Middle Student, Instructor's Comments in Green

NAME

ESM 693 Final Exam

I suggest you download this file and splice your answers after the appropriate sub-paragraphs. When you finish, send it to me via the dropbox. If anything is unclear on the exam, please email me. Also, if any glitches in the exam turn up that might affect an answer, I will post the correction in the Announcements, so you should check Blackboard from time to time before you hand the exam in. The exam must be in by May 10th, but there is no problem with sending it in early.

It is an "open book" exam, so you can use any non-human resource, including any electronic resources that are not specific to this examination.

The exam has several picture files, gif files, in it. These should open in Word as you get there. If there is a problem, let me know. Several of the gif files show results from two runs of RISC. That should be all you need for the questions. If you wanted to see the RISC output, the files are also in this exam sub-folder, and you are welcome to look at them, but you should not need them to complete the exam.

The exam will be graded out of 250 points, then scaled to 100 points, per the syllabus.

1. You are the newly hired "hazardous materials specialist" for the Alaska Department of Transportation. You get a call from the State Troopers. A railroad tank car of MethyEthylGoopanol, (MEG) a chemical you have never heard of, derailed and spilled its 40,000 gallons into a drainage ditch whence it flowed toward the Parks Highway. Fortunately the culvert under the highway was blocked. Unfortunately this formed a pool near the highway. The troopers have blocked traffic and are keeping well back from the pool. They want to know if the material in the pool is "safe" to drive past. Traffic is backing up. You tell them you will get back to them in "about half an hour." Answer the questions below in 5 or 6 paragraphs, read all sub-questions before answering any. Also, I have put a few hints in square brackets. These words might help you answer the question.

1.A. (10) A co-worker who overheard all this says, "Chemicals released into the environment never hurt people." Do chemicals released into the environment harm humans?

Chemicals released into the environment can harm people, depending on a large number of things, including the type of chemical, amount of chemical, characteristics of the chemical, and most importantly, the mechanism of exposure of humans to the chemical.

OK, .8 I was looking for a few examples of harm: Bhopal, Minamata Karen Wetterhahn

1.B. (15) You have the standard DOT emergency response booklets and data, including a CD, but they do not mention MEG. (The only visible placard on the tank car just said the name of the chemical, no other help. You called the emergency response number, but there was no answer.) How might you proceed to learn something about MEG? What kinds of things do you need to know, at this time?

The most immediate concern of the State Troopers is the safe passage of traffic past the site. The second concern, although it should be first, is usually the safety of the troopers themselves. Inhalation hazards and explosive hazards are the most immediate concerns. The vapor pressure, flashpoint, boiling point and melting point of MEG are the physical characteristics that are most desirable to find out. Other physical characteristics of interest include: density, specific gravity, and solubility. This information may be available in a chemistry textbook (surprisingly, this is not a good place to look, for most hazards.) if one is around, or it is probably possible to find the physical properties by searching the Internet. If a blanket Internet search for the chemical turns up nothing, then there are a few specific databases that could be searched on the Internet. 9

1.C. (20) From Step 1.B, you now find lots of information on MEG. Prepare a "back of the envelope" risk assessment for your boss. Discuss in a general way the different types of hazard, receptors, fate and transport issues. [accident, illness, ecological]

The accident provided a release mechanism to the environment, mostly to the soil, although the pool is providing a release directly to the air. The chemical in the air is a hazard to people/things (receptors) downwind of the site. This hazard is an acute hazard, but will be mostly removed when the puddle is mopped up. The material will remain an acute hazard for people on the site through ingestion, contact, and inhalation. Potential receptors include motorists, residents, workers, and land animals.

