September 23, 1998
ENVIRONMENTAL LAW AND SCIENCE
CURRICULUM:
Evaluating Risk to Human Health and the Environment
A Project of
The University of Maryland School of Law
working in conjunction with
Dr. Linda Greer
CLASS EXERCISES FOR LECTURES 1-8
CLASS EXERCISE: LECTURE 1
SCENARIO
Welcome to Chemtown, a Midwestern city in America’s heartland. Chemtown is the capital of the state of Wichison, with a population of 250,000 and an enviable location on the shores of the lovely but neglected Lake Woebehere. Like other Rust Belt towns, Chemtown's economic base of heavy industrial manufacturing is eroding, and city officials are searching frantically for profitable alternatives.
Last year, the Wichison legislature passed a new "brownfields” law designed to encourage redevelopment of contaminated property in urban areas. Chemtown's mayor has identified the old industrial district of South Barge Street as Chemtown's top priority for this new program. The South Barge Street District covers a 50-square block area that overlooks the southeastern bank of Lake Woebehere. Some 800 people live in the South Barge Street District, 300 in a mobile home park and the rest in small apartment buildings that typically accommodate multiple families.
The mayor has his eye on a ten-block strip of vacant lots, closed warehouses, and abandoned factories right at the water’s edge. This property, known as the South Barge Site, is owned by DuDow, a Fortune 100 petrochemical company, and PruMutual, the largest insurance company in the Midwest. In addition to owning the property of interest to the mayor, DuDow runs a modern manufacturing plant on the north shore of Lake Woebehere, some distance from the South Barge Site.
The centerpiece of the mayor's redevelopment plan is to construct a shopping and entertainment center on the ten-block South Barge Site, taking whatever remedial action is necessary to receive clearance from the Wichison EPA. The new center would include a marina for lake craft such as motor boats, small sailboats, and canoes, two movie theaters, ten restaurants, 25 retail stores, a public swimming pool, a day care center, and parking for 2,000 cars. A map of the site (titled Map #1) is attached to this exercise.
Several developers have expressed interest in the project. The mayor has formed a South Barge Steering Committee composed of representatives of the current owners, the three largest development companies, and the Chemtown Planning Department. The Steering Committee has been meeting for six months to develop a remedial action plan for the site.
Last month, the mayor and the South Barge Steering Committee submitted their proposed remedial action plan to the Wichison EPA. The EPA has called a town meeting to get public comment on the plan and discuss next steps for the project. At the meeting, the mayor hands out a two-page fact sheet summarizing the plan that explains that the primary remedial technique to be employed is to build a large parking lot over five "hot spots" of lead contamination found during the South Barge Steering Committee's investigation of the site. The fact sheet explains that each hot spot has levels as high as 10,000 ppm of lead, but that these locations are confined to a two-acre area on the western periphery of the site.
Local representatives of the Sierra Club, angry that the site investigation was done "in secret" by the Steering Committee and that the remedial action plan is being presented as a fete accompli, demand time to make a statement. The Sierra Club announces that it has compiled a report regarding toxic releases in the area from a 1987 TRI report. This data was aggregated by the zip code in which the brownfields site is located. It reveals the following releases over a twelve-month period, reported in pounds:
Lead 5,000 lbs.
Arsenic 5,000 lbs.
Trichloroethylene (TCE)15,000 lbs.
Pentachlorophenol (PCP) 5,000 lbs.
Benzene45,000 lbs.
Total Emissions75,000 lbs.
QUESTIONS:
You are a toxicologist who is attempting to facilitate this meeting for the Wichison EPA. In preparation for the meeting you decide to:
1.categorize the five chemicals included in the Sierra Club report;
2.compile a list of questions that the group needs to answer in order to evaluate (a) the remedial action plan and (b) the data presented by the Sierra Club.
INSERT MAP # 1
1
ANSWERS TO EXERCISE FOR LECTURE 1:
Categorizing the Chemicals
Lead:metal
Arsenic:metal
TCEorganic , aliphatic, solvent
PCPhalogenated organic (aromatic)
Benzeneorganic
Questions regarding the Remedial Action Plan
1.Is the lead contamination reported by the Steering Committee naturally occurring or is it the result of human activities? What is the range in concentrations of naturally occurring lead (i.e., background concentrations)?
2.Does lead contamination at a level of 10,000 ppm constitute a level of contamination that should be “of concern” ?
3.What is the form of this lead? Is it a form that is particularly toxic or mobile? Is it an organic lead compound such as tetraethyl lead?
4.Why is lead contamination the only problem reported? Were samples analyzed for other chemicals?
5.Did the Steering Committee compile information about industries that once were located at the South Barge Site? If not, why not?
6.If the Steering Committee did compile information about industries that once used the South Barge Site, what did this investigation discover? What kinds of chemicals were typically used and generated as wastes by those industries? Are these chemicals so common that it will be difficult to determine their precise sources?
