Historical Hydrocarbon Usage for Chemicals Detected in Groundwater near a Former US Air Force Test Cell Facility [LOCATION OMITTED]
Analytical Results Overview
The ground water at the Test Cells Site located in [location omitted] is impacted by many hydrocarbon contaminants (Ellis, 2001, URS, 1999, URS, 2001). Primarily halogenated solvents exist at elevated levels, as detected analytically in groundwater samples from several monitoring wells. However, the hydrocarbons are not distributed uniformly across the site. In fact, some of the wells do not contain many of the analytical detects that were found in others, while a few had no detect in samples. Most notably, monitoring wells in the measured upgradient direction (northwest property extent) were found to contain only a few types of chlorinated solvents while downgradient wells had detects of several of the chlorinates as well as non-halogenated hydrocarbons. Additionally, near the northeast and southwest property lines, in wells at locations that are perpendicular (sidegradient) to the onsite groundwater flow, none of the analytes were detected.
Such a configuration of groundwater impact is a likely result of separate releases of various contaminants occurring over time at different locations. As a frame of reference for the site, its first industrial use was as an aeronautical engine test facility from 1953 to 1955. After being abandoned for several years, Newton Iron & Steel conducted operations there from 1960 to 1965. Subsequently, Big Ben Chemicals operated there until 1971. Since then, Ashland Chemical Company has been in charge of the facility. Because the use of different chemicals has varied over time, it is possible to gain an idea of the time frame of releases based upon historical chemical usage. In order to determine potential responsibility for past releases, a detailed study of solvent histories is related in the following.
First, the chemicals detected onsite as presented in a map by URS, 1999 and in Ellis, 2001, are outlined below with common alternate names given for each and the year of the first literature reference (not discovery) and/or patent (ATSDR, 1996, Budavari, 1989, Sheffield, 2001). Second, chemicals of concern (COCs) listed by URS in the 4(q) Notice (attached) are similarly outlined, without duplicating those included on the map in both reports. It must be noted that the Ellis report references the 1999 URS report and also the URS 1996 and 1998 data. Moreover, the Ellis report uses URS mapping, from which the first list of COCs is derived.
COCs Mapped in Ellis, 2001 for the Former Air Force Test Cells Site
1) Benzene (1945, 1961 pat.)
Benzol
2) 1,3-Dichlorobenzene (1957, 1964 pat.)
m-Dichlorobenzene
3) 1,4-Dichlorobenzene (1948)
p-Dichlorobenzene
4) 1,1-Dichloroethane (1925)
5) 1,2-Dichloroethene isomers (1934)
Dichloroethylene
6) Ethylbenzene (1913)
7) Styrene (1942)
Ethenylbenzene
Styrol
8) Tetrachloroethene (1929, 1960 pat.)
Tetrachloroethylene
Perchloroethylene
9) Toluene (1942)
Methylbenzene
Toluol
10) 1,1,1-Trichloroethane (1931, 1931 pat.)
Methychloroform
11) Trichloroethene (1910, 1946 pat.)
Trichloroethylene
12) Vinyl Chloride (1835, 1959 pat.)
Chloroethylene
13) Xylene isomers (1850, 1960 pat.)
Dimethylbenzene
Xylol
URS Reports 4(q) Notice COCs for the Ashland Chemical Site (not listed above)
Carbon Tetrachloride (1921)
Tetrachloromethane
Chlorobenzene (1934)
Benzene Chloride
Chloroethane (1925, 1933 pat.)
Ethyl Chloride
Chloroform (1924)
Trichloromethane
1,2-Dichloroethane (1918)
Ethylene Dichloride
1,1-Dichloroethene (1949)
Vinylidene Chloride
Methylene Chloride (1931, 1957 pat.)
Dichloromethane
1,2-Dichlorobenzene (1975)
o-Dichlorobenzene
Mineral Spirits (1922)
Petroleum Spirits
There were COCs in the reports that were common to both and are not repeated in the second list. The COCs that are the same in both cited listings are: Benzene; 1,1-Dichloroethane; Ethylbenzene; Toluene; 1,2-Dichloroethene isomers; 1,1,1-Trichloroethane; Trichloroethene; Vinyl Chloride; 1,4-Dichlorobenzene, and; Xylene isomers. Additionally, the COC occurrences that were mapped but not listed in the 4(q) Notice are 1,3-Dichlorobenzene and Styrene. Previously, as mentioned in the URS 2001 report, 3 analytical parameters were excluded from the 4(q) Notice monitoring in 1990: benzo(a)pyrene; bis-(2-ethylhexyl)phthalate, and; di-n-butyl phthalate. As recently as the year 2000 to 2001, however, groundwater monitoring included analysis for more than 40 volatile hydrocarbons. Of these, 28 were analytically detected and 14 exceeded groundwater standards (see Recent Analytical Detects below). According to an interview conducted during the course of the site investigation, more than 300 chemicals were stored or used at the facility. One important analyte, which is mentioned in text (Ellis 2001) but not mapped or included in the 4(q) Notice, is methyl tert-butyl ether (MTBE) occurring in hydrostratigraphic unit 1 (uppermost aquifer).
Offsite contamination sources apparently impact ground water moving onto the site. Such flow has been consistently mapped as generally moving toward the southeast and the flow onto the site from the northwestern boundary contains contaminants. Moreover, the observed gradient is consistent with onsite topography and hydrology. The COCs from the upgradient direction are 1,2-Dichloroethene isomers, Vinyl Chloride and 1,1-Dichloroethane.
Historical COC Usage
The date of the first mention of chemicals in recorded literature is useful for finding when a release(s) of a particular chemical into the environment could have taken place. Moreover, knowing the year that a substance, or its method of production, was patented can yield further information about when a material could or could not have been released. Following the date of issuance of a patent associated with a substance, subsequent years are expected to experience increased use of it. Such dating is only a general indication of usage during a decadal time frame, and potential release, so more information is required. Because a substance is usually used widely before being accidentally (or otherwise) released in appreciable quantities, specific data on particular uses need to be known to attribute releases to any single decade. For example, trichloroethene (TCE) production began in Great Britain in 1910, though a suitable container was not available for use until 18 years later (Sheffield, 2002). TCE was used as an anesthetic during from around 1940 to 1970, as a degreaser by the 1980’s to being limited in use by 1990 (ATSDR, 1996). Therefore, large releases of it could be expected at the latest during the decade of the 80’s and potentially through 1990. While TCE was produced in 1910, significant environmental impact would not occur until decades later as a function of its usage. Also, because of its predominant uses during specific time frames, the chemical can be expected at particular types of facilities over time.
The likelihood of a release at any given time is particularly important in terms of pollution liability. Because the uses of any single chemical within a specific time frame is evidence of its distribution and presence in a given area or industry, such information is helpful in tracing the source(s) of a contaminant release. Alternatively, the non-availability of a substance could rule out or limit the probability that it could be released during a particular period. Additionally, knowing the role of natural processes can assist in pinpointing a release in time and by location. For example, if ground water is known to flow in a certain, general direction and the permeabilities of subsurface formations are determined, then it is possible to trace contaminant movement, within a margin of error. Also because contaminants tend to degrade over time, knowing the half-life of a substance (ATSDR, 1996, Howard, 1991), or it’s first-order degradation constant (IPCB, 1998), is useful for correlating information of contaminant concentrations over time.
The contaminants detected at the site are similar, yet differences exist in their chemistry as well as in past usage. Though all are volatile organic compounds, a review of their characteristics is indicative of how differently many react in the environment at large. In point of fact, some float of water (LNAPL) while others sink (DNAPL). Another difference is an important factor of composition; most of the chemicals are chlorinates. This fact results in a large distinction among the contaminants in terms of toxicity as well as environmental fate. To illustrate their similarities and differences, a general overview is tabulated in the following. The tabulation below is illustrative of certain chemical characteristics and their uses for the purpose of identifying potential source areas and associated processes. A total of 29 contaminants are listed, which include those that have been of interest, as above, and those recently detected in ground water on site. The half-life range for degradation in ground water (GW) is also included.
TABULATION KEY:
Contaminant Dates LNAPL/DNAPL Parent Product(s)* Half-Life (GW) Soil/Water Daughter Product(s)* Uses (some discontinued)
Benzene 1945, 1961 pat. LNAPL Petrochemicals, coal tar 10 days to 24 months Catecol, hydroquinone chemical manufacture intermediate, solvent, gasoline component
1,3-Dichlorobenzene 1957, 1964 pat. DNAPL Benzene, chlorobenzene 8 wks to 12 mos 2-chloroaceto-acrylic acid (similar to 1,4-DCB)
1,4-Dichlorobenzene 1948 DNAPL Benzene, chlorobenzene 8 wks to 12 mos
2-chloroaceto-acrylic acid deodorant, fumigant, insecticide, chemical manufacture intermediate
1,1-Dichloroethane 1925 DNAPL Vinyl chloride, 1,1,1-trichloro-ethane 64 days to 24 weeks Chloroethane, ethanol chemical manufacture intermediate, solvent, cleaning/degreasing, insecticide, etc. formerly anesthetic
1,2-Dichloroethene 1934 DNAPL 1,1,2-trichloro-ethane 8 wks to 95 mos Chloroethane, vinyl chloride chemical manufacture intermediate, solvent, refrigerant
Ethylbenzene 1913 LNAPL Petrochemicals 6 days to 228 days Peroxyacetyl-nitrate, phenyl-acetic acid, etc. chemical manufacture intermediate, solvent, gasoline component
Styrene 1942 LNAPL Ethylbenzene 4 weeks to 30 weeks Phenyl acetic acid, etc chemical synthesis intermediate, gasoline component
Tetrachloroethene 1929, 1960 pat. DNAPL Ethylene dichloride 1 year to 2 years Dichloroethylene vinyl chloride chemical manufacture intermediate, solvent, degreasing, dry cleaning
Toluene 1942 LNAPL Petrochemicals, coal tar 1 week to 4 weeks Benzoic Acid, benzylsuccinic acid, etc. chemical manufacture intermediate, solvent, gasoline component
1,1,1-Trichloroethane 1931, 1931 pat. DNAPL 1,1-dichloroethane 20 weeks to 78 weeks 1,1-dichloroethene, acetic acid solvent, cleaning/degreasing, chemical intermediate in vinylidene chloride production,
formerly fumigant
Trichloroethene 1910, 1946 pat. DNAPL Ethylene dichloride 10.7 mos to 4.5 yrs Dichloroethylene vinyl chloride, ethylene degreasing, solvent, chemical manufacture intermediate
Vinyl Chloride 1835, 1959 pat. LNAPL 1,2-dichloroethane, tetrachloroethene etc. 8 weeks to 95 months Formaldehyde, formyl chloride, acetylene, etc. chemical synthesis intermediate, formerly refrigerant, solvent, etc.
Xylenes 1850, 1960 pat. LNAPL Petrochemicals, coal tar, toluene 2 weeks to 12 months Tolualdehyde and methyl benzyl alcohols chemical manufacture intermediate, solvent, gasoline component
Carbon Tetrachloride 1921 DNAPL Carbon disulfide, methanol, methane, propane, ethylene dichloride 1 week to 1 year (dechlorination) chemical synthesis intermediate, degreaser, formerly fumigant, solvent, etc.
Chlorobenzene 1934 DNAPL Chlorine, benzene 136 days to 300 days Chlorine, benzene chemical manufacture and synthesis intermediate, pesticides, silicone resin
Chloroethane 1925, 1933 pat. LNAPL 1,l ,l trichloroethane, cis- 1,2-dichloroethylene 2 wks. to 8 wks. Ethane, hydrochloric acid, acetaldehyde, 2-chloroethanol, formerly for chemical manufacture, solvent, refrigerant, anesthetic
Chloroform 1924 DNAPL Methanol, hydrogen chloride, chlorine, water 8 weeks to 5 years Phosgene, hydrogen chloride CFC production, solvent chemical production intermediate
1,2-Dichloroethane 1918 DNAPL Chlorine, ethane 100 days to 6 mos. Phosgene, hydrogen chloride Chemical intermediate, solvent, gasoline
1,1-Dichloroethene 1949 DNAPL Polyvinylidene chloride products
8 weeks to 132 days Vinyl chloride chemical synthesis intermediate, esp. polyvinylidene chloride copolymers
Methylene Chloride 1931, 1957 pat. DNAPL methane, chlorine, methanol, methyl chloride, hydrogen chloride – (volatilization) solvent, propellant, chemical manufacture process solvent, extraction solvent, foam manufacture
1,2-Dichlorobenzene 1975 DNAPL Benzene, chlorobenzene 8 wks to 12 mos
2-chloroaceto-acrylic acid (similar to 1,4-DCB)
Mineral Spirits 1922 DNAPL petroleum – – (various of the above, analytical total hydrocarbon category)
1,2-Dichloropropane 1932 DNAPL Chlorine, propylene 334 d. to 7.1 years (little or no degradation) Solvent, pesticide, painting products, chemical manufacture
2-Butanone (MEK) 1913 LNAPL Butane, butene 2 days to 14 days Methane Solvent, various manufacturing products
