Drinking Water and Water

Arsenic in Drinking Water

In the past few years, the topic of health as it relates to environmental awareness has emerged as a significant concern for global leaders, government officials and the common family. Arsenic, a ubiquitous element found in the atmosphere, soils, rocks, natural waters and organisms, is one of the current leading environmental health issues. Most environmental arsenic problems are the result of mobilization under natural conditions, but man has contributed to the release of arsenic in the environment through mining activity, combustion of fossil fuels, herbicides, and the use of arsenic as an additive to livestock feed. Of the various sources of arsenic in the environment, drinking water is estimated to pose the greatest threat to human health. Since drinking water is derived from a wide variety of sources, levels of arsenic vary depending on the source that the water originated from. Arsenic is odorless, tasteless, and enters drinking water supplies from natural deposits in the earth or from industrial and agricultural practices.

Higher levels of arsenic tend to be found in more ground water sources than in surface water sources, such as lakes and rivers. The demand on ground water from municipal systems and private drinking water wells may cause water levels to drop and release arsenic from rock formations. All of these various releases of arsenic into the drinking water supply raise very important health concerns in humans. Some of these health concerns include thickening and discoloration of the skin, stomach pain, nausea, vomiting, diarrhea, numbness in the hands and feet, partial paralysis, and blindness. Furthermore, arsenic has been linked to cancer of the bladder, lungs, skin, kidney, nasal passages, liver and prostate. This paper will analyze the issue of arsenic in drinking water, will discuss different points-of-view regarding this problem, and will raise concerns regarding any contradicting research. It will also discuss limitations and developments, and conclude with new developments in this area.

Arsenic in Drinking Water as a Topic of Interest

As discussed above, the topic of arsenic in drinking water is a significant topic of interest because of the major health implications involved, and the ease of which it can enter into drinking water supplies. Human exposure to arsenic can cause both short-term and long-term health effects. Short or acute effects can occur within hours or days of exposure; long-term or chronic effects occur over many years. Short-term exposure to very high levels of arsenic can still cause other adverse health problems, but the United States Environmental Protection Agency (EPA), reports that such effects are unlikely to occur from U.S. water supplies that are in compliance with the arsenic standard. The original standard was set by the EPA in 1975, but a 1999 report by the National Academy of Sciences concluded that the standard did not achieve the EPA's goal of protecting public health and should be lowered as soon as possible. That standard was later revised under the Safe Drinking Water Act Amendments of 1996. This final rule set the standard at a level that maximizes health risk reduction benefits at a cost that is justified by the benefits.

The new standard applies in the U.S. To all 54,000 community water systems; systems that serve 15 locations or 25 residents year-round, including most cities and towns, apartments, and mobile home parks with their own water supplies. Estimates by the EPA state that roughly five percent, or 3,000, of community water systems, serving 11 million people, have taken corrective action to lower the current levels of arsenic in their drinking water. The new standard also applies to 20,000 water systems that serve at least 25 of the same people more than six months of the year, such as schools, churches, nursing homes, and factories. In the U.S., the average increase in household cost for water that meets the new arsenic standards depends on the size of the water system and how many people are served by that system. For small community water systems (those serving fewer than 10,000 people), the increase in cost is expected to range between $38 and $327. In the U.S., financial assistance for this is available through the EPA's drinking water state revolving fund, which has funded over 1000 loans for projects around the country. However, the real concern regarding arsenic in drinking water supplies does not lie in the U.S., where as illustrated above, this problem is easily solved.

Different Points-of-View & Conflicting Information

Differences in the point-of-view regarding arsenic in drinking water involve countries of poverty where this issue is not regulated or controlled as it is in the U.S. Arsenic in drinking water in other countries was first noted by the World Health Organization (WHO), after conducting extensive reviews. Following the accumulation of evidence for the chronic toxicological effects of arsenic in drinking water, the recommended and regulatory limits of many governmental authorities were reduced. The WHO guideline value for arsenic in drinking water was provisionally reduced in 1993 from 50 ug 1(-1) to 10ug 1(-1). The U.S. EPA limit was also reduced in 2001 from 50 ug 1(-1) to 10ug 1(-1), after a prolonged debate, as was the Japanese limit. However, differences between countries still exist; for example, Canada's limit is 25 ug 1(-1). Unfortunately, many developing countries are still operating at the 50 ug 1(-1) limit as a result of a lack of adequate testing facilities for lower concentrations.

In this area, conflicting information exists regarding the potential hazards in drinking water. For example, in the U.S., the EPA claims that some geographic areas of the U.S. may have higher levels of arsenic, but the hazards presented have been drastically reduced. However, recent tests by the WHO indicate that both the WHO guideline value and current national standards are very often exceeded in drinking-water sources. The WHO recognizes arsenic as one of the most serious contaminants of drinking water in the world, and in areas of high arsenic concentrations, drinking water provides a potentially major source of arsenic in the diet and so its early detection is of great importance. One of the poorer countries with high levels of arsenic in well-water is Bangladesh, which attracted much attention to the health hazards posed by arsenic as a result of multiple problems in the 1990s.

