REGULATORY
TOXICOLOGY
AND
PHARMACOLOGY
13,
195-222 (1991)
The Health Hazards Posed by Chromium-Contaminated Soils in Residential and Industrial Areas: Conclusions of an Expert Panel D. J.~AUSTENBACH,*
W.E. RINEHART,~AND
P.J. SHEEHAN*
ThemRisk, McLaren/Hart Environmental Engineering, I135 Atlantic Avenue, Alameda, California 94501: and tlndustrial Health Foundation, 34 Penn Circle West, Pittsburgh, Pennsylvania 15206
Received August 25, 1990
Between 1905 and 1971, over 2 million tons of residue from chromite ore processing was generated in Hudson County, New Jersey, of which substantial amounts were used as fill and tank diking. A panel of medical, toxicology, and risk assessment experts was convened in early 1990 to evaluate the potential health hazards posed by the resulting chromium contaminated soil. The Panel concluded that soils containing concentrations of 75 ppm hexavalent chromium [Cr(VI)] and 1000 ppm total chromium compounds (about 95% was trivalent chromium [Cr(III)]) did not pose a significant health hazard to nearby residents and workers. They also determined that exposure to chromium from Hudson County sites posed a negligible cancer hazard to residents. Using risk assessment methods, the Panel estimated that the plausible incremental cancer risk to individuals at residential siteswould be substantially lessthan I in 1,OOO,OOO. The average measured levels of airborne Cr(VI) at typical industrial sites were more than IOOO-fold lower than the current OSHA Permissible Exposure Limit (PEL). The maximum plausible increased cancer risk for an average worker at a dusty industrial site was estimated to be less than 1 in 100,000. The Panel also concluded that chromium-containing crystals, which have occasionally been found in Hudson County buildings, do not pose a significant hazard. However, they suggested that were the concentration to exceed 5000 ppm Cr(V1) in the crystals, site-specific health risk assessments would be conducted and remediation considered. The Panel evaluated the dermal hazard posed by chromium-contaminated soil and acknowledged that there is a small group of persons (approximately 0.1% of the United States population) who currently have a dermal sensitization to Cr(V1) primarily through occupational exposure. Based on published studies of human volunteers. the Panel concluded that a small percentage (less than 5%) of persons already sensitized may respond to Cr(V1) in solution at concentrations above 35 ppm. They decided that a much higher concentration in soil, perhaps 350 ppm Cr(VI), would be necessary to elicit dermatitis because only a fraction of the chromium in soil is soluble. The Panel concluded that it was highly unlikely (if not impossible) for a person to become dermahy sensitized to Cr(V1) or Cr(III) at the soil concentrations found in most areas in Hudson County. The Panel was of the opinion that the 75 ppm total chromium [Cr(III) and Cr(VI)] cleanup requirement for Hudson County soils, which was established by the New JerseyDepartment of Environmental Protection (NJDEP), is unusually stringent and that much higher levels would still be protective of public health. Last, the Panel noted that although biological monitoring can be useful for evaluating persons exposed to relatively high concentrations of Cr(VI), the urine or blood sampling of persons living or working near these sites would probably not be beneficial until a more sensitive analytical method is available and/or until a very large control group is evaluated so that the background concentrations of chromium in biological fluids (and the variability) can be defined. o 1991 Academic RW, IW. 195 0273-2300/91
$3.00
Copyright 0 199 I by Academic Press, Inc. All rights of reproduction in any form reserved
196
PAUSTENBACH,
RINEHART,
AND SHEEHAN
