Skip directly to search Skip directly to A to Z list Skip directly to site content

PUBLIC HEALTH ASSESSMENT

LOXAHATCHEE NURSERY
PALM CITY, MARTIN COUNTY, FLORIDA



APPENDIX A -- ACRONYMS

The acronyms used in this public health assessment are listed below, in alphabetical order.
ATSDR
Agency for Toxic Substances and Disease Registry
bls below land surface
BHC Hexachlorocyclohexane
DDD 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane
DDE 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene
DDT 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane
CLHA Child Longer Term Health Advisory
CREG Cancer Risk Evaluation Guide
EMEG Environmental Media Evaluation Guide
EPA Environmental Protection Agency

FDEP

Florida Department of Environmental Protection
HRS Department of Health and Rehabilitative Services
IARC International Agency for Research on Cancer
kg kilograms
L liter
LTHA Lifetime Health Advisory

MCHD

Martin County Health Department
MCL Maximum Contaminant Level
MCPHU Martin County Public Health Unit
mg milligrams
MRL Minimal Risk Level
NOAEL No Observed Adverse Effect Level
NTP National Toxicology Program
PCBs Polychlorinated Biphenyls
ppb parts per billion
ppm parts per million
RBCn Risk-Based Concentration (noncancer)
RMEG Reference Dose Media Evaluation Guide
SVOCs Semi-Volatile Organic Compounds
g micrograms
VOCs Volatile Organic Compounds



APPENDIX B -- FIGURES

Figure 1.  March 1998 Sampling Event Location Map -- Draft
Figure 1. March 1998 Sampling Event Location Map -- Draft

Figure 2.  Demographic Information
Figure 2. Demographic Information




APPENDIX C -- TABLES



Table 1.

Completed Exposure Pathways
Pathway Name Source Contaminants Environmental Medium Point of Exposure Route of Exposure Exposed Population Time Exposed
Groundwater Potentially the Nursery See Table 4 (private well data) Off-Site Groundwater Water from private drinking wells Ingestion, Inhalation,
Dermal
Residents with private drinking wells Past, Current, Future



Table 2.

Potential Exposure Pathways
Pathway Name Source Contaminants Environmental Medium Point of Exposure Route of Exposure Exposed Population Time Exposed
On-Site SoilNurserySee Tables 5 and 6On-Site SoilDirect contact with on-sitesoilsDermal, IncidentalIngestionResidents living on-site; TrespassersPast, Current, Future
Off-Site SoilPotentiallytheNurserySee Table 7Off-Site SoilDirect contact with off-sitesoilsDermal, IncidentalIngestionResidentsPast, Current, Future
On-Site Sediment Nursery See Table 8 On-Site Sediment Direct contact with on-site sediment in drainage ditches and the pond Dermal, Incidental Ingestion Trespassers

Past,
Current,
Future

Off-siteSedimentPotentiallytheNurserySee Table 8Off-Site SedimentDirect contact with off-sitesediment in drainageditches and the South Forkof the St. Lucie RiverDermal, IncidentalIngestionResidentsPast, Current, Future



Table 3.

HOn-Site Groundwater Sampling Results
Contaminant Concentration
Range1 (ppb)2
Year of Max,
Sample ID
Comparison Value3
Value (ppb) Source
Benzene 8 1994, Temporary Well 5 MCL
beta-BHC 0.025 I6 - 3.3 1995, MW#3 6 Intermediate EMEG (child)
20 Intermediate EMEG (adult)
gamma-BHC 0.05 1995, MW#3 0.4 Intermediate EMEG (child)
1 Intermediate EMEG (adult)
0.2 MCL
delta-BHC 0.11 (2 hits) 1995, MW#3 None
Chlordane 0.27 I - 200 1992, 1A#1A 6 Chronic EMEG (child)
20 Chronic EMEG (adult)
Chloromethane 0.54 I 1998, TW03 3 LTHA
400 CLHA
4,4 - DDD 0.031 I; 1.49 1992, 1A#1A 0.1 CREG
4,4 - DDE 0.12 1992, 1A#1A 0.1 CREG
Diazinon 4.9 1992, TW#2 2 Intermediate EMEG (child)
7 Intermediate EMEG (adult)
5 CLHA
Endosulfan I 0.12 1992, 1A#1A 20 Chronic EMEG (child)5
70 Chronic EMEG (adult)5
Endosulfan Sulfate 1.46 1992, 1A#1A 20 Chronic EMEG (child)5
70 Chronic EMEG (adult)5
Aluminum 220 1998, TW04 37,000 RBCn
Arsenic 3 I; 11.2 1998, TW04 3 Chronic EMEG (child)
10 Chronic EMEG (adult)
50 MCL
Barium 3.75 J4 - 20 1998, TW04 700 RMEG (child)
2,000 RMEG (adult)
Cadmium 0.05 I; 0.1 I 1998, TW03 7 Chronic EMEG (child)
20 Chronic EMEG (adult)
Calcium 30,000 J - 85,000 J 1998, TW04 None
Chromium 2 J - 5 I 1998, TW03 100 MCL
Copper 15 J - 25 J 1998, TW04 1,500 RBCn
Iron 91 - 1,600 1998, TW04 11,000 RBCn
Lead 0.58 - 4 J 1998, TW03 15 EPA Action Level
Magnesium 1,000 - 4,000 1998, TW04 None
Manganese 15 J - 41 1998, TW03 50 RMEG (child)
200 RMEG (adult)
Potassium 1,100 - 1,600 1998, TW04 None
Sodium 3,000 - 30,000 1998, TW04 None
Zinc 17 J - 33 1998, TW04 3,000 Chronic EMEG (child)
10,000 Chronic EMEG (adult)

Sources: ATSDR, 1996a; EPA, 1998b; Evergreen Engineering, 1996; FDEP, 1998; and McGinnes Laboratories, 1992.

