AUSTIN, Texas >> Fire ants in bunches the size of basketballs bobbing along in creeks and rivers. Floodwaters that could leave homes contaminated with bacteria, viruses and mold. Fire and explosions at a chemical plant. Emissions of toxic and cancer-causing substances into the air from petrochemical plants. State parks closed indefinitely. Rivers choked with sewage, fertilizer and all manner of debris rushing headlong into bays that are home to shrimp and other aquatic life.

The scope of the ecological and pollution challenges wrought by Hurricane Harvey on Texas has begun to emerge, and it is vast.

“This is a major disaster,” said Lynn Katz, a professor in the civil, architectural and environmental engineering department at the University of Texas. “The first goal is to keep people safe in the short term, and get them clean water and clean air. Beyond that, you have to look at providing a sustainable, healthy environment in the future.”

The task will play out in the coming days, weeks, months and years. Experts say Harvey also underscores the need for the state or local governments to guard against even more destructive floods by purchasing undeveloped land, or development rights to such land, in the Houston area and the Hill Country. Construction of homes, offices, parking lots and other impervious surfaces reduces the land’s ability to absorb rainfall and runoff.

“The wakeup call is primarily on the eastern edge of the Hill Country, where growth is among the most rapid in the United States and where the ecology and landscape are iconic,” said Andrew Sansom, a geography professor and executive director of Texas State University’s Meadows Center for Water and the Environment. “The Hill Country is flood-prone. There’s not much soil.”

WATER PROBLEMS

Samples of floodwaters from the Houston area showed levels of E. coli bacteria 125 times higher than is considered safe for swimming and 15 times higher than acceptable levels for wading, according to a Texas A&M University researcher. Those readings indicate the likely presence of disease-causing bacteria, viruses and other organisms, said Terry Gentry, an associate professor of soil and crop sciences.

More than 50 public drinking water systems are inoperable, including the one serving the 118,000 residents of Beaumont, where the rising Neches River knocked out the main pump station, and the city of Victoria’s system, which serves 63,000. About 20 wastewater systems also were not working, including those serving the cities of Pearland, Beeville and Conroe, according to the Texas Commission on Environmental Quality.

Many thousands of people in the Texas counties affected by Harvey use private wells. Owners of such wells should get the water tested because of the potential for bacterial and other contamination, said Kerry Kinney, an engineering professor at UT.

The surge of sea water inland could taint groundwater supplies as the salty water seeps through the ground, said M. Bayani Cardenas, a professor of geological sciences at UT. “If any of that water has industrial contaminants and it seeps into groundwater, it’s there for weeks to months, even years. Water travels perhaps a foot per day in an aquifer compared with river water that might travel a foot per second.”

In something of a cruel irony, people who fled their homes because of rising waters could face other threats when the waters recede and they return.

“During a flood cleanup, the indoor air quality in your home or office may appear to be the least of your problems,” the U.S. Environmental Protection Agency explains on its website. “However, failure to remove contaminated materials and to reduce moisture and humidity can present serious long-term health risks. Standing water and wet materials are a breeding ground for microorganisms, such as viruses, bacteria, and mold. They can cause disease, trigger allergic reactions, and continue to damage materials long after the flood.”

A moldy area less than about 3 feet by 3 feet in a home or office can be a do-it-yourself job, but larger areas might well require the services of an experienced professional, according to the EPA. And if the heating or air conditioning system is contaminated, running the system could spread mold throughout the structure.

“If people have to wait two weeks to get back into their homes, it’s going to be a pretty moldy mess,” Kinney said.

ANIMALS ALSO DISPLACED

Floodwaters displace animals as well as people. When water invades underground fire ant nests, for example, the ants rise to the surface, cling to each other and float away. Woe to anyone wading through the water who comes in contact with them.

“That whole mass will climb onto you like you’re dry land,” said Lawrence Gilbert, a professor of integrative biology at UT. “You’re going to try to wipe them off and that pisses them off. All the pheromones start going and they start stinging the hell out of you.”

Snakes, alligators and other critters will be floating around for a while, said Steve Lightfoot, a spokesman for the Texas Parks and Wildlife Department. Raccoons, opossums and deer also had to flee floodwaters.

“We can expect some mortality from newborn fawns and small mammals. The flooding probably impacted ground-nesting species like quail and turkey,” Lightfoot said.

Bat colonies have also taken a hit. The flying mammals roost in crevices on the underside of 30 bridges in the Houston area, some of which took on water. The Waugh Drive Bridge over Buffalo Bayou just west of downtown harbors up to 300,000 Mexican free-tailed bats at this time of year.

“Dead bats have been found on the Waugh bridge,” said Kelly Norrid, an urban wildlife biologist with the Parks and Wildlife Department. “Bats typically don’t like to fly out when it’s raining. A number of bats have escaped the flood, but it’s difficult to say at this point what the damage is.”

More than two dozen state parks, including Brazos Bend, Matagorda Island and Sheldon Lake, are closed for the foreseeable future because of flooding. “It would be impossible to predict the financial challenges (of cleanup and restoration) and how we’re going to address them,” Lightfoot said.

OIL, CHEMICAL POLLUTANTS

On a brighter note, no major oil spills have been reported in the Gulf of Mexico, although five drilling rigs and 102 oil and natural gas production platforms have been evacuated, according to the U.S. Department of the Interior’s Bureau of Safety and Environmental Enforcement.

However, there have been small spills from some of the boats that were grounded or otherwise damaged by Harvey. The Texas General Land Office will work with the Coast Guard to round up and pump out those vessels, said David Green, the land office’s deputy director for coastal resources. He said there were 270 such vessels in the Corpus Christi area alone.

“So there will be hundreds if not thousands of vessels up and down the coast that we’ll have to work on removing,” Green said.

Petrochemical plants in the Houston area have emitted substantial quantities of toxic and cancer-causing chemicals, such as benzene and butadiene, into the air in recent days as a result of Harvey-related shutdowns and problems with storage tanks. The total exceeds 2 million pounds, said Luke Metzger, director of Environment Texas, an advocacy group that tracks reports filed by the companies with the Commission on Environmental Quality.

“There isn’t any way to measure what the ambient exposure would be for the community, but we do know anecdotally that people are smelling these chemicals and being exposed to them,” Metzger said.

Andrew Keese, a spokesman for the environmental commission, said it’s premature to speculate on the impact of the emissions on air quality and public health.

Another concern, Metzger said, is that children in the Houston area have been seen swimming in floodwaters near some of the dozen or so locations known as Superfund toxic waste sites, which the EPA has targeted for long-term cleanup. Flooding of such sites sometimes causes pollutants to migrate.

Explosions and fires Thursday at the Arkema Inc. chemical plant 25 miles northeast of Houston were set in motion after flooding cut off electrical service and backup generators, shutting down refrigeration essential to keep stable the organic peroxides manufactured by the plant.

Authorities urged residents downwind to stay indoors with windows closed to avoid inhaling the smoke. The plant’s employees and people living within 1 1/2 miles were evacuated two days earlier. More than a dozen Harris County sheriff’s deputies who complained of respiratory irritation from the acrid smoke were examined at a hospital and released, officials said.

Harvey’s effects on the coast could be a mix of good news and bad news. Waterfowl are likely to benefit from floodwaters that surged into rice fields along the lower Colorado River, said Texas State’s Sansom.

“Usually the fresh water surge that accompanies a hurricane can actually be beneficial. It’s a natural part of the cycle in bays and estuaries,” Sansom said. “In this case the water will be so contaminated that I can’t imagine that huge pulse is going to be particularly beneficial.”

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