The aquifers of Bangladesh and West Bengal represent the most serious occurrences of arsenic in drinking water in the world. Concentrations in these ground waters have a very large range from

China has also been identified as a high area of concern, with Taiwan being noted for the identification of black foot disease and internal cancers as a result of arsenic levels in the drinking water. Samples of groundwater taken from south-west Taiwan are reported to have concentrations of arsenic ranging from 400 ug 1(-1) to 700 ug 1(-1). This appears to be even greater dangers than the arsenic levels in Bangladesh and West Bengal, but are not as publicized. Reasons for this conflicting information could be that China and Taiwan are better equipped financially to handle cleaning up the public drinking water supply than Bangladesh and West Bengal. A large study carried out by the Taiwan Provincial Institute of Environmental Sanitation established that 119 townships had concentrations of over 50 ug 1(-1) and 58 townships levels over 350 ug 1(-1). While this is a problem, it does not appear to compare to the 36 million people estimated to be infected in Bangladesh. Thus, that may be a reason why this factor is not as widely publicized.

Finally, the worst recorded care of arsenic poisoning in the world related to mining activity occurred in one of the northern provinces of Thailand. These health problems were first noticed in 1987, where arsenic concentrations have been found at up to 5000 ug 1(-1) in shallow ground waters. This is a direct result of sediment that had been extensively dredged during tin mining operations, and the more recent occurrences in ground water have occurred during post-mining ground water rebound. Water-flow problems such as this one described in Thailand attribute to much of arsenic flow in drinking water throughout the world. For example, flat, low-lying areas such as large plains and delta regions are more prone to high arsenic ground waters. The process of delta development also leads to high deposit levels, because the higher the delta, the less flushing is likely to have occurred.

Research Limitations and Assumptions

The limitations of studies involving arsenic levels in drinking water supplies is that the health risks associated with such levels were not identified until much later. As a result, there is little data ranging from the time period where the levels were first likely to have started to effect people. In other words, detailed studies and notes must be taken to provide a sounder basis for understanding the causes of the problem as it applies in a time frame. Other limitations include the fact that local geology and hydrogeology have not been measured to include water level monitoring, studies or mineralogy, chemical composition and adsorption behavior of aquifer materials. Either purpose built piezometers or suitable production wells should be monitored for changes in arsenic and other water quality parameters; however, such studies are expensive and are not warranted unless the scale of the problem is large. Thus, an important limitation is that unless million of people are affected, as in the case in Bangladesh, this type of monitoring may not occur.

Additional limitations include the fact that since high arsenic ground waters are found in aquifers in which the sediments have been deposited in the last ten thousand years, these deposits will be flushed away. As long as these sediments are flushed away in the normal ground water flow, it may be unknown what levels existed there or were deposited there to begin with. Thus, an important limitation is the timescale of the arsenic being deposited which is difficult if not impossible to detect, even with the proper equipment. Also, wells that are currently arsenic free does not give a guarantee that they will remain that way in the future. Other limitations include the fact that in poorer countries in which arsenic in the drinking water supply does exist, the country cannot afford to pay for this type of testing or lacks testing facilities. Significant changes in arsenic transport transportation in groundwater may occur locally due to the influence of mining, groundwater pumping and irrigation. Other limitations include the possibility that heavy pumping of deep aquifers could draw contaminated groundwater down to the aquifer, or that poor well construction may lead to the rapid movement of contaminated water. As a result, new developments must be implemented to deal with this problem before it takes years to become apparent.

New Developments

New developments must dealt with the challenging issue of identifying and mitigating existing contaminated wells. Those most badly contaminated must be addressed first, and then other water sources that have not ever been evaluated must be evaluated and tested. New developments could consist of a new method of flushing out arsenic contaminated sources, at a cost that is low enough fro poorer countries to afford. Rural communities in developing countries pose the biggest threat, which is poorly understood by these poverty stricken communities. As indicated by a review of the literature, many of the worst problems occur in poor countries that do not have the necessary infrastructure and financial means to be able to properly respond. The U.S. has many companies that manufacture household and industrial level water filters that can test the levels of arsenic and filter arsenic from drinking water supplies. Unfortunately, not all countries can afford these products, as there are other life threatening issues that they must deal with first, such as starvation.

Personal Thoughts

In the area involving contaminated water supplies, I believe that some of the information available appears to be conflicting with the available and timely solutions. Most of these conflicts rest between the U.S. And other parts of the world. For example, arsenic was noted as a significant problem contributing to health hazards in Bangladesh and West Bengal in the 1980s and early 1990s, but it does not appear that this problem is even on its way to being solved. It is now roughly about 15 to 17 years later, and the water supplies in these poorer countries are still contaminated. If the U.S. EPA offers financial assistance to local governments to assist them comply with regulations, it is assumable that the WHO could do the same, especially for poor countries where it is obvious that compliance is an issue. Also, there does not seem to be any penalties for not complying with the WHO regulations and standards, because many countries are not in compliance. The WHO should recognize that a viable health risk exists, and that this risk could potentially be transferred in the future to other nearby countries in accordance with the natural flow of water sources.

I believe that the topic could be expanded to include other potential health hazards that are just as harmful as arsenic that exist in drinking water supplies. Large companies such as water distributors and manufacturers of water filtering and treatment equipment, such as Culligan International Company, could lead the way and assist funding new studies or contributing testing equipment to nations. Additionally, since it took so long to recognize arsenic as a health problem, maybe there are other substances in water that are just as harmful. Many households in the U.S. have the ability to purchase water treatment and filtering equipment for their own homes, to get rid of "hard" water. Large corporations in the U.S. regularly conduct tests to prove why "soft" water is better for laundry and cleaning than hard water. The problem of arsenic in the drinking water supply in the U.S. is so minimal that large water companies are focusing on other means to sell water filtering devices to consumers. Instead of this focus, international companies should shift their focus on water to the harms caused by arsenic and methods of protecting the available water supply. These large corporations should not only be willing to assist those in the U.S. with equipment, but mainly poorer countries that cannot afford this type of equipment.