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HEALTH CONSULTATION


PUBLIC COMMENT RELEASE


Review of Dioxin and Metals Sampling Data

INTERNATIONAL MINERALS AND CHEMICALS (IMC)
AND
ARKWRIGHT DUMP
SPARTANBURG, SPARTANBURG COUNTY, SOUTH CAROLINA


Use of trade names and commercial sources is for identification only and does not imply endorsement by the Agency for Toxic Substances and Disease Registry or the U.S. Department of Health and Human Services.


BACKGROUND AND STATEMENT OF ISSUES

The U.S. Environmental Protection Agency (EPA) Region IV office asked the Agency for ToxicSubstances and Disease Registry (ATSDR) to review and evaluate analytical data acquired byBoston Chemical Data Corporation for contaminants in surface soil, sediments, and home dustnear the International Minerals and Chemical (IMC) and Arkwright Dump sites in Spartanburg,Spartanburg County, South Carolina (SC), and address possible health effects to currentresidents living near the sites [1]

The IMC site is a former nitrogen-phosphate-potassium fertilizer production facility with approximately 41 acres located in a mixed residential, industrial and undeveloped area. This facility operated from 1910 to 1986. The site is surrounded by undeveloped property and Fairforest Creek to the north, Seaboard Railroad to the west, Fairforest Creek to the east, and residences and the Arkwright Dump to the south (see intro map). The 30-acre Arkwright Dump received municipal, automotive, and medical waste from 1954 to 1972. Since 1991, a series of activities was conducted at these two sites. These activities include preliminary site assessments, hydrogeological assessments, site inspections, and public health consultations. On-site contaminants identified include metals (arsenic, cadmium, mercury, lead, and nickel), and organic compounds such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and dioxins [2,3,4]. Previous ATSDR health consultations for these two sites concluded that the contaminants present in the on-site surface soil, subsurface soil, and sediment do not pose a public health hazard [3,4]. Recent site visit conducted by EPA, ATSDR and IMC representatives confirmed that (1) the main plant building and most structures on the IMC site were demolished and removed, (2) small amounts of demolition debris and production waste remained on the property, and (3) no obvious signs of stressed vegetation were noted on the former surface impoundments and backfilled settling pond areas.

This health consultation will review and evaluate available analytical data collected on March 22through June 19, 2001, by Boston Chemical Data Corporation, under contract to the communitygroup ReGenesis. Samples were collected from on-site and off-site surface soil, sediments, andhome dust and analyzed for metals, dioxin, and some soil nutrients.


DISCUSSION

The potential health effects associated with environmental exposure depends on several factors,such as type and amount of contaminants, amount of contaminants absorbed by the body, routeand duration of exposure, site-specific conditions, genetic factors, and individual lifestyle.ATSDR uses different comparison values (CVs) (i.e., all of the chemical-specific, health-basedstandards and guidelines) derived by various government agencies to screen and identifycontaminants that require further evaluation for possible health effects. While concentrations ator below the relevant CV might reasonably be considered safe, it does not imply that a levelgreater than the screening value will necessarily lead to harmful health effects. For contaminantswith concentrations exceeding their respective CVs, ATSDR performs a more in-depthevaluation using site-specific exposure scenarios.

The following CVs are used for this health consultation: ATSDR environmental mediaevaluation guidelines (EMEGs), minimal risk levels (MRLs), reference dose media evaluationguides (RMEGs), cancer risk evaluation guides (CREGs), and EPA soil screening levels.

The most likely human exposure to contaminants found in surface soil, sediments, and homedust is incidental ingestion and/or dermal contact through gardening, doing yard work, accessingcrawlspace areas, and children playing in the dirt. Inhalation exposures to the above media areconsidered to be minimal.

It should be noted that environmental data for this evaluation is not sufficient and subject tosome limitations. Results for dioxin in home dust, metals in home dust, and metals in surface soiland sediments are discussed below.

Dioxin in home dust

Dioxins are a family of 75 chlorinated organic compounds that are formed during combustion(e.g., burning of wood and other fuels, and smoking cigarettes) and certain industrial processes(e.g., incineration of municipal and medical solid waste, and manufacture of certain pesticides).Dioxins are found everywhere in the environment at very low levels. For the general population,the majority of the daily intake of dioxins and other dioxin-like compounds comes from foodsuch as meat, dairy products, and fish. Since individual dioxins have varying toxicity, toxicityequivalency factors (TEFs) are established to estimate the relative toxicity of dioxin and dioxin-like compounds to the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxicand extensively studied form of dioxin. TEF for TCDD is assigned as 1.0. All other forms ofdioxin (congeners) and dioxin-like compounds (including furans) have lower TEF valuesranging from 0.00001 to 0.5. Calculating the toxic equivalency (TEQ) of a mixture involvesmultiplying the concentration of individual congeners by their respective TEF, and adding up theTEQ concentrations for the individual congeners as total TEQ for the mixture. TEFsrecommended by the world health organization (WHO) in 1998 were used for this healthconsultation [5].

Dioxin was detected in eight dust samples collected from the refrigerator coils in houses near theIMC and Arkwright Dump sites as summarized in Table 1. The highest concentration was foundin sample I93 at a concentration of 568 parts per trillion (ppt) dioxin total TEQ. ATSDR has notestablished a media specific CV for dioxin in home dust. ATSDR guidelines recommend that ifdioxin levels exceed 50 ppt in surface soil, further evaluation is needed to assess site-specificexposures. ATSDR has recommended that at a concentration of 1,000 ppt dioxin total TEQ,actions should be taken to reduce or eliminate exposure [6]. Soil in a residential yard is readilyaccessible and children would come into contact with the contaminated soil on a frequent andlong-term basis. However, since the dust samples were taken from the refrigerator coils, the mostlikely human exposures are incidental ingestion and/or contact with contaminated dust bypersons participating in occasional housework activities such as cleaning or moving. The intakefrom these activities is considered minimal. However, dioxin contamination in the refrigeratorcoils dust indicated that dioxins might exist in living surface areas in houses. Furtherinvestigation is needed to verify dioxin contamination on living surface areas ( i.e., points ofexposure) in homes.

Table 1.

Summary of Total Dioxin TEQs (ppt) in Home Refrigerator Coils Dust Samples
Sample ID Sample Date Results (TEQ)
I90 3/22/2001 180 ppt
I87 3/22/2001 145 ppt
I93 3/22/2001 568 ppt
I95 3/22/2001 421 ppt
I101 3/22/2001 116 ppt
I105 3/22/2001 269 ppt
I109 6/19/2001 189 ppt
I111 6/19/2001 75 ppt

Metals in home dust

As summarized in Table 2, 33 dust samples were collected for metal analysis from therefrigerator coils and vacuum bags in houses near the IMC and Arkwright Dump sites. Results ofseven metals (i.e., beryllium, chromium, copper, mercury, nickel, zinc, and cadmium) werebelow their respective comparison values. One metal (i.e., antimony) was not analyzed. Arsenicand lead concentrations exceeded the ATSDR screening values as noted below.

Arsenic is a naturally occurring element, present at low levels in soil, water, food, and air. TheU.S. Geological Survey reports the range of arsenic in soil and other surficial materials as lessthan 0.1 mg/kg to 97 mg/kg, with a mean value of 7.2 mg/kg [7]. SC background level forarsenic in soil is approximately 20 mg/kg [8]. In the dust samples, arsenic concentrations rangedfrom nondetect to 25 mg/kg, with an average of 8.97 mg/kg. The ATSDR chronic EMEG foradults is 200 mg/kg, which is much higher than the concentrations found in the dust samples. Forchildren, the chronic EMEG is 20 mg/kg. The chronic EMEGs are soil arsenic concentrationsthat are unlikely to be associated with any appreciable risk of adverse noncancer effects forexposures over the course of 1 year. It is unlikely that residents would be exposed to themaximum concentration on a daily basis. Therefore, no adverse health effects (noncarcinogenic)would result from incidental ingestion and/or contact with the house dust.

The ATSDR CREG for arsenic in soil is 0.5 mg/kg. The CREG is an estimated arsenicconcentration in soil that would be expected to cause no more than 1 excess cancer in 1 millionpersons exposed over a lifetime. The following is a dose calculation based on very conservativeexposure assumptions for the site. A 70 kg adult ingesting 100 mg of dust per day containing 25mg/kg of arsenic would be exposed to an estimated dose of 0.000035 mg/kg/day. EPA uses anoral cancer slope factor of 1.5 per mg/kg/day for arsenic based on a conservative assumption ofcancer risk. On the basis of these assumptions, we can say that persons who have a continuouslifetime exposure to arsenic at an estimated dose of 0.000035 mg/kg/day face no apparentincreased risk of developing cancer.

Lead is another naturally occurring element found in small amounts in the earth's crust. The general population is exposed to lead in air, food, drinking water, soil, and dust. Multimedia contamination of lead at residential areas results from many different sources such as lead-based paint, old plumbing fixtures, soil and dust contaminated by combustion of leaded gasoline and other industrial sources. Lead-contaminated soil and home dust present a health concern to children, particularly for children less than 2 years old. ATSDR considers residential soil levels of 400-1,000 mg/kg as needing further evaluation on the basis of children's unique susceptibility (See "Child Health Initiative" below) [9]. In the dust samples, lead concentrations ranged from 21 to 560 mg/kg, with an average of 84.8 mg/kg. In three dust samples, lead concentrations were above 400 mg/kg. Since the dust samples were taken from the refrigerator coils and vacuum bags, where children are unlikely to have access, lead intake is considered minimal. However, high lead concentration on the refrigerator coils and in the vacuum bags indicated that lead contamination might exist on surface living areas in houses. Further investigation is needed to verify lead contamination on surface living areas in homes.

Metals in surface soil and sediments

As summarized in Table 3, 52 surface soil and sediment samples were collected for metalanalysis from residential yards and other areas near the IMC and Arkwright Dump sites. Resultsof eight metals (i.e., beryllium, chromium, copper, mercury, nickel, antimony, zinc, andcadmium) were below their respective CVs. Arsenic and lead concentrations exceeded ATSDRscreening values as noted in the following paragraphs.

Arsenic analysis was conducted on 31 samples. Arsenic concentrations ranged from nondetect to7.7 mg/kg, with an average of 3.8 mg/kg. As mentioned previously, arsenic concentrationsexceeded the ATSDR CREG of 0.5 mg/kg for arsenic in soil. However, dose calculations basedon very conservative assumptions of exposures indicated that concentrations were below levelsexpected to cause adverse health effects.

Among the 49 samples analyzed, lead concentrations ranged from 9-2,100 mg/kg, with anaverage of 125.67 mg/kg. Three samples with the sample identification numbers 30, 52, and I119contained 2,100, 550, and 530 mg/kg of lead, respectively. If those sample "hot spots" are inareas where contact with soil is frequent, such as play areas with residential bare surface soil, they might present a health hazard for children.


CHILD HEALTH INITIATIVE

ATSDR considers children in the evaluation of all exposures and uses health guidelines that areprotective of children. In evaluating any potential health effects from environmental exposures,children were considered a special population because of their size, body weight, frequent hand-to-mouth activity, and unique susceptibility to chemicals. For this health consultation, ATSDRhas taken into account that children are at a greater risk for lead poisoning than adolescents oradults: (1) the normal behavior of children might result in higher rates of ingestion of soil anddust, (2) children might also receive a higher dose of lead because following ingestion theyabsorb more lead into their blood and they have lower body weights than adults, (3) some children might eat soil excessively (called pica behavior), and (4) the centers fordisease control and prevention (CDC) and ATSDR report that blood levels in young childrenhave been raised, on average, 5 micrograms per deciliter of blood for every 1,000 mg/kg of leadin residential soil or dust [10,11]. CDC recommends that young children be tested for leadpoisoning if they have been in contact with lead-contaminated soil or dust [8].


EVIRONMENTAL DATA LIMITATIONS AND GAPS

Available environmental data for this evaluation is not sufficient and subject to some limitations.The following issues were identified regarding data quality and adequacy according to the EPAenvironmental investigation standard operating procedures and quality assurance manual[12,13]:

  • Site sampling plan and data quality objectives were not available. Development of a site-specific sampling plan is essential to all environmental sampling events. A sampling plan shouldidentify sampling objectives, describe sample collection and analyze methodology andprocedures, define data quality objectives, and establish a quality control (QC) and qualityassurance (QA) program. Without this information, it is difficult to make complete and definitive public health evaluations for the community from data received.

  • Field QA/QC samples were not identifiable or not sufficient. Only one sample (sampleID 39) was identified as a field blank out of approximately 110 samples taken on March 22through June 19, 2001. Typical field quality control samples should include (1) a sufficientamount of QA/QC samples (e.g., one for every 20 field samples), and (2) a variety of QA/QCsamples such as splits, duplicates, trip and field blanks, etc.

  • Chain-of-custody procedures were not established or implemented. For example, (1)home dust samples for dioxin were sent to the lab without custody seals or broken seals, (2)home dust samples for dioxins were sent to the laboratory outside of its temperaturespecification of 21 C (This might not affect the results for dioxins for the event, but it is anindication of a limited QA/QC program).

  • No documentation was available for laboratory procedures and the analytical method for metals. Only summary tables with detected concentrations were submitted to ATSDR.

  • Data representative of the points of exposure, i.e., surface soil samples for dioxins andsurface living area dust samples for lead and dioxins are not available for this evaluation.

CONCLUSIONS

On the basis of the available information, ATSDR concludes the following:

  1. The extent of dioxin and lead contamination in surface soil and surface living area dust has not been fully characterized.

  2. Data characterizing the extent of lead contamination in the surface soil is limited. However, some samples of residential soil lead above 400 mg/kg were reported. The "hot spots" might present a health hazard for children if frequent contact occurs.

  3. Because of the environmental data limitations and gaps as outlined in this report, ATSDR has categorized this site as an "Indeterminate Public Health Hazard" until sufficient data becomes available.

RECOMMENDATIONS

On the basis of the best public health practices, ATSDR recommends the following:

  1. Characterize and evaluate the extent of dioxin and lead contamination in surface soil andcontamination on surface living areas. It is important to address multimedia contamination to establish the best overall site management strategy.

  2. Determine the extent of contact in areas where lead is greater than 400 mg/kg. Evaluatesite-specific exposure scenarios for those areas. A comprehensive approach could include healtheducation, community involvement, and prevention and surveillance programs supported byappropriate federal and local health agencies as well as potentially responsible parties and individual homeowners.

  3. Ensure that future environmental data collections are carried out according to the EPA environmental investigation standard operating procedures and quality assurance requirements.

PREPARERS OF REPORT

Jane Zhu, MPH
Health Consultations Section
Exposure Investigations and Consultations Branch
Division of Health Assessment and Consultation


Reviewed by

Benjamin Moore
Regional Representative
Office of Regional Operations, Region IV
Agency for Toxic Substances and Disease Registry

Tracy Shelly, MS
Division of Health Hazard Evaluation
Department of Health and Environmental Control
South Carolina

Susan Moore
Chief, Health Consultations Section
Exposure Investigations and Consultations Branch
Division of Health Assessment and Consultation

John E. Abraham, PhD
Branch Chief
Exposure Investigations and Consultations Branch
Division of Health Assessment and Consultation


REFERENCES

  1. Agency for Toxic Substances and Disease Registry. Technical assistance request to the Exposure Investigation and Consultations Branch from Benjamin Moore, ATSDR Region IV representatives. Atlanta: US Department of Health and Human Services; 2001 Aug 27.

  2. Tetra Tech EM Inc. Final expanded site inspection report--International Mineral andChemical Corp. EPA Contract No. 68-W-00-120, Technical Direction Document No. 4T-01-11-A-003. Pasadena, California: Tetra Tech EM Inc.; 2000.

  3. Agency for Toxic Substances and Disease Registry. Health consultation for InternationalMineral and Chemical, Spartanburg, South Carolina. Atlanta: US Department of Health andHuman Services; 1999 Nov 8.

  4. Agency for Toxic Substances and Disease Registry. Health consultation for ArkwrightDump, Spartanburg, South Carolina. Atlanta: US Department of Health and Human Services;2000 May 26.

  5. Agency for Toxic Substances and Disease Registry. Toxicological profile for chlorinateddibenzo-p-dioxins (update). Atlanta: US Department of Health and Human Services; 1998

  6. Agency for Toxic Substances and Disease Registry. Dioxin and dioxin-like compoundsin soil, part I: ATSDR interim policy guideline. Atlanta: US Department of Health and HumanServices; 1997.

  7. Agency for Toxic Substances and Disease Registry. Toxicological profile for arsenic(update). Atlanta: US Department of Health and Human Services; 2000 Sep.

  8. Personal Communication. SCHEC-HHE. Comments on the ATSDR Draft HealthConsultation for IMC and Arkwright Dump Sites. Tracy Shelley. 2002.

  9. Agency for Toxic Substances and Disease Registry. Toxicological profile for lead(update). Atlanta: US Department of Health and Human Services; 1999 Jul.

  10. Centers for Disease Control and Prevention. Preventing lead poisoning in young children:a statement by CDC--October 1991. Atlanta: US Department of Health and Human Services.

  11. Agency for Toxic Substances and Disease Registry. Analysis paper: impact of lead-contaminated soil on public health. Atlanta: US Department of Health and HumanServices; 1992.

  12. US Environmental Protection Agency. Region 4 environmental investigation standardoperating procedures and quality assurance manual. Washington, DC: US EnvironmentalProtection Agency; 1996 May. Available from: URL:http://www.epa.gov/region4/sesd/eisopqam/eisopqam.html .

  13. US Environmental Protection Agency. A rationale for the assessment of errors in the sampling of soils. Washington, DC: US Environmental Protection Agency; 1990 May.

Demographic Statistics
Figure 1. Demographic Statistics

Table 2.

Summary of Analytical Results for Metals in Refrigerator Coil and Vacuum Bags Dust Samples (mg/kg)
ID # As Be Cr Cu Hg Pb Ni Sb Zn Cd
29 U3 U 0.5 20 34 U 0.04 31 - - 270 0.1
31 7.7 U 0.6 47 530 0.37 130 - - 640 6.4
34 24 U 0.3 61 140 0.24 60 - - 590 3.2
46 U 6 - - 23 - 21 - - 190 U 1
47 U 6 - - 190 - 110 - - 1500 4.9
49 U 7 - - 73 - 62 - - 250 93
50 U 6 - - 33 - 68 - - 220 U 1
I64 - - - 130 - 38 - - 290 -
I76 - - - 45 - 22 - - 79 U 1.
I84 U 8.0 - - 200 - 55 50 - 770 5.6
I85 4.4 - - 98 - 39 4.4 - 620 6.6
I87 5.8 - - 210 - 46 33 - 540 5.8
I89 16 - - 74 - 37 35 - 300 19
I90 9.7 - - 1300 - 480 45 - 1300 11
I92 U 32 - - 180 - 250 47 - 1200 7.4
I93 12 - - 5300 - 560 40 - 1000 7.6
I94 U 24 - - 140 - 79 U 48 - 600 U 5.0
I95 5.5 - - - - 41 - - 720 3.8
I97 - - - - - 47 - - 280 1.8
I99 U 36 - - 900 - 430 730 - 2900 520
I100 13 - - 180 - 90 38 - 1000 7.5
I101 - - - 36 - 36   - 380 2.8
I103 4.4 - - 120 - 41 24 - 860 5.3
I104 - - - - - 37 - - 1200 2.4
I105 - - - - - 26 - - 330 1.5
I106 25 - - 1100 - 260 49 - 1400 8.5
I107 4.9 - - 91 - 33 26 - 440 2.4
I111 - - - - - - - - 710 2.9
SSL* 0.4 150 210 2900 230 400 1600 310 23000 390


U the analyte was not detected. The associated number is the sample quanitation limit.
- The analyte was not tested.
SSL* Soil Screening Levels
Symbols As-arsenic, Be-beryllium, Cr-chromium, Cu-copper, Hg-mercury, Pd-lead, Ni-nickel, Sb-antimony, Zn-zinc, Cd-cadmium.
Data provided by Boston Chemical Data Corporation.


