To date, the Water Authority has tested more than 13,000 samples for arsenic.

• Arsenic Compliance Achieved
• Arsenic Occurrence
• Arsenic Compliance Strategy
• USEPA Arsenic Health Effects Language

Arsenic Compliance Achieved

After many years of debate on the health effects of arsenic in drinking water and the accuracy of estimates of costs and benefits, USEPA lowered the Maximum Contaminant Level to 10 Parts Per Billion. The lower drinking water standard became effective in January 2006.  The New Mexico Environment Department (NMED) granted the Water Authority an exemption to the new arsenic standard to allow time to complete the Arsenic Compliance Strategy. As a result, the MCL remained at 50 Parts Per Billion until December 31, 2008.

The Water Authority, and its predecessors, have worked hard to meet the challenge of a lower arsenic standard.  In November 2008, quarterly monitoring results demonstrated that the Water Authority had achieved compliance with the lower USEPA standard throughout the distribution system.  All Arsenic Compliance Strategy requirements had been met.

Arsenic Occurrence

When rocks, minerals, and soil erode, they release naturally occurring arsenic into groundwater. Arsenic occurs in varying amounts in groundwater in Albuquerque and throughout New Mexico.  Arsenic concentrations in Water Authority wells range from No Detection to 49 PPB.

USEPA defines where and how often compliance samples must be collected for analysis.  For arsenic, samples must be collected at each Entry Point to the Distribution System (EPTDS) once every three years.  During the arsenic exemption period, NMED also required quarterly monitoring at each EPTDS.

The citywide results of compliance monitoring completed in 2007 and quarterly monitoring completed in November 2008 are shown in the map below.

Although all of the drinking water supplied to our customers in 2008 met the 50 PPB standard and the 35 PPB excess exposure level allowed by law during the exemption period, some of the water did not meet the 10 parts per billion standard that became effective on December 31, 2008. Consumers need to be aware of USEPA's health effects language for arsenic.

To use the map below:

1. Find your location on the map.
2. Determine your distribution zone. The distribution zones are outlined by a dark blue line and the distribution zone number is the large number printed in that zone. Drinking water supplied within a distribution zone is of the same water quality.
3. Look for the water drop in your distribution zone. The top (dark blue) number in the water drop is your distribution zone.
4. The middle (light blue) number in the water drop is the amount of arsenic in the compliance sample(s) collected at the EPTDS for your distribution zone in 2007.
5. The bottom (black) number is the monitoring value for November 2008, in PPB.
6. A single number for arsenic in a water drop indicates there is a single EPTDS for that distribution zone. If a range of numbers is given for a distribution zone, there are multiple EPTDS to that distribution zone.
7. Find the appropriate health effects language below for the amount of arsenic on your distribution zone.

The Arsenic Compliance Strategy Includes:

1. Continued protection of public health during the time of the exemption by blending groundwater to keep quarterly arsenic concentrations at all EPTDS below the 35 PPB excess exposure level allowed by law.

By selectively pumping wells, arsenic concentrations are lowered. To lower the arsenic concentration even more, water with low arsenic concentrations is pumped between storage tanks. Some water lines were reconfigured and new pump stations were constructed to create more blending opportunities.

With the completion of the San Juan-Chama Drinking Water Project finished water distribution pipelines in 2007, low arsenic concentration water could be moved from South to North and from the east side of the river to the west side.  There are 38 miles of distribution pipeline, including a pipeline that crosses the river.

All of the water supplied to our customers in 2008 met the 35 PPB excess exposure level allowed by law.

Microfiltration Units at the Arsenic Removal Demonstration Plant

2. Construction of an Arsenic Removal Demonstration Plant on the West Side.

The plant was completed and in operation in July 2007. The plant removes arsenic from water pumped from two West Side wells. The plant is used in combination with the San Juan-Chama Drinking Water Project distribution pipelines to carry the low arsenic water to other storage tanks across the West Side. The plant, which can treat 5.2 million gallons per day, is the largest facility of its kind in the world. The $6.3 million plant was built with financial assistance from the Federal government. Water customers, students, regulators and officials from other water utilities may visit the demonstration plant to see firsthand how the process works.

3. Completion of the Surface Water Treatment Plant.

Construction was completed and drinking water was produced by the new plant in December 2008. Water provided by the San Juan-Chama Drinking Water Treatment Plant contains little or no arsenic.

You can learn more about the Surface Water Treatment Plant and other project components by visiting the San Juan Chama Drinking Water Project.

USEPA Arsenic Health Effects Language Applies As Follows:

For water containing greater than 5 PPB of arsenic and up to and including 10 PPB of arsenic: While your drinking water meets USEPA’s standard for arsenic, it does contain low levels of arsenic. USEPA’s standard balances the current understanding of arsenic’s possible health effects against the costs of removing arsenic from drinking water. USEPA continues to research the health effects of low levels of arsenic, which is a mineral known to cause cancer in humans at high concentrations and is linked to other health effects such as skin damage and circulatory problems.

For water containing greater than 10 PPB of arsenic, but not greater than 50 PPB of arsenic: Some people who drink water containing arsenic in excess of the new MCL over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer.