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HEALTH CONSULTATION

COEUR D'ALENE RIVER BASIN
PANHANDLE REGION OF IDAHO
INCLUDING BENEWAH, KOOTENAI, & SHOSHONE COUNTIES

APPENDICES

 

Appendix A: Coeur d'Alene River Basin Residential Properties

Analytical Results for Lead in Soil, Dust, and Paint.

Location ID

Average Lead Concentration in Residential Yard (mg/kg)

Lead Concentration in Play Area (mg/kg)

Lead Concentration in Garden (mg/kg)

Lead Conc. in Mat

Lead Conc. in Vacuum Bag

Lead Conc. in Exterior Paint

Lead Conc. in Interior Paint

Water Sample Results exceeding RAL/MCL

 

Surface Soil

Sub-surface

Surface Soil

Sub-surface

Surface Soil

Sub-surface

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

(µg/L) all first-run

1

663

495

-

-

721

592

841

606

30300

409

-

2

804

729

-

-

-

-

797

480

98600

-

-

3

174

132

154

121

-

-

4250

764

-

-

-

4

448

343

-

-

-

-

658

173

-

-

-

5

1190

1100

-

-

-

-

790

978

2390

-

-

6

227

382

-

-

319

475

673

422

-

-

-

7

979

1460

-

-

-

-

588

154

-

-

-

8

290

321

-

-

-

-

300

389

-

-

-

9

665

408

-

-

-

-

15500

765

5300

-

-

10

342

777

-

-

-

-

1020

332

205

-

-

11

760

245

-

-

2440

266

2030

1260

-

-

-

12

3490

6820

-

-

1000

714

2800

604

-

-

-

13

5570

1980

-

-

1080

1210

995

1960

-

-

-

14

794

767

-

-

-

-

4250

1200

-

-

-

15

3790

4260

-

-

-

-

767

-

905

-

-

16

1010

307

-

-

213

218

1660

1660

-

-

-

17

276

236

-

-

-

-

1260

680

-

197

-

18

796

358

-

-

-

-

332

818

-

93

26.4

19

953

1050

-

-

315

473

950

512

-

-

-

20

451

1030

613

747

-

-

1280

639

-

-

-

21

1340

1250

-

-

-

-

3440

1350

-

-

-

22

1690

2760

1120

1290

1120

972

1660

798

130000

-

-

23

977

805

-

-

626

618

734

808

-

-

-

24

813

1190

-

-

257

245

847

703

-

-

-

25

438

153

-

-

-

-

-

84

-

-

-

26

682

886

-

-

-

-

-

762

20600

-

-

27

622

282

-

-

-

-

566

349

-

-

-

28

1320

858

-

-

-

-

2120

767

-

-

-

29

437

474

-

-

-

-

812

383

119

10

-

30

1580

1230

-

-

-

-

1550

1020

4140

86000

-

31

827

627

-

-

-

-

1250

710

-

-

-

32

3600

8570

12100

36100

885

732

1780

1020

-

-

-

33

278

377

-

-

278

693

496

427

783

-

-

34

1420

594

-

-

587

589

1490

1020

949

-

-

35

364

116

155

71.5

-

-

374

341

15800

-

-

36

766

958

-

-

-

-

2370

882

101000

-

-

37

769

433

-

-

-

-

732

23

-

-

56.1

38

688

346

-

-

-

-

8840

1820

-

-

-

39

16000

17300

-

-

-

-

14000

6150

-

-

-

40

718

536

-

-

-

-

791

2430

-

-

-

41

503

207

-

-

103

96.7

1640

769

19100

-

-

42

500

388

-

-

180

1590

713

387

-

-

-

43

3050

3510

-

-

5480

4770

27800

2730

-

-

-

44

3210

7030

-

-

-

-

59500

-

-

-

-

45

843

849

-

-

-

-

1020

619

-

-

-

46

852

994

-

-

1200

911

2040

3300

10900

47400

-

47

56.2

29.5

-

-

-

-

655

626

4860

-

-

48

319

186

-

-

-

-

468

504

-

-

-

49

256

224

-

-

-

-

368

492

1140

-

-

50

7060

12000

-

-

6605

15020

2420

-

-

-

15.7

51

3030

900

-

-

1240

1170

1060

621

19200

6820

-

52

787

759

-

-

406

895

1600

1550

-

-

-

53

735

739

1120

1530

89.6

80.4

380

315

-

-

-

54

544

213

316

109

85.8

80.7

778

504

679

-

-

55

642

650

-

-

-

-

615

384

-

-

-

56

353

179

-

-

-

-

1120

833

5210

-

-

57

1190

1470

-

-

-

-

1210

-

7600

-

-

58

2710

6970

-

-

-

-

1620

353

10700

-

-

59

1170

786

-

-

-

-

790

778

29900

-

26.9

60

188

182

48.7

15.9

142

133

182

232

-

-

-

61

284

234

-

-

-

-

2050

1680

-

-

-

62

2920

186

-

-

-

-

-

-

-

-

-

63

563

943

-

-

-

-

1370

655

31900

-

-

64

2700

4220

-

-

-

-

4460

1540

15300

-

-

65

1210

1190

516

558

287

292

858

937

4040

-

-

66

1090

1140

-

-

-

-

990

780

2250

1370

39.8

67

2430

2190

-

-

11800

9900

1130

1380

-

-

-

68

479

500

-

-

-

-

604

727

-

-

-

69

1270

663

-

-

-

-

-

-

115000

27400

-

70

1380

984

-

-

-

-

3100

405

1110

-

-

71

346

465

-

-

-

-

1730

942

155000

-

-

72

26.9

-

-

-

-

-

-

292

-

-

-

73

34

26.8

-

-

-

-

440

53

590

-

-

74

3840

2190

-

-

-

-

1360

362

-

-

-

75

453

958

216

444

365

314

1090

-

-

-

-

76

3290

3440

-

-

-

-

3210

2840

-

-

-

77

2560

2860

995

3250

1120

949

1550

-

1110

2170

-

78

654

249

-

-

-

-

2080

2400

-

-

-

79

510

120

-

-

-

-

-

-

-

-

-

80

748

333

354

281

-

-

1410

1000

142000

-

-


APPENDIX B: METHODS

Method I: Calculation of an estimated dose and comparison to the IOC

The following routes of exposure were considered:

Ingestion:

Soil & Dust - Soil and dust ingestion were analyzed quantitatively through calculation of an external dose using average lead concentrations.

Homegrown Foods - Lead levels in garden vegetables were analyzed and their contribution examined quantitatively. However, this data was not incorporated with garden soil lead levels, because sources of the vegetables were not matched with soil sample locations. Future work should include this pathway.

Tap Water - Potable water was included where sampling indicated lead levels exceeded the EPA's action level for lead.

Inhalation:

Air particulates - No sampling data were available, therefore background levels were used.

Dermal:

Soil - This pathway is considered negligible as appreciable levels of lead do not penetrate through the skin (ATSDR, 1999)

External dose for children's soil ingestion was calculated:

Dosesoil =
C x IR x BF x CF
BW
=
Conc x 0.5 x 200mg/day x 10 -6
16kg

where

C = concentration of lead in soil, mg/kg
IR = ingestion rate, mg/day
BF = bioavailability factor
BW = body weight, kg
CF = conversion factor (kg to mg)

Concentrations used were the surface soil composite samples. The ingestion rate of 200 mg/day was used as a conservative mean estimate of children's soil ingestion (EPA, 1999)*. An average recommended body weight of 16 kg was used as a mean estimate (EPA, 1999)*. An absolute bioavailability factor of 50% for soil-born lead was used.** This leads to a mean estimate of children's exposed dose, although it needs to be remembered that use of composite surface soil measurements may result in an underestimation of the true concentration, because Ahotspots@ may not be detected.

