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1. ATSDR > Public Health Assessments & Consultations

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
µg	micrograms
VOCs	Volatile Organic Compounds

APPENDIX B -- FIGURES

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

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 Soil	Nursery	See Tables 5 and 6	On-Site Soil	Direct contact with on-site soils	Dermal, Incidental Ingestion	Residents living on-site; Trespassers	Past, Current, Future
Off-Site Soil	Potentially the Nursery	See Table 7	Off-Site Soil	Direct contact with off-site soils	Dermal, Incidental Ingestion	Residents	Past, 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-site Sediment	Potentially the Nursery	See Table 8	Off-Site Sediment	Direct contact with off-site sediment in drainage ditches and the South Fork of the St. Lucie River	Dermal, Incidental Ingestion	Residents	Past, Current, Future

Table 3: On-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	1998	ND5	1	CREG
				5	MCL
Bromodichloro- methane	1.3; 3.4	1996	ND	0.6	CREG
				200	Chronic EMEG (child)
				700	Chronic EMEG (adult)
Bromoform	1.2	1996	ND	4	CREG
				2,000	Chronic EMEG (child)
				7,000	Chronic EMEG (adult)
Chloroform	0.51; 9.9	1996	ND	6	CREG
				100	Chronic EMEG (child)
				400	Chronic EMEG (adult)
Chloromethane	0.13 - 0.82 I6	1998	0.58 I	3	LTHA
				400	CLHA
Dibromochloro- methane	0.54; 2.8	1996	ND	0.4	CREG
				300	Chronic EMEG (child)
				1,000	Chronic EMEG (adult)
Di (2-ethylhexyl) phthalate	3.0	1996	ND	3	CREG
				200	RMEG (child)
				700	RMEG (adult)
1,1-Dichloroethane	0.21	1996	ND	810	RBCn
1,2-Dichloropropane	0.1 - 330	1996	ND	900	Chronic EMEG (child)
				3000	Chronic EMEG (adult)
				5	MCL
Naphthalene	0.22; 0.37	1996	ND	200	Intermediate EMEG (child)
				700	Intermediate EMEG (adult)
Styrene	0.23; 0.31	1996	ND	2,000	Intermediate EMEG (child)
				7,000	Intermediate EMEG (adult)
				100	MCL
1,2,3- Trichloropropane	1.8 - 3.6	1996	ND	60	RMEG (child)
				200	RMEG (adult)
Aluminum	89	1998	ND	37,000	RBCn
Arsenic	ND	1998	27; 28.3	0.02	CREG
				3	Chronic EMEG (child)
				10	Chronic EMEG (adult)
Barium	15.6 - 23	1998	2.16 J	700	RMEG (child)
				2,000	RMEG (adult)
Calcium	1,500 J - 90,000 J	1998	68,000 J	None
Chromium	3 J	1998	2 J	100	MCL
Copper	15 J, 25 J	1998	ND	1,500	RBCn
Iron	47 - 7,200	1998	380	11,000	RBCn
Lead	0.4 I - 3 J	1998	0.3 I	15	EPA Action Level
Magnesium	730 - 3,200	1998	16,000	None
Manganese	6 J - 46	1998	16	50	RMEG (child)
				200	RMEG (adult)
Potassium	210 - 1,400	1998	1,800	None
Sodium	3,400 - 160,000	1998	15,000	None
Vanadium	3 J	1998	ND	30	Intermediate EMEG (child)
				300	Intermediate EMEG (adult)
Zinc	38 - 210	1998	ND	3,000	Chronic EMEG (child)
				10,000	Chronic 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, #1Soil	1	Chronic EMEG (pica child)
			30	Chronic EMEG (child)
beta BHC	0.0052	1992, #1Soil	0.6	Intermediate EMEG (pica child)
			20	Intermediate EMEG (child)
gamma BHC	0.0038	1992, #1Soil	0.08	Intermediate EMEG (pica child)
			2	Intermediate EMEG (child)
delta BHC	0.0045	1992, #1Soil	None
DDE	0.012 - 0.072	1996, West	2	CREG
DDD	0.015 - 0.030	1996, West	3	CREG
DDT	0.0062; 0.011	1996, West	1	RMEG (pica child)
			30	RMEG (child)
Dieldrin	0.013	1996, West	0.1	Chronic EMEG (pica child)
			3	Chronic EMEG (child)
Endosulfan II	0.0103	1992, #2Soil	4	Chronic EMEG (pica child)4
			100	Chronic EMEG (child)4
Endrin	0.037	1992, #1Soil	0.6	Chronic EMEG (pica child)
			20	Chronic EMEG (child)
Endrin Aldehyde	0.032	1992, #2Soil	None
Heptachlor Epoxide	0.005	1992, #1Soil	0.08	CREG

