Reducing Air Pollution via Oxygenated Gasoline - Essay Example

Environmental Health Science - Reducing Air Pollution through the use of Oxygenated Gasoline Use the information on MTBE’s Material Safety Data Sheet (MSDS) to a) describe 1 acute and 1 chronic health effect associated with MTBE exposure in humans or animals, Short term exposure to MTBE may cause nose and throat irritation. Prolonged exposure which might be due to pumping gasoline, driving automobiles, or working in gas stations have reported having headaches, nausea, dizziness, and mental confusion, chemical pneumonitis, CNS depression and suffocation. One study with rats found that exposure to high levels of MTBE for long periods may cause kidney and liver cancer. Adverse reproductive effects have been reported in animals. MTBE has been reported to induce lymphomas, leukemias, and testicular tumors in rats exposed by the oral route. b) To report the oral LD50 dose in mice (be sure to include units). Because there are many versions of the MSDS on the internet, refer to the one posted on Fisher Scientific’s website (https://fscimage.fishersci.com/msds/00978.htm) to answer this question. Oral dose of LD50 for mice= 5960 uL/kg 2. Using pubmed1, locate one published article that describes a toxic endpoint associated with MTBE. In your answer, include: •: Journal Name : Environ Pollut. 2001;111(1):83-8 • Article Title: Toxicity of methyl-tert-butyl ether to freshwater organisms. Werner I, Koger CS, Deanovic LA, Hinton DE. • Brief description of methods (1-3 sentences) used to assess the toxic endpoint. Your description should include a description of 1) who (or what) was studied, 2) what type of study was used (toxicology or epidemiology, and which study design if the latter), 3) how exposure occurred and 4) one toxic endpoint. Use your own words; do not copy from the paper or abstract. Scientists for the State of California, the Aquatic Toxicology Laboratory, UC Davis, reviewed existing literature on toxic effects of MTBE to freshwater organisms, and new information was generated on chronic, developmental toxicity in fish, and potential toxicity of MTBE on the California resident species. Based on the time of exposure and endpoint measured, MTBE was found to be toxic to various aquatic organisms at concentrations of 57-> 1000 mg/l (invertebrates), and 388-2600 mg/l (vertebrates). Developmental effects in medaka (Oryzias latipes) were not observed up to a concentration of 480 mg/l, and all fish hatched and were found to be performing feeding and swimming in a normal manner. Bacterial assays peformed proved to be most sensitive to toxicity to Salmonella typhimurium measured at 7.4 mg/l within 48 h. when observed for 5 days micro algae, showed decreased growth at 2400 and 4800 mg/l. This study concludes that MTBE does not appear to bioaccumulate in fish and is rapidly excreted or metabolized. Although the available data suggests that at environmental MTBE exposure levels found in surface waters (< 0.1 mg/l) it is likely not acutely toxic to aquatic life. However, more information is needed on chronic and sub lethal effects before we can eliminate the possibility of risk to aquatic communities at currently detected concentrations 3. What routes of exposure, in humans, are associated with MTBE? For each route of exposure you identify, provide two examples to describe how this route of exposure might occur. Exposure in human beings might occur through contact with skin, breathing exhaust fumes, consumption of contaminated water. For example: breathing fumes while pumping gasoline or in polluted city air, drinking or swimming in contaminated water and receiving MTBE treatment for gallstones. 4. For one of the exposure routes identified in question 3, think about how you would assess this route of MTBE exposure for all residents in Berkeley, California. In your answer: • Name one sub-population among Berkeley residents that might be especially sensitive to MTBE exposure. Briefly describe why this sub-population may be more sensitive to MTBE than the general population. Young to middle aged men are most susceptible to MTBE exposure especially those who work at gas stations, garages and spend most of their time driving. This is due to the increased exposure by inhalation of fumes and contact through skin. • Name one analytic method for measuring MTBE. Do not use abbreviations to describe the method. The most commonly used analytic method for measuring MTBE is Biological Sampling. The primary method of analysis is Gas Chromatography (GC) with Flame Ionization Detection (FID) or Mass Spectrometry (MS). • Assume that you will also use a questionnaire to gather information to better understand this exposure route. Give examples of two important questions to include on your questionnaire. The two most important questions to be included in the questionnaires would be: 1. The occupation of the individual. 2. The time spent per day in the area of high MTBE concentration. 5. a. What is the difference between an individual’s exposure to MTBE and an individual’s dose of MTBE? Exposure Contact with a substance by swallowing, breathing, or touching the skin or eyes. Exposure may be short-term (acute exposure), of intermediate duration, or long-term (chronic exposure) Dose is defined as: The amount of a substance to which a person is exposed over some time period. Dose is a measurement of exposure. Dose is often expressed as milligram (amount) per kilogram (a measure of body weight) per day (a measure of time) when people eat or drink contaminated water, food, or soil. In general, the greater the dose, the greater the likelihood of an effect. An "exposure dose" is how much of a substance is encountered in the environment. An "absorbed dose" is the amount of a substance that actually got into the body through the eyes, skin, stomach, intestines, or lungs. b. Consider the inhalation route of exposure. If you collected data on an individual’s exposure to MTBE, what additional information would you need to calculate the Individual’s dose? In order to calculate an individual’s dose from an individual’s exposure we would need: 1. The time period of exposure 2. Body weight of the individual 3. Concentration of the toxin c. Where would you find this information? If time period and individuals body weight is known the concentration of MTBE can be calculated by biological or environmental sampling methods. 