Poor air quality and potential health concerns promoted the creation of the Clean Air Act. Cities with the worst air pollution started using a new type of gasoline.
The Clean Air Act of 1990 permitted the use of oxygenated gasoline (“Gasoline”, 2006). Oxygenated gasoline contains hydrocarbons with one or more oxygen atoms. Oxygen causes gasoline to burn cleaner. There are different types of additives used in gasoline such as ethanol, methyl tert-butly ether (MTBE) and ethyl tertiary butyl ether (ETBE) (“MTBE, Oxygenates, and Motor Gasoline”, 2006). In 1981 the Environmental Protection Agency allowed MTBE to use in gasoline up to eleven percent per volume and then raised that percentage to fifteen percent in 1988. The oxygenates can reduce air pollution. In cities with the heaviest air smog such as Los Angeles, Chicago and New York, oxygenates seemed to have provided an economically efficient solution to their air quality problems (“Control of MTBE in Gasoline”, 2006). How ever recent evidence has caused many to take a look at some of the additives as potential health concerns.
The cities with the worst air quality are required by the Clean Air Act to have reformulated gasoline. There are seventeen states plus the District of Columbia with mandatory reformulated gasoline (“EPA Commission Facts”, 2006). There are two types of oxygenated programs. The winter oxygenated program is for cities with poor air quality and only during the winter months. This was created in 1992 and the additive used is ethanol. The second program is a year round program for the cities with the worst air quality and the additive used in 87% of the gasoline is MTBE (Methyl tert-Butly Ether) (“Gasoline”, 2006). Thirty percent of the gasoline used is reformulated and approximately 86% uses MTBE (“Gas”, 2006).
Methyl tert-Butly Ether (MTBE) is formed from a reaction between isobutylene and methanol. MBTE is produced in high quantities and mainly used as a gasoline additive (“Gasoline”, 2006). A small portion of MBTE is also used in dissolving gallstones (“Methyl tert Butyl Ether”, 2006). MBTE had been around since 1979 when it replaced lead in gasoline (“Gasoline”, 2006). Although the MBTE does reduce the release of air pollutants such as carbon monoxide into the air, there are some negative characteristics associated with this gas additive. MBTE is highly flammable in liquid form. There is a distinctive taste and odor associated with MBTE. This makes it easy to detect MBTE in drinking water. In its vapor form MBTE can be broken down by sunlight and quickly evaporates from open containers. MBTE can leak into the underground water supply and can stay there for an indefinite amount of time. Fortunately, there is no evidence indicating that MBTE builds up in animals or plants (“Tox FAQs for Methyl tert Butyl Ether (MTBE)”, 2006).
MBTE may or may not build up in animals, but there are some acute and chronic effects of MBTE. Touching, inhaling, or drinking are just some of the ways an individual can come exposed to MBTE (“ToxFAQs for Methyl tert-Butyl Ether (MTBE)”, 2006). An acute illness an individual can get with exposure is respiratory tract irritation through inhalation (“Material Data Safety Sheet”, 2004). Any damage to the inner lining of the tract can cause respiratory irritation. The respiratory tract and lungs have special organs that trap dust and toxins that enter through the nose (Campbell, Reece, Mitchell and Taylor, 2003). A chronic problem associated with MBTE that has not been documented in humans, but have turned up in lab mouse is cancer. In lab mice testicular cancer, liver and kidney cancer has been researched (“ToxFAQs for Methyl tert-Butyl Ether (MTBE)”, 2006). In lab mouse the LD-50 dose was 5960 micro liters per kilogram (“Material Safety Data Sheet”, 2004). Test show increase in ‘Leydig’ cell tumors through oral dosage and increase of lymphomas along with leukemia in female rats (2004). However, there were limitations of these tests. Tumors can occur in mice with the highest dose. Certain tumors have been known to show up these animals and limiting reporting of the combined lymphomas and leukemia (Williams and Sheehan, pg 94, 2002). The length of type determines how the exposure will be placed. A single event is an acute illness, less than seven years it is called sub-chronic and more than seven years is chronic (“Example Exposure Scenarios”, pg 3 2004).
The effects of MTBE have been tested using to species sensitive to certain toxins-Daphinia magna (zooplankton) and Vibrio fisheri (bacteria). The name of the article is Combined toxicity effects of MTBE and pesticides measured with Vibrio fischeri and Daphnia magna bioassays. The journal is Water Research. This was a toxicology study. Mixtures of distilled water and 0.1 mg/L of MTBE at their effective concentration level. The bacteria and zooplankton were introduced into the mixture with different exposure times. One toxic endpoint was studied was the effective concentration that caused a fifty percent reduction in light production. The results were that MTBE is not very toxic to freshwater organsims depending on exposure time (Hernando, Ejerhoon, Fernandez-Alba and Christi, 2002).
