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PRELIMINARY PUBLIC HEALTH ASSESSMENT

WILLIAMS PIPE LINE COMPANY
SIOUX FALLS, MINNEHAHA COUNTY, SOUTH DAKOTA

APPENDICES

Appendix A - Two Figures

Appendix B - Tables

Appendix C - Response to Public Comments



Appendix A - Figures

Figure 1
Figure A.1.

Figure 2
Figure A.2.



Appendix B - Tables

Table 1 - Contaminants of Concern in On-Site Soil Samples
Chemical On-site pit sludge
mg/kg		 Year of sample/
reference		 On-site soil conc.
mg/kg		 Year of sample/
reference		 Background soil
mg/kg		 Year of sample/reference C.V. C.V. Source
benzene 8.4-32 87, 88/PACE, E&E, WPL NA
.003* 87/E&E 24 CREG
b-BHC 4.5 87/E&E ND 88/WPL ND 87/E&E 0.39 CREG
a,g-chlordane .5-10.0 87, 88/E&E, WPL 24-43 88/WPL NA
0.54 CREG
4,4-DDE 5.4 87/E&E ND 88/WPL ND 87/E&E 2.1 CREG
dibenzofuran 10 87/E&E NA
ND 87/E&E none none
heptachlor epoxide .320-3.3 87, 88/E&E, WPL ND 88/WPL ND 87/E&E 0.077 CREG
lead 130-698 87,88/E&E, WPL 3.7-5.6 88/WPL RD 87/E&E none none
2-methyl-naphthalene 74-130 88/WPL NA
ND 87/E&E none none
naphthalene 4.1*-33 87, 88/E&E, WPL 21-23 88/WPL ND 87/E&E none none

C.V. = Comparison Value
* after value indicates the value is estimated.
NA = not analyzed, ND = not detected, RD= rejected data
All samples are from the north side of the site.
References for tables are found at the end of Appendix tables.

Table 2 - Contaminants of Concern in On-Site Water Samples
Contaminant On-site monitor well
(mg/L)		 Year of sample/
reference		 Background sample
(mg/L)		 Year of sample/reference C.V
(mg/L)		 C.V.
Source
aldrin .0003*-.001* 87/E&E ND 87/E&E 2.0 E-6 CREG
arsenic .027-.18 87/E&E, PACE .004 87/E&E 0.011 RfD
barium .7-3.9 87/E&E, PACE .102 87/E&E 2.5 RfD
benzene (N).005-.75
(S).3		 87/PACE, E&E, SD-GW ND 87/E&E 0.0012 CREG
b-BHC .001* 87/E&E ND 87/E&E 1.9E-5 CREG
bis(2ethyl-hexyl)phthalate .012 -1.0 87/PACE ND 88/PACE 0.01 RfD
cadmium (N).0003-.018 87/E&E .0002- .004 87/E&E, PACE 0.007 EMEG
diesel fuel (N)ND-1200
(S) ND		 87/SD-GW NA
none none
fluorene .95*-3.6 87/PACE,E&E ND 87/PACE 1.4 RfD
gasoline (N)ND-74
(S)59		 87/SD-GW NA
none none
kerosene (N) ND-280
(S) ND		 87/SD-GW NA
none none
lead (N) .002-1.3
(S) .47		 87/E&E, SD-GW .0006 87/E&E .015 EPA AL
manganese .618-6.17 87/E&E .011 87/E&E 3.5 RfD
mercury ND-.009 87/E&E, PACE .0002 87/PACE 0.002 LTHA
2-methyl naphthalene .014*-11* 87/E&E ND 87/E&E none none
naphthalene 3.7*-19* 87/E&E, PACE ND 87/E&E 0.02 LTHA
nitrate ND-31 90/WPL NA
16 RfD
phenanthrene .013-11 87/E&E, PACE ND 87/E&E none none
toluene (S)38 87/PACE, E&E, SD-GW ND-.012 87/PACE 7 RfD
trimethyl-benzene .840-1.0 87/PACE .064 87/PACE none none

Notes:
C.V. = Comparison Value
* after value indicates the value is estimated.
NA = not analyzed, ND = not detected, RD= rejected data
(N) or (S) before value indicates samples taken on the North or South side of WPL property. If not indicated sample is from the north side of the site.
References for tables are found at the end of Appendix tables.