External dose for children indoor dust ingestion was calculated:

Dosedust =
C x IR x BF x CF
BW
=
Conc x IR x BF x 10 -6
16kg

The ingestion rate for dust was taken from estimates of soil and total soil and dust ingestion from the Exposure Factors Handbook (EPA, 1999). Average dust ingestion as a percentage of total soil and dust ingestion was calculated for mean and high-end estimates. Dust ingestion was separated from soil ingestion in this consultation in order to ascertain the specific contributions of dust lead and soil lead to total exposure. Prior studies have ascertained a high indoor dust contribution to total lead exposures (IDHW, 1999).

Similar methodologies were utilized for the other input routes, with the input variables presented in Table B-1 below.

Table B-1. Input parameters used to quantify mean background air and food lead exposures, and tap water lead exposures when the action level was exceeded.

Route

Lead concentration

Reference

Ingestion/
Inhalation rate

Reference

Tap water

residence-specific

see data, Appendix A

0.58 L/day

EPA, 1999
for children ages 1-4

Air
(background only)

0.10 µg/m3

EPA, 1994

5 m3/day

EPA, 1994
median ventilation rate

Food

6 µg/day

EPA, 1994, median value

n/a


L/day = liters per day  m3/day = cubic meters per day

µg/m3 = micrograms per cubic meter  n/a = not applicable

Method 2: Calculation of expected blood lead levels

Surface soil and indoor house dust lead levels were entered into the EPA's IEUBK model (EPA, 1994). Based on the above calculations, soil and dust incidental ingestion were found to have an appreciably greater contribution to total dose than other exposure routes. Therefore, when using the model, other input distributions were left at default values. Only the effect of soil and indoor dust lead levels were examined. In order to keep the IEUBK model consistent with the previous calculations, soil ingestion as a percentage of total soil and dust ingestion was increased from the default value of 45% to 71%. Expected blood lead levels were then recorded as being between an upper and lower range. Expected blood lead level data can be seen in Appendix C. The blood lead upper and lower range values were then averaged to calculate an average blood lead level, and locations were categorized as having an average blood lead level either greater or less than 10 µg/dl. Several residences had average blood lead levels less than 10 µg/dl, but as the blood lead range included 10 µg/dl they were considered to represent an intermediate category.

In the IEUBK model, the Geometric mean blood lead level which corresponds to a probability of 10 µg/dl is approximately 5 µg/dl. This relationship is sensitive to the geometric standard deviation (GSD): default = 1.6.

Method 3: ATSDR's integrated exposure regression analysis

Numerous longitudinal and cross-sectional studies have attempted to correlate environmental lead levels with blood lead levels. These studies have provided a number of regression analyses and corresponding slope factors () for various media including air, soil, dust, water, and food. The ATSDR integrated exposure regression analysis utilizes slope values from select studies to integrate all exposures from various pathways, thus providing a cumulative exposure estimate expressed as total blood lead (ATSDR 1999).

The general form of the model is:

where,
Pbs = soil lead concentration
Pbd = dust lead concentration
Pbw = water lead concentration
Pbao = outside air lead concentration
Pbai = inside air lead concentration
Pbf = food lead concentration
T = relative time spent

Table B- 2: Selected Slope Factors for Specific Media (ATSDR 1999)

Media

Population

Slope

Source

Air

Children (1-18 yrs)

1.92 + 0.60

Angle et al, 1984 as cited in ATSDR 1999, App D

Water

Children

0.16 at <15 µg/L
0.03 at >15 µg/L

Laxen et al, 1987 as cited in ATSDR 1999, App D

Diet

Infants & Toddlers

0.24

Ryu et al, 1983 as cited in ATSDR 1999, App D

Soil

Children (1-72 mo)

0.002 + 0.00082

Stark et al, 1982 as cited in EPA 1986

Dust

Children (2 yrs old)

0.002 + 0.00066

Stark et al, 1982 as cited in ATSDR 1999, App D

µg/L = micrograms per liter

Table B-3: Default Values for Missing Data (ATSDR 1999)

Media

Default

Outdoor Air

0.1-0.2 µg/m3

Indoor Air

0.03-0.06 µg/m3 (0.3 x outdoor conc.)

Food

5 µg/day

Water

4 µg/L

Indoor Dust

947 (ave. Indoor dust conc. for 71 residences sampled)

µg/m3 = micrograms per cubic meter
µg/day = micrograms per day
µg/L = micrograms per liter

Bioavailability was not estimated for this method, as each slope factor is based upon observed blood lead levels correlated with environmental concentrations. The average surface soil concentration was used unless a surface soil concentration was available in a Aplay area@, which was then used. For indoor dust, vacuum bag concentrations were used. For those few residences without vacuum bag data, the average vacuum bag concentration of the other 71 residences with data was used.

The example described within Appendix D of the ATSDR Toxicological Profile for Lead selected larger soil/dust slope values plus or minus three standard deviations to determine the high and low range of blood leads. In this health consultation, values more specific to children aged 1- 3 were selected, and only one standard deviation was added or subtracted for determining the low and high range of blood leads. Subtracting three standard deviations from the slope values selected for this health consultation created negative slopes at the low end, therefore, this was not done. The net effect would be to make the method utilized in this health consultation much less conservative than the example outlined in Appendix D of the Toxicological Profile. Based upon the results provided in Table 5, Appendix D of the Toxicological Profile (which showed this method to correlate well with actual blood lead levels), this would result in an underestimation of the number of residences at which the blood lead range could exceed 10 µg/dl. A benefit to be gained by this method, however, is that those residences most likely to be a problem should be highlighted in this health consultation.

Appendix C: Coeur d'Alene River Basin Residential Properties.

Estimated dose, the number of time the dose is greater than the IOC, and the expected blood lead ranges by residential location ID.

Location ID

Total Pb dose

Times Dose > IOC

EPA IEUBK
BPb Range
(µg/dl)

ATSDR Regression
BPb Range
(µg/dl)

 

mg/kg/day

[-]

Lower

Upper

Lower

Upper

1

0.0054

2.9

5.6

9.9

3.4

5.3

2

0.0061

3.3

6

10.5

3.4

5.4

3

0.0027

1.5

3.7

6.4

3

4.3

4

0.0033

1.8

3.8

6.7

2.6

3.6

5

0.0094

5.1

8.4

14.4

4.4

7.7

6

0.0024

1.3

3.3

5.6

2.6

3.6

7

0.0066

3.6

6.2

10.8

3.2

5.1

8

0.0027

1.5

3.5

6.1

2.7

3.7

9

0.0058

3.1

5.9

10.4

3.6

5.7

10

0.0030

1.6

3.6

6.3

2.7

3.7

11

0.0072

3.9

7.1

12.4

4.3

7.2

12

0.0231

12.5

15

24

6.7

13.3

13

0.0386

20.8

22

33

10.7

22.5

14

0.0074

4.0

7.2

12.5

4.2

7.2

15

0.0239

12.9

15

25

7.3

14.5

16

0.0095

5.1

8.8

15

5

8.9

17

0.0032

1.7

4

7

3

4.4

18

0.0072

3.9

6.5

11.4

3.9

6.4

19

0.0071

3.8

6.7

11.7

3.6

5.9

20

0.0042

2.3

4.7

8.3

3.4

5.3

21

0.0111

6.0

9.6

16.2

5

9.1

22

0.0122

6.6

10

16.9

4.1

7.1

23

0.0078

4.2

7.3

12.6

4

6.7

24

0.0066

3.5

6.4

11.2

3.7

6

25

0.0031

1.7

3.6

6.3

2.5

3.4

26

0.0058

3.2

6

10.5

3.6

5.8

27

0.0047

2.5

5

8.7

3

4.6

28

0.0098

5.3

8.6

14.7

4.3

7.6

29

0.0036

2.0

4.2

7.3

2.9

4.1

30

0.0120

6.5

9.9

16.8

4.9

8.9

31

0.0066

3.6

6.5

11.4

3.7

6

32

0.0246

13.3

16.5

25.8

17.4

38.6

33

0.0027

1.5

3.5

6.1

2.7

3.8

34

0.0110

5.9

9.3

15.9

4.8

8.5

35

0.0031

1.7

3.8

6.6

2.5

3.2

36

0.0066

3.6

6.5

11.4

3.8

6.3

37

0.0060

3.3

5

8.9

3.9

5.2

38

0.0078

4.2

7.8

13.4

4.8

8.4

39

0.1114

60.2

42.5

60.9

27.9

62.3

40

0.0091

4.9

8.9

15.1

5.6

10

41

0.0048

2.6

5.2

9.2

3.4

5.3

42

0.0040

2.2

4.5

7.9

2.9

4.3

43

0.0242

13.1

16.9

26.3

8.7

17.3

44

0.0202

10.9

14.1

22.5

74.7

158.6

45

0.0066

3.6

6.4

11.2

3.6

5.9

46

0.0115

6.2

10.7

17.8

6.7

12.5

47

0.0017

0.9

2.8

4.8

2.7

3.7

48

0.0031

1.7

3.9

6.8

2.9

4.1

49

0.0027

1.5

3.5

6.2

2.8

3.9

50

0.0446

24.1

24.1

35.5

12.9

27.7

51

0.0202

10.9

14.3

22.9

6.2

12

52

0.0080

4.3

7.7

13.4

4.6

8

53

0.0054

2.9

5.4

9.5

3.6

5.9

54

0.0045

2.4

4.9

8.6

2.9

4.1

55

0.0049

2.6

5.1

9

3.1

4.7

56

0.0039

2.1

4.6

8.2

3.3

5

57

0.0076

4.1

6.8

11.9

4.3

8.3

58

0.0178

9.6

12.9

21

5.5

10.5

59

0.0094

5.1

8

13.8

4.3

7.3

60

0.0018

1.0

2.7

4.5

2.2

2.7

61

0.0050

2.7

5.9

10.3

4.2

6.9

62

0.0184

10.0

13.2

21.3

5.4

10.4

63

0.0049

2.6

5.2

9.3

3.3

5.2

64

0.0198

10.7

14.5

23

6.9

13.4

65

0.0094

5.1

8.4

14.4

3.6

5.7

66

0.0092

4.9

7.7

13.3

4.6

7.5

67

0.0179

9.7

13.4

21.6

6

12.2

68

0.0045

2.4

5

8.8

2.9

5.1

69

0.0081

4.4

7.1

12.4

3.1

5.7

70

0.0096

5.2

8.2

14.2

3.6

6.8

71

0.0040

2.2

4.8

8.5

3

5.3

72

0.0009

0.5

2

3.2

1.9

2.8

73

0.0005

0.3

1.6

2.2

1.6

2.2

74

0.0248

13.4

16.4

25.6

6.4

13.7

75

0.0031

1.6

3.5

6.1

3

5.3

76

0.0259

14.0

17.7

27.3

8.7

18.3

77

0.0162

8.8

11.9

19.6

6.3

13

78

0.0086

4.7

8.6

14.7

5

9.7

79

0.0034

1.8

3.8

6.6

2.2

3.6

80

0.0067

3.6

6.6

11.6

3.5

6.5

Appendix D. Health Effects Summary Table

Species

System

Exposure Duration

LOAEL
mg/kg/day

Effect

Human

hemato

7 wk at7 days/wk

0.01

decrease ALAD activity; increased RBC porphyrin

Human

hemato

21days at 7 days/wk

0.02

increased protoporphyrin IX in RBC (F)