The contaminated soil will remain and the contaminate may migrate from this “secondary” source to the air or the groundwater depending on the various partition coefficients. The MEG concentrations from this secondary source soil will probably be less than that associated with the initial aftermath of the spill. This may cause acute and chronic effects in human and ecologic receptors including allergy, illness, reproductive, developmental, and neurological problems, and possibly death. The groundwater in the area may reach the nearby river prior to natural degradation of MEG, so potential receptors include residents with wells, anglers and other recreational users of the river, and aquatic and terrestrial animals. Most notably, MEG is very toxic to the albino whitefish, so it is expected that this species will act as a sentinel. Yes, but such knowledge is rare. 18

1.D. (15) Your boss asks, "Does this stuff cause cancer?" You found out that the EPA considers MEG a "Group 2B" chemical. So you answer her in one sentence. Then your boss asks, "What the hell does that mean?" Explain in more than one sentence. [MTD]

Well, clearly, this is a probable human carcinogen. For this chemical, there is “sufficient evidence from animal studies to support causal association between exposure and cancer.” This boils down to evidence in animal studies that identifies a link between MEG and cancer in the particular animal that was studied. The animal was sufficiently human-like to suggest the likelihood of cancer in human, however, the animal that was studied was not human and human studies (historical or new) have not been done. This does not say anything about the exposure method or dose given to the animal. 9

1.E (10) In quick risk assessment (1.C above) you determined that the levels of MEG to which the nearby residents might be exposed was less than 10% of the concentration that OSHA says are legal for workers. Is this a good criterion for assuring the residents that MEG will not be a problem for them?

This is not a good criterion because the OSHA guidelines are subject to the political process and are based on an 8hr/day and 40hr/week exposure. Residents are exposed to the MEG for significantly more than 40hrs/week, especially the young and the old, which OSHA was also not intended to cover. In addition, the OSHA guidelines are subject to political review, often by the companies that produce/use the chemicals and have a vested interested in the continued use of the chemical. 9

Question 2

2. (50) The material in the barrels was dumped off the truck of a "midnight dumper." most of the barrels were open and the material spilled to the ground. The barrels contained four substances: Aroclor 1242, a hydrocarbon mix that is mostly benzene, acrylonitrile, and tetrachloroethylene. Describe in one paragraph for each of those four substances: the likely exposure pathways to the farmer and the likely fate of the substance. [You could use Level I and/or RISC for some information, but I am not looking for quantitative answers from those programs. Some of the substances you will have to search for, they are not in the RISC or Level I database. A neat way to organize your answer is to start with a five column table that has those 4 substances as the column labels, and the important parameters as row labels, then put numbers or descriptions. Then your descriptions may be shorter.]

Parameter	Aroclor 1242 (PCB)	Benzene	Acrylonitrile	Tetrachloroethylene (PCE)
Vapor Pressure	8e-5	9.5e+1	1.08e+2	1.9e+1
Solubility	4.2e-1	1.75e+3	73000	2.0e+2
Henry’s Law	1.1e-2	2.28e-1	.21	7.54e-1
Log Kow	5.7	2.1	0.92	2.7
Veg Uptake	Kow	Kow		Kow

Aroclor 1242 is a tradename for a mixture of polychlorinated biphenols (PCBs), of which there are over 200 different chemical formulas. In general, PCBs have a low vapor pressure and do not volatize into the air. They also are not very water soluble and do not migrate through soil into the groundwater. These compounds are persistent in the environment and can accumulate in animals and possibly plants. The PCBs are not likely to leave the soil under the barrel, but if they are left long enough, the farmer will probably be exposed to small amounts through all exposure pathways, including meat and dairy products. PCBs persist in the environment for many years and natural degradation is slow, if at all. 9 dermal at site and dust.

Benzene can evaporate into the air from the drums and the benzene soaked soil and last several days in the air, putting the farmer at risk from inhalation of benzene. Benzene is also likely to pass through the soil and into the groundwater, resulting in ingestion exposure through the groundwater. Benzene is not likely to accumulate in plants or animals, so crop and meat/milk ingestion is not a serious exposure. Once in the soil and groundwater, benzene is likely to persist at some levels for many years, although there will be a reduction over time. 9

Acrylonitrile readily evaporates into the air and will dissolve in water, if it reaches water. It also breaks down fairly readily in air (hours) and water (weeks). The primary concern with acrylonitrile is inhalation exposure coming from the drums and possibly the soil, although if a large amount was dumped there may be sufficient concentration to reach the groundwater and possibly the well. Acrylonitrile is not expected to buildup in crops or livestock. This compound will breakdown relatively quickly in the environment and will not be a long-term threat to the farmer. 9.

