AECOM, a global infrastructure firm, announced that Zeynep Erdal, Ph.D., P.E., has been named regional business line leader for its water business...
General Information and Background
Arsenic is a naturally occurring metal found in rocks and soil, which can be released into the environment through geological events such as volcanic activity and erosion. Other releases of arsenic into the environment occur through industrial processes such as production of paints, metals, soaps, dyes, drugs, semi-conductors and wood preservatives, as well as in mining and smelting.
Here in the United States most cases of arsenic contaminated water are a result of geochemical soil leaching, where naturally occurring arsenic in the rock and soil is solublized by contact with ground or surface water.While the Environmental Protection Agency (EPA) regulates the amount of arsenic an industrial process can release into the environment, oversights can occur, creating an added source of contamination.
Arsenic occurs in two common valence states, arsenite (arsenic III) and arsenate (arsenic V). Arsenic V is the easier of the two forms to remove from drinking water and most often is found in chlorinated water systems. Arsenic III is more difficult to remove and more hazardous to human health.
In the United States, high concentrations of arsenic most often are found at the foothills of mountain ranges. Western states and parts of the Midwest and New England show increasing arsenic levels well above the current EPA standard of 50 parts per billion (ppb).
Although these areas have the highest concentrations of arsenic overall, communities all over the United States are finding increased levels of arsenic in their drinking water. Wisconsin, for example, is not within a high risk area for arsenic, yet 18 percent of its wells exceed the World Health Organization (WHO) standard of 10 ppb and 3 percent exceed the current EPA standard of 50 ppb.
Some 13 million people in the United States routinely drink water with more than 10 parts per billion of arsenic, according to EPA figures.
Many countries around the world have a significant problem with arsenic poisoning.Argentina, Bangladesh, India and Japan are just a few of the countries that have high levels of arsenic in their water supplies. Bangladesh, for example, estimates between 35 to 77 million of its 125 million citizens are at risk of drinking contaminated water.
High concentrations of arsenic ingested into the body can produce lethal effects. Arsenic has long been known as a poison and has been the tool of many vengeful conspirators including, it appears, even for our earliest settlers at Jamestown, Virginia, where Spain tried to ensure the failure of the original English colony through repeated use of arsenic via an internal spy (“Secrets of the Dead II - Death at Jamestown”, PBS).
Initial effects of arsenicosis, the disease caused from excessive exposure to arsenic, include stomach pain, vomiting, skin lesions, pigmentation, difficulty in swallowing, excessive thirst, low blood pressure, convulsions and gastrointestinal problems. Long-term effects include cancer of the bladder, skin, kidney, liver, prostate, lung and nasal passages.
It currently is estimated that one in 100 people exposed to arsenic levels above 50 ppb (the current United States standard) will die from cancer.In areas where the arsenic levels are even higher, such as India and Bangladesh, one in 10 people exposed to arsenic levels above 500 ppb will suffer the same fate.
Non-cancer health effects include gangrene, limb loss, keratosis, neurological effects, cardiovascular disease, pulmonary disease, immunological and endocrine disorders, hematological disorders and reproductive/developmental problems.The EPA’s Office of Research and Development also may have discovered a link to DNA damage caused by arsenic compounds. The research shows arsenic inducing a reaction between itself and DNA causing certain genetic alterations in the DNA resulting in breakage.
In addition, arsenic is an accumulative enabler, meaning that people who are pre-disposed to various cancers, diabetes, high blood pressure and other ailments, are more likely to fall ill. Studies also have shown that arsenic may pass through the placenta, causing birth defects, and that exposure to it may negatively affect children’s intelligence levels and ability to learn.
The EPA set the current MCL of arsenic in drinking water at 50 ppb in 1975, based on the Public Health Service standard originally established in 1942.A report by the National Academy of Sciences in March 1999 concluded that the standard of 50 ppb does not achieve the EPA’s goal of protecting public health and should be lowered as soon as possible.
It has been determined that 0 ppb is the only level of arsenic in water that is completely safe for human consumption.However, the cost required to implement a compliance standard of 0 ppb is too high. Prior to the end of President Clinton’s last term in office in January 2001, the EPA issued a new standard of 10 ppb for arsenic in public drinking water supplies.
In March 2001 the EPA announced that it would withdraw the 10 ppb standard until further studies related to costs associated with lowering the standard and impact on public health could be conducted. Although the EPA agrees the current standard of 50 ppb should be lowered, the agency is undecided of where the standard should lie and has requested time to gather data in order to make an appropriate decision.
Currently, the World Health Organization (WHO) and European Union (EU) set the world standard of arsenic in drinking water at 10 ppb, well below the current MCL of the United States.
The EPA estimates that approximately 13 million people in the United States routinely drink water with more than 10 parts per billion of arsenic.The proposed MCL would require that all drinking water and industry wastewater be treated to this limit by the year 2006, which has been estimated to cost consumers somewhere between $5-20/month in areas affected.Small water systems -- those serving less than 1,000 people -- will feel a greater financial impact from the new arsenic rule. The EPA estimates approximately 2,526 of 2,912 or 86 percent of small community water (groundwater) systems serving less than 3,300 people will be impacted at a 10 ppb MCL.
Recent studies indicate that treatment costs can be minimized for the small communities by implementing a point-of-use (POU) approach rather than through a centralized treatment system.A POU system is a filtration device that is attached under a household’s sink to treat the water that comes from that particular faucet. The short turn-around time for installing a POU system is one key advantage of this approach given that the majority of homeowners, parents in particular, are not willing to wait until the 2006 deadline imposed by EPA.
Since 1996, the EPA’s Drinking Water State Revolving Fund (DWSRF) has made $3.6 billion available to assist water systems in financial need with projects to improve their infrastructure. The EPA has funded more than 1000 loans for water systems in the United States.There are also federal funds available through such groups as the Housing and Urban Development’s Community Development Block Grant Program and the UNITED STATES Department of Agriculture.In 2000, the DWSRF and Rural Utilities Service together provided $1.7 billion to states and public water systems for improvements and infrastructure needs.