february 13, 2008 stakeholder request for information from … of umdes 011608... · dfp29-2005...

$: FEBRUARY 13, 2008 STAKEHOLDER REQUEST FOR INFORMATION FROM … of UMDES 011608... · DFP29-2005 (ppt), with values below LOD replaced by LOD/√2 N:\Secure\UMDES\Presentations\Explanation$
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FEBRUARY 13, 2008 STAKEHOLDER REQUEST FOR INFORMATION FROM THE UMDES

February 13, 2008 Request from Michigan Department of Environmental Quality, By Dr. Deborah Mackenzie-Taylor Dr. Garabrant, Thank you for inviting the state and federal agency risk assessors to meet with the study team on January 16, 2008. The additional information provided at these type of sessions continues to be informative. During the meeting, you showed some updated presentation materials including residual plots for TCDD soil vs. blood levels that you indicated you would send to us. Please let me know when you can make those available. I need to schedule some time with our statistical consultant in the next week or so and would like his input on those evaluations. When do you expect the team to complete similar evaluations for TEQs (including DF only TEQ) and other congeners? After the last few public meetings including last Thursdays meeting, it is critical for us to have a clear understanding of the number of participants with elevated soil concentrations. We can estimate some values based on the percentages provided in presentations, but would prefer specific numbers for accuracy. We are interested in the number of participants with soil concentrations at or above 1,000 ppt and 90 ppt for each area and TEQ listed below in the tables. In addition, it would helpful to know how many participants live on properties with more than one sample that is at or above these values. I have provided a table below to assist this effort and as an attached Excel® spreadsheet. I expect the agencies will have some additional requests in the near future, but I wanted to follow up on the issues that arose at the February 7, 2008 DEQ Community Meeting. Thank you for your continued assistance. Deb

# of participants

with soil concentration = 1,000 ppt

TEQDFP29-2005

# of participants


TEQDF17-2005

# of participants


TEQDFP29-1998

# of participants

with soil concentration = 1,000 ppt TEQdf17-1998

Any soil Overall FP Near FP Other M/S Jackson


# of participants


TEQDFP29-2005

# of participants


TEQDF17-2005

# of participants


TEQDFP29-1998

# of participants

with soil concentration = 1,000 ppt TEQdf17-1998

House Perimeter 0-1” Overall FP Near FP Other M/S Jackson Soil Contact Zone 0-6” Overall FP Near FP Other M/S Jackson Near River Floodplain 0-1” FP More than 1 location on a property = 1,000 ppt

# of participants

with soil concentration

= 90 ppt TEQDFP29-2005

# of participants


= 90 ppt TEQDF17-2005

# of participants



# of participants


= 90 ppt TEQdf17-1998

Any soil Overall FP Near FP Other M/S Jackson House Perimeter 0-1” Overall FP Near FP Other M/S Jackson Soil Contact Zone 0-6” Overall FP Near FP Other M/S


# of participants



# of participants


= 90 ppt TEQDF17-2005

# of participants



# of participants


= 90 ppt TEQdf17-1998

Jackson Near River Floodplain 0-1” FP More than 1 location on a property = 90 ppt

# of participants

with soil concentration ≥ 1,000 ppt

TEQDFP29-2005

# of participants

with soil concentration ≥ 1,000 ppt TEQDF17-2005

# of participants

with soil concentration ≥ 1,000 ppt

TEQDFP29-1998

# of participants

with soil concentration ≥ 1,000 ppt TEQdf17-1998

Any soil Overall FP Near FP Other M/S Jackson House Perimeter 0-1” Overall FP Near FP Other M/S Jackson Soil Contact Zone 0-6” Overall FP Near FP Other M/S Jackson Near River Floodplain 0-1” FP

More than 1 location on a property ≥ 1,000 ppt


# of participants


≥ 90 ppt TEQDFP29-2005

# of participants


≥ 90 ppt TEQDF17-2005

# of participants


≥ 90 ppt TEQDFP29-1998

# of participants


≥ 90 ppt TEQdf17-1998

Any soil Overall FP Near FP Other M/S Jackson House Perimeter 0-1” Overall FP Near FP Other M/S Jackson Soil Contact Zone 0-6” Overall FP Near FP Other M/S Jackson Near River Floodplain 0-1” FP

More than 1 location on a property ≥ 90 ppt


April 1, 2008 RESPONSE BY UMDES INVESTIGATORS TO REQUEST FOR INFORMATION FROM MDEQ ON FEBRUARY 13, 2008

Discussion of soil dioxins as predictors of serum dioxins

Three different soil dioxin variables were allowed to enter each model. (house perimeter top 1 inch soil concentration, garden soil concentration, and the maximum concentration found in any soil sample from the property) Slide 4-7 (below) shows the results of the regression models in which serum TEQ, serum 2378-TCDD, and serum 23478-PeCDF are the outcome and significant predictors are listed in the left column.

• The maximum soil TEQ concentration was statistically significantly associated with serum TEQ concentration.

• The garden soil 2378-TCDD concentration was statistically significantly associated with serum 2378-TCDD.

These soil variables are not shown in the slides because the results were unstable, as is discussed below.


TEQ: Figure 1 shows the studentized residuals* for the serum TEQ model plotted against the maximum soil TEQ concentration (s_TEQ2006_sqr2_max), where the model does not include the soil TEQ concentration as a predictor. The size of each circle represents the population weight associated with the observation. The graph shows that the residuals are randomly scattered above and below 0 at low soil TEQ concentrations, with some indication of slightly elevated residuals for soil TEQ values above 2500 ppt. Figure 1.

At the far right, a single observation is located at a maximum soil TEQ value of about 11,000 ppt. This observation is highly influential. If this observation is included in the regression analysis, there is a statistically significant association between maximum soil TEQ and serum TEQ (parameter estimate = 0.0000067, p = 0.02). If this observation is excluded from the regression analysis, there is no statistically significant relationship between maximum soil TEQ and serum TEQ (parameter estimate = -0.0000075, p = 0.69). The observation appears to be valid and has not been excluded from the regression model shown in slides 4-7. The importance of maximum soil TEQ concentration as a predictor of serum TEQ should be interpreted with caution insofar as the association is extremely small and is highly dependant on a single observation.

Stud

entiz

ed R

esid

ual f

or S

erum

TEQ

2006

Con

cent

ratio

n

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

s_TEQ2006_sqr2_max

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Maximum soil TEQDFP29-2005 (ppt), with values below LOD replaced by LOD/√2


Examination of