured through mats of the algae.
“It looks like the world’s worst shower-clogged hairball,’’ said Ferry, who is studying the Lake Wateree algae problem. “It can be many feet long.’’
Lake Wateree, a man-made reservoir developed in the early 20th century, is one of the most popular recreational areas in central South Carolina. A state park and hundreds of private homes line its shoreline, which includes Fairfield and Kershaw counties. Popular with anglers, boats are easy to spot on the lake on many summer days.
But Lake Wateree has had problems in the past.
It is at the bottom of the Catawba River, a major waterway that runs from north of Charlotte to the Camden area near Columbia. Some people question whether runoff pollution from the lake’s shoreline, as well as contamination washing down the Catawba from Charlotte, are contributing to water quality problems. Years ago, DHEC began warning people not to eat more than moderate amounts of some Lake Wateree fish because of contamination from PCBs, compounds that can cause cancer.
DHEC officials said they don’t know what’s causing the algae blooms at Lake Wateree. But fertilizer from lawns and farms can stimulate algae growth in water. Lake Wateree in recent years has had a problem with sediment draining into some coves and clogging them. DHEC established a web page this week to explain issues about algae.
Lake Wateree’s troubles this summer are occurring at a time of increasing questions nationally about toxic algae outbreaks. Earlier this month, a prominent environmental group released a report linking the earth’s changing climate to increasing outbreaks of harmful algae blooms.
Tests have found “dangerous toxins’’ like that found in blue-green algae in hundreds of lakes, rivers and other waterways across the country in recent years, according to the report released last week by the Environmental Working Group, a national organization that tracks the issue. The problem is worsening because global warming is resulting in heavier rains and higher water temperatures, which combined with farm runoff, make conditions right for algae blooms, organization officials said.
Dog owners are worried.
Between 2007 and 2011, thirteen states reported 67 cases of dogs getting sick from exposure to blue-green algae, according to DHEC and the U.S. Centers for Disease Control and Prevention. In more than half of the cases, the dogs died, state and federal agencies said. Recent reports in North Carolina and Georgia have reignited concerns.
“While no (algae)-associated human deaths have been reported in the United States, many pet deaths, especially dogs, have been reported after the animal swam in or drank from water bodies with ongoing .... blooms,’’ according to DHEC and the Centers for Disease Control.
The algae at Lake Wateree prompted researchers at the University of South Carolina to look more carefully at the outbreak, including whether the earth’s changing climate is contributing.
Ferry, the USC scientist who is heading research on the Lake Wateree algae, said lyngbya algae may be affecting miles of shoreline. The university’s research initiative examines the impacts of global warming on coastal waters and health. His work includes a look at how algae are affecting drinking water disinfection on the lake.
Algae outbreaks, like those at Lake Wateree, can be an immediate concern to people who develop rashes soon after coming in contact with the toxic plants, but they also can be a long-term threat.
Saurabh Chatterjee, a USC scientist who works with Ferry at the university’s center for human health and climate change interactions, has found a connection between long-term exposure to some some types of algae and illness. His research, done in collaboration with other scientists, says one toxic component in algae contributed to intestinal diseases for people who are out of shape, maintain poor diets and have liver problems. The work was highlighted in “Scientific Reports’’ and “American Journal of Physiology,’’ two prestigious scientific publications.
Climate change is a major factor in algae outbreaks, he said, because floods and warm weather are making conditions better for algae growth.
“The blooms are there and they are affecting more and more water bodies,’’ Chatterjee said. “They are increasing, and most importantly, the toxicity of the blooms are increasing.’’