Table Notes:

1. The values listed in this column indicate the range of detected concentrations for each contaminant.
2. ppb = parts per billion.
3. Please refer to Appendix D for an explanation of the comparison values used in this public health assessment.
4. J = estimated value.
5. Comparison value is for Endosulfan.
6. I = value reported is less than the minimum quantitation limit, and greater than or equal to the minimum detection limit.




Table 4.

Private Well and Off-Site Temporary Well Sampling Results
Contaminant Private Wells Concentration Range1 (ppb)2 Private Wells Year of Max Temporary Well Concentration in ppb (1998) Comparison Value3
Value (ppb) Source
Benzene

0.31 - 1 J4

1998ND51CREG
5MCL
Bromodichloro-
methane
1.3; 3.41996ND0.6CREG
200Chronic EMEG (child)
700Chronic EMEG (adult)
Bromoform1.21996ND4CREG
2,000Chronic EMEG (child)
7,000Chronic EMEG (adult)
Chloroform0.51; 9.91996ND6CREG
100Chronic EMEG (child)
400Chronic EMEG (adult)
Chloromethane0.13 - 0.82 I619980.58 I3LTHA
400CLHA
Dibromochloro-
methane
0.54; 2.81996ND0.4CREG
300Chronic EMEG (child)
1,000Chronic EMEG (adult)
Di (2-ethylhexyl)phthalate3.01996ND3CREG
200RMEG (child)
700RMEG (adult)
1,1-Dichloroethane0.211996ND810RBCn
1,2-Dichloropropane0.1 - 3301996ND900Chronic EMEG (child)
3000Chronic EMEG (adult)
5MCL
Naphthalene0.22; 0.371996ND200Intermediate EMEG (child)
700Intermediate EMEG (adult)
Styrene0.23; 0.311996ND2,000Intermediate EMEG (child)
7,000Intermediate EMEG (adult)
100MCL
1,2,3-Trichloropropane1.8 - 3.61996ND60RMEG (child)
200RMEG (adult)
Aluminum891998ND37,000RBCn
ArsenicND199827; 28.30.02CREG
3Chronic EMEG (child)
10Chronic EMEG (adult)
Barium15.6 - 2319982.16 J700RMEG (child)
2,000RMEG (adult)
Calcium1,500 J - 90,000 J199868,000 JNone
Chromium3 J19982 J100MCL
Copper15 J, 25 J1998ND1,500RBCn
Iron47 - 7,200199838011,000RBCn
Lead0.4 I - 3 J19980.3 I15EPA Action Level
Magnesium730 - 3,200199816,000None
Manganese6 J - 4619981650RMEG (child)
200RMEG (adult)
Potassium210 - 1,40019981,800None
Sodium3,400 - 160,000199815,000None
Vanadium3 J1998ND30Intermediate EMEG (child)
300Intermediate EMEG (adult)
Zinc38 - 2101998ND3,000Chronic EMEG (child)
10,000Chronic EMEG (adult)

Sources: EPA, 1998b; EPA, 1998f; FDEP, 1998; HRS, 1996b; and HRS, 1996c.

Table Notes:

1. The values listed in this column indicate the range of detected concentrations for each contaminant.
2. ppb = parts per billion.
3. Please refer to Appendix D for an explanation of the comparison values used in this public health assessment.
4. J = estimated value.
5. ND = material was analyzed for but not detected (value below the minimum quantitation limit).
6. I = value reported is less than the minimum quantitation limit, and greater than or equal to the minimum detection limit.




Table 5.

On-Site Soil Sampling Results - Soil Depth Unspecified
Contaminant Concentration Range1 (ppm)2 Year of Max, Sample ID Comparison Value 3
Value (ppm) Source
Chlordane

0.015 - >1.0

1992, #1Soil1Chronic EMEG (pica child)
30Chronic EMEG (child)
beta BHC0.00521992, #1Soil0.6 Intermediate EMEG
(pica child)
20Intermediate EMEG (child)
gamma BHC0.00381992, #1Soil0.08 Intermediate EMEG
(pica child)
2Intermediate EMEG (child)
delta BHC0.00451992, #1SoilNone
DDE0.012 - 0.0721996, West2CREG
DDD0.015 - 0.0301996, West3CREG
DDT0.0062; 0.0111996, West1RMEG (pica child)
30RMEG (child)
Dieldrin0.0131996, West0.1Chronic EMEG (pica child)
3Chronic EMEG (child)
Endosulfan II0.01031992, #2Soil4Chronic EMEG (pica child)4
100Chronic EMEG (child)4
Endrin0.0371992, #1Soil0.6Chronic EMEG (pica child)
20Chronic EMEG (child)
Endrin Aldehyde0.0321992, #2SoilNone
Heptachlor Epoxide0.0051992, #1Soil0.08CREG

Sources: ATSDR, 1996a; Evergreen Engineering, 1996; and McGinnes Laboratories, 1992.

Table Notes:

1. The values listed in this column indicate the range of detected concentrations for each contaminant.
2. ppm = parts per million.
3. Please refer to Appendix D for an explanation of the comparison values used in this public health assessment.
4. Comparison Value is for Endosulfan.




Table 6.