7.Where was testing done at the site? Are the results representative of the whole site? What other environmental media should have been included?
Questions regarding the Sierra Club Data
1.Is more recent TRI data available?
2.What area does the zip code cover?
3.Are the amounts of the five chemicals listed unusually high for this size of area?
4.What is the disaggregated release data?
5.What do TRI reports show about the industries that are located in the area? About the chemicals they use? Are all the chemicals they use required to be reported under TRI?
6.Can any facilities be ruled out as contributors to contamination at the South Barge Site because they are too far away?
CLASS EXERCISE: LECTURE 2
SCENARIO
Welcome back to Chemtown. When we last left our scenario, a town meeting called by the Wichison EPA to discuss the South Barge Steering Committee's remedial action plan had ended in disarray because the Sierra Club had reported that major emissions of five chemicals -- lead, arsenic, trichloroethylene (TCE), pentachlorophenol (PCP), and benzene -- were present in the area. As the state toxicologist assigned to help the group, you developed a series of questions about the information needed to evaluate the plan and the Sierra Club data. The answers to several of those questions are now in, and you know the following additional information:
1.The South Barge Site was used for 40 years -- until 1975 -- by two large wood preserving companies that treated all kinds of wood, producing everything from picnic tables to utility poles to railroad ties. DuDow Chemical owns one of these sites and PruMutual Insurance owns the other.
2.The most prevalent chemicals used by wood preserving plants include benzene, TCE, and PCP. Such operations do not use lead.
3.During the course of your research, you found the table attached to this exercise as Exhibit 1 and entitled Chemical Properties in a well-known textbook on wood preserving techniques.
As the toxicologist from the Wichison EPA assigned to help facilitate this exciting new brownfields project, you have explained to the various participants that the industry study is far too limited to support any conclusion about what remedy should be implemented at the South Barge Site. You have also explained that because the Sierra Club TRI data is aggregated, it does not explain much about environmental conditions at the South Barge Site. You have urged that the participants focus on new, additional information you have developed, especially the table showing the characteristics of dangerous chemicals prevalent at wood-preserving sites, three of which appear to be present at the South Barge Site.
QUESTIONS:
1.Based on the table showing chemical characteristics, predict the environmental fate and location at the site of each of the chemicals reported in the TRI report.
2.TCE is a solvent. How might it affect the fate of the PCP?
3.Based on the structure of TCE and PCP, do you think they will degrade?
4.The group decides that it needs still more information before it can determine what to do next. The Wichison EPA has a small testing budget available. How should the group spend this money? What chemicals should be its priorities among the three chemicals for each media of concern (soil, water, and air)?
INSERT EXHIBIT 1
ANSWERS TO EXERCISE FOR LECTURE 2:
Fate and Transport
1.Benzene would not persist in the air because it will photodegrade. It will not persist in surface soil or surface water because it will biodegrade. It might be found in groundwater or deeper soil where micro-organisms are not sufficiently available for significant degradation to occur.
2.Trichloroethylene would evaporate into the air based on its high Henry’s Law coefficient. Its low octanol water coefficient suggests it would be sorbed to the soil to some extent. Because it does not degrade readily, it would persist in the soil. Its moderate solubility will allow some to go into the groundwater.
3.Pentachlorophenol’s high octanol water coefficient suggests it will stick well to soil. It should not be in the air, due to a very low Henry’s Law coefficient and vapor pressure. The solubility number suggests it should not be found dissolved in groundwater. However, pentachlorophenol is a dense non-aqueous phase liquid and hence could appear in high concentrations in the subsurface in a DNAPL pool.
TCE (a Solvent) Effect on PCP
TCE would increase the solubility of pentachlorophenol (PCP) if it is co-disposed with the PCP in a way that allows the two chemicals to come into contact with it. (If the two chemicals have no contact, there will be no effect.) TCE would cause more PCP to appear dissolved in the groundwater than one might otherwise predict.
TCE and PCP Potential to Degrade
These two chemicals will not degrade readily because they are heavily chlorinated.
Spending the Limited Testing Budget
The group’s priorities should be to test for:
1.TCE in soil, groundwater, and air;
2.PCP in soil and groundwater (and as a DNAPL);
3.benzene in soil, groundwater, and air (in case the source of benzene emissions is close and there is little opportunity for photodegradation prior to exposure); and
4.lead and arsenic in soil, groundwater, and air (as dust).
CLASS EXERCISE: LECTURE 3
Assessing Releases of Chemicals and Fate and Transport Models
SCENARIO (in two parts)
Part I
Two months have gone by, and the mayor of Chemtown is getting restless. He wants to apply for special federal and state funding for brownfields redevelopment and his time is running out. At the behest of the Sierra Club and the large crowd of citizen activists that attended his first community meeting, the mayor has established a multi-stakeholder South Barge Site Dialogue Group to review the results of the additional testing that was ordered by the Wichison EPA. The Dialogue Group, which includes representatives of every major interest group affected by the South Barge Site development project, is meeting to review the testing report submitted by the Wichison State Testing Lab. Here is the report the lab has submitted:
*********************************************************************
CONFIDENTIAL PRELIMINARY DRAFT
Report on Environmental Conditions
at the
South Barge Street Redevelopment Site
Prepared for the South Barge Site Dialogue Group
by Steve Stress, M.D.