6. You are the epidemiologist, with a limited budget, in charge of designing a study to evaluate the relationship between MTBE exposure and its potential health endpoints. Of the following study designs (Prospective cohort, Case-control, Retrospective cohort, Cross-sectional, Ecological, Disease clusters, Case series), which one would you select for use in Berkeley, California? In your answer, include: • Name of your preferred study design: prospective cohort. • Brief explanation (one sentence) of why you selected this design: because this type of design is one in which the out come has not yet occurred at the beginning of the investigation. • Brief description of the population you will include in your study: a group from the population which is exposed to MTBE and a population which is not exposed to MTBE (control group) • Provide 1 example for how one of the biases (Selection bias, Information bias (also known as misclassification bias, observation bias, and measurement bias), and Confounding) might influence the results of this study. Remember to include the name of the bias you are describing: Selection bias is one of the bias which can occur because it is difficult to find a population which has never been exposed to MTBE at any point of time. 7. The US EPA’s model for risk assessment described by Dr. Wilson in his PowerPoint lecture makes use of safety guidelines. a. Describe how you would use this method and US EPA’s guideline for MTBE (see Below) to estimate the number of Berkeley, California residents that might suffer adverse health effects due to MTBE exposure. Limit your response to 2 to 5 sentences. US EPA’s guideline for MTBE recommends that levels in drinking water levels not exceed 4 mg/L of water for an exposure of 1-10 days, and 3 mg/L for longer-term exposures. Evidence regarding the level of MTBE is gathered and evaluated. Based on pre established standards and comparing it with our own calculated value, the acceptability value of the harm can be assessed. The established standards considered in this case are the US EPA’s guidelines b. Name two factors that influence the risk assessment process within the context of MTBE; 1 factor should reflect a strength of the risk assessment process and 1 should reflect a weakness of the process. Two major factors which will affect the risk –assessment process are: 1. The baseline (standard) value : this is a strength of the assessment process because MTBE levels are always compared to a standard value and hence we have a constant baseline to compare and contrast different populations and areas. 2. Sampling: this may give rise to a bias because the population and area chosen may have lower levels of MTBE which could give us an under-estimation of the hazard. 8. Clearly, the MTBE story provides an example where a “solution” in one sense becomes a pollutant in another sense. Depending on your interest, respond – in one paragraph or less – to either choice a or choice b. a. Considering Dr. Nelson’s PowerPoint lecture, could engineering controls be implemented to remove MTBE from our water sources? In your response, 1) mention whether or not MTBE is on the EPA’s contaminant candidate list, 2) briefly describe 2 of the 6 general steps to the treatment of drinking water in the US and mention whether or not you think these steps would be appropriate for treatment of a chemical contaminant like MTBE and 3) list 2 types of information you would need to determine whether an engineering control would be effective. Yes, engineering controls like water treatment plants can be used to remove MTBE from our water sources. a)MTBE has been added to EPA’s contaminant candidate list in the last update. b) U.V. Treatment and Waste water Stabilization Pond System are appropriate for treating water for MTBE c) source of the water and purpose for which it is going to be used. b. Considering Dr. Jackson’s PowerPoint lecture, describe 2 changes that could be made to the built environment as an alternative to using MTBE to reduce air pollution. Make sure to include 1-2 sentences describing your strategy to promote implementation of your proposed changes. According to Dr. Jackson, we need to build a community, which is the hub and support for the routine demands of life: learning, shopping, socializing, mourning and rejoicing. This can be achieved by a well planned infrastructure. Communities should be denser and have privacy, safety, beauty, tranquility, and culture. The focus should be on mass-transit which encourages people to walk. this would have a major positive impact in reduction of automobile pollution, global warming and would also serve as a weapon against life threatening diseases like obesity, diabetes and hypertension as walking and physical exercise is a scientifically proven cure for these ailments. This can be implemented by designing cities in a way so that there is adequate open space for playing and safe walkways for pedestrians which would encourage people to use their feet more than their cars. Read More