Harvey’s floodwaters are a foul mix of sewage, chemicals – Omaha World-Herald

Harveys filthy floodwaters pose significant dangers to human safety and the environment even after water levels drop, experts say.

Houston already was notorious for sewer overflows following rainstorms. Now the system, with 40 wastewater treatment plants across the far-flung metropolis, faces an unprecedented challenge.

State officials said several dozen sewer overflows had been reported in areas affected by the hurricane, including in Corpus Christi. Private septic systems in rural areas could fail as well.

Also in the noxious mix are spilled fuel, runoff from waste sites, lawn pesticides and pollutants from the regions many petroleum refineries and chemical plants.

Houstons mayor said Tuesday that Americas fourth-largest city was open for business, but with many areas under water and some residents not able to get to work, many huge problems remained.

The potentially toxic water is a big one. Floodwaters have inundated at least seven Superfund toxic waste sites near Houston and some may be damaged, though Environmental Protection Agency officials have yet to assess the full extent of what occurred.

The Houston area has more than a dozen Superfund sites, among the nations most intensely contaminated places. Texas Gov. Greg Abbott told CNN that the EPA is working on some of them already, but they have restraints on their ability to check out some of them just simply because of the water.

Meanwhile, repairs continued on the water treatment plant in Beaumont, about 85 miles from Houston, which failed during flooding. Houston said its water was safe to drink. Keeping it that way will require stepped-up chemical treatments because of the flooding.

Its prudent to pump more chlorine and other disinfectants into drinking water systems in emergencies like this, to prevent outbreaks of diseases such as cholera and dysentery, said David Andrews, senior scientist with the Environmental Working Group, an advocacy organization. But doing so poses its own risks, he said.

Theres often more organic matter sewage, plants, farm runoff in reservoirs or other freshwater sources during heavy rains. When chlorine reacts with those substances, it forms chemicals called trihalomethanes, which can boost the risk of cancer and miscarriages, Andrews said.

Right now its a tough time to deal with that, when youre just trying to clean the water up and make sure its not passing illnesses through the system, he said. But we should do better at keeping contamination out of source water in the first place.

A report by the nonprofit research group Climate Central said more than 10 billion gallons of sewage was released along the East Coast during Superstorm Sandy.

The Houston Chronicle reported last year that Houston averages more than 800 sewage overflows a year and is negotiating an agreement with the EPA that would require system improvements.

A Texas A&M analysis of floodwater samples from the Houston area revealed levels of E. coli bacteria that signal the presence of fecal matter 125 times higher than is safe for swimming. Even wading through such tainted water could cause infections and sickness, said Terry Gentry, an associate professor and specialist in detecting tiny disease-producing organisms.

Precautions should be taken by anyone involved in cleanup activities or any others who may be exposed to floodwaters, said a statement from the EPA.

Hazards will remain as waters gradually recede. Puddles, tires and other pools of standing water will attract mosquitoes, which can spread viruses such as West Nile and Zika.

Much of the dirty water will flow through rivers, creeks and bayous into Galveston Bay, renowned for its oyster reefs, abundant wildlife and seagrass meadows. Then officials will need to monitor shellfish for signs of bacterial contamination.

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Harvey's floodwaters are a foul mix of sewage, chemicals - Omaha World-Herald