Tetrachloroethylene (PCE) exposure is likely to come from inhalation, as it evaporates fairly readily from the drum and the surface soil. The compound is also likely to reach and dissolve in the groundwater, creating and exposure through groundwater usage. The chemical is denser than water and may sink through the aquifer, contaminating it at all levels. PCE has the potential to accumulate in meat/dairy products, but it is unclear if it accumulates in plants. Once in the environment, particularly groundwater, this compound does not readily degrade and is difficult to remove. 8

3. (50) For each of the four substances from Question 2, consult IRIS and an MSDS sheet and then describe the acute toxicity for cleanup workers and the chronic toxicity for the farmer. These responses should parallel your answers from 2. above, but in all cases assume for this question that there is enough exposure to warrant an analysis of the toxicity data. Try to explain what the data is based upon [epidemiology, laboratory] [You'll be using some numbers here, but be sure to explain, what the numbers mean. You may need to spend some more time explaining the first time the word comes up, less the second time it comes up.]

Acrylonitrile CAS # 107-13-1

The acute toxicity data for acrylonitrile indicate that workers should use protective equipment, particularly for inhalation. The short-term effects of exposure to the chemical include respritory tract irritation and eye and skin irritation. Death has been observed in children, but child labor is not expected in this case. Children are a issue at uncontrolled hazardous waste sites. Inhalation and ingestion have been tested most thouroughly. Long-term exposure to the farmer will results in the same types of effects.

There is a fair amount of uncertainty regarding the non-carcinogenic hazard relating to acrylonitrile. This may be due to the fact that the chemical has been tested for carcinogenity and many of the experiments have been stopped early due to high cancer and mortality rates. In addition, the hazard evaluation experiments have been done a limited number of times and only on rats, not any other species, including humans. More carcinogenic studies have been done on animals, and limited data has been collected on human exposure. The human data is not really conclusive due to confounding factors such as smoking, but it is somewhat useful. Animal studies are also useful and the results are fairly clear that long term exposure increases the risk of cancer.

Arochlor 1242

The acute dangers to the short-term worker include irritation of most parts of the body, including eyes, skin, and the gastrointestinal tract. Exposure routes include inhalation, ingestion, and direct contact. There appears to be some cancer risk associated with handling this product, even for limited durations, ie during cleanup. I'm not aware of any evidence to support that.

There is a cancer risk with long-term exposure to PCBs, of which Arorclor is a mixture, through most exposure routes. Although the data does not exist for every environmental mixture, there are a number of human and animal studies indicating a significant degree of risk. B2

Benzene CAS# 71-43-2

Benzene is a known human carcinogen. This data is based on several human (cohort) studies and a large number of animal studies with a variety of species. During short-term exposure, including inhalation and contact, exposure, benzene depresses the central nervous system and can cause headaches, dizziness, drowsiness, nausea and possible unconsciousness. Benzene can be fatal if aspirated into the lungs. Leukemia and other blood disorders are the primary effects of long-term exposure through inhalation, ingestion, and contact with benzene. As mentioned above, the farmer’s increased risk of cancer from exposure to benzene is well documented.

Tetrachloroethylene (PCE) CAS# 127-18-4

Short-term exposure to PCE appears to result in similar effects as benzene, including headaches, dizziness, nausea, and possible unconsciousness. In addition, contact may cause blisters and other irritation. Inhalation, ingestions, and contact are all exposure methods that should be avoided. The short term exposure is

The long-term effects of PCE exposure are not as clear. Central nervous system, liver, and kidney damage is expected. The chemical may also be a human carcinogen. The IRIS database cites only a few studies and rates the confidence of the conclusions as low to medium. This is due to the fact that only rat and mouse studies were cited and none were sufficient to address all the confounding concerns simultaneously. However, there is sufficient data from other sources to suggest that PCE may be a carcinogen depending on the amount and duration of exposure.