Rat

hepatic

20-30 d

0.05

decreased RNA, glycogen: pyknosis of Kupffer cells; increased liver weight

Rat

hemato

6-12 mo

0.005

impaired heme synthesis

Rat

hepatic

6-12 mo

0.005

decreased glycogen, RNA, sulfhydryl groups, alterations in activities of oxidizing enzymes

Rat

cardio

159 d

0.3

increased systolic blood pressure

Monkey

neuro

200 d; 5 d/wk

0.05

Impaired nonspatial discrimination at 3 yrs of age

Rat

neuro

6-12 mo

0.005

disruption of conditioned responses and motor activity

Rat

repro

30 d

0.013

increased prostate weight (M)

Rat

repro

30 d

0.014

irregular estrus cycles (F)

Rat

repro

6-12 mo

0.05

decreased activity of AIDH, SDH, NAD, and DADPH-diaphorase in spermatogenic epithelium and swelling of lollicular epithelial cells in males

Rat

repro

23-30 d

0.005

dystrophy of Leydig cells

Rat

cardio

<18 mo; 7 d/wk

0.014

increase in systolic blood pressure

Monkey

neuro

1 yr; 7 d/wk

0.19

deficit in fixed interval schedule

ALAD = aminolevulinic acid dehydratase; cardio = cardiovascular; d = days; F = female; hemato = hematological;
LOAEL = lowest-observable-adverse-effect level; M = male; mg/kg/day = milligrams per kilogram per day; mo =
month; neuro = neurological; RBC = red blood cell; repro = reproductive; RNA = ribonucleic acid; wk = week; yr = year

Appendix E. Comprehensive Follow-up Services Recommended According to Diagnostic*
Blood Lead Level (BLL); (CDC 1997, table 4.3)

BLL
(µg/dl)

Action

<10

Reassess or rescreen in 1 year. No additional action necessary unless exposure source changes.

10-14

Provide Family lead education.
Provide follow-up testing.
Refer for social services, if necessary.

15-19

Provide Family lead education.
Provide follow-up testing.
Refer for social services, if necessary.
If BLLs persist (i.e., 2 venous BLLs in this range at least 3 months apart) or worsen, proceed according to actions for BLLs 20-44.

20-44

Provide coordination of care (case management).
Provide clinical management (described in text).
Provide environmental investigation.
Provide lead-hazard control.

45-69

Within 48 hours, begin coordination of care (case management), clinical management (described in text), environmental investigation, and lead hazard control.

>70

Hospitalize child and begin medical treatment immediately. Begin coordination of care (case management), clinical management (described in text), environmental investigation, and lead hazard control immediately.

ATSDR Plain Language Glossary of Environmental Health Terms

Absorption: How a chemical enters a person's blood after the chemical has been swallowed, has come into contact with the skin, or has been breathed in.

Acute Exposure: Contact with a chemical that happens once or only for a limited period of time. ATSDR defines acute exposures as those that might last up to 14 days.

Adverse Health Effect: A change in body function or the structures of cells that can lead to disease or health problems.

ATSDR: The Agency for Toxic Substances and Disease Registry. ATSDR is a federal health agency in Atlanta, Georgia that deals with hazardous substance and waste site issues. ATSDR gives people information about harmful chemicals in their environment and tells people how to protect themselves from coming into contact with chemicals.

Background Level: An average or expected amount of a chemical in a specific environment. Or, amounts of chemicals that occur naturally in a specific environment.

Biota: Used in public health, things that humans would eat B including animals, fish and plants.

Cancer: A group of diseases which occur when cells in the body become abnormal and grow, or multiply, out of control

Carcinogen: Any substance shown to cause tumors or cancer in experimental studies.

Chronic Exposure: A contact with a substance or chemical that happens over a long period of time. ATSDR considers exposures of more than one year to be chronic.

Completed Exposure Pathway:  See Exposure Pathway.

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA): CERCLA was put into place in 1980. It is also known as Superfund. This act concerns releases of hazardous substances into the environment, and the cleanup of these substances and hazardous waste sites. ATSDR was created by this act and is responsible for looking into the health issues related to hazardous waste sites.

