Grantee Research Project Results

Final Report: Rapid, Accurate, Single-Step Test Strip for Low Level of Arsenic in Water

EPA Contract Number: 68D00226
Title: Rapid, Accurate, Single-Step Test Strip for Low Level of Arsenic in Water
Investigators: Bognar, John A.
Small Business: ADA Technologies Inc.
EPA Contact:
Phase: I
Project Period: September 1, 2000 through March 1, 2001
Project Amount: $69,991
RFA: Small Business Innovation Research (SBIR) - Phase I (2000) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , SBIR - Monitoring , Small Business Innovation Research (SBIR)

Description:

This report summarizes the work conducted under an EPA Phase I SBIR investigation into the development of a rapid, sensitive, single-step test for arsenic in drinking and other water. Arsenic contamination in groundwater is recognized as a severe health risk to populations throughout the world. For example, the arsenic crisis in Bangladesh is perhaps the worst environmental catastrophe of the 20th century, with as many as 70 million people suffering from arsenic poisoning. Arsenic contamination in an estimated 5 million existing wells is causing mass poisoning in Bangladesh; although the exact number of affected wells is unknown because of a lack of suitable testing methods. Bangladesh is not the only country with significant arsenic contamination in its drinking water. For example, countries including Chile, Bolivia, and Peru that derive their drinking water from the altiplano of the Andes, a well-recognized arsenic province, also are affected. The World Health Organization (WHO) has compiled reports of arsenic in drinking water for countries that include Argentina, China, Ghana, Hungary, India, Mexico, and portions of the United States, especially the Western States and Michigan. As with Bangladesh, the major source of the arsenic contamination in these countries is naturally occurring subsurface minerals.

Exposure to arsenic and arsenic compounds is associated with acute and chronic toxicity. Low levels of arsenic exposure can cause a number of adverse health effects, including decreased production of red and white blood cells, abnormal heart function, blood vessel damage, liver or kidney injury, and impaired nerve function. Arsenic and its compounds are listed as known carcinogens and have been linked to skin, liver, kidney, bladder, and lung cancer.

In response to the international nature of this problem, the WHO has established 10 parts per billion (ppb) as a provisional guideline limit for arsenic in drinking water. This guideline limit is provisional because of the lack of suitable testing methods. Based on health effects alone, the WHO has stated that it probably would set the standard even lower if improved test methods were available. In view of the different levels of danger presented by As(V) and As(III), it is possible that different standards could be imposed for the different species, if a suitable, inexpensive test to easily distinguish between the two forms of arsenic was available. This is important, as with the ever-increasing pressures on water suppliers, it is essential that potentially safe drinking water supplies are not excluded from use for no good reason.

In the United States, the current drinking water standard for arsenic is 50 ppb. That standard is more than 50 years old. The U.S. Public Health Service established this standard in 1942, based on available data related only to skin cancer risks. EPA adopted this standard in 1976, under the Safe Drinking Water Act. However, new data from Bangladesh and the Bengal region of India indicate significant cancer rates at this level. These cancer risks are especially significant for rural areas in the United States, which may unwittingly be threatened by arsenic problems, as they are not monitored by federal agencies.

Based on a review of the new data, a National Research Council committee recommended that EPA lower its standards on the amount of arsenic allowed in drinking water, as soon as possible. The committee found "a combined cancer risk of 1 in 100" from drinking water with the currently allowed maximum level of arsenic. EPA now is considering lowering the limit to between 2 ppb and 20 ppb. A proposed standard was published, with a final rule due by January 1, 2001. However, the new administration has requested a 60-day extension period before issuing the rules, to further study the scientific evidence. It has been indicated that the only question is the targeted level of arsenic, not that the 50 ppb limit should be reduced. This standard will be reevaluated at least every 6 years, as mandated by the Safe Drinking Water Act Amendments of 1996. The more stringent standards that are anticipated likely will have a significant impact on U.S. water supplies. As many as 25 percent of domestic wells could be out of compliance. Given the potential health risks, it is important that a new generation of economical and effective testing and treatment technologies be developed to protect physical and economic health in this country.

In the United States, arsenic contamination above the existing 50 ppb standard is not a widespread problem in municipal drinking water supplies. However, almost 15 percent of the U.S. population obtains water from private, domestic wells, which are defined as wells that supply water to fewer than 25 people. About 95 percent of rural residents use groundwater to supply their drinking water and farmstead needs. Most of these wells have never been tested for arsenic, and all of them fall outside of federal regulatory control.

There clearly is an opportunity in the United States for a simple, safe, one-step test kit that will achieve reliable detection limits of 10 ppb As or less, for use by individual homeowners to ensure that their drinking water is safe and that they are not being poisoned by arsenic.

Summary/Accomplishments (Outputs/Outcomes):

The SBIR Phase I project conducted by ADA Technologies, Inc. (ADA) has successfully developed a test kit that responds to approximately 200 ng (200 x 10^-9 g) of arsenic, giving a detection limit of 10 ppb arsenic in a 20 mL sample. The user is required only to measure the sample into a small vial and attach the cap. The results are read as a colorimetric change in the filter held within the cap. The device is responsive to both arsenate and the more dangerous arsenite ions; however, the design also will allow an alternative chemical system that will only respond to arsenite ions.

The test is conducted in a sealed vial, increasing the sensitivity of the test and eliminating the risk of accidental exposure of the user to highly poisonous arsine gas. The products of the reaction are not hazardous and do not require any special disposal.

Conclusions:

Despite the considerable advances in intellectual property, ADA has elected not to submit a Phase II proposal for continued funding. ADA is, however, pursuing contacts with two companies in the water-testing business who are interested in the innovations. It is expected that the advances made during the investigation will enter a new or improved product to the marketplace.

Supplemental Keywords:

water treatment, drinking water, monitoring, analytical, engineering, chemistry., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Water, Toxics, National Recommended Water Quality, Ecological Indicators, Chemical Engineering, Engineering, Ecosystem Protection, Chemistry, HAPS, Environmental Chemistry, Ecosystem/Assessment/Indicators, Engineering, Chemistry, & Physics, Monitoring/Modeling, Arsenic, Ecological Effects - Environmental Exposure & Risk, Ecological Effects - Human Health, Drinking Water, Environmental Engineering, Environmental Monitoring, Arsenic Compounds (inorganic including arsine), single-step test strip, test strip, single-step test strip, monitoring, risk management