Table 3 - Contaminants of Concern in Off-Site Soil
Chemical Off-site soil
mg/kg		 Year of sample/
reference		 C.V. C.V.
Source
arsenic 2.3-4.3 87/E&E 0.6 RfD
lead RD 87/E&E none none
mercury .4-.6 87/E&E none none

C.V. = Comparison Value
* after value indicates the value is estimated.
NA = not analyzed, ND = not detected, RD= rejected data
All samples are from the north side of the site.
References for tables are found at the end of Appendix tables.

Table 4 - Contaminants of Concern in Off-Site Ground Water Samples
Contaminant off-site monitor well
(mg/L)		 year of sample/
reference		 off-site private wells
(mg/L)		 year of sample/
reference		 C.V
(mg/L)		 C.V.
Source
aldrin .000015-.0003* 88/WPL, E&E .0001 87/E&E 2.0 E-6 CREG
ammonia-N .05-50.6
(S).05-20.1		 89,90/HK NA
3 IMRL
arsenic .002-.019 87/E&E .0037-.0064 87/E&E .03 RfD
barium .130-1.160 87/E&E .211-.261 87/E&E 0.70 RfD
benzene .0062-.067 87, 89, 90/HK, E&E,WPL (N)ND-.550
(S).37-.5		 86-89/SD
86/Johnson		 .0012 CREG
a-BHC .00009 87/E&E ND-.0002 87/E&E 5.5E-6 CREG
b-BHC .0004* 87/E&E ND 87/E&E 1.9E-5 CREG
bromodichloromethane 0.006 87/E&E .0063-.027 86-89/SD 0.00027 CREG
cadmium .0044* 87/E&E .004* 87/E&E 0.002 EMEG
a,g-chlordane .0005-.003 87/E&E ND 87/E&E 2.7E-5 CREG
chloroform ND 87/E&E .004-.073 86-89/SD 0.0057 CREG
chloromethane NA
0.15-0.046 86-89/SD none none
chromium .006-.018 87/E&E .006 87/E&E .05 RfD
dieldrin .0000064-.0001 88/PACE ND 87/E&E 2.2E-6 CREG
1,2-dichloroethane .001*-.002* 87/E&E 6.6 86-89/SD 3.8E-4 CREG
diesel fuel .67-85 90/WPL NA
none none
gasoline 46-78 90/WPL NA
0.005 LTHA
heptachlor .000018-.000051 88/PACE ND 87/E&E 7.7E-6 CREG
heptachlor epoxide .00023-.0007 88/PACE NA
3.8E-6 CREG
jet fuel 240 90/WPL NA
none none
lead .0006-.009 87/E&E .0007-.0015 87/E&E 0.015 EPA AL
manganese .033-1.7 87/E&E .0033-3.2 87/E&E 1.0 RfD
nitrate .03-45.6 89-90/HK (N)11
(S)12-99		 86-89/SD 16 RfD
zinc .011-.149 87/E&E .066- 29.3 87/E&E 2.1 LTHA

Notes:
C.V. = Comparison Value
* after value indicates the value is estimated.
NA = not analyzed, ND = not detected, RD= rejected data
(N) or (S) before value indicates samples taken on the North or South side of WPL property. If not indicated sample is from the north side of the site.
References for tables are found at the end of Appendix tables.

Table 5 - Contaminants of Concern in Air from Hayward School
Contaminant School air
(mg/m3)		 Year of sample Reference C.V.
(mg/m3)		 C.V.
Source
occupied unoccupied
Benzene .0096-.671 1.88-8.3 86 Lybarger 86 0.0001 CREG
Hexane .017-13.0 3.5-28.9
.458-105.7		 86
86		 Lybarger 86
Posid 86		 0.2 RfC
Pentane 2.06-11.2 32.2 86 Posid 86 none none

Notes: C.V stands for Comparison Value
NA = not analyzed, ND = not detected.
CREG = cancer risk evaluation guide, RfC = reference concentration
References for tables are found at the end of the Appendix tables.

Table 6 - Completed Exposure Pathways
Pathway Name Exposure Pathway Elements Time
Source Environmental Media Point of Exposure Route of Exposure Exposed Population
Private Well WPL Burn Pit-North Ground Water Residences and Businesses Ingestion Private well users northeast and east of WPL Past
Present
Future
Private Well Storage Tank Leaks and Spills South and Southwest Ground Water Residences and Businesses Ingestion Private well users south and southwest of WPL Past
Present
Future
Ambient Air WPL Spills-South Vapors from Ground Water School and Residence Inhalation School children, faculty, and resident on south side of WPL Past

Table 7 - Potential Exposure Pathways
Pathway Name Exposure Pathway Elements Time
Source Environmental Media Point of Exposure Route of Exposure Exposed Population
Pit Sludge and On-site Soil WPL Burn Pit Pit Sludge and on-site soil WPL Burn Pit Area Inhalation
Ingestion
Skin Contact		 WPL Site and Remedial Workers Past
Off-Site Soil WPL Burn Pit and natural conditions Surface soils Residences Ingestion,
Inhalation,
Skin Contact		 Residents northeast and south of WPL property Past
Present
Future

Table 8 - Estimated Population for Completed and Potential Exposure Pathways
Contaminant in Completed or Potential Exposure Pathway Exposed Population and Potentially Exposed Population
Location Completed Exposure Pathway-Northeast employees Completed Exposure Pathway-South side residents Potential Exposure Pathway-WPL site workers Completed Exposure Pathway-Old Hayward School
Estimated Persons 10-15 25-30 9 full-time
20+ transient		 437 students
43 staff
benzene Not Known Not Known soil/sludge Air
b-BHC Not Known Not Known sludge/soil Not Known
bromodichloromethane Private well Not Known Not Known Not Known
a,g chlordane Not Known Not Known soil/sludge Not Known
chloromethane Private well Not Known Not Known Not Known
4,4-DDE Not Known Not Known sludge Not Known
dibenzofuran Not Known Not Known sludge Not Known
heptachlor epoxide Not Known Not Known sludge Not Known
hexane Not Known Not Known Not Known Air
lead Not Known Not Known sludge Not Known
2-methylnaphthalene Not Known Not Known sludge Not Known
naphthalene Not Known Not Known sludge/soil Not Known
nitrate Private well Private well Not Known Not Known
pentane Not Known Not Known Not Known Air

TABLE 9 - COMPARISON OF ESTIMATED EXPOSURE DOSE TO HEALTH GUIDELINES
Chemical Pathway Health Guideline Source Exceeded by estimated exposure dose
benzene air 0.0065 mg/m3* Acute MRL yes
bromodichloromethane water-northeast 0.02 mg/kg/day Chronic MRL no
chloromethane water-northeast none none NA
4,4-DDE soil/sludge none none NA
dibenzofuran soil/sludge none none NA
hexane air 0.2 mg/m3 RfC yes
lead soil/sludge none none NA
2-methyl naphthalene soil/sludge none none NA
naphthalene soil/sludge none none NA
nitrate water-south 1.6 mg/kg/day Chronic RfD only for children
nitrate water-northeast 1.6 mg/kg/day Chronic RfD no
pentane air none none NA

Note:
* The acute MRL of 0.002 ppm for benzene was converted to mg/m3 by multiplying 0.002 by 3.25, which is the conversion factor listed for benzene in the NIOSH Pocket Guide to Chemical Hazards (1990).

Abbreviations Used in Appendix Tables 1 - 9

CDC      Centers for Disease Control
CREG      Cancer Risk Evaluation Guide for environmental media
C.V      Comparison Value
EMEG      Environmental Media Evaluation Guide established by the Agency for Toxic Substances and Disease Registry
EPA AL      U.S. Environmental Protection Agency Action Level for lead in drinking water
IMRL      Intermediate Minimal Risk Level established by ATSDR
LTHA      Lifetime Health Advisory established by the Environmental Protection Agency
MCL      Maximum Contaminant Level established by the Environmental Protection Agency
MRL      Minimum Risk Level established by the Agency for Toxic Substances and Disease Registry
N      North
NA      Not Analyzed
ND      Not Detected
PMCL      Proposed Maximum Contaminant Level established by the Environmental Protection Agency
RD      Rejected Data
RfD      Reference Dose established by the Environmental Protection Agency and used to develop the RfD comparison value
S      South
WPL      Williams Pipe Line
1.0E-6      This is an abbreviation for 1 X 10-6 or 0.000001



Appendix C - Public Comments

COMMENTS RECEIVED ON THE WILLIAMS PIPE LINE TWELVE STREET TERMINAL PUBLIC HEALTH ASSESSMENT

The Williams Pipe Line Twelfth Street Terminal Public Health Assessment was available for public review and comment from March 25, 1992 through April 23, 1992. The Public Comment Period was announced in local newspapers. Copies of the public health assessment were made available for review at the Sioux Falls Main Library, and the Sioux Falls office of the South Dakota Department of Environment and Natural Resources. In addition, the public health assessment was sent to 7 individuals or organizations who had requested that they receive copies. Thirty-one comments were received from three organizations. Two of these organizations made a combined response.

Comments and responses are summarized below. The page numbers referred to in the comments are from the Public Comment Release and thus may not match those in this document. The comment letters can be requested from ATSDR through the Freedom of Information Act.

COMMENT 1: Contrary to the suggestions in the Preliminary Health Assessment (PHA) report, the extent of the petroleum and nitrate that originated from the site has been defined, controlled, and is being successfully remediated.

RESPONSE:

The public health assessment contains no positive or negative evaluation of site remediation activities. ATSDR did conclude that the extent of contamination had not been completely identified.

COMMENT 2: The PHA report was critical of the fact that the pesticide contamination associated with the burn pit had not yet been remediated. Anyone familiar with the Superfund process should know that EPA will not allow such activity to occur until the RI/FS process is completed.

RESPONSE:

In Site Visits portion of the Background section of the public health assessment, the following observation is made about a March 1991 visit to the site by Dr. Robin Brothers, "No further remedial activities had taken place on the burn." This is an observation not a criticism. Incidentally, the same section also describes a 1990 site visit by ATSDR and EPA staff where Williams Pipeline staff demonstrated the interceptor trench and treatment facilities being used to remediate groundwater contaminated by the burn pit. EPA does allow remediation activity before the RI/FS is completed.

COMMENT 3: The commenter was concerned that the public health assessment described a number of health hazards not related to the site including arsenic.

RESPONSE:

A public health assessment describes the possible health impact of the contaminants identified, no matter what the source.

COMMENT 4: It would appear that the authors of the report chose not to access all the extensive and most pertinent data that is available for this site.

RESPONSE:

The public health assessment cites only those documents actually used. ATSDR searched the files for this site at EPA and the Sioux Falls office of the South Dakota Department of Environment and Natural Resources with the expectation that these files would be the most complete.

COMMENT 5: The public health assessment unnecessarily duplicates the efforts being made by the State and EPA.

RESPONSE:

The Superfund law and its amendments require that ATSDR evaluate the possible health impact of each site proposed for the National Priorities List (NPL) through the development of a public health assessment. The efforts of EPA and the State are legislatively mandated towards the cleanup of the site, not the evaluation of health impact.

COMMENT 6: The public health assessment is complicated and confusing because it considers the whole facility instead of just the burn pit, and, therefore, may evoke unnecessarily community anxiety.

RESPONSE:

ATSDR decided to evaluate the whole facility because the actual sources of the contaminants have not been fully identified, and because of the community concerns about the Hayward School incident.

COMMENT 7: The boundaries of the study area and the specific population at risk were not adequately identified in the public health assessment.

RESPONSE:

The public health assessment has been revised to provide this information.

COMMENT 8: The relationships between sources, the extent of contamination, and the potential exposure pathways need to be better elucidated

RESPONSE:

The Pathways Analyses section has been revised to address this concern.

COMMENT 9: The summary should state the private home and the old Hayward school are demolished and the lots are level.

RESPONSE:

The summary of the public health assessment has been revised to include this information.

COMMENT 10: The discussion of the potential exposure of children to contaminated soil should be expanded to include where the exposure might occur and who else might be at risk.

RESPONSE:

This discussion was deleted as part of an extensive revision of the public health assessment. It was the evaluation of the health assessor (John Crellin) doing the revision that the data, currently available, does not support the existence of this pathway.

COMMENT 11: The statement about the levels of increased arsenic in the municipal water supply being a cancer risk, should be balanced by the fact that these levels are considered to be background. Further, it should be stated that these levels are below EPA's drinking water standards.

RESPONSE:

The public health assessment has been revised to delete this discussion.

COMMENT 12: The summary should state how many of the contaminated wells are still being utilized. It should also state that users of contaminated wells should receive information concerning the contamination.

RESPONSE:

The summary has been revised to include the number of contaminated wells.

COMMENT 13: The levels of hexane, benzene, and pentane in the old Hayward School and a residence should be identified. The fire and explosion risks are negligible with the removal of the two structures.

RESPONSE:

The levels of hexane, benzene, and pentane are described in the Environmental Contamination and Other Hazards section. The summary does not say that there are fire and explosion risks; it only states that this is community health concern.

COMMENT 14: A list of the hazardous substances and their location on the site would give a clear picture of what the report is to encompass.

RESPONSE:

This is done in the Environmental Contamination and Other Hazards and Pathways Analyses section.

COMMENT 15: The background information does not list the petroleum leak near the loading rack area in October 1983.

RESPONSE:

This information can be found in the first paragraph of the History of Contamination portion of the Background section.

COMMENT 16: The third paragraph of the Site History should include information that the burn pit was built into the regional groundwater table and product accumulated from tank cleaning and an oil water separator.

RESPONSE:

This is done in the fourth paragraph of the History of Contamination portion of the Background section.

COMMENT 17: The fifth paragraph of the Site History should mention that tank 1341 was the cause of the spill.

RESPONSE:

This is already done.

COMMENT 18: The History of Contamination section should describe the court case on the pipeline leak at the northeast part of the site in 1969. It should also mention the vapors found when sewer line were put in place.

RESPONSE:

This section is not intended as an all-inclusive summary.

COMMENT 19: The fourth paragraph should be revised to indicate that EPA, not the South Dakota Department of Wildlife and Natural Resources, have concluded that pesticides were probably also dumped in the burn pit.

RESPONSE:

The public health assessment has been revised to make this change.

COMMENT 20: In the Remedial Activities section, there is no mention of other off-site releases near the facility and how they relate to the problems at the facility.

RESPONSE:

This information is described elsewhere in the public health assessment.

COMMENT 21: The Environmental Contamination and Other Hazards section should include a better identification of the potentially affected population and off-site boundaries.

RESPONSE:

The Pathways Analyses section has been revised to include this information. It is not appropriate for inclusion in the Environmental Contamination and Other Hazards section.

COMMENT 22: The first paragraph of the Municipal Well Pathways section identifies arsenic as a ubiquitous contaminant in the Sioux Falls area. This should also be mentioned in the discussion of the "increased risk of cancer from arsenic.

RESPONSE:

The Municipal Well Pathways section and the discussion of the carcinogenicity of arsenic have been deleted.

COMMENT 23: The statement in the second paragraph of the section titled Soil and Burn Pit Sludge, "Soil sampling across the site did not reveal significant soil contamination" appears to conflict with "A significant data gap exists concerning the extent of on-site soil sampling. Most on-site soil samples were collected from the area around the burn pit."

RESPONSE:

The public health assessment has been revised to remove this apparent conflict.

COMMENT 24: There appear to be a conflict between question 8 which identifies private well-water users at a high increased risk to cancer and question 9 which states that the safety of private wells can not be established, because the extent of contamination is not fully determined.

RESPONSE:

The responses to those two questions have revised to resolve this apparent conflict.

COMMENT 25: The conclusion that high levels of arsenic in municipal and private water, and soils may pose a health threat should include a explanation of the threat for each media. The Conclusion section should also state that the arsenic levels are naturally occurring. In addition, there should be mentioned that ATSDR's conclusion about the health risk from arsenic in the municipal water supply is inconsistent with the EPA Drinking Water Standard.

RESPONSE:

Nearly all the discussions of arsenic have been removed from the public health assessment, because the arsenic present in the Sioux Falls public water supply is considered to be naturally- occurring and not site-relate. However, ATSDR's conclusion in the public comment release that the arsenic levels (maximum concentration of 17 ppb) in the Sioux Falls water supply may represent a health risk is not inconsistent with EPA's drinking water standard of 50 ppb. The following discussion is based on a review of information in ATSDR's Toxicological Profile for Arsenic and EPA's Integrated Risk Information System (IRIS).

EPA's drinking water standards, also known as Maximum Contaminant Levels (MCLs) are not based solely on health guidelines. A MCL will often be greater than the health guideline for the chemical if it is not technologically feasible to remove the contaminant down to the health guideline. The MCL also may be greater than the health guideline if it is not possible to analytically detect the chemical at the guideline level.