Table 3.

Summary of Results for Metals in Surface Soil and Sediment Samples (mg/kg)
ID # As Be Cr Cu Hg Pb Ni Sb Zn Cd
15 2.47 - 11.9 2.2 1.29 54 3 0.67 33.3 ND
20 5.7 1.43 35.2 56.1 ND 336 13.9 ND 630 4.3
30 5.6 U 0.7 30 13 0.3 2100 - - 690 2.6
32 3.8 U 0.2 43 44 U 0.05 27 - - 76 0.47
33 5.8 0.6 24 13 U 0.05 42 - - 810 0.54
35 7.7 0.44 83 38 0.12 89 - - 140 0.89
36 1.9 - - 7.1 - 10 - - 34 0.19
37 U 7 - - 28 - 59 - - 94 U 1
38 U 6 - - 26 - 47 - - 78 U 1
39 U 0.010 - - - - U 0.005 - - U 0.050 U 0.001
40 U 8 - - 22 - 48 - - 120 U 2
41 U 6 - - 33 - 52 - - 84 U 1
42 U 6 - - 35 - 35 - - 87 U 1
43 6.5 - - 34 - 160 - - 130 U 1
44 U 7 - - 28 - 120 - - 85 U 1
45 U 6 - - 32 - 19 - - 70 U 1
51 U 6 0.29 - 21 0.097 60 - - 160 0.8
52 U 9 0.56 - 120 3.7 550 - - 530 3.3
53 U 10 0.57 - 40 0.12 92 - - 160 0.92
56 U 6 0.79 - 24 0.23 33 - - 78 U 0.4
57 U 6 0.59 - 18 U 0.06 45 - - 55 U 0.3
58 U 6 1.1 - 3400 U 0.06 100 - - 140 U 0.8
59 U 7 U 0.4 - 22 U 0.1 47 - - 120 0.41
60 U 8 U 0.4 - 16 U 0.1 47 - - 190 0.85
61 U 7 U 0.4 - 32 U 0.06 29 - - 63 U 0.4
62 U 6 0.96 - 10 U 0.06 20 - - 81 0.37
63 U 7 - - 77 0.58 53 - - 340 1.7
I65 - - - 30 - 120 - - 110 -
I67 - - - 14 - 100 - - 100 -
I68 - - - 27 - 55 - - 89 -
I69 - - - 25 - 44 - - 56 -
I70 - - - 6 - 9 - - 38 -
I71 - - - 11 - 14 - - 65 -
I72 - - - 15 - 14 - - 50 -
I73 - - - 52 - 130 - - 230 -
I74 - - - 11 - 29 - - 30 -
I75 - - - 32 - 120 - - 160 -
I77 - - - 12 - 35 - - 53 -
I78 - - - 25 - 72 - - 80 -
I83 3.4 - - 41 - 78 18 - 160 0.79
I86 2.6 - - 25 - 67 12 - 190 0.75
I88 2.5 - - 36 - 69 14 - 250 2.5
I91 4.6 - - 220 - 140 20 - 430 2
I96 5.8 - - 17 - 38 18 - 140 0.5
I98 - - - - - - - - 110 -
I102 - - - 22 - - - - 130 -
I108 - - - 28 - 27 - - 540 0.94
I110 - - - 70 0.053 25 - - 49 0.82
I112 - - -   - - - - - -
I113 - - - 180 - 78 37 - 420 5.1
I114 - - - 90 - 120 17 - 440 1.5
I119 - - - 200 - 530 37 - 1800 6.2
SSL* 0.4 150 210 2900 230 400 1600 310 23000 390


U The analyte was not detected. The associated number is the sample quantitation limit.
- The analyte was not tested.
SSL* Soil Screening Levels
ND The analyte was not detected.
Symbols As-arsenic, Be-beryllium, Cr-chromium, Cu-copper, Hg-mercury, Pd-lead, Ni-nickel, Sb-antimony, Zn-zinc, Cd-cadmium
Data provided by Boston Chemical Data Corporation.


Table of Contents

  
 
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