On-Site Surface Soil Sampling Results - 1998
Contaminant Concentration Range1 (ppm)2 Sample ID of Maximum Concentration Concentration On-Site Residence (ppm) Comparison Value 3
Value (ppm) Source
Acenaphthylene0.053 J4SS09AND7None
Carbon Disulfide0.004 J; 0.005 JSS07B0.003 J200RMEG (pica child)
5,000RMEG (child)
Alpha - Chlordane

0.0042 - 1

SS03AND1Chronic EMEG (pica child)8
30Chronic EMEG (child)8
Gamma - Chlordane 0.0044 - 1.1SS03AND1Chronic EMEG (pica child)8
30Chronic EMEG (child)8
Chlordane 0.006 I10 - 14SS03AND1Chronic EMEG (pica child)
30Chronic EMEG (child)
Bis (2-ethylhexyl)phthalate0.470 - 6.2 JSS03AND50CREG
40RMEG (pica child)
1000RMEG (child)
Captan0.003SS03BND300RMEG (pica child)
7,000RMEG (child)
Chrysene0.077 J - 0.19 JSS09AND88RBCc
Flouranthene0.041 J - 0.38SS09AND80RMEG (pica child)
2,000RMEG (child)
Benzo (a) anthracene0.065 J - 0.2 JSS09AND0.88RBCc
Benzo (b and/or k)flouranthene0.051 J - 0.24 JSS09AND0.88RBCc [benzo(b)flouranthene]
8.8RBCc [benzo(k)flouranthene]
Benzo (g,h,i) perylene0.046 J; 0.099 JSS09ANDNone
Benzo (a) pyrene0.050 J - 0.17 JSS09AND0.1CREG
4,4' - DDE0.0034 I - 0.36SS09AND2CREG
4,4' - DDD0.0013 I - 0.069 JSS03AND3CREG
4,4' - DDT0.0014 I - 0.33SS03AND1RMEG (pica child)
30RMEG (child)
Indeno (1,2,3-cd)pyrene0.055 J; 0.11 JSS09AND0.88RBCc
PCB - 12600.050 - 0.79SS02BND1RMEG (child) 9
Phenanthrene0.23 JSS09ANDNone
Pyrene0.047 J - 0.47SS09AND60RMEG (pica child)
2,000RMEG (child)
Total XylenesND--0.002 J400 Intermediate EMEG
(pica child)
10,000Intermediate EMEG (child)
Aluminum19 - 3,000SS02A51078,000RBCn
Arsenic0.7 I - 2.3SS09AND0.5CREG
0.6Chronic EMEG (pica child)
20Chronic EMEG (child)
Barium0.45 I - 12SS07A6.9100RMEG (pica child)
4,000RMEG (child)
Cadmium0.28 I - 1.1SS10AND0.4Chronic EMEG (pica child)
10Chronic EMEG (child)
Calcium220 - 66,000SS06A87,000None
Chromium0.51 I - 96.7SS10A3.610RMEG (pica child)5
300RMEG (child)5
Copper3.7 J - 130 JSS07A7.6 J3,100RBCn
Iron110 - 2,900SS03A46023,000RBCn
Lead0.7 J - 31SS03A3.1 J500EPA Action Level
Magnesium170 - 920SS07A330None
Manganese2.1 J - 650 JSS07A4.7 J10RMEG (pica child)
300RMEG (child)
4,000RMEG (adult)
Total Mercury0.19SS09AND4Intermediate EMEG

(pica child)6

100Intermediate EMEG (child)6
Potassium18 - 150SS07A69None
Selenium0.9 I; 1 ISS02AND10Chronic EMEG (pica child)
300Chronic EMEG (child)
Silver0.19 I - 1.3SS06AND10RMEG (pica child)
300RMEG (child)
Sodium500SS06A990None
Vanadium1.1 J - 3 JSS07A2.5 J6 Intermediate EMEG
(pica child)
200Intermediate EMEG (child)
Zinc4.6 J - 290 JSS07A12 J600Chronic EMEG (pica child)
20,000Chronic EMEG (child)
Cyanide0.61 J (2 hits)SS03BND100 Intermediate EMEG
(pica child)
3,000Intermediate EMEG (child)

Sources: EPA, 1998b; EPA, 1998d; EPA, 1998e; EPA, 1998f; and FDEP, 1998.

Table Notes:

1. The values listed in this column indicate the range of detected concentrations for each contaminant.
2. ppm = parts per million.
3. Please refer to Appendix D for an explanation of the comparison values used in this public health assessment.
4. J = estimated value.
5. Comparison value is for hexavalent chromium.
6. Comparison value is for inorganic mercury.
7. ND = material was analyzed for but not detected (value below the minimum quantitation limit).
8. Comparison value is for chlordane.
9. Comparison value is for PCB - 1254.
10. I = value reported is less than the minimum quantitation limit, and greater than or equal to the minimum detection limit.




Table 7.

Off-Site Surface Soil Sampling Results - 1998
Contaminant Concentration Range1 (ppm)2 Sample ID of Maximum Concentration Comparison Value 3
Value (ppm) Source
Bis (2-ethylhexyl)phthalate0.62 J 4SS0850CREG
40RMEG (pica child)
1000RMEG (child)
Carbon Disulfide0.015SS01200RMEG (pica child)
5,000RMEG (child)
4,4' - DDD0.00097 I6SS013CREG
4,4' - DDE0.0019 ISS012CREG
4,4' - DDT0.0037SS012CREG
1RMEG (pica child)
30RMEG (child)
Aluminum310; 640SS0178,000RBCn
Arsenic22.3; 43 J SS010.5CREG
0.6Chronic EMEG (pica child)
20Chronic EMEG (child)
200Chronic EMEG (adult)
Barium4.24 - 6.4SS08100RMEG (pica child)
4,000RMEG (child)
Calcium1,800; 8,100SS01None
Chromium2.75 A7 - 53SS0110RMEG (pica child)5
300RMEG (child)5
Copper21 J; 83 JSS013,100RBCn
Iron220; 610SS0123,000RBCn
Lead2.1 A - 9.3SS01500EPA Action Level
Magnesium170SS08None
Manganese15 J; 68 JSS0810RMEG (pica child)
300RMEG (child)
4,000RMEG (adult)
Potassium34; 43SS08None
Vanadium0.48 J; 1.3 JSS016 Intermediate EMEG
(pica child)
200Intermediate EMEG (child)
Zinc16; 57 JSS08600Chronic EMEG (pica child)
20,000Chronic EMEG (child)

Sources: EPA, 1998b; EPA, 1998d; EPA, 1998f; and FDEP, 1998.

