Revised EPA Guidelines for Arsenic

In January 2001, the Environmental Protection Agency (EPA) revised its national drinking water regulations for the Maximum Contaminant Level (MCL) of arsenic, reducing the allowed concentration from 50 ppb to 10 ppb. This regulation significantly reduces the permitted concentration of arsenic in the drinking water of all Americans.

Background

Before January 2001, the EPA drinking water regulations allowed an arsenic MCL of 50 ppb. The EPA established this contaminant level in 1975, based on a standard originally set in 1942. In March 1999, the National Academy of Sciences reported that the 50 ppb standard did not adequately protect the publics health and recommended that the allowed concentrations of arsenic in drinking water be lowered. In June 2000, the EPA proposed a new arsenic drinking water standard of 5 ppb and solicited public input on several different proposed MCLs for the Nations drinking water. After considering public input and many other factors, the EPA established the new MCL for arsenic in drinking water in January 2001 as 10 ppb.

Details of Arsenic Rule

The purpose of the new, more stringent arsenic rule is to protect citizens from the health effects resulting from long term, chronic exposure to arsenic in drinking water. According to the EPA, the guidelines have been set to a level that maximizes health risk reduction benefits at a cost that is justified by the benefits (2001).

The new arsenic rule requires the following:

· All 54,000 community water systems must meet an arsenic MCL of 10 ppb.

· Requires compliance of 20,000 non-community water systems, such as those of schools, churches, and factories.

· A system must collect a minimum number of samples to test for arsenic.

· All systems must come into compliance with the new standards within 5 years.

· Water system operators must inform users of arsenic levels in drinking water.

The EPA estimates that 5.5% of community water systems and 5.5% of non-community water systems, a total of 4,100 systems, will be required to reduce arsenic levels in the drinking water in order to comply with the new 10 ppb arsenic MCL standards (2001). The arsenic rule will affect 13 million people who rely on these systems for water supply.

Benefits

The new rule aims to protect public health at a justifiable cost. The EPA estimates that by reducing the national MCL to 10 ppb, an additional 13 million Americans will be protected from chronic exposure to arsenic in drinking water. According to the EPA, the new arsenic rule will result in prevention of: 19-31 cases of bladder cancer, 5-8 deaths due to bladder cancer, 19-25 cases of lung cancer, and 6-22 deaths due to lung cancer per year. These and other benefits amount to approximately $140 - $198 million in benefits per year (EPA, 2001).

Costs

The estimated total annual cost of implementation of the new arsenic rule is $181 million. The household cost, for users of water systems that are now required to remove arsenic, averages an additional $32 per year after implementation of the new rule (EPA, 2001). This amount varies greatly depending on system size and other factors.