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
Acenaphthylene	0.053 J4	SS09A	ND7	None
Carbon Disulfide	0.004 J; 0.005 J	SS07B	0.003 J	200	RMEG (pica child)
				5,000	RMEG (child)
Alpha - Chlordane	0.0042 - 1	SS03A	ND	1	Chronic EMEG (pica child)8
				30	Chronic EMEG (child)8
Gamma - Chlordane	0.0044 - 1.1	SS03A	ND	1	Chronic EMEG (pica child)8
				30	Chronic EMEG (child)8
Chlordane	0.006 I10 - 14	SS03A	ND	1	Chronic EMEG (pica child)
				30	Chronic EMEG (child)
Bis (2-ethylhexyl) phthalate	0.470 - 6.2 J	SS03A	ND	50	CREG
				40	RMEG (pica child)
				1000	RMEG (child)
Captan	0.003	SS03B	ND	300	RMEG (pica child)
				7,000	RMEG (child)
Chrysene	0.077 J - 0.19 J	SS09A	ND	88	RBCc
Flouranthene	0.041 J - 0.38	SS09A	ND	80	RMEG (pica child)
				2,000	RMEG (child)
Benzo (a) anthracene	0.065 J - 0.2 J	SS09A	ND	0.88	RBCc
Benzo (b and/or k) flouranthene	0.051 J - 0.24 J	SS09A	ND	0.88	RBCc [benzo(b)flouranthene]
				8.8	RBCc [benzo(k)flouranthene]
Benzo (g,h,i) perylene	0.046 J; 0.099 J	SS09A	ND	None
Benzo (a) pyrene	0.050 J - 0.17 J	SS09A	ND	0.1	CREG
4,4' - DDE	0.0034 I - 0.36	SS09A	ND	2	CREG
4,4' - DDD	0.0013 I - 0.069 J	SS03A	ND	3	CREG
4,4' - DDT	0.0014 I - 0.33	SS03A	ND	1	RMEG (pica child)
				30	RMEG (child)
Indeno (1,2,3-cd) pyrene	0.055 J; 0.11 J	SS09A	ND	0.88	RBCc
PCB - 1260	0.050 - 0.79	SS02B	ND	1	RMEG (child) 9
Phenanthrene	0.23 J	SS09A	ND	None
Pyrene	0.047 J - 0.47	SS09A	ND	60	RMEG (pica child)
				2,000	RMEG (child)
Total Xylenes	ND	--	0.002 J	400	Intermediate EMEG (pica child)
				10,000	Intermediate EMEG (child)
Aluminum	19 - 3,000	SS02A	510	78,000	RBCn
Arsenic	0.7 I - 2.3	SS09A	ND	0.5	CREG
				0.6	Chronic EMEG (pica child)
				20	Chronic EMEG (child)
Barium	0.45 I - 12	SS07A	6.9	100	RMEG (pica child)
				4,000	RMEG (child)
Cadmium	0.28 I - 1.1	SS10A	ND	0.4	Chronic EMEG (pica child)
				10	Chronic EMEG (child)
Calcium	220 - 66,000	SS06A	87,000	None
Chromium	0.51 I - 96.7	SS10A	3.6	10	RMEG (pica child)5
				300	RMEG (child)5
Copper	3.7 J - 130 J	SS07A	7.6 J	3,100	RBCn
Iron	110 - 2,900	SS03A	460	23,000	RBCn
Lead	0.7 J - 31	SS03A	3.1 J	500	EPA Action Level
Magnesium	170 - 920	SS07A	330	None
Manganese	2.1 J - 650 J	SS07A	4.7 J	10	RMEG (pica child)
				300	RMEG (child)
				4,000	RMEG (adult)
Total Mercury	0.19	SS09A	ND	4	Intermediate EMEG (pica child)6
				100	Intermediate EMEG (child)6
Potassium	18 - 150	SS07A	69	None
Selenium	0.9 I; 1 I	SS02A	ND	10	Chronic EMEG (pica child)
				300	Chronic EMEG (child)
Silver	0.19 I - 1.3	SS06A	ND	10	RMEG (pica child)
				300	RMEG (child)
Sodium	500	SS06A	990	None
Vanadium	1.1 J - 3 J	SS07A	2.5 J	6	Intermediate EMEG (pica child)
				200	Intermediate EMEG (child)
Zinc	4.6 J - 290 J	SS07A	12 J	600	Chronic EMEG (pica child)
				20,000	Chronic EMEG (child)
Cyanide	0.61 J (2 hits)	SS03B	ND	100	Intermediate EMEG (pica child)
				3,000	Intermediate 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) phthalate	0.62 J 4	SS08	50	CREG
			40	RMEG (pica child)
			1000	RMEG (child)
Carbon Disulfide	0.015	SS01	200	RMEG (pica child)
			5,000	RMEG (child)
4,4' - DDD	0.00097 I6	SS01	3	CREG
4,4' - DDE	0.0019 I	SS01	2	CREG
4,4' - DDT	0.0037	SS01	2	CREG
			1	RMEG (pica child)
			30	RMEG (child)
Aluminum	310; 640	SS01	78,000	RBCn
Arsenic	22.3; 43 J	SS01	0.5	CREG
			0.6	Chronic EMEG (pica child)
			20	Chronic EMEG (child)
			200	Chronic EMEG (adult)
Barium	4.24 - 6.4	SS08	100	RMEG (pica child)
			4,000	RMEG (child)
Calcium	1,800; 8,100	SS01	None
Chromium	2.75 A7 - 53	SS01	10	RMEG (pica child)5
			300	RMEG (child)5
Copper	21 J; 83 J	SS01	3,100	RBCn
Iron	220; 610	SS01	23,000	RBCn
Lead	2.1 A - 9.3	SS01	500	EPA Action Level
Magnesium	170	SS08	None
Manganese	15 J; 68 J	SS08	10	RMEG (pica child)
			300	RMEG (child)
			4,000	RMEG (adult)
Potassium	34; 43	SS08	None
Vanadium	0.48 J; 1.3 J	SS01	6	Intermediate EMEG (pica child)
			200	Intermediate EMEG (child)
Zinc	16; 57 J	SS08	600	Chronic EMEG (pica child)
			20,000	Chronic 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
Atrazine	ND	0.0027 I9	SD01	70	RMEG (pica child)
				2,000	RMEG (child)
Alpha - Chlordane	ND6	0.014	SD04	0.5	CREG7
				1	Chronic EMEG (pica child)7
				30	Chronic EMEG (child)7
Gamma - Chlordane	ND	0.016	SD04	0.5	CREG7
				1	Chronic EMEG (pica child)7
				30	Chronic EMEG (child)7
Chlordane	0.025 I	0.058 - 0.44	SD04	0.5	CREG
				1	Chronic EMEG (pica child)
				30	Chronic EMEG (child)
Bis (2-ethylhexyl) phthalate	1.3	4.8	SD01	50	CREG
				40	RMEG (pica child)
				1000	RMEG (child)
Chrysene	ND	0.071 J4 - 0.120 I	SD04	88	RBCc
Flouranthene	ND	0.13 J - 0.150 I	SD04	80	RMEG (pica child)
				2,000	RMEG (child)
Benzo (b and/or k) flouranthene	ND	0.13 - 0.22 I	SD04	0.88	RBCc [benzo(b)flouranthene]
				8.8	RBCc [benzo(k)flouranthene]
Benzo (a) pyrene	ND	0.063 J	SD03	0.1	CREG
4,4' - DDD	0.0014 I	0.0023 I - 0.0024 I	SD02	3	CREG
4,4' - DDE	0.0015 I	0.0096 - 0.030	SD02	2	CREG
4,4' - DDT	0.012	0.0042 J; 0.0092	SD02	2	CREG
				1	RMEG (pica child)
				30	RMEG (child)
(3 and/or 4) methylphenol	0.058 J	ND	--	100	RMEG (pica child) (3-methylphenol)
				3,000	RMEG (child) (3- methylphenol)
				390	RBCn (4-methylphenol)
PCB - 1242	0.039 J	ND	--	1	RMEG (child)8
Pyrene	ND	0.12 J - 0.18 I	SD04	60	RMEG (pica child)
				2,000	RMEG (child)
Toluene	ND	0.003 J; 0.0039 I	SD03	400	RMEG (pica child)
				10,000	RMEG (child)
Aluminum	230	300 - 4,000	SD02	78,000	RBCn
Arsenic	ND	0.7 I - 1 I	SD04	0.5	CREG
				0.6	Chronic EMEG (pica child)
				20	Chronic EMEG (child)
Barium	1.1; 7.48	3.06 - 10	SD02	100	RMEG (pica child)
				4,000	RMEG (child)
Cadmium	ND	0.25 I - 0.53 I	SD04	0.4	Chronic EMEG (pica child)
				10	Chronic EMEG (child)
Calcium	1,800	1,800 - 19,000	SD01	None
Chromium	1.2 - 4.06	2.1 J - 20.4	SD04	10	RMEG (pica child)5
				300	RMEG (child)5
Copper	7.2 J	5.9 J - 51 J	SD04	3,100	RBCn
Iron	2,700	480 - 3,100	SD02	23,000	RBCn
Lead	1.8 - 2.0 I	2.5 - 10	SD04	500	EPA Action Level
Magnesium	ND	590; 640	SD02	None
Manganese	15 J	2.4 J - 110 J	SD02	10	RMEG (pica child)
				300	RMEG (child)
				4,000	RMEG (adult)
Potassium	8.9 J	14 - 52	SD04	None
Silver	ND	0.25 I	SD04	10	RMEG (pica child)
				300	RMEG (child)
Vanadium	0.78 J	0.82 J - 8.9 J	SD02	6	Intermediate EMEG pica child)
				200	Intermediate EMEG (child)
Zinc	7.6 J	4.4 J - 68	SD04	600	Chronic EMEG (pica child)
				20,000	Chronic 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
Chlordane	8	6	Chronic EMEG (child)
		20	Chronic EMEG (adult)
4,4' - DDD	0.3	0.1	CREG
4,4' - DDE	1.0	0.1	CREG
4,4' - DDT	0.5	5	RMEG (child)
		20	RMEG (adult)
Dieldrin	0.75	0.5	Chronic EMEG (child)
		2	Chronic EMEG (adult)
Endosulfan II	0.4	20	Chronic EMEG (child)3
		70	Chronic EMEG (adult)3
Ethyl benzene	8	1,000	RMEG (child)
		4,000	RMEG (adult)
		700	MCL
p-Xylene	2	520	RBCn
m-Xylene	11	6,000	Intermediate EMEG (child)
		20,000	Intermediate EMEG (adult)
o-xylene	12	1,400	RBCn