Table Notes:

1. The values listed in this column indicate the range of detected concentrations for each contaminant.
2. ppm = parts per million.
3. Please refer to Appendix D for an explanation of the comparison values used in this public health assessment.
4. J = estimated value.
5. Comparison value is for hexavalent chromium.
6. I = value reported is less than the minimum quantitation limit, and greater than or equal to the minimum detection limit.
7. A = value reported is the mean of two or more determinations.




Table 8.

Sediment Sampling Results - 1998
Contaminant Sediment
St. Lucie River Concentration Range (ppm)2
Sediment Drainage Ditches Concentration Range1 (ppm) Sediment Drainage Ditches Sample ID of Maximum Concentration Comparison Value 3
Value (ppm) Source
AtrazineND0.0027 I9SD0170RMEG (pica child)
2,000RMEG (child)
Alpha - Chlordane ND6 0.014SD040.5CREG7
1Chronic EMEG (pica child)7
30Chronic EMEG (child)7
Gamma - Chlordane ND 0.016SD040.5CREG7
1Chronic EMEG (pica child)7
30Chronic EMEG (child)7
Chlordane0.025 I0.058 - 0.44SD040.5CREG
1Chronic EMEG (pica child)
30Chronic EMEG (child)
Bis (2-ethylhexyl)phthalate1.34.8SD0150CREG
40RMEG (pica child)
1000RMEG (child)
ChryseneND0.071 J4 - 0.120 ISD0488RBCc
FlourantheneND0.13 J - 0.150 ISD0480RMEG (pica child)
2,000RMEG (child)
Benzo (b and/or k)flourantheneND0.13 - 0.22 ISD040.88RBCc [benzo(b)flouranthene]
8.8RBCc [benzo(k)flouranthene]
Benzo (a) pyreneND0.063 JSD030.1CREG
4,4' - DDD0.0014 I0.0023 I - 0.0024 ISD023CREG
4,4' - DDE0.0015 I0.0096 - 0.030SD022CREG
4,4' - DDT0.0120.0042 J; 0.0092SD022CREG
1RMEG (pica child)
30RMEG (child)
(3 and/or 4)methylphenol0.058 JND--100RMEG (pica child) (3-methylphenol)
3,000 RMEG (child) (3-
methylphenol)
390RBCn (4-methylphenol)
PCB - 12420.039 JND--1RMEG (child)8
PyreneND0.12 J - 0.18 ISD0460RMEG (pica child)
2,000RMEG (child)
TolueneND0.003 J; 0.0039 ISD03400RMEG (pica child)
10,000RMEG (child)
Aluminum230300 - 4,000SD0278,000RBCn
ArsenicND0.7 I - 1 ISD040.5CREG
0.6Chronic EMEG (pica child)
20Chronic EMEG (child)
Barium1.1; 7.483.06 - 10SD02100RMEG (pica child)
4,000RMEG (child)
CadmiumND0.25 I - 0.53 ISD040.4Chronic EMEG (pica child)
10Chronic EMEG (child)
Calcium1,8001,800 - 19,000SD01None
Chromium1.2 - 4.062.1 J - 20.4SD0410RMEG (pica child)5
300RMEG (child)5
Copper7.2 J5.9 J - 51 JSD043,100RBCn
Iron2,700480 - 3,100SD0223,000RBCn
Lead1.8 - 2.0 I2.5 - 10SD04500EPA Action Level
MagnesiumND590; 640SD02None
Manganese15 J2.4 J - 110 JSD0210RMEG (pica child)
300RMEG (child)
4,000RMEG (adult)
Potassium8.9 J14 - 52SD04None
SilverND0.25 ISD0410RMEG (pica child)
300RMEG (child)
Vanadium0.78 J0.82 J - 8.9 JSD026Intermediate EMEG pica child)
200Intermediate EMEG (child)
Zinc7.6 J4.4 J - 68SD04600Chronic EMEG (pica child)
20,000Chronic EMEG (child)

Sources: EPA, 1998b; EPA, 1998d; EPA, 1998e; EPA, 1998f; and FDEP, 1998.

Table Notes:

1. The values listed in this column indicate the range of detected concentrations for each contaminant.
2. ppm = parts per million.
3. Please refer to Appendix D for an explanation of the comparison values used in this public health assessment.
4. J = estimated value.
5. Comparison value is for hexavalent chromium.
6. ND = material was analyzed for but not detected (value below the minimum quantitation limit).
7. Comparison value is for chlordane.
8. Comparison value is for PCB - 1254.
9. I = value reported is less than the minimum quantitation limit, and greater than or equal to the minimum detection limit.




Table 9.

Tank Pull Sampling Results - 1992
Contaminant Concentration (ppb)1 Comparison Value2
Value Source
Chlordane86Chronic EMEG (child)
20Chronic EMEG (adult)
4,4' - DDD0.30.1CREG
4,4' - DDE1.00.1CREG
4,4' - DDT0.55RMEG (child)
20RMEG (adult)
Dieldrin0.750.5Chronic EMEG (child)
2Chronic EMEG (adult)
Endosulfan II0.420Chronic EMEG (child)3
70Chronic EMEG (adult)3
Ethyl benzene81,000RMEG (child)
4,000RMEG (adult)
700MCL
p-Xylene2520RBCn
m-Xylene116,000 Intermediate EMEG
(child)
20,000Intermediate EMEG (adult)
o-xylene121,400RBCn

Sources: ATSDR, 1996a; and Evergreen Engineering, 1996.