Need to run the spell checker.

4. New situation. You are an environmental scientist/engineer working for the North End Refinery. About 20 years ago the refinery has a massive leak in its main carbon tetrachloride (CCl4) tank, and several million gallons of this chemical were released to the groundwater. The refinery put in wells and removed most of the chemical. Groundwater movement is slow and the CCl4 mixed into the groundwater. And it now appears that the residents of the subdivision nearby, where many of the residents are refinery workers, will be exposed to 0.04 mg/L of CCl4 in their water supply wells for a long time (Assume that is the same as 0.04 ppm). The expert consultants the refinery hired have determined the following risk.

You can get the RISC prj file from Blackboard, Course Information, Final Exam folder, but you should not need it.

Your boss has asked you to help on this issue and advise the "external affairs" person the refinery uses to talk to the public. Your consultants have advised that each home in the subdivision should have a charcoal filter put into the water supply lines from their wells. The filers have been advertised to reduce CCl4 from 0.04 mg/L to 0.004 mg/L. Here is the associated risk based on 0.004 mg/L:

The filters cost $750, which the refinery will pay for, plus a $1250 one-time fee to compensate the residence for maintenance of the filters. That is, each home will get a check for $2000. Your consultant tells you that the filters need to be changed every three months and cost $25. Also the consultant admits he has never used the filters, and had based his opinion on the manufacture's literature. He also tells you that filters sometimes need changing more often if there is iron in the water (and you know there is a lot of iron in the water at this location) and that the filters have never been tested in cold water.

[Look at this EPA site about CCl4

http://www.epa.gov/OGWDW/dwh/t-voc/carbonte.html]

You see two problems: First, refinery workers who live in the subdivision will not notice the CCl4, because they smell it at much higher concentrations all day. You are concerned they will use the money to change the sparkplugs in their airboats and not bother installing the filters. Second, the non-refinery workers, who have hired a lawyer and their own consultant, a former high-school science teacher, want the refinery to remove "all" the CCl4, or pipe them water from the town, 20 miles away. Both of which the refinery, state, and federal environmental agencies believe are infeasible. The $2000 offer has been in the paper, so everyone knows a little about it. The lawyer has asked you to address an informal meeting of the residents.

4.A. (30) Write a brief (two or three paragraph) memo to the refinery workers who live in the subdivision. Describe the risks and hazards if they do not install the filters. You may use some numbers for reference and in order to be technically correct, but assume the workers do not understand the numbers and you must communicate with them via your text description.

Dear Fellow Employee:

As you are aware, carbon tetrachloride was released from the refinery and reached the groundwater. The groundwater contamination has now migrated from the refinery property and has reached the subdivision, in which many of you live. This contaminated groundwater poses a risk to residents that use the groundwater for drinking, washing, and showering. The refinery is supplying filters and additional money for filter maintenance that will reduce the risk associated with using the groundwater.

A general carcinogenic risk and a general health hazard risk are associated with this contamination. There is an increased cancer risk compared to the regular population of 1 in 100,000 due to the contamination, meaning that there will [too strong a word, this is a mathematical projection, the actual risk may be zero.] be a case of cancer in one additional person out of one hundred thousand people due to the groundwater. When properly installed and maintained, the filter can reduce this risk to 1 in 1,000,000 (one additional case in one million people), which is a standard considered acceptable to regulatory agencies. The other risk is a health hazard risk, which is the additional risk due to using the contaminated groundwater. This has been calculated and is slightly above one, the generally acceptable risk level. Installation and proper usage of the filter will reduce this risk to an acceptable level that is well below one.

These numbers do not sound like very many people, and it is hard to imagine that the one person might be you. One additional case in one hundred thousand may not seem significant in a subdivision of this size. In fact, it would probably not be noticed. However, stated differently, proper usage of the filter system reduces your statistical risk of cancer and other health effects from the contaminated water by a factor of ten. This is true for each and every resident of the subdivision, including you.

4.B (30) Prepare a set of notes that you will give to the external affairs person that you expect he will have written up for a press release and will use for notes at the public meeting. You will go to the meeting also. He already has a draft of the memo to the workers. Describe the chemical and it toxicity. Prepare some information about the risk that remains after the water is filtered. Explain why you think the residents will be "safe." Explain the residual is below the MCL. What will you say, if asked, about the MCLG. (See bottom of http://www.epa.gov/safewater/mcl.html#1 for explanation). As you did for the workers, you must use some numbers, but the explanation must be clear to people who are not facile with numbers.

Carbon tetrachloride has been and continues to be used for a number of familiar tasks, including refrigerant and propellant production, dry cleaning, and insecticide. Use of the chemical has declined in recent years and appears to be continuing downward. Carbon tetrachloride has been shown to produce liver, kidney, and lung damage in relatively short term exposures, while long term (lifetime) exposures result in liver damage and cancer.

The EPA has offered two guidance levels for drinking water standards for all chemicals, including carbon tetrachloride. The Maximum Contaminant Level (MCL) is an enforceable standard that has been set at 5 parts per billion (ppb). Exposures to carbon tetrachloride levels above 5 ppb have been observed to produce the health effects mentioned above and the EPA feels that 5 ppb is the best cleanup level at this time. In addition to the MCL system, the EPA also has Maximum Contaminant Level Goals (MCLG) for many chemicals. This is the value that the EPA feels presents no potential health threats, and has been set at zero for carbon tetrachloride. The MCLG is an ideal goal, but is not enforceable and is not considered currently technologically feasible or practical. EPA feels that it is currently technologically feasible to treat water until it is below the MCL.

In addition to contaminant levels, the EPA offers guidance on acceptable levels of risk associated with contamination. Acceptable risk levels apply to all chemicals. The EPA considers one additional cancer patient ["incidence"] in one million people (1 per 1,000,000) due to the presence of a contaminant to be an acceptable risk. A higher increase in contaminant related cancer is non acceptable. The health risk is also a calculated number that is compared to one. A health risk greater than one is not acceptable to the EPA, while a health risk below one is considered acceptable to the EPA. While there are risks associated with contaminant levels below the values that EPA considers acceptable, these levels are considered safe for people.

The carbon tetrachloride level in the groundwater in the subdivision is currently 40 ppb, exceeding the MCLG and the MCL. This presents an increased risk of cancer and other health related effects that are not acceptable to the EPA. Carbon filtering is an effective and acceptable treatment technology to reduce carbon tetrachloride levels to below the MCL prior to usage of the water at a residence or business. Estimated residual levels of carbon tetrachloride will still be present in the water at 4 ppb, between the MCL and the MCLG. This residual level presents an increased cancer risk of one in one million and an increased health risk of about 0.13. These values are an acceptable level of risk according to the EPA and the treated water is considered safe for all types of usage. Treatment to the MCLG (zero ppb) is not considered necessary or feasible at this time.

The refinery has agreed to purchase the filter system and provide additional money for operation and maintenance of the filters. Based on the manufacturer’s recommendations, this money should provide proper filtration of the water to an average household for 10 to 12 years. However, these filters may need replacing more frequently in iron rich waters, such as this neighborhood. In addition, the filters have not been tested with cold water. Each household should inspect the filter system regularly to verify that the filter is operating correctly and is not completely fouled with iron or other substances. In addition, filter installation is recommended after the pressure tank to allow the water to warm prior to filtration, if possible.

4.C (20) Consider the Sandman site on outrage. Write out 3 or 4 reasons the non-refinery subdivision residents might be outraged.

Non-refinery subdivision residents have many reasons that they might be outraged. The refinery has polluted their groundwater, without providing anything in return, such as a good job. While they may have moved in near a refinery and may have been aware of the potential for contamination, they may not have been aware that a large spill had already taken place and contaminated water that was moving towards their wells. They may feel tricked to learn that property they paid money for has now lost most of its value and is unlikely to sell.