Concern: A belief or worry that chemicals in the environment might cause harm to people.

Concentration: How much or the amount of a substance present in a certain amount of soil, water, air, or food.

Contaminant: See Environmental Contaminant.

Delayed Health Effect: A disease or injury that happens as a result of exposures that may have occurred far in the past.

Dermal Contact: A chemical getting onto your skin. (see Route of Exposure).

Dose: The amount of a substance to which a person may be exposed, usually on a daily basis. Dose is often explained as Aamount of substance(s) per body weight per day@.

Dose / Response: The relationship between the amount of exposure (dose) and the change in body function or health that result.

Duration: The amount of time (days, months, years) that a person is exposed to a chemical.

Environmental Contaminant: A substance (chemical) that gets into a system (person, animal, or the environment) in amounts higher than that found in Background Level, or what would be expected.

Environmental Media: Usually refers to the air, water, and soil in which chemcials of interest are found. Sometimes refers to the plants and animals that are eaten by humans. Environmental Media is the second part of an Exposure Pathway.

U.S. Environmental Protection Agency (EPA): The federal agency that develops and enforces environmental laws to protect the environment and the public's health.

Epidemiology: The study of the different factors that determine how often, in how many people, and in which people will disease occur.

Exposure: Coming into contact with a chemical substance.(For the three ways people can come in contact with substances, see Route of Exposure.)

Exposure Assessment: The process of finding the ways people come in contact with chemicals, how often and how long they come in contact with chemicals, and the amounts of chemicals with which they come in contact.

Exposure Pathway: A description of the way that a chemical moves from its source (where it began) to where and how people can come into contact with (or get exposed to) the chemical.

ATSDR defines an exposure pathway as having 5 parts:

    1. Source of Contamination,
    2. Environmental Media and Transport Mechanism,
    3. Point of Exposure,
    4. Route of Exposure, and
    5. Receptor Population.

When all 5 parts of an exposure pathway are present, it is called a Completed Exposure Pathway. Each of these 5 terms is defined in this Glossary.

Frequency: How often a person is exposed to a chemical over time; for example, every day, once a week, twice a month.

Hazardous Waste: Substances that have been released or thrown away into the environment and, under certain conditions, could be harmful to people who come into contact with them.

Health Effect: ATSDR deals only with Adverse Health Effects (see definition in this Glossary).

Indeterminate Public Health Hazard: The category is used in Public Health Assessment documents for sites where important information is lacking (missing or has not yet been gathered) about site-related chemical exposures.

Ingestion: Swallowing something, as in eating or drinking. It is a way a chemical can enter your body (See Route of Exposure).

Inhalation: Breathing. It is a way a chemical can enter your body (See Route of Exposure).

LOAEL: Lowest Observed Adverse Effect Level. The lowest dose of a chemical in a study, or group of studies, that has caused harmful health effects in people or animals.

MRL: Minimal Risk Level. An estimate of daily human exposure B by a specified route and length of time -- to a dose of chemical that is likely to be without a measurable risk of adverse, noncancerous effects. An MRL should not be used as a predictor of adverse health effects.

NPL: The National Priorities List. (Which is part of Superfund.) A list kept by the U.S. Environmental Protection Agency (EPA) of the most serious, uncontrolled or abandoned hazardous waste sites in the country. An NPL site needs to be cleaned up or is being looked at to see if people can be exposed to chemicals from the site.

NOAEL: No Observed Adverse Effect Level. The highest dose of a chemical in a study, or group of studies, that did not cause harmful health effects in people or animals.

No Apparent Public Health Hazard: The category is used in ATSDR's Public Health Assessment documents for sites where exposure to site-related chemicals may have occurred in the past or is still occurring but the exposures are not at levels expected to cause adverse health effects.

No Public Health Hazard: The category is used in ATSDR's Public Health Assessment documents for sites where there is evidence of an absence of exposure to site-related chemicals.