Table Notes:

1. ppb = parts per billion.
2. Please refer to Appendix D for an explanation of the comparison values used in this public health assessment.
3. Comparison value is for Endosulfan.

APPENDIX D -- COMPARISON VALUES

Comparison Values

ATSDR comparison values are media-specific concentrations that are considered to be safeunder default conditions of exposure. They are used as screening values in the preliminaryidentification of site-specific "contaminants of concern". The latter term should not bemisinterpreted as an implication of "hazard". As ATSDR uses the phrase, a "contaminant ofconcern" is merely a chemical substance detected at the site in question and selected by thehealth assessor for further evaluation of potential health effects. Generally, a chemical is selectedas a "contaminant of concern" because its maximum concentration in air, water, or soil at thesite exceeds one of ATSDR's comparison values.

However, it must be emphasized that comparison values are not thresholds of toxicity. Whileconcentrations at or below the relevant comparison value may reasonably be considered safe, itdoes not automatically follow that any environmental concentration that exceeds a comparisonvalue would be expected to produce adverse health effects. The whole purpose behind highlyconservative, health-based standards and guidelines is to enable health professionals torecognize and resolve potential public health hazards before they can become actual publichealth consequences. Thus, comparison values are designed to be preventive, rather thanpredictive, of adverse health effects. The probability that such effects will actually occurdepends, not on environmental concentrations alone, but on a unique combination of site-specific conditions and individual lifestyle and genetic factors that affect the route, magnitude,and duration of actual exposure.

Listed and described below are the various comparison values that ATSDR uses to select chemicals for further evaluation, as well as other non-ATSDR values that are sometimes used to put environmental concentrations into a meaningful frame of reference.

CREG = Cancer Risk Evaluation Guides
MRL = Minimal Risk Level
EMEG = Environmental Media Evaluation Guides
IEMEG = Intermediate Environmental Media Evaluation Guide
RMEG = Reference Dose Media Evaluation Guide
RfD = Reference Dose
RfC = Reference Dose Concentration
RBC = Risk-Based Concentration
DWEL = Drinking Water Equivalent Level
MCL = Maximum Contaminant Level
CLHA = Child Longer Term Health Advisory

Cancer Risk Evaluation Guides (CREGs) are estimated contaminant concentrations expected to cause no more than one excess cancer in a million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors, or cancer potency factors, using default values for exposure rates. However, neither CREGs nor CSFs can be used to make realistic predictions of cancer risk. The true risk is always unknown and may be as low as zero.

Minimal Risk Levels (MRL) are estimates of daily human exposure to a chemical (dosesexpressed in mg/kg/day) that are unlikely to be associated with any appreciable risk ofdeleterious noncancer effects over a specified duration of exposure. MRLs are calculated usingdata from human and animal studies and are reported for acute (< 14 days), intermediate (15-364 days), and chronic (> 365 days) exposures. MRLs are published in ATSDR ToxicologicalProfiles for specific chemicals.

Environmental Media Evaluation Guides (EMEGs) are concentrations that are calculatedfrom ATSDR minimal risk levels by factoring in default body weights and ingestion rates.

Intermediate Environmental Media Evaluation Guides (IEMEG) are calculated fromATSDR minimal risk levels; they factor in body weight and ingestion rates for intermediateexposures (those occurring for more than 14 days and less than 1 year).

Reference Dose Media Evaluation Guide (RMEG) is the concentration of a contaminant inair, water or soil that corresponds to EPA's RfD for that contaminant when default values forbody weight and intake rates are taken into account.

EPA's Reference Dose (RfD) is an estimate of the daily exposure to a contaminant unlikely tocause noncarcinogenic adverse health effects. Like ATSDR's MRL, EPA's RfD is a dose expressed in mg/kg/day.

Reference Concentrations (RfC) is a concentration of a substance in air that EPA considersunlikely to cause noncancer adverse health effects over a lifetime of chronic exposure.

Risk-Based Concentrations (RBC) are media-specific concentrations derived by Region III ofthe Environmental Protection Agency Region III from RfDs, RfC's, or EPA's cancer slopefactors. They represent concentrations of a contaminant in tap water, ambient air, fish, or soil(industrial or residential) that are considered unlikely to cause adverse health effects over alifetime of chronic exposure. RBCs are based either on cancer ("c") or noncancer ("n") effects.

Drinking Water Equivalent Levels (DWEL) are based on EPA's oral RfD and representcorresponding concentrations of a substance in drinking water that are estimated to havenegligible deleterious effects in humans at an intake rate of 2 L/day for life, assuming thatdrinking water is the sole source of exposure.

Maximum Contaminant Levels (MCLs) represent contaminant concentrations in drinkingwater that EPA deems protective of public health (considering the availability and economics ofwater treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters of waterper day.

Child Longer Term Health Advisory (CLHA) represents the concentration of a substance indrinking water that would have no deleterious effect on a child exposed for up to 7 years.

Reference for Comparison Values:
Agency for Toxic Substances and Disease Registry. Health Assessment Guidance Manual.Atlanta: ATSDR, March, 1992.


APPENDIX E -- ATSDR METHODOLOGY

ATSDR Methodology

ATSDR evaluates contaminants detected in environmental media at the site and determineswhether an exposure to them has public health significance. ATSDR selects and discusses thecontaminants based upon the following factors:

  • concentrations of contaminants on and off site;
  • community health concerns; and
  • comparison of on- and off-site concentrations with ATSDR health comparisonvalues for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints.