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 safe under default conditions of exposure. They are used as screening values in the preliminary identification of site-specific "contaminants of concern". The latter term should not be misinterpreted as an implication of "hazard". As ATSDR uses the phrase, a "contaminant of concern" is merely a chemical substance detected at the site in question and selected by the health assessor for further evaluation of potential health effects. Generally, a chemical is selected as a "contaminant of concern" because its maximum concentration in air, water, or soil at the site exceeds one of ATSDR's comparison values.

However, it must be emphasized that comparison values are not thresholds of toxicity. While concentrations at or below the relevant comparison value may reasonably be considered safe, it does not automatically follow that any environmental concentration that exceeds a comparison value would be expected to produce adverse health effects. The whole purpose behind highly conservative, health-based standards and guidelines is to enable health professionals to recognize and resolve potential public health hazards before they can become actual public health consequences. Thus, comparison values are designed to be preventive, rather than predictive, of adverse health effects. The probability that such effects will actually occur depends, 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.

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 (doses expressed in mg/kg/day) that are unlikely to be associated with any appreciable risk of deleterious noncancer effects over a specified duration of exposure. MRLs are calculated using data 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 Toxicological Profiles for specific chemicals.

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

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

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

EPA's Reference Dose (RfD) is an estimate of the daily exposure to a contaminant unlikely to cause 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 considers unlikely to cause noncancer adverse health effects over a lifetime of chronic exposure.

Risk-Based Concentrations (RBC) are media-specific concentrations derived by Region III of the Environmental Protection Agency Region III from RfDs, RfC's, or EPA's cancer slope factors. 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 a lifetime 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 represent corresponding concentrations of a substance in drinking water that are estimated to have negligible deleterious effects in humans at an intake rate of 2 L/day for life, assuming that drinking water is the sole source of exposure.

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

Child Longer Term Health Advisory (CLHA) represents the concentration of a substance in drinking 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 determines whether an exposure to them has public health significance. ATSDR selects and discusses the contaminants 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 comparison values 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 default conditions 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 that were detected above the screening comparison values and contaminants without comparison values. However, the comparison values in the Tables in Appendix C are those that ATSDR considers to be the most appropriate, considering site-specific conditions of exposure, i.e., specifically the duration of exposure (acute, intermediate or chronic) to the environmental medium in question most likely to prevail at the site. Please refer to the Toxicological Evaluation section and Appendix D for further clarification and description of the comparison values used in this public health assessment.

Following the preliminary identification of site-specific "contaminants of concern", which are described in the Environmental Contamination and Other Hazards section, ATSDR staff discuss in the Pathways Analyses section whether nearby residents are exposed to contamination migrating from the site. If exposure to contamination is identified, the significance of this exposure, with relation to adverse health effects, is discussed in the Toxicological Evaluation section. ATSDR staff also address specific community concerns in the Community Health Concerns Evaluation section. Finally, based on the evaluations from all preceding sections of the public 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 public comment period for the Loxahatchee Nursery public health assessment. Each comment was logged and became part of the administrative record. Both the comments and ATSDR's responses 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 names mentioned in the comments ATSDR received have not been included. Also, similar comments received from different individuals have been combined into one comment.

1.       We want this nursery resampled for the breakdown products of benlate along with its contaminants, flusilazole and chlorothalonil. We want two sets of samples taken at the same time 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 chemical flusilazole. Please refer to the Community Health Concerns Evaluation section of this public health assessment, which has been modified from the public comment version to include more information concerning flusilazole. Benlate's breakdown product, carbendazim, has been analyzed for in private wells, monitoring wells, soil, and sediment without being detected. Therefore, ATSDR does not recommend any further analyses for benlate or its breakdown products.

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

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

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

At this time, ATSDR does not recommend any further residential soil sampling. Soil and water analyses have been performed on the properties surrounding the nursery. No contaminants at levels of health concern were detected. Of note, the MCHD plans to periodically monitor the groundwater 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 related to the release of hazardous substances from the site being investigated. ATSDR reviewed environmental 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 the community to review the rate of cancer, the MCHD plans to review cancer incidence data. For more 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 and state agencies collaborating with DuPont to withhold crucial life and health information from the 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 of 1,2-dichloropropane was receiving bottled water and the report made recommendation #5 that more information is needed to stop exposure. This well was fitted with a charcoal filter almost immediately after the contamination was found. When ATSDR investigators visited the site, the filter 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 our September 1996 health consultation. These are not our current recommendations which are found 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 recommended additional sampling activities. Information contained in the copy of the 1996 health consultation found 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 operators from 1944 to 1992, none of whom report ever using this chemical on the premises. They did use 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 public comment release of the document. All references to the use of 1,2-dichloropropane on site have been removed from the main text of the final release public health assessment because the reports of its use are conflicting. Of note, not stating the source of the 1,2-dichlorpropane in the public health assessment does not affect ATSDR's conclusions and recommendations regarding this site. Further, in the Community Health Concerns Evaluation section , ATSDR states that 1,2-dichloropropane has not been detected in on-site monitoring well, soil, or sediment samples which suggests the nursery is not the source.

8.       The Background section reports that pesticides were applied via injection through the irrigation 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 the plants through the nursery's irrigation system.

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

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

10.       The report indicates a septic tank system is present on site. Was this located during the March 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. ATSDR believes the septic tank is used by the on-site residence; however, ATSDR was not able find any documentation 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 beneath the site.

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

12.       In the Pathway Analysis section, the document reports one Completed Exposure Pathway beginning with 1,2-dichloropropane applied at the nursery and ending with it in a drinking water well. As this chemical was not used on site, it originated elsewhere. In fact, the high relative concentration in the one well, which is located in a drainage swale north of the nursery, along with failure to find 1,2-dichloropropane anywhere else within the nursery or surrounds, argues against the nursery being the source. It is much more likely that a local homeowner used this chemical as a degreaser, which is one on its known applications, and disposed 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 a completed 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 from August 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 main text 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 Health Department (MCHD).

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

15.       The pond was sampled by FDEP and two 7-day chronic static-renewal definitive toxicity bioassays were performed on the samples collected. The samples did not demonstrate chronic 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-specific environmental sampling data (i.e., for surface water or sediment) have not been collected for the pond, ATSDR recommends additional characterization of the pond as indicated in the Recommendation section of the public health assessment.

16.       How can LN-SS08, LN-SS01, and LN-TW01 be considered background or off site as they 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 of this public health assessment, ATSDR did not consider the sampling locations mentioned in this comment to reflect "background" conditions. Please refer to the main text for further clarification of the background issue. Additionally, references to "on -site" and "off site" in public health assessments are arbitrary boundaries created by ATSDR staff for the purpose of delineating data and evaluating human exposure pathways. The parcel in question is across the street from where primary nursery operations occurred. The parcel is directly adjacent to the county park. The data reports that ATSDR received indicated this parcel was outside of property 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 included sampling 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 States soil and are probably not due to nursery activities." A more recent report (Ma et al, 1997) on Florida soils suggests that the arsenic level at LN-SS01 and the chromium level at LN-SS10A are indicative of anthropogenic sources.

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

18.       The sediment analytical results revealed exceedances of the Sediment Guidance Criteria 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 for residential direct exposure for arsenic in several samples. The soil analytical results revealed exceedances of the Florida Soil Cleanup Goals for residential direct exposure and leachability for chlordane in two samples. The soil analytical results revealed exceedances of the Florida Soil Cleanup Goals for leachability for chromium and dieldrin in one sample each. The groundwater analytical results revealed exceedances of the Florida Drinking Water Standards for 1,2-dichloropropane in one private well. As discussed in the text of ATSDR's report, this well 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, ATSDR concluded that under site-specific conditions of exposure, none of the contaminants detected in soil or sediment are likely to pose a hazard to public health. ATSDR understands that if the site is to be developed residential, certain criteria and cleanup goals set by the state of Florida must be met; however, as a nonregulatory agency, commenting on the cleanup goals set by the state are out of the purview of this public health assessment.

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