INTRODUCTION Chromium processing in Hudson County, New Jersey, began around 1905 and continued, at varying activity levels, through 197 1 (ESE, 1985, 1989a). Chromite ore was processed in kilns to produce various hexavalent [Cr(VI)] and trivalent [Cr(III)] chromium products. An ore residue (slag) was a by-product of these manufacturing activities. Some of this residue, which resembled gravel, was used as fill material at numerous locations within the County to reclaim marshlands (so-called “New Jersey meadowlands”), for industrial building pads and parking lots, for tank dikes, and for backfill at sites following demolition. Since 1980, there has been significant public and regulatory concern regarding the potential risk to human health posed by the presence of the chromite ore residue (Hanley, 1989; Diamond, 1990). The reasons for these concerns are varied, ranging from the potential cancer risk and dermatitis hazard to residents to the potential impact on wildlife. Because the chronic inhalation of Cr(V1) has been shown to cause an increase in the rate of lung cancer in individuals occupationally exposed during the production of dichromate compounds and chromic acid, there was concern that these Hudson County residues might pose a potential hazard for persons working at or living near these sites (Mancuso and Hueper, 195 1). In light of these concerns, an expert review panel was convened in January 1990 to evaluate the possible health hazards posed by the contamination. This Panel was organized by the Industrial Health Foundation (IHF). Since its formation in 1935, the IHF has studied a variety of occupational health issues involving exposure to industrial chemicals including silica, asbestos, and fiberglass. IHF’s interest in chromium began in 1973 when it served as the coordinating body for an international group of chromium producers. Since that time, IHF has sponsored various conferences and meetings with an emphasis on health-related chromium research in the United States (IHF, 1980, 1986). Funding for the Chromium Panel was provided by AlliedSignal, Inc., Maxus Energy Corp. (on behalf of the Occidental Chemical Corp.), and PPG Industries, Inc.’ The Panel was charged with three objectives. The first was to review two risk assessments of selected Hudson County sites which were prepared by independent consulting firms and to offer an opinion regarding the validity of each. The second objective was to assess the scientific merit of the New Jersey Department of Environmental Protection (NJDEP) document titled “Derivation of a Risk Based Chromium Cleanup Level in Soil Contaminated with Chromite Ore Processing Residue: Hudson County” (NJDEP, 1989). Based on that analysis, the NJDEP (the lead regulatory agency) proposed a 75 ppm total chromium [Cr(III) and Cr(VI)] soil cleanup level. Third, the Panel was asked to offer an opinion regarding the health protectiveness and reasonableness of a 1000 ppm total chromium and 75 ppm hexavalent chromium cleanup criterion for soil. HISTORY
OF CHROMIUM
RESIDUES
IN HUDSON
COUNTY
Chromate and bichromate compounds were produced from chromite ore by three manufacturing plants located in Hudson County. These were the Mutual Chemical ’ The authors of this paper served as scientific advisors and support staff to the panel.
CHROMIUM-CONTAMINATED
SOILS
197
Co. (later Allied Chemical Co.) located in Jersey City (1905-l 954); Natural Products Refining Co. (later Columbia Southern Chemical, then PPG Industries) also in Jersey City (1924-1963); and Diamond Alkali Shamrock Co. (later Diamond Shamrock Corp., then Diamond Shamrock Chemicals Co.) in Keamy ( 19 16- 197 1). Chromite ore processing at these facilities produced an estimated two million tons of an alkaline waste residue containing 2 to 5% total chromium (NJDEP, 1984/1985). This residue was mixed with clean dirt, which resulted in soil concentrations of about 1000 to 5000 ppm total chromium. This waste slag resembles gravel in texture but is reddish-brown in color (ESE, 1989a). Today, over 40 sites have been identified where this chromite residue was used as fill material in Hudson County (ESE, 1989b). A remedial investigation was conducted at 42 Hudson County sites by Environmental Science and Engineering (ESE), a contractor to NJDEP (ESE, 1989a). ESE determined that 11 of the suspect sites did not contain the slag fill, since less than 100 ppm total chromium was found in the soil. Twenty-seven sites were reported to have concentrations greater than 1000 ppm, and two sites were not tested. At the remaining two sites, only one soil sample each was collected and analyzed, so it is not possible to draw any conclusions regarding the extent of contamination at these sites. The depth of maximum chromium contamination ranges from the surface to about 9 feet (Table I), but at most sites contamination is limited to the top 3 to 5 feet. At most locations, only a portion of the site required fill; therefore, chromiumcontaminated soils are found only in discrete areas. Of the 100 or so total suspected sites, about 20 to 30 are currently vacant lots in Jersey City, 28 others are residential, 12 are industrial/commercial, and 2 are recreational. Of the original 42 suspect sites, 4 were selected by ESE as representative of worst-case conditions for the following land use categories: residential, public land, industrial with no truck traffic, and industrial with heavy truck traffic (ESE, 1989b). Information on these 4 representative, worst-case sites is presented in Table 1. The major bodies of water near the pertinent sites are the Hackensack River, Hudson River, Newark Bay, Upper New York Bay, and Penhorn Creek. Most of the region is tidal marsh intersected by streams, with elevations only a few inches above high tide (ESE, 1989a). Groundwater moves toward the two bays. There is a surhcial and a bedrock aquifer. The shallow groundwater is not used for any purpose and the bedrock aquifer’s use is limited due to its high mineral content (ESE, 1989a). Chromium contaminated fill has a minimal to moderate impact on the shallow groundwater since the USEPA MCL for total chromium in water is 100 pug/liter (Marshack, 1989), and the soluble total chromium concentrations detected range from less than 20 pg/liter (limit of detection, LOD) to 200 pug/liter (ESE, 1989a). Hexavalent chromium was not detected in any of the groundwater samples. SOIL DATA Analyses of soil samples obtained during the ESE remedial investigation indicated that total chromium concentrations measured at the 42 suspect sites range from 4.7 ppm to 19,800 ppm, with an arithmetic mean of 1138 ppm (ESE, 1989a). These results are graphically portrayed in Fig. 1. The average Cr(V1) soil concentration at these sites was 2.6% of the average total chromium concentration; that is, if the soil contained 1000 ppm total chromium,
198
PAUSTENBACH.
RINEHART,
AND
TABLE CHROMIUM
Site number 1 2 3 4 5 6 1 8 9 10 11 12 13 14 15” 16 17 18’ 19’ 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 31 38 39 40 41 42’
LEVEL.Y AT VARIOUS
Maximum depth of total Cr contamination (feet) 6 9 9 Not sampled 9 9 6 6 SF* 6 6 5.5 6 3 6 6 6 6 9 9 6 Not sampled 3 SF SF* 36 SFb 3 3 SF* SF* 3* 3b SF* SF* SF* 9 3 9 9 9 6
Arithmetic
SHEEHAN
1 HUDSON
COUNTY
mean
ttobl Cd (m-4 259 3264 319 Not sampled 1859 4265 25.8 110 47.1 2181 54.1 1049 388 1031 628 2513 1273 2335 2179 3326 22.7 Not sampled 112 716 26.9 21 44.1 155 40 14.6 14.5 17 64d 20.4 16.5 3gd 172 897 2158 4024 1542 3695
SITES (1990)”
Geometric
mean
[total Crl bpm) 80 1005 158 Not sampled 1413 768 22.9 33 40.3 884 46.6 218 74.8 122 76.6 1518 130 426 323 2472 17.7 Not sampled 182 120 23.1 18.7 29.5 120 34 14.3 13.6 57 64d 17.3 13.4 3Sd 108 60 183 709 499 182
Note. SF, surface sample. a Source: ESE Remedial Investigation, 1989. * Depth sampling insufficient; indicated maximum ’ Sites selected by ESE for risk assessment ( 1989). d Only one sample analyzed.
contamination
depth
may not be reliable.
Range [total Cr]
km4 20-1,800 93-8,400 27-1.600 Not sampled 5 10-5.800 93-19.000 9.2-58 6.6-640 24-88 76-4,700 29- 100 17-8,800 20-2,300 17-4,800 4.7-4,960 410-7,300 16-7.700 9.3-13,000 8%12,500 410-8.100 7.1-47 Not sampled 22-2.500 13-4.400 14-37 1 l-55 8.4-90 53-270 24-93 12-22 8.4-23 31-190 64d 9.2-5 1 7.9-38 3Sd 30-590 12-6,100 25-19,800 21-18,000 43-9,300 120-7,500
CHROMIUM-CONTAMINATED
199
SOILS
n
I
q
ARITHMETIC MEAN CONCENTRATIONS GEOMETRIC MEAN CONCENTRATIONS
# Sites
o-25
26-50
51-75
>lOl
76-100
ICr (VU (twm)l 35 30 25
1 Sites
20
r-l
O-250
251-500
501-750 lrotal
751-1000
1001-2000
12001
CrI (pm)
FIG. 1. Soil concentrations of Cr(II1) and Cr(V1) at 42 selected sites in Hudson County, New Jersey (Source: ESE, 1989a).
then approximately 26 ppm was Cr(V1). At most of the sampled sites, the highest chromium concentrations were found at or near the surface (Table 1). Leachate concentrations (extraction procedure (EP) toxicities) based on the extraction procedure presented in USEPA Method 13 10 (USEPA, 1986) were above USEPA’s hazardous waste classification limit for total chromium of 5 mg/liter in only 4 of the 43 soil samples tested (ESE, 1989a). The criteria used for selecting samples for EP analysis are not known. The soil sampling conducted during the initial remedial investigation of the Hudson County sites was not random and not all samples collected were submitted for laboratory analysis. Samples thought to contain elevated chromium levels were submitted for laboratory quantitation (ESE, 1989a). Consequently, the final analytical results may not be representative of the typical level of contamination at the sites. Broad spectrum metals analysis was performed for 24 metals in 28 of the soil samples (ESE, 1989a). These analyses indicated higher than naturally occurring levels of chromium, cobalt, lead, and magnesium. For magnesium and iron, this was logical since
200
PAUSTENBACH,
RINEHART,
AND
SHEEHAN
chromium ore often contains concentrations of some metals above background levels. The presence of other metals was due to other factors, AIR SAMPLING
DATA
Samples of airborne chromium-contaminated dust were collected between August and October 1989 at 17 different Kearny, New Jersey, locations known to contain chromium residue. The sampling was conducted at the time of year during which the potential for dust generation was the greatest. The average temperatures during the sampling period ranged from 53 to 85”F, the average relative humidity ranged from 50 to 80% and winds averaged 5 to 12 mph. In the event of rain, sampling was postponed until the next day. The particulate sampling method was developed by the California Air Resources Board (CARB) and the South Coast Air Quality Management District (SCAQMD), which uses an impinger collection method for Cr(V1) particulate sampling, modified from USEPA Method 5 (CARB, 1986). This method involves collection of airborne particulates carrying adsorbed Cr(V1) compounds in a series of Greenberg-Smith impingers. Each impinger contains a slightly alkaline buffer solution to trap and stabilize the reactive Cr(V1) valence state. CARB has also proposed an ion chromatography (IC) method for the separation of Cr(V1) from Cr(II1) in the impinger solutions (CARB Method ADDL006). The separated Cr(V1) is then quantified by visible absorption spectroscopy (VAS) according to NIOSH Method 7600 (NIOSH, 1984). Using this impinger-IC-VAS method for the detection of very low levels of airborne Cr(VI), an LOD of 0.1 ng/m3 can be attained. The exact procedures used to measure airborne concentrations of Cr(V1) at Hudson County sites, along with data validating these methods, have been reported elsewhere (Sheehan et al., 1991). The method used to obtain the air sampling results assessed by the Panel differs from the CARB procedure in two ways: (1) the volume of buffer in each impinger is 200 ml rather than 100 ml, and (2) the third impinger contains buffer solution rather than being empty. These modifications were introduced to enhance the particulate collection efficiency and to improve the overall precision of the method (Sheehan et al., 1991). Outdoor sampling for total chromium was conducted in accordance with the method described in the Code of the Federal Register (40 CFR, Part 50). This method involves the use of a high-volume sampler that draws air through a glass fiber filter at a flow rate of 1lOO- 1700 liters per minute (lpm) for a period of approximately 24 hr. The filter is then digested in nitric acid, and the chromium collected is quantified using atomic absorption spectrometry according to USEPA Method 2 18.2 CLP-M, or by inductively coupled plasma-mass spectrometry (ICP-MS) (USEPA Method 6020). Total chromium in indoor air was collected on a mixed cellulose ester filter. The air sampling was performed over a 24-hr period at a flow rate of approximately 20 lpm, and the analysis was by ICP-MS. The limit of detection of this method is l-10 rig/m’, depending on the performance of the ICP-MS instrument. The Panel evaluated the results of the air sampling program conducted at the 17 industrial/commercial sites in Keamy (Table 2). This program is discussed elsewhere (Falerios et al., 199 1). The outdoor total chromium concentrations range from 0.6 to 57 ng/m3 (arithmetic mean of 16.7 ng/m3). The outdoor Cr(V1) concentrations were