ATSDR health comparison values are concentrations of contaminants that are media specific(e.g., water, air, or soil). The comparison values are considered to be safe under defaultconditions of exposure and are used as screening values in the preliminary identification of site-specific "contaminants of concern." The "contaminants of concern" are those contaminants thatwere detected above the screening comparison values and contaminants without comparisonvalues. However, the comparison values in the Tables in Appendix C are those that ATSDRconsiders to be the most appropriate, considering site-specific conditions of exposure, i.e.,specifically the duration of exposure (acute, intermediate or chronic) to the environmentalmedium in question most likely to prevail at the site. Please refer to the ToxicologicalEvaluation section and Appendix D for further clarification and description of the comparisonvalues used in this public health assessment.

Following the preliminary identification of site-specific "contaminants of concern", which aredescribed in the Environmental Contamination and Other Hazards section, ATSDR staff discussin the Pathways Analyses section whether nearby residents are exposed to contaminationmigrating from the site. If exposure to contamination is identified, the significance of thisexposure, with relation to adverse health effects, is discussed in the Toxicological Evaluationsection. ATSDR staff also address specific community concerns in the Community Health Concerns Evaluation section. Finally, based on the evaluations from all preceding sections of thepublic health assessment, ATSDR staff determine conclusions and prepare recommendations.


APPENDIX F -- ATSDR HEALTH CONSULTATION

The following section was not available in electronic format for conversion to HTML at the time of preparation of this document. To obtain a hard copy of the document, please contact:

Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation Branch, E-56
1600 Clifton Road NE, Atlanta, Georgia 30333


APPENDIX G -- ATSDR RESPONSE TO COMMENTS

ATSDR RESPONSE TO COMMENTS

This appendix contains a summary of the comments ATSDR received during the publiccomment period for the Loxahatchee Nursery public health assessment. Each comment waslogged and became part of the administrative record. Both the comments and ATSDR'sresponses are included in the text below. The comments have been numbered and are in italic with ATSDR's response directly below each comment. Personal identifiers and namesmentioned in the comments ATSDR received have not been included. Also, similar commentsreceived from different individuals have been combined into one comment.

1. We want this nursery resampled for the breakdown products of benlate along with itscontaminants, flusilazole and chlorothalonil. We want two sets of samples taken at the sametime and one set sent to an out-of-state laboratory of our choosing.

ATSDR is considering sampling at the Loxahatchee Nursery site and testing for the chemicalflusilazole. Please refer to the Community Health Concerns Evaluation section of this publichealth assessment, which has been modified from the public comment version to include moreinformation concerning flusilazole. Benlate's breakdown product, carbendazim, has beenanalyzed for in private wells, monitoring wells, soil, and sediment without being detected.Therefore, ATSDR does not recommend any further analyses for benlate or its breakdownproducts.

2. We want the pond and its fish to be tested.

Because ATSDR has no chemical-specific environmental data from the pond, the agency hasidentified the pond as a "data gap" and is considering sampling water and sediment from thepond.

3. Independent soil and water analysis should be conducted on the properties surroundingthe nursery.

At this time, ATSDR does not recommend any further residential soil sampling. Soil and wateranalyses have been performed on the properties surrounding the nursery. No contaminants atlevels of health concern were detected. Of note, the MCHD plans to periodically monitor thegroundwater quality of private potable water sources in the area.

4. We want a cancer survey of the residents of the surrounding area.

From ATSDR's perspective, an adverse health effect to be evaluated should be plausibly relatedto the release of hazardous substances from the site being investigated. ATSDR reviewedenvironmental data for the Loxahatchee Nursery site and did not identify any contaminants at levels of concern for increased cancer risk. Of note, in response to a request from thecommunity to review the rate of cancer, the MCHD plans to review cancer incidence data. Formore information on this issue, please contact the MCHD directly.

5. We would like a federal investigation before a grand jury into the matter of federal andstate agencies collaborating with DuPont to withhold crucial life and health information fromthe people of the United States and the State of Florida.

This request is out of the purview of ATSDR's activities at the site.

6. In Appendix G, Health Consultation, it stated that the resident that had a high level of1,2-dichloropropane was receiving bottled water and the report made recommendation #5 thatmore information is needed to stop exposure. This well was fitted with a charcoal filter almostimmediately after the contamination was found. When ATSDR investigators visited the site, thefilter was installed on the well. This affects section B on page 4.

The information referred to in this comment pertains to recommendations ATSDR made in ourSeptember 1996 health consultation. These are not our current recommendations which arefound in the Recommendation section of this public health assessment. To avoid confusion,ATSDR has modified section B to only state that the 1996 health consultation recommendedadditional sampling activities. Information contained in the copy of the 1996 health consultationfound in Appendix G cannot be modified as it is considered a released, final document.

7. Several sections of the public health assessment reference historical use of 1,2-dichloropropane as a soil fumigant at the nursery. I have spoken with all owners or operatorsfrom 1944 to 1992, none of whom report ever using this chemical on the premises. They diduse methyl bromide as a nematocide.

ATSDR thanks the commentor for this information. It was reported to ATSDR that 1,2-dichloropropane was used on site and the agency included this information in the publiccomment release of the document. All references to the use of 1,2-dichloropropane on site havebeen removed from the main text of the final release public health assessment because thereports of its use are conflicting. Of note, not stating the source of the 1,2-dichlorpropane in thepublic health assessment does not affect ATSDR's conclusions and recommendations regardingthis site. Further, in the Community Health Concerns Evaluation section , ATSDR states that1,2-dichloropropane has not been detected in on-site monitoring well, soil, or sediment sampleswhich suggests the nursery is not the source.

