Las Vegas Sun

July 29, 2021

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As the federal government wonders how to refill Lake Mead and warns states of cutbacks, Nevada plans to put another straw in the water.

The fish are thick at Hemenway Harbor - giant carp and foot-long striped bass writhing and wrestling each other, struggling to poke their heads out of the water in the off chance a few bread crumbs might get tossed their way.

A similarly congested scene of fish plays out at nearby Las Vegas Bay - but they're not on the hunt for bread crumbs. At Las Vegas Bay, the thriving population of fish gorge on vegetation and bugs enriched by nutrients flushed into Lake Mead through the Las Vegas Wash, a stream that delivers treated wastewater and urban runoff to the lake.

The effluent is mostly just water, a most welcome albeit drop-in-the-bucket addition to the declining water levels in Lake Mead. But scientists and policymakers worry that the sewage might be too much of a good thing in one respect, and too much of too many bad things in another.

Because weird things are happening in Lake Mead.

The water is rich in phosphorus, a nutrient that sparks plant growth. Too much phosphorus can lead to too much algae growth that chokes the water and kills other plants and animals. And with the effluent comes trace amounts of contaminants that scientists believe can also profoundly affect fish and other animals in the lake waters. Some fish, for instance, seem to be changing sex.

Little wonder, then, that urban planners worry for the lake's future, and our's. We need a healthy lake both for its life-sustaining water and as a receptacle for treated wastewater. And in each case, the lake's fate is at a crossroads.

The treated wastewater is not toxic. In fact, it is purer than the water that is available for municipal use in many parts of the world.

But advancements in technology allow detection of trace contaminants, down to a few molecules among billions in a solution.

With such specific measuring devices, scientists who monitor the treated wastewater entering Lake Mead are finding pharmaceuticals that have already coursed through bodies, antibacterial additives in common cleaning products, and chemicals that give personal hygiene products their fragrances.

Add to that the untreated runoff into Lake Mead with every passing rainstorm, over-watered lawn and car that's washed in the front driveway - water that carries pesticides, herbicides, animal waste, motor oil and gasoline down our curbs, storm drains and washes.

And then there's the continued presence of perchlorate, a rocket-fuel ingredient produced in Henderson and slowly seeping into the wash.

The combined effect of all the contamination is a toxic stew that could get nastier as the population in the Las Vegas Valley grows and the lake's water level drops because of the ongoing drought and increasing demand - resulting in less water to dilute the incoming contaminants.

So far, improvements in sewage treatment have kept the level of contamination more or less stable, but Alan O'Neill, a former Lake Mead National Recreation Area superintendent who is now executive director of Outside Las Vegas, a nonprofit conservation group, worries that could change as more treated sewage enters the lake from regional growth beyond the urban valley.

"A lot of the treated discharge, from St. George (Utah) to Moapa and Mesquite, all ends up in Lake Mead," he notes.

Municipal sewage discharge into lakes and rivers is nothing new; it is as old as cities themselves. But today we are only starting to learn about new classes of largely uncontrolled pollutants, generically termed "emerging contaminants," in the waters throughout the United States and the world.

Discovery of relatively high levels of emerging contaminants in the Potomac River - a water source for millions in and around Washington - startled the region, but, in fact, federal researchers have found the contaminants virtually everywhere they look.

Evidence that these emerging contaminants are affecting fish in Lake Mead has been around for at least a decade.

Treated waste from Las Vegas, urban Clark County, Henderson and North Las Vegas is pumped into the Las Vegas Wash and flows into Lake Mead at Las Vegas Bay. Although the wash contributes only 1.5 percent of the water in Lake Mead, scientists believe it contributes a disproportionately larger amount of nutrients and contaminants, especially in Boulder Basin, the southern end near Hoover Dam.

Contamination concerns have captured the attention of scientists from several universities and an alphabet soup of agencies, including the U.S. Geological Survey, the U.S. Fish and Wildlife Service, the National Park Service and the Southern Nevada Water Authority.

They're wondering why male fish are undergoing "feminization."

Scientists believe that pharmaceuticals, plastic byproducts, fire retardants and perchlorate - a chemical used in rocket engines - may be affecting the hormones and development of the fish.

The managers also are concerned about what is happening to the razorback sucker, a fish that is native to the Colorado River but whose dwindling numbers sparked its listing and federal protection as endangered in 1991.