Methodology
On May 1 and 2, 199X, I tested three samples provided to me by our summer intern, Bill Bluster. According to Mr. Bluster and as illustrated by Map #2 (attached), these samples were taken under the following conditions:
1.Air sample was taken by appropriate monitoring equipment located in the geographical dead center of the South Barge Street brownfields site.
2.Two soil samples were taken, one at the proposed location for the new development and the other in an adjacent residential area.
3.Similarly, one shallow eight-feet and a second deep 30-feet groundwater samples were taken. (In conducting this test, Mr. Bluster reports that he determined that the water table at the site is five feet below the surface.)
1
Test Results
The results of my tests on the three samples provided by Mr. Bluster are presented on the following table:
SOUTH BARGE STREET SITE TEST RESULTS
Shallowgroundwater / Deep
groundwater / Air / Soil
Location A / Soil
Location B
arsenic / 0 / 0 / 0 / 369 ppm / N.D.*
TCE / 0 / 0 / 2 g/m³ / 200 ppm / 5 ppm
PCP / 0 / 0 / 0 / 10,000 ppm / N.D.*
*N.D. means non-detectable.
Although we were only hired to test for the three chemicals listed above, three additional lab test analyses that we undertook are worth noting:
Shallowgroundwater / Deep
groundwater / Air / Soil
Location A / Soil
Location B
benzene / 1,000 ppb / 150 ppb / 0 / 15,000 ppb / 15,000 ppb
DDT / 0 / 0 / 1 g/m³ / 5,000 ppb / N.D.*
lead / 0 / 0 / 0 / 10,000 ppm / 15,000 ppm
*N.D. means non-detectable.
Conclusions
The site is in good condition for redevelopment with minimal cleanup. Groundwater looks unaffected by site activities, as does the air quality. Although the soil is somewhat contaminated in Location A, the levels reported do not exceed levels typically found across the county. The high benzene readings in soil and groundwater likely did not occur from wood preserving at the site, and further investigation may be in order. Similarly, the DDT detected at the site is a bit of a mystery; perhaps these readings, particularly the air reading, are in error for this compound. My biggest concern at the site is lead, another contaminant not typically found at wood preserving sites.
Our invoice will be transmitted shortly.
QUESTIONS:
1.Dr. Steve Stress from the Wichison State Testing Lab comes to make a presentation to the South Barge Site Dialogue Group. What questions should the group ask?
2.Assume that the Dialogue Group decides that it does not have enough data to make a determination about what to do with the site and that it needs to gather more reliable and comprehensive information. What are the arguments for and against doing a model of environmental conditions at the site, as opposed to doing considerably more monitoring?
3.Why should the citizens be doubtful about Dr. Stress’s data and conclusions?
INSERT MAP # 2
Part 2
The South Barge Street Dialogue Group’s last meeting ended in a shouting match because the Wichison State Testing Lab's environmental sampling was so poorly done that it offered little reliable information about environmental conditions at this brownfields site. The mayor has now prevailed upon the current and prospective site owners to put up some real money, and they have hired Private Enterprise Supreme, a new consulting firm that comes highly recommended by EPA’s regional office.
Private Supreme has reviewed all available data about the South Barge Street Site and undertaken a visual field investigation of the property. It has advised the mayor that no additional monitoring should be done at the site because models developed by Private Supreme can answer all remaining questions for significantly less money. The lake model developed by Private Supreme shows that the lake does not contain any pollutants at concentrations of significance. The company’s groundwater model shows that groundwater flow is not in the direction of residential neighborhoods, and hence groundwater contamination does not pose a problem. Furthermore, the pentachlorophenol and DDT sorb heavily and are not expected to migrate into the groundwater. Because the direction of prevailing winds is primarily away from residential neighborhoods, Private Supreme did not develop an air model.
The results of this technical evaluation have stirred a new round of controversy in Chemtown, and the Dialogue Group has scheduled a meeting to review its options.
QUESTIONS:
1.What do you need to know about the models used by Private Enterprise Supreme?
2.The class should be divided into two groups. One group should represent the technical consultant hired by the current owners, DuDow Chemical and PruMutual, to review Private Supreme’s report and make recommendations on behalf of their clients about what steps to take next. The second group should represent the Wichison EPA, which is intent on determining what remedial action is necessary before the South Barge Site can be redeveloped in a manner that protects human health and the environment. Each group should decide if additional monitoring should be done and, if so, when and for what contaminants.