8. The Background section reports that pesticides were applied via injection through theirrigation system. Fertilizers were occasionally applied in this fashion, but pesticides were not.

The sentence in question has been modified to indicated that fertilizers were delivered to theplants through the nursery's irrigation system.

9. The Background section reports that the nursery was developed on filled wetlands. Thisis not true. The topography, except for beds graded up from original grade, remains the sameas when the land was cleared in 1944. The same sentence also indicates that a tile drainagesystem exists beneath the site.

Based on this information, ATSDR has deleted the sentence in question from the main text ofthe public health assessment. Deleting this sentence does not alter ATSDR's conclusions andrecommendations regarding this site.

10. The report indicates a septic tank system is present on site. Was this located during theMarch 1998 sampling event? If so, why was the septic tank system not sampled?

The septic tank sy

APPENDIX G -- ATSDR RESPONSE TO COMMENTS

ATSDR RESPONSE TO COMMENTS

This appendix contains a summary of the comments ATSDR received during the publiccomment period for the Loxahatchee Nursery public health assessment. Each comment waslogged and became part of the administrative record. Both the comments and ATSDR'sresponses are included in the text below. The comments have been numbered and are in italic with ATSDR's response directly below each comment. Personal identifiers and namesmentioned in the comments ATSDR received have not been included. Also, similar commentsreceived from different individuals have been combined into one comment.

1. We want this nursery resampled for the breakdown products of benlate along with itscontaminants, flusilazole and chlorothalonil. We want two sets of samples taken at the sametime and one set sent to an out-of-state laboratory of our choosing.

ATSDR is considering sampling at the Loxahatchee Nursery site and testing for the chemicalflusilazole. Please refer to the Community Health Concerns Evaluation section of this publichealth assessment, which has been modified from the public comment version to include moreinformation concerning flusilazole. Benlate's breakdown product, carbendazim, has beenanalyzed for in private wells, monitoring wells, soil, and sediment without being detected.Therefore, ATSDR does not recommend any further analyses for benlate or its breakdownproducts.

2. We want the pond and its fish to be tested.

Because ATSDR has no chemical-specific environmental data from the pond, the agency hasidentified the pond as a "data gap" and is considering sampling water and sediment from thepond.

3. Independent soil and water analysis should be conducted on the properties surroundingthe nursery.

At this time, ATSDR does not recommend any further residential soil sampling. Soil and wateranalyses have been performed on the properties surrounding the nursery. No contaminants atlevels of health concern were detected. Of note, the MCHD plans to periodically monitor thegroundwater quality of private potable water sources in the area.

4. We want a cancer survey of the residents of the surrounding area.

From ATSDR's perspective, an adverse health effect to be evaluated should be plausibly relatedto the release of hazardous substances from the site being investigated. ATSDR reviewedenvironmental data for the Loxahatchee Nursery site and did not identify any contaminants at levels of concern for increased cancer risk. Of note, in response to a request from thecommunity to review the rate of cancer, the MCHD plans to review cancer incidence data. Formore information on this issue, please contact the MCHD directly.

5. We would like a federal investigation before a grand jury into the matter of federal andstate agencies collaborating with DuPont to withhold crucial life and health information fromthe people of the United States and the State of Florida.

This request is out of the purview of ATSDR's activities at the site.

6. In Appendix G, Health Consultation, it stated that the resident that had a high level of1,2-dichloropropane was receiving bottled water and the report made recommendation #5 thatmore information is needed to stop exposure. This well was fitted with a charcoal filter almostimmediately after the contamination was found. When ATSDR investigators visited the site, thefilter was installed on the well. This affects section B on page 4.

The information referred to in this comment pertains to recommendations ATSDR made in ourSeptember 1996 health consultation. These are not our current recommendations which arefound in the Recommendation section of this public health assessment. To avoid confusion,ATSDR has modified section B to only state that the 1996 health consultation recommendedadditional sampling activities. Information contained in the copy of the 1996 health consultationfound in Appendix G cannot be modified as it is considered a released, final document.

7. Several sections of the public health assessment reference historical use of 1,2-dichloropropane as a soil fumigant at the nursery. I have spoken with all owners or operatorsfrom 1944 to 1992, none of whom report ever using this chemical on the premises. They diduse methyl bromide as a nematocide.

ATSDR thanks the commentor for this information. It was reported to ATSDR that 1,2-dichloropropane was used on site and the agency included this information in the publiccomment release of the document. All references to the use of 1,2-dichloropropane on site havebeen removed from the main text of the final release public health assessment because thereports of its use are conflicting. Of note, not stating the source of the 1,2-dichlorpropane in thepublic health assessment does not affect ATSDR's conclusions and recommendations regardingthis site. Further, in the Community Health Concerns Evaluation section , ATSDR states that1,2-dichloropropane has not been detected in on-site monitoring well, soil, or sediment sampleswhich suggests the nursery is not the source.

8. The Background section reports that pesticides were applied via injection through theirrigation system. Fertilizers were occasionally applied in this fashion, but pesticides were not.

The sentence in question has been modified to indicated that fertilizers were delivered to theplants through the nursery's irrigation system.

9. The Background section reports that the nursery was developed on filled wetlands. Thisis not true. The topography, except for beds graded up from original grade, remains the sameas when the land was cleared in 1944. The same sentence also indicates that a tile drainagesystem exists beneath the site.

Based on this information, ATSDR has deleted the sentence in question from the main text ofthe public health assessment. Deleting this sentence does not alter ATSDR's conclusions andrecommendations regarding this site.

10. The report indicates a septic tank system is present on site. Was this located during theMarch 1998 sampling event? If so, why was the septic tank system not sampled?