ATSDR bases its conclusions solely on health guidelines. In the case of arsenic, ATSDR uses EPA's oral reference dose to calculate drinking water comparison values of 3 ppb for children and 11 ppb for adults. No cancer slope factor is available for arsenic, a known human carcinogen, so a comparison value based on carcinogenicity can not be calculated. Exceeding a comparison value do not necessarily indicate the level found is a health hazard. Further evaluation is necessary.

The maximum concentration of arsenic for the Sioux Falls water supply, 17 ppb, is somewhat greater than as the no observed adverse effect level (NOAEL), 9 ppb, in the human epidemiological study on which EPA's RfD is based. However, it is 10 times lower than the lowest observed adverse effect level (LOAEL), 170 ppb, in that same study. The question is, therefore, where do health effects begin? This can not be answered definitively, so it is the practice of ATSDR in these situations to say that there is some health risk.

Incidentally, EPA is currently reviewing its MCL for arsenic of 50 ppb and it is expected that the revised MCL will be lower.

COMMENT 26: The report identified several areas where data were not available or were severely limited, such as surface-soil, ambient air data, and contaminant level of private wells, yet the report identified the site as a public health hazard in the conclusions. It is also valuable to distinguish the extent of a public health hazard for both on- and off-site areas.

RESPONSE:

The Conclusions section has been revised to incorporate these suggestions.

COMMENT 27: The report leaves some unanswered questions for the reader. What should follow this report? How are the recommendations to be carried out? Who is the appropriate agency to do the follow-up studies? Is there funding available for additional studies?

RESPONSE:

The Recommendation section has been revised to identify EPA as the agency responsible to implement the NPL-related recommendations.

COMMENT 28: Recommendation 10 (cease/reduce exposure) states that childcare facilities in the area should use municipal water for all purposes. An explanation of this recommendation would clarify its need. How many childcare facilities are there? How many of these are not on municipal water?

RESPONSE:

This recommendation has been deleted. Based on the information reviewed in this public health assessment, it is unlikely that the soil or drinking water at this facility are contaminated with site-related substances. There is no evidence of off-site soil contamination on the south side of WPL. This faculty is probably on public drinking water. While the exact location of this day care facility is not known, it is not located in the area of known groundwater contamination.(5) No samples were taken in areas designated as childcare centers.

COMMENT 29: Recommendation 11 (cease/reduce exposure) states that institutional controls for the Skunk Creek aquifer preventing future development of this aquifer be implemented. An explanation of this recommendation would clarify its need. Is it in reference to the entire aquifer or that portion affected by contamination?

RESPONSE:

This recommendation has been deleted.

COMMENT 30: Recommendation 2 on site characterization states sampling municipal water at the tap should be done. An explanation of this recommendation needs to list the area to be sampled and frequency and the reason for the sampling.

RESPONSE:

This recommendation has been deleted.

COMMENT 31: Recommendation 5 on site characterization states soil sampling in areas surrounding the WPL site and schools in the area should be done. An explanation of this recommendation would clarify its need. What areas and parameters should be sampled?

RESPONSE:

The Recommendation section has been revised (see page 36) to indicate that EPA, SDDWNR, and ATSDR should work cooperatively to determine what additional sampling should be done.

FOOTNOTES

1. The National Toxicology Program in its Annual Report on Carcinogens classifies a chemical as a"known human carcinogen" based on sufficient human data. Its classification of a chemical as being "reasonablely anticipated to be a carcinogen" is based on limited human or sufficient animal data.

2. IARC defines a class 1 carcinogen as a substance which studies in humans indicate a causal relationship between the agent and human cancer. Class 2 carcinogens are those reasonably anticipated to be carcinogens. For a 2A classification, there is limited evidence of carcinogenicity from human studies which indicate that a causal interpretation is credible, but not conclusive. A classification of 2B indicates that there is sufficient evidence of carcinogenicity from studies in experimental animals.

3. In EPA's classification scheme, a chemical is considered a class A or human carcinogen based on sufficient evidence from studies of humans. A substance is considered class B1 if there is limited evidence from human studies. B2 is used when evidence for carcinogenicity is inadequate or non-existent based on human studies, but sufficient based on animal studies.

4. This is based on an extensive drive-through of the area south of WPL by Dr. John Crellin in 1990.

5. This is based on an extensive drive-through of the area south of WPL by Dr. John Crellin in 1990.

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