Pollution is just one of the challenges to the razorback sucker, which federal officials fear could become extinct in the river and its tributaries. Predation from non-native species such as striped bass and the loss of habitat through the dams constructed along the river are other challenges.

But because of its status as a federally protected fish, any threat to the razorback sucker has to be taken seriously, which is why scientists from the Park Service, Fish and Wildlife, the Geological Survey and other agencies are investigating the effect of pollution on the animal.

Nonetheless, the Park Service insists that recreational use of the lake is safe. Swimming, fishing, and even eating the fish is not a problem, says Kent Turner, chief of resource management for Lake Mead National Recreation Area.

"There have been contaminant studies in the past for everything from hydrocarbons to heavy metals, and endocrine-disrupting compounds," Turner says. "There is nothing from any of the work that points to a problem with eating the fish or going swimming."

If you want to talk about polluted waterways, he says, just go back East.

Doug Karafa, chief administrator of the regional Clean Water Coalition, thinks he knows how to limit the inevitable pollution of Lake Mead: Carry the treated wastewater by pipe deep beneath the lake, emptying the effluent in the depths of Boulder Basin, where it would be more effectively diluted with purer Colorado River water.

The Clean Water Coalition was created to build the massive sewer project by the Clark County Water Reclamation District and Henderson and Las Vegas, which run their own sewage-treatment agencies. North Las Vegas is expected to also participate. The coalition also works closely with the Water Authority in the planning of the massive project.

Karafa said he hopes the federal government will give its final OK for the new treatment system, including the deep pipe, by the end of January.

To help cover the $750 million price tag, Clark County, Las Vegas and Henderson have instituted new sewer connection fees for businesses and residences, and monthly sewer charges for existing sewer users.

The agencies hope to begin the four-year construction project in 2008.

Karafa says the project will help the lake even if water levels continue to fall. But the dropping lake is making the job of keeping the lake clean a lot tougher, he said.

Jim Deacon, a UNLV professor emeritus of environmental studies, worries that the coalition's plans to flush effluent back into Lake Mead might backfire.

Deacon, who has studied water and biology in Southern Nevada for more than four decades, argues that mixing effluent with the lake water could increase the amount of contaminants flowing back into the valley's water systems, especially after a third intake pipe is installed to suck water out of Lake Mead to help sustain the region's growth.

"We're likely to see a pooling of those contaminants in those deep waters of Lake Mead, which is exactly where we are putting the new straw," Deacon says. "If we don't get the mixing that the model suggested we should get, the pooling of contaminants in the wintertime could be much more extensive than their models suggest."

Deacon's solution: Don't send wastewater to the lake. Instead, treat the effluent before it even leaves the valley, with industrial-sized versions of what is beneath many kitchen sinks - reverse osmosis membranes. Reverse osmosis cleans water at the molecular level by forcing it through filters which trap the heavier, larger molecules of pollutants and salts.

Such a system would prevent the further contamination of Lake Mead and cost about the same as the planned system, Deacon says.

Besides, he adds, if the federal government passes new regulations governing the disposal of emerging contaminants, then reverse osmosis treatment will be needed in any case - so just build it in the first place.

Reverse osmosis treatment of ground water, seawater and wastewater are still relatively rare in municipal and large commercial applications. Reverse osmosis is used to treat wastewater in water-short areas, including Singapore, Kuwait and Orange County, Calif. - where the treated water is returned to the aquifer to be tapped later.

Last year, the first municipal reverse osmosis plant in Utah went into operation in the southwest Jordan Valley, outside Salt Lake City, to turn saline ground water into drinking water.

A water recycling facility in El Segundo, Calif., is using reverse osmosis to treat wastewater for irrigation, commercial and industrial purposes - but not for residential or public drinking water because of concern that consumers would be put off by it.

Reverse osmosis was considered and rejected by the Clean Water Coalition, according to its spokesman, Eric Hawkins, because it would be expensive, would create a salt-heavy solution that would still have to be disposed of, and because up to 30 percent of the water would be lost to the system. The present system of returning wastewater to Lake Mead - which provides credits for more clean water to be pumped up to Las Vegas - loses about 5 percent.

Hawkins says some people also have a psychological reluctance to consume treated effluent water that was cleansed through membranes.

So for now, our sewage will still be treated to levels that make it drinkable, and then poured into the depths of the shrinking Lake Mead.

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