The septic tank system was not located during the March 1998 sampling event. ATSDRbelieves the septic tank is used by the on-site residence; however, ATSDR was not able find anydocumentation to indicate the septic tank's location or use.

11. Pages 6 and 10 of the report appear to contradict the depth to the water table beneaththe site.

ATSDR does not believe the sentences in question contradict one another. Page 6 states, "Inthis area, the water table is encountered at 8 feet or less below ground surface." Page 10 thengoes on to state that, during the March 1998 sampling event, groundwater was encountered at1.5-2 feet below land surface. ATSDR does not see a contradiction with stating thatgroundwater in the area is encountered at 8 feet or less , because 1.5-2 feet falls within thepreviously defined range. The water table in this area fluctuates depending on the season.

12. In the Pathway Analysis section, the document reports one Completed ExposurePathway beginning with 1,2-dichloropropane applied at the nursery and ending with it in adrinking water well. As this chemical was not used on site, it originated elsewhere. In fact, thehigh relative concentration in the one well, which is located in a drainage swale north of thenursery, along with failure to find 1,2-dichloropropane anywhere else within the nursery orsurrounds, argues against the nursery being the source. It is much more likely that a localhomeowner used this chemical as a degreaser, which is one on its known applications, anddisposed of it in the drainage swale upgradient of the well in question.

As stated in comment number 7, ATSDR has removed references to the use of 1,2-dichloropropane on-site because the Agency has received conflicting information on this issue.However, a human exposure pathway can be "complete" even if the source of contamination is not known, so exposure to 1,2-dichloropropane remains in the public health assessment as acompleted exposure pathway.

13. The report states that three private wells had trace levels of 1,2-dichloropropane.However, trace levels of this solvent have been found in five private wells.

The draft public health assessment contained private well data sampled from 1992 to July 1996.Based on this comment, ATSDR requested updated data from MCHD. Additional data fromAugust to December 1996 were obtained and are included in this final public health assessment.Two additional wells were found to contain 1,2-dichloropropane at trace levels and the maintext of this document has been modified to indicate five wells instead of three.

14. The Martin County Public Health Unit (MCPHU) is now the Martin County HealthDepartment (MCHD).

ATSDR thanks the commentor for this information which has been added to the final publichealth assessment text in the Public Health Actions section.

15. The pond was sampled by FDEP and two 7-day chronic static-renewal definitivetoxicity bioassays were performed on the samples collected. The samples did not demonstratechronic toxicity to the test species. Although the samples had exceeded normal holding times,toxicants were expected to be stable.

ATSDR thanks the commentor for this information. However, because chemical-specificenvironmental sampling data (i.e., for surface water or sediment) have not been collected for thepond, ATSDR recommends additional characterization of the pond as indicated in theRecommendation section of the public health assessment.

16. How can LN-SS08, LN-SS01, and LN-TW01 be considered background or off site asthey appear to be on the triangular parcel of land that is part of the Loxahatchee Nursery?This parcel of land was a part of the nursery operations and did have ornamentals on it.

As indicated in several places in the Environmental Contamination and Other Hazards section ofthis public health assessment, ATSDR did not consider the sampling locations mentioned in thiscomment to reflect "background" conditions. Please refer to the main text for furtherclarification of the background issue. Additionally, references to "on -site" and "off site" inpublic health assessments are arbitrary boundaries created by ATSDR staff for the purpose ofdelineating data and evaluating human exposure pathways. The parcel in question is across thestreet from where primary nursery operations occurred. The parcel is directly adjacent to thecounty park. The data reports that ATSDR received indicated this parcel was outside ofproperty boundaries. For this public health assessment, ATSDR assumed that off-site exposures would occur more frequently than on-site exposures. For these reasons, ATSDR staff includedsampling data from the locations mentioned in this comment with the "off-site" data.

17. In the Community Health Concerns Evaluation section of the report, ATSDR states that"levels detected of these metals fall within observed ranges for metals in eastern United Statessoil and are probably not due to nursery activities." A more recent report (Ma et al, 1997) onFlorida soils suggests that the arsenic level at LN-SS01 and the chromium level at LN-SS10Aare indicative of anthropogenic sources.

ATSDR reviewed the report (Ma et al, 1997) the commentor graciously provided. The reportconcluded that background values of most metals in 40 Florida soils were lower than theaverage of United States soils. ATSDR has deleted the sentence in question from the main textof the public health assessment.

18. The sediment analytical results revealed exceedances of the Sediment GuidanceCriteria for chlordane; 4,4'-DDD; 4,4'-DDE; 4,4'-DDT; chrysene; flouranthene; and pyrene.The soil analytical results revealed exceedances of the Florida Soil Cleanup Goals forresidential direct exposure for arsenic in several samples. The soil analytical results revealedexceedances of the Florida Soil Cleanup Goals for residential direct exposure and leachabilityfor chlordane in two samples. The soil analytical results revealed exceedances of the FloridaSoil Cleanup Goals for leachability for chromium and dieldrin in one sample each. Thegroundwater analytical results revealed exceedances of the Florida Drinking Water Standardsfor 1,2-dichloropropane in one private well. As discussed in the text of ATSDR's report, thiswell has been fitted with a carbon filter which removes the contaminant from the water.

ATSDR thanks the commentor for this information. As stated in the main text, ATSDRconcluded that under site-specific conditions of exposure, none of the contaminants detected insoil or sediment are likely to pose a hazard to public health. ATSDR understands that if the siteis to be developed residential, certain criteria and cleanup goals set by the state of Florida mustbe met; however, as a nonregulatory agency, commenting on the cleanup goals set by the stateare out of the purview of this public health assessment.

Table of Contents

  
 
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #