The U.S. Environmental Protection Agency (EPA) in late October brought enforcement actions against 11 water agencies for failing to reduce arsenic levels in drinking water to meet the federal 10 parts per billion (ppb) limit. Water system operators can expect more of the same in the foreseeable future. While the chemical industry is on the sidelines, it should take note of the moves and particularly of the technology developed to monitor levels of arsenic.
EPA issued a final rule in 2001, under the Safe Drinking Water Act, that established a new drinking water standard for arsenic of 10 ppb. The standard was based in part on the National Academies of Science recommendation that this level is needed to protect consumers against the effects of long-term exposure to arsenic in drinking water. The rule was effective in February 2002, and required, among other things, compliance with the standard by all public water systems by January 2006.
As EPA knows well, arsenic is a ubiquitous, naturally occurring contaminant found in groundwater supplies,and is especially abundant in Southwestern states. Water agencies from this area of the country, particularly small water systems, faced a daunting job in reducing arsenic concentrations to achieve the new, rigorous 10 ppb limit. Typical challenges included inadequate resources to monitor and acquire and/or enhance arsenic treatment equipment.
With the Jan. 23, 2006, deadline now long past, EPA has stepped up its enforcement efforts to ensure compliance. EPA, on Oct. 28, ordered 11 public water systems in California to take steps to reduce arsenic in drinking water supplies. Arsenic levels in the 11 water systems targeted for enforcement action range from 10 ppb to 40 ppb, according to EPA. Under the terms of the enforcement actions, the water systems have until 2010 to achieve the new drinking water standard. Failure to achieve the deadline could result in penalties of up to $32,500 a day for each violation. EPA Region 9 (San Francisco) reportedly mentioned that a second wave of enforcement actions could target an additional 30 water systems.
While there’s not a lot of good news here, some comfort can be taken in that since the final rule was issued, many more methods have been developed to identify and determine levels of arsenic, arsenite and arsenate. The methods are listed in the Standard Methods for the Examination of Water and Wastewater, issued by the American Public Health Association, the American Water Works Association, and the Water Environment Federation.
Another useful resource is EPA’s Environmental Technology Verification (ETV) Advanced Monitoring System (AMS) Center, available at www.epa.gov/etv/vertiications/vcenter1-21.html. The AMS Center has verified 10 technologies of arsenic water monitoring, falling into two classes: colorimetric and anodic stripping voltammetry (ASV). These technologies are portable and designed for rapid on-site analysis of arsenic in water.
Colorimetric test kits are based on a chemical reaction that converts the arsenic compounds present in the water into arsine gas. The arsine gas is exposed to a test strip that changes color from white to shades of yellow or brown with increasing arsine levels. ASV is an analytical technique in which analyte concentration is derived from the measurement of electric current as a function of applied potential. The analyte of interest is identified and plated onto an electrode by applying a negative potential for a predetermined period of time. After deposition, the analyte is oxidized, brought back into solution, and measured against known standard solutions.
For water system operators, complying with the new arsenic standard has been challenging. As with any new and controversial regulatory limitation, however, the need to come into compliance has jump-started innovation, which has resulted in new and exciting technologies that are available to everyone. As noted, these technologies will come in handy for those wishing to avert enforcement actions, which are sure to be filed in the months ahead.
Lynn is managing director of Bergeson & Campbell, P.C., a Washington, D.C.-based law firm that concentrates on chemical industry issues. The views expressed herein are solely those of the author. This column is not intended to provide, nor should be construed as, legal advice. You can e-mail Lynn at [email protected].