PHA: Public Health Assessment. A report or document that looks at chemicals at a hazardous waste site and tells if people could be harmed from coming into contact with those chemicals. The PHA also tells if possible further public health actions are needed.

Point of Exposure: The place where someone can come into contact with a contaminated environmental medium (air, water, food or soil). For examples:

the area of a playground that has contaminated dirt, a contaminated spring used for drinking water, the location where fruits or vegetables are grown in contaminated soil, or the backyard area where someone might breathe contaminated air.

Population: A group of people living in a certain area; or the number of people in a certain area.

Public Health  Assessment(s): See PHA.

Public Health Hazard: The category is used in PHAs for sites that have certain physical features or evidence of chronic, site-related chemical exposure that could result in adverse health effects.

Public Health Hazard Criteria: PHA categories given to a site which tell whether people could be harmed by conditions present at the site. Each are defined in the Glossary. The categories are:

Receptor Population: People who live or work in the path of one or more chemicals, and who could come into contact with them (See Exposure Pathway).

Reference Dose (RfD): An estimate, with safety factors (see safety factor) built in, of the daily, life-time exposure of human populations to a possible hazard that is not likely to cause harm to the person.

Route of Exposure: The way a chemical can get into a person's body. There are three exposure routes:

- breathing (also called inhalation),

- eating or drinking (also called ingestion), and

- or getting something on the skin (also called dermal contact).

Safety Factor: Also called Uncertainty Factor. When scientists don't have enough information to decide if an exposure will cause harm to people, they use Asafety factors@ and formulas in place of the information that is not known. These factors and formulas can help determine the amount of a chemical that is not likely to cause harm to people.

Source (of Contamination): The place where a chemical comes from, such as a landfill, pond, creek, incinerator, tank, or drum. Contaminant source is the first part of an Exposure Pathway.

Special Populations: People who may be more sensitive to chemical exposures because of certain factors such as age, a disease they already have, occupation, sex, or certain behaviors (like cigarette smoking). Children, pregnant women, and older people are often considered special populations.

Statistics: A branch of the math process of collecting, looking at, and summarizing data or information.

Subclinical: The presence of a disease without apparent symptoms in the individual. May be an undiagnosed or early stage of a disease, or result in impaired development or reduced potential. Effects may only be apparent after scientific comparisons of many children.

Superfund Site: See NPL.

Toxic: Harmful. Any substance or chemical can be toxic at a certain dose (amount). The dose is what determines the potential harm of a chemical and whether it would cause someone to get sick.

Toxicology: The study of the harmful effects of chemicals on humans or animals.

Uncertainty Factor: See Safety Factor.

Urgent Public Health Hazard: This category is used in ATSDR's Public Health Assessment documents for sites that have certain physical features or evidence of short-term (less than 1 year), site-related chemical exposure that could result in adverse health effects and require quick intervention to stop people from being exposed.

FIGURES



Figure 1 - Effects of Inorganic lead in children and adults


     * The typical infant and toddler oral exploratory behaviors include repetitive mouthing which results in continuous ingestion by these children of small amounts of dust and soil over the course of a play period, ultimately adding up to a daily intake of 100 to 200 mg (Mushak 1998).

  * 16 kg (roughly 35 pounds) is approximately the body weight of a child one to two years of age. The Centers for Disease Control and Prevention (CDC) has said that focus should be on children between the ages of 12 and 36 months (1-and 2-year-old children) because blood lead levels tend to be highest in this age group, and more chiuldren in this age group have blood lead levels equal to or greater than 10 µg/dl (CDC, 1997).

    **The value of 50% bioavailability was selected as representative of the upper range of values seen in a variety of studies measuring absolute and relative lead bioavailability (Mushak, 1998; Maddaloni, 1998; Henningsen, 1998).

  * A diagnostic BLL is the first venous BLL obtained within 6 months of an elevated screening for BLL.

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