As mentioned earlier there are several routes of exposure for MBTE. With the skin there is touching gasoline and/or contaminated water. Inhalation can involve breathing exhaust fumes and air near highways and ingestion of contaminated water during drinking and swimming (“Fox FAQs for Methyl tert Butyl Ether (MTBE)”, 2006). In Berkeley, California there are several sub populations that have a high risk of exposure of MBTE. One group is service station attendants. They have a greater chance than the general population in coming in constant contact with MBTE from exhaust fumes and skin absorption from pumping gas (Williams and Sheehan, pg 97, 2002). The analytical method that could be used to test the concentration levels of MBTE among gas station attendants is obtaining blood samples and using gas chromatography-flame ionization detection. The gas chromatography would subject the samples to a flame causing the MBTE to vaporize. The chromatogram would show the levels of MBTE in each blood samples (Harrison, 2005). It probably is easier to obtain blood samples from healthy individuals. Two important questions to ask the participant would be how long have you been exposed to MBTE and is there a history of respiratory problems such as asthma or bronchitis before or after exposure.
Exposure is the length of time a person in which the substance comes in contact with the skin, respiratory tract and lining of the stomach. Dose is the internal consumption of a substance through skin absorption, mouth and breathing (Bates, 2006). To calculate the individual dose is relatively simple. The absorption rate for inhalation is fifty percent. Other parameters need to calculate the dosage is frequency, time, and intake rate and body weight. The researcher would be able to find out this information by asking the participants about exposure time, body weight and the frequency of exposure. The intake rate would have to be calculated using microgram per kilogram per day. This formula will give you the average daily dose or ADD for the individual (Williams and Sheehan, pg 96, 2002).
One way to study the exposure rate in service station attendants and also an inexpensive one would be a retrospective cohort studies. A retrospective cohort study uses records to track a specific group through a period of time. These studies are good, cheap, and can study multiple causes of death. Since records are used to tract MBTE exposure then information bias would probably blemish the overall study. Exposure types and the length of time could be misinformed on the health records (Bates, 2006).
Every new program involves a risk assessment. A risk assessment is the possibility of harm and the evaluation of the evidence. A risk assessment of the levels of MBTE in drinking water would involve first sampling the water supply in a given area where MBTE is in high usage. The concentration in water must not be above the EPA’s recommended level of 4 mg/L of water between one to ten days and 3mg/L for longer times. The area surrounding the contaminated drinking supply would also be tested for exposure rate. Factors that would influence the risk assessment in MBTE are using the assessment to make the best decision for a given area. In this case this could mean to ban MTBE and come up with another clean air alternative. However, cost and society concerns could influence environmental decisions. If alternatives to MBTE prove to be too costly, those consumers may overlook the health concerns of the additive (Wilson, 2006).
There are low health risk alternatives that may not be costly. Dr. Jackson has stated that we are living in obese and self consumed world. Most people do not take the time to be concern for their health until health problems arise. Easy alternatives to this issue and improve air quality is doing more health conscious activities such as walking. Walking is the simplest and easiest for of exercise. Governments could build parks in or near new developments. Mass transits near developments would also benefit air quality in a given area (Jackson, 2006). Car makers should make more fuel alternative cars and the White House should lobby for fuel alternatives such as naturally cleaning burning fuels.
To promote these changes pressure could be put on local governments through community meetings or petitions asking that land be allocated for a park or a walking area. Any new development wishing to build must include a park or walking area. The development must also be willing to build near public transportation such as bus station or commuter train. Another way to get people to become environmentally friendly is to offer rebates to those who carpool or tax breaks to those who use public transportation.
MTBE may have been a cheap fix to a growing concern. However, to what price must people pay for cheap fuel alternatives? As the country struggle with growing gas prices it seems the nation has be forced to seek other fuel types or a change in lifestyle.
Work Cited
- Campbell, N, Reece, J, Mitchell, L and Martha T. (2003). Biology Concepts and Connection. San Francisco: Pearson Education, Inc.
- Control of MTBE in Gasoline. (2006, March 7). Retrieved April 27, 2006
- Example of Exposure Scenarios. National Center for Environmental Assessment. Retrieved April 28, 2006.
- Gasoline. (2006, March 7). Retrieve April 27, 2006
- Harrison, G. (2005, April). Application of a Hydrogen/Zero Air Gas System in GC-FID Operation at a Crime Laboratory. American Laboratory.
- Hernando, M, Ejerhoon, M., Fernandez-Alba, A, and Y. Christi. (2003, June 12). Combined toxicity effects of MTBE and Pesticides measured with Vibrio fischeri and Daphnia magna bioassays. Water Research. pp. 4091-4098.
- Material Safety Data Sheet.
- Methyl tert-Butly Ether. Retrieved April 28, 2006.
- MTBE (Methyl Tertiary-Butyl Ether. (2006, March 7). Retrieve April 27, 2006.
- Reformulated Gasoline. (1999, November). Retrieved April 27, 2006.