Where I Stand—Patricia Mulroy: Ensuring clean water

Tuesday, Aug. 7, 2001 | 8:46 a.m.

Editor's note: In August Where I Stand is written by guest columnists. Today's writer, Patricia Mulroy, is general manager of the Southern Nevada Water Authority.

FEW ISSUES are as compelling to water agencies as the quality of the water they deliver to their customers. Since the middle of the last century, Americans have increasingly become aware of the interrelationship between their health and the environment in which they live. Science is increasingly sophisticated both in its ability to detect previously invisible compounds and its understanding of how these compounds may affect human health.

We are fortunate that those who built the original water system at Lake Mead were keenly aware of water quality issues. They built a state-of-the-art water treatment system that has protected us from many of the problems experienced in other communities. However, continued diligent stewardship of our water source is critical.

Recently the presence of the chemical perchlorate and a prolonged algae bloom in Lake Mead have raised concerns about the lake's health. Perchlorate is a chemical manufactured in Southern Nevada since the 1950s. In the early years this contaminant entered the shallow groundwater system, which over time carried it to Lake Mead. It wasn't, however, until the late 1990s that the technology existed to allow us to detect the chemical at the low concentrations in which it exists in Lake Mead.

Now that perchlorate has been detected in water supplies around the country, the Environmental Protection Agency -- which sets the water quality standards for every public water agency in the country -- is working to complete the studies necessary to determine what levels are acceptable in drinking water. However, these studies provide little comfort to Southern Nevada's residents, who simply want the contaminant eliminated from their water.

Recognizing that only the EPA can establish an enforceable federal limit for perchlorate, local and state agencies have partnered with the manufacturers of perchlorate to focus their energy on removing the salt. Scientists have isolated the perchlorate's source and are working with engineers to remove it.

An interception system activated last year has already begun removing the chemical, and a larger system is under construction. The debate over what the standard should be rages on. Regardless, our goal is that perchlorate no longer be detectable in Lake Mead. Given the efforts currently under way, we believe that goal is achievable in the not-too-distant future.

This year the algae bloom has attracted widespread attention. While it has not posed any threat to our drinking water, the algae has raised questions about the lake's health. The emergence of algae in lakes during the spring is common; however, this season's bloom is unique both in its breadth and persistence. Scientists are working feverishly to try to determine the cause. It is not appearing exclusively in the Las Vegas Wash. Plumes exist at the mouth of the Muddy and Virgin Rivers, as well as farther upstream along the Colorado River. At this point, scientists are examining all possibilities.

Disposal of the valley's wastewater has been another key issue. Despite the stringent water quality standards governing the three wastewater entities, public concern about the potential impact of this effluent on our water supply continues. To reduce treated wastewater flows into the wash, the city of Las Vegas and the Clark County Sanitation District have partnered with the Las Vegas Valley Water District to develop satellite reuse facilities throughout the valley. Large turf users, such as golf courses, pay for these facilities, which divert millions of gallons of treated wastewater for reuse. In the next few years Las Vegas will lead the nation in the use of these pioneering satellite systems.

In recent years, water quality discussions have centered on the Las Vegas Wash, which is the terminus of our groundwater flow system, the exit for all stormwater flows and the conduit for much of the valley's treated wastewater. In the 1990s the Las Vegas Wash Coordination Committee was created. Twenty-four federal, state and local agencies have developed and are implementing a coordinated plan to address issues related to the wash. Resolving the issues surrounding the Las Vegas Wash is critical, not just to the quality of our own drinking water but to that of millions of people downstream.

Water quality is of great concern to Southern Nevada's water agencies. Natural events, environmental changes and scientific advancements will always have us reacting and refining the tools and methods we use. When a new compound is discovered or new medical research suggests that certain areas of concern may exist, extra caution may be warranted. If you choose to buy a water treatment system for your home or purchase bottled water, we encourage you to make an informed decision. Not all systems are equally effective, and not all bottled water is treated in the same fashion.

If you have questions about water quality, please call us at 258-3930. We will be happy to assist you.