The contamination of the property is certainly not natural, nor is there anything that the residents can do about it. This combination of circumstances makes them feel helpless and trapped in a situation that they did not create and they cannot escape from. In addition, the chemical involved has been linked to cancer at concentrations below the levels in the groundwater. The only apparent remedy offered is being stuffed down their throat by someone else, the responsible party that they do not work for, have no control over, do not trust, and may not even like.

4.D (30) Your memo to external affairs included information about the iron in the water and the lack of cold water experience with the filters. At the public meeting the external affairs did not bring this up, neither did you or the subdivision people. You were happy that you did have to deal with this. Now it is 2 o'clock Sunday morning, you are lying wide-awake, and berating yourself and the refinery for not mentioning the iron in the water and the lack of cold water testing. Here are two sets of principles:

Fundamental Canons from the National Society of Professional Engineers (NSPE)

http://www.nspe.org/ethics/eh1-code.asp

or

Canons of Ethical Conduct from the American Board of Industrial Hygiene (ABIH).

http://www.abih.org/Docs/Code-of-Ethics.htm

Both have similar information, six basic principles in the front and more detailed explanation further back. Select one or the other (they are similar, so tell me which you are using). Pick two or three of the fundamental principles (canons) and write two or three paragraphs (total) about applying them to your situation. Several of the principles might conflict; you should describe at least one of these conflicts.

Engineers, in the fulfillment of their professional duties, shall:

1. Hold paramount the safety, health and welfare of the public.

2. Perform services only in areas of their competence.

3. Issue public statements only in an objective and truthful manner.

4. Act for each employer or client as faithful agents or trustees.

5. Avoid deceptive acts.

6. Conduct themselves honorably, responsibly, ethically, and lawfully so as to enhance the honor, reputation, and usefulness of the profession.

In this case, the safety, health, and welfare of the public are the concern of all parties involved. The refinery, the consultants, the state agencies, and the public all want the public to be safe for various reasons, but mostly so the public will not sue them. If they are ethical, that is also a reason of itself. However, people with technical training often have a different view of the health and welfare of the public than the public does because there are numbers and equations that apply to the public in general, but not to any individual in particular. The public, on the other hand, is made up of individuals that do not want to be the lonely 1, however many thousand or millions that the 1 might be in. Engineers also have a better grasp of the effort required to perform the work, which has a dollar value associated with it. They may feel that putting this dollar value on the public is not a big deal, but it may have the appearance of putting a dollar value on the safety, health, and welfare of an individual that is in the meeting. This may lead to outrage.

Truthful and objective public statements are very difficult to create while staying in your area of competence and trying not to be deceptive. [Yes, and this is one reason we prepare for our public utterances.] The iron and temperature issues of the filters are not really in your area of competence, as you have not tested them and are relying on the manufacture’s specifications. By mentioning these issues, you raise questions that you do not know the answer to, and are therefore outside your competence. In addition, since you do not know the answer, and the filters may work fine, you could be betraying the faith of your client. . The only thing I could say truthfully, objectively, and not deceptively, is that according to the manufacturer’s instructions this is how the filters should work and that additional replacement may be necessary if high amount of iron are encountered. Those are the things that I know, and if people ask about temperature, then I would have to say that I did not know.

“I don’t know” is not an answer that people like to hear in public meetings. After all, you are the expert, and you should know. In addition, not raising all your issues, whether having immediate answers or not, may be viewed as deceptive by some. This is particularly the case where the health of the public is in serious question, not so much because the public is in danger, but because many vocal individuals are in danger.

In addition to the ethical debates, the simple solution to the filter question is to test the filters. The refinery has obviously spent a great deal of money working on this problem. To cavalierly approach the final stage of the problem (although the final stage may take many years) and not throw some more money at it is silly. Although all the other solutions may not be feasible, the proposed solution may not be a solution at all. In this case, no one has done anything good, and the honor, reputation, and perceived usefulness of the profession will certainly be damaged. Yes, or to offer continue testing to revisit the settlement if the filers don't hold up. But here we are only considering the ethics of not bringing up something that you know MAY be a problem.