2.2. 2.6
2.7,
TOXICOLOGY
AND
PHARMACOLOGY
13,
195-222 (1991)
The Health Hazards Posed by Chromium-Contaminated Soils in Residential and Industrial Areas: Conclusions of an Expert Panel D. J.~AUSTENBACH,*
W.E. RINEHART,~AND
P.J. SHEEHAN*
ThemRisk, McLaren/Hart Environmental Engineering, I135 Atlantic Avenue, Alameda, California 94501: and tlndustrial Health Foundation, 34 Penn Circle West, Pittsburgh, Pennsylvania 15206
Received August 25, 1990
Between 1905 and 1971, over 2 million tons of residue from chromite ore processing was generated in Hudson County, New Jersey, of which substantial amounts were used as fill and tank diking. A panel of medical, toxicology, and risk assessment experts was convened in early 1990 to evaluate the potential health hazards posed by the resulting chromium contaminated soil. The Panel concluded that soils containing concentrations of 75 ppm hexavalent chromium [Cr(VI)] and 1000 ppm total chromium compounds (about 95% was trivalent chromium [Cr(III)]) did not pose a significant health hazard to nearby residents and workers. They also determined that exposure to chromium from Hudson County sites posed a negligible cancer hazard to residents. Using risk assessment methods, the Panel estimated that the plausible incremental cancer risk to individuals at residential siteswould be substantially lessthan I in 1,OOO,OOO. The average measured levels of airborne Cr(VI) at typical industrial sites were more than IOOO-fold lower than the current OSHA Permissible Exposure Limit (PEL). The maximum plausible increased cancer risk for an average worker at a dusty industrial site was estimated to be less than 1 in 100,000. The Panel also concluded that chromium-containing crystals, which have occasionally been found in Hudson County buildings, do not pose a significant hazard. However, they suggested that were the concentration to exceed 5000 ppm Cr(V1) in the crystals, site-specific health risk assessments would be conducted and remediation considered. The Panel evaluated the dermal hazard posed by chromium-contaminated soil and acknowledged that there is a small group of persons (approximately 0.1% of the United States population) who currently have a dermal sensitization to Cr(V1) primarily through occupational exposure. Based on published studies of human volunteers. the Panel concluded that a small percentage (less than 5%) of persons already sensitized may respond to Cr(V1) in solution at concentrations above 35 ppm. They decided that a much higher concentration in soil, perhaps 350 ppm Cr(VI), would be necessary to elicit dermatitis because only a fraction of the chromium in soil is soluble. The Panel concluded that it was highly unlikely (if not impossible) for a person to become dermahy sensitized to Cr(V1) or Cr(III) at the soil concentrations found in most areas in Hudson County. The Panel was of the opinion that the 75 ppm total chromium [Cr(III) and Cr(VI)] cleanup requirement for Hudson County soils, which was established by the New JerseyDepartment of Environmental Protection (NJDEP), is unusually stringent and that much higher levels would still be protective of public health. Last, the Panel noted that although biological monitoring can be useful for evaluating persons exposed to relatively high concentrations of Cr(VI), the urine or blood sampling of persons living or working near these sites would probably not be beneficial until a more sensitive analytical method is available and/or until a very large control group is evaluated so that the background concentrations of chromium in biological fluids (and the variability) can be defined. o 1991 Academic RW, IW. 195 0273-2300/91
$3.00
Copyright 0 199 I by Academic Press, Inc. All rights of reproduction in any form reserved
196
PAUSTENBACH,
RINEHART,
AND SHEEHAN
INTRODUCTION Chromium processing in Hudson County, New Jersey, began around 1905 and continued, at varying activity levels, through 197 1 (ESE, 1985, 1989a). Chromite ore was processed in kilns to produce various hexavalent [Cr(VI)] and trivalent [Cr(III)] chromium products. An ore residue (slag) was a by-product of these manufacturing activities. Some of this residue, which resembled gravel, was used as fill material at numerous locations within the County to reclaim marshlands (so-called “New Jersey meadowlands”), for industrial building pads and parking lots, for tank dikes, and for backfill at sites following demolition. Since 1980, there has been significant public and regulatory concern regarding the potential risk to human health posed by the presence of the chromite ore residue (Hanley, 1989; Diamond, 1990). The reasons for these concerns are varied, ranging from the potential cancer risk and dermatitis hazard to residents to the potential impact on wildlife. Because the chronic inhalation of Cr(V1) has been shown to cause an increase in the rate of lung cancer in individuals occupationally exposed during the production of dichromate compounds and chromic acid, there was concern that these Hudson County residues might pose a potential hazard for persons working at or living near these sites (Mancuso and Hueper, 195 1). In light of these concerns, an expert review panel was convened in January 1990 to evaluate the possible health hazards posed by the contamination. This Panel was organized by the Industrial Health Foundation (IHF). Since its formation in 1935, the IHF has studied a variety of occupational health issues involving exposure to industrial chemicals including silica, asbestos, and fiberglass. IHF’s interest in chromium began in 1973 when it served as the coordinating body for an international group of chromium producers. Since that time, IHF has sponsored various conferences and meetings with an emphasis on health-related chromium research in the United States (IHF, 1980, 1986). Funding for the Chromium Panel was provided by AlliedSignal, Inc., Maxus Energy Corp. (on behalf of the Occidental Chemical Corp.), and PPG Industries, Inc.’ The Panel was charged with three objectives. The first was to review two risk assessments of selected Hudson County sites which were prepared by independent consulting firms and to offer an opinion regarding the validity of each. The second objective was to assess the scientific merit of the New Jersey Department of Environmental Protection (NJDEP) document titled “Derivation of a Risk Based Chromium Cleanup Level in Soil Contaminated with Chromite Ore Processing Residue: Hudson County” (NJDEP, 1989). Based on that analysis, the NJDEP (the lead regulatory agency) proposed a 75 ppm total chromium [Cr(III) and Cr(VI)] soil cleanup level. Third, the Panel was asked to offer an opinion regarding the health protectiveness and reasonableness of a 1000 ppm total chromium and 75 ppm hexavalent chromium cleanup criterion for soil. HISTORY
OF CHROMIUM
RESIDUES
IN HUDSON
COUNTY
Chromate and bichromate compounds were produced from chromite ore by three manufacturing plants located in Hudson County. These were the Mutual Chemical ’ The authors of this paper served as scientific advisors and support staff to the panel.
CHROMIUM-CONTAMINATED
SOILS
197
Co. (later Allied Chemical Co.) located in Jersey City (1905-l 954); Natural Products Refining Co. (later Columbia Southern Chemical, then PPG Industries) also in Jersey City (1924-1963); and Diamond Alkali Shamrock Co. (later Diamond Shamrock Corp., then Diamond Shamrock Chemicals Co.) in Keamy ( 19 16- 197 1). Chromite ore processing at these facilities produced an estimated two million tons of an alkaline waste residue containing 2 to 5% total chromium (NJDEP, 1984/1985). This residue was mixed with clean dirt, which resulted in soil concentrations of about 1000 to 5000 ppm total chromium. This waste slag resembles gravel in texture but is reddish-brown in color (ESE, 1989a). Today, over 40 sites have been identified where this chromite residue was used as fill material in Hudson County (ESE, 1989b). A remedial investigation was conducted at 42 Hudson County sites by Environmental Science and Engineering (ESE), a contractor to NJDEP (ESE, 1989a). ESE determined that 11 of the suspect sites did not contain the slag fill, since less than 100 ppm total chromium was found in the soil. Twenty-seven sites were reported to have concentrations greater than 1000 ppm, and two sites were not tested. At the remaining two sites, only one soil sample each was collected and analyzed, so it is not possible to draw any conclusions regarding the extent of contamination at these sites. The depth of maximum chromium contamination ranges from the surface to about 9 feet (Table I), but at most sites contamination is limited to the top 3 to 5 feet. At most locations, only a portion of the site required fill; therefore, chromiumcontaminated soils are found only in discrete areas. Of the 100 or so total suspected sites, about 20 to 30 are currently vacant lots in Jersey City, 28 others are residential, 12 are industrial/commercial, and 2 are recreational. Of the original 42 suspect sites, 4 were selected by ESE as representative of worst-case conditions for the following land use categories: residential, public land, industrial with no truck traffic, and industrial with heavy truck traffic (ESE, 1989b). Information on these 4 representative, worst-case sites is presented in Table 1. The major bodies of water near the pertinent sites are the Hackensack River, Hudson River, Newark Bay, Upper New York Bay, and Penhorn Creek. Most of the region is tidal marsh intersected by streams, with elevations only a few inches above high tide (ESE, 1989a). Groundwater moves toward the two bays. There is a surhcial and a bedrock aquifer. The shallow groundwater is not used for any purpose and the bedrock aquifer’s use is limited due to its high mineral content (ESE, 1989a). Chromium contaminated fill has a minimal to moderate impact on the shallow groundwater since the USEPA MCL for total chromium in water is 100 pug/liter (Marshack, 1989), and the soluble total chromium concentrations detected range from less than 20 pg/liter (limit of detection, LOD) to 200 pug/liter (ESE, 1989a). Hexavalent chromium was not detected in any of the groundwater samples. SOIL DATA Analyses of soil samples obtained during the ESE remedial investigation indicated that total chromium concentrations measured at the 42 suspect sites range from 4.7 ppm to 19,800 ppm, with an arithmetic mean of 1138 ppm (ESE, 1989a). These results are graphically portrayed in Fig. 1. The average Cr(V1) soil concentration at these sites was 2.6% of the average total chromium concentration; that is, if the soil contained 1000 ppm total chromium,
198
PAUSTENBACH.
RINEHART,
AND
TABLE CHROMIUM
Site number 1 2 3 4 5 6 1 8 9 10 11 12 13 14 15” 16 17 18’ 19’ 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 31 38 39 40 41 42’
LEVEL.Y AT VARIOUS
Maximum depth of total Cr contamination (feet) 6 9 9 Not sampled 9 9 6 6 SF* 6 6 5.5 6 3 6 6 6 6 9 9 6 Not sampled 3 SF SF* 36 SFb 3 3 SF* SF* 3* 3b SF* SF* SF* 9 3 9 9 9 6
Arithmetic
SHEEHAN
1 HUDSON
COUNTY
mean
ttobl Cd (m-4 259 3264 319 Not sampled 1859 4265 25.8 110 47.1 2181 54.1 1049 388 1031 628 2513 1273 2335 2179 3326 22.7 Not sampled 112 716 26.9 21 44.1 155 40 14.6 14.5 17 64d 20.4 16.5 3gd 172 897 2158 4024 1542 3695
SITES (1990)”
Geometric
mean
[total Crl bpm) 80 1005 158 Not sampled 1413 768 22.9 33 40.3 884 46.6 218 74.8 122 76.6 1518 130 426 323 2472 17.7 Not sampled 182 120 23.1 18.7 29.5 120 34 14.3 13.6 57 64d 17.3 13.4 3Sd 108 60 183 709 499 182
Note. SF, surface sample. a Source: ESE Remedial Investigation, 1989. * Depth sampling insufficient; indicated maximum ’ Sites selected by ESE for risk assessment ( 1989). d Only one sample analyzed.
contamination
depth
may not be reliable.
Range [total Cr]
km4 20-1,800 93-8,400 27-1.600 Not sampled 5 10-5.800 93-19.000 9.2-58 6.6-640 24-88 76-4,700 29- 100 17-8,800 20-2,300 17-4,800 4.7-4,960 410-7,300 16-7.700 9.3-13,000 8%12,500 410-8.100 7.1-47 Not sampled 22-2.500 13-4.400 14-37 1 l-55 8.4-90 53-270 24-93 12-22 8.4-23 31-190 64d 9.2-5 1 7.9-38 3Sd 30-590 12-6,100 25-19,800 21-18,000 43-9,300 120-7,500
CHROMIUM-CONTAMINATED
199
SOILS
n
I
q
ARITHMETIC MEAN CONCENTRATIONS GEOMETRIC MEAN CONCENTRATIONS
# Sites
o-25
26-50
51-75
>lOl
76-100
ICr (VU (twm)l 35 30 25
1 Sites
20
r-l
O-250
251-500
501-750 lrotal
751-1000
1001-2000
12001
CrI (pm)
FIG. 1. Soil concentrations of Cr(II1) and Cr(V1) at 42 selected sites in Hudson County, New Jersey (Source: ESE, 1989a).