4-Methyl-2-pentanone – – (no data in cited literature) – – –
Acetone 1919 LNAPL Cumene, isopropanol 2 days to 14 days (biodegradation) Solvent, chemical production intermediate
Carbon disulfide 1931 DNAPL Natural gas, sulfur – (volatilization) Industrial solvent, rayon, cellophane manufavture
Chloromethane 1927 LNAPL Methane- hydrogen chloride, chlorine-methanol – Formaldehyde, methane, acetate Solvent, chemical production intermediate, propellant, pesticide, refrigerant
Dichlorodifluoro-methane 1907 DNAPL – 8 weeks to 1 yr. – propellant, refrigerant
* Parent products for manufacturing, except for parent products of vinyl chloride
* Carbon dioxide and water excluded
– No information in cited literature
Recent Analytical Detects
The most recent report available (URS, 2001) contains the tabulated analytical results from sampling events occurring during the fourth quarter of 2000 and the second quarter of 2001. While the reported data are compiled according to monitoring wells, the purpose of presenting the laboratory detects here is simply to be indicative of current onsite groundwater contamination. Only information as to whether each was detected in any monitoring well in the sampling events is indicated below, and also if the levels exceeded limits. If the detection exceeds the Class I Groundwater Standard (IPCB, 1998), the name of the chemical is emboldened. First, the 22 analytes as listed above are presented, followed by other compounds that were detected during the period. While many of the lab results at most wells were non-detect, the laboratory detection limit exceeded the groundwater standard for some of those. The actual tables from the reports are attached.
Benzene detected
1,3-Dichlorobenzene detected
1,4-Dichlorobenzene detected
1,1-Dichloroethane detected
1,2-Dichloroethene isomers detected
Ethylbenzene detected
Styrene detected
Tetrachloroethene detected
Toluene detected
1,1,1-Trichloroethane detected
Trichloroethene detected
Vinyl Chloride detected
Xylene isomers detected
Carbon Tetrachloride detected
Chlorobenzene detected
Chloroethane detected
Chloroform detected
1,2-Dichloroethane detected
1,1-Dichloroethene non-detect
Methylene Chloride detected
1,2-Dichlorobenzene detected
Mineral Spirits detected
1,2-Dichloropropane detected
2-Butanone (MEK) detected
4-Methyl-2-pentanone detected
Acetone detected
Carbon disulfide detected
Chloromethane detected
Dichlorodifluoromethane detected
A total of 42 specific volatile organic compounds (VOCs) were analyzed for groundwater from the sampling events. Of these, 28 were detected and 14 of the detections exceed Class I Groundwater Standards. Of the initial 22 VOCs that were detailed above, 21 were detected, the exception being 1,1-dichloroethene. Given the above information, this compound could be degraded to vinyl chloride.
REFERENCES
Budavari, Susan (ed.), 1989, The Merck Index, Merck & Co., Inc., Rathway, NJ
Ellis Environmental Group, LC (Ellis), May 2001, Draft Preliminary Assessment Report for Former Air Force Test Cells Site [location omitted], Newberry, FL
Howard, P. H., 1991, Handbook of Environmental Degradation Rates, Lewis Publishers, Inc., USA
Illinois Pollution Control Board (IPCB), 1998, Tiered Approach to Corrective Action Objectives, Illinois Register, Title 35, Subtitle G, Chapter I, Subchapter f, Part 742, Springfield, IL
University of Sheffield (Sheffield), 2002, Solvent Use History, http://www.shef.ac.uk/~dnapl/hist.htm
U.S. Agency for Toxic Substances and Disease Registry (ATSDR), August 1996, Public Health Statements, http://www.atsdr.cdc.gov/ToxProfiles
U.S. Environmental Protection Agency (EPA), July 1998, Envirofacts Chemical References, http://www.epa.gov/enviro/html/emci/chemref/index.html
URS Corporation (URS), January 1999, Draft Revised Site Characterization Report Ashland Chemical Co. [location omitted] DSO Facility, Chicago, IL
URS Corporation (URS), August 2001, RCRA Post-Closure Groundwater Monitoring, Fourteenth Annual Environmental Status Report – Ashland Distribution Co. [location omitted] Facility, Chicago, IL