then approximately 26 ppm was Cr(V1). At most of the sampled sites, the highest chromium concentrations were found at or near the surface (Table 1). Leachate concentrations (extraction procedure (EP) toxicities) based on the extraction procedure presented in USEPA Method 13 10 (USEPA, 1986) were above USEPA’s hazardous waste classification limit for total chromium of 5 mg/liter in only 4 of the 43 soil samples tested (ESE, 1989a). The criteria used for selecting samples for EP analysis are not known. The soil sampling conducted during the initial remedial investigation of the Hudson County sites was not random and not all samples collected were submitted for laboratory analysis. Samples thought to contain elevated chromium levels were submitted for laboratory quantitation (ESE, 1989a). Consequently, the final analytical results may not be representative of the typical level of contamination at the sites. Broad spectrum metals analysis was performed for 24 metals in 28 of the soil samples (ESE, 1989a). These analyses indicated higher than naturally occurring levels of chromium, cobalt, lead, and magnesium. For magnesium and iron, this was logical since
200
PAUSTENBACH,
RINEHART,
AND
SHEEHAN
chromium ore often contains concentrations of some metals above background levels. The presence of other metals was due to other factors, AIR SAMPLING
DATA
Samples of airborne chromium-contaminated dust were collected between August and October 1989 at 17 different Kearny, New Jersey, locations known to contain chromium residue. The sampling was conducted at the time of year during which the potential for dust generation was the greatest. The average temperatures during the sampling period ranged from 53 to 85”F, the average relative humidity ranged from 50 to 80% and winds averaged 5 to 12 mph. In the event of rain, sampling was postponed until the next day. The particulate sampling method was developed by the California Air Resources Board (CARB) and the South Coast Air Quality Management District (SCAQMD), which uses an impinger collection method for Cr(V1) particulate sampling, modified from USEPA Method 5 (CARB, 1986). This method involves collection of airborne particulates carrying adsorbed Cr(V1) compounds in a series of Greenberg-Smith impingers. Each impinger contains a slightly alkaline buffer solution to trap and stabilize the reactive Cr(V1) valence state. CARB has also proposed an ion chromatography (IC) method for the separation of Cr(V1) from Cr(II1) in the impinger solutions (CARB Method ADDL006). The separated Cr(V1) is then quantified by visible absorption spectroscopy (VAS) according to NIOSH Method 7600 (NIOSH, 1984). Using this impinger-IC-VAS method for the detection of very low levels of airborne Cr(VI), an LOD of 0.1 ng/m3 can be attained. The exact procedures used to measure airborne concentrations of Cr(V1) at Hudson County sites, along with data validating these methods, have been reported elsewhere (Sheehan et al., 1991). The method used to obtain the air sampling results assessed by the Panel differs from the CARB procedure in two ways: (1) the volume of buffer in each impinger is 200 ml rather than 100 ml, and (2) the third impinger contains buffer solution rather than being empty. These modifications were introduced to enhance the particulate collection efficiency and to improve the overall precision of the method (Sheehan et al., 1991). Outdoor sampling for total chromium was conducted in accordance with the method described in the Code of the Federal Register (40 CFR, Part 50). This method involves the use of a high-volume sampler that draws air through a glass fiber filter at a flow rate of 1lOO- 1700 liters per minute (lpm) for a period of approximately 24 hr. The filter is then digested in nitric acid, and the chromium collected is quantified using atomic absorption spectrometry according to USEPA Method 2 18.2 CLP-M, or by inductively coupled plasma-mass spectrometry (ICP-MS) (USEPA Method 6020). Total chromium in indoor air was collected on a mixed cellulose ester filter. The air sampling was performed over a 24-hr period at a flow rate of approximately 20 lpm, and the analysis was by ICP-MS. The limit of detection of this method is l-10 rig/m’, depending on the performance of the ICP-MS instrument. The Panel evaluated the results of the air sampling program conducted at the 17 industrial/commercial sites in Keamy (Table 2). This program is discussed elsewhere (Falerios et al., 199 1). The outdoor total chromium concentrations range from 0.6 to 57 ng/m3 (arithmetic mean of 16.7 ng/m3). The outdoor Cr(V1) concentrations were
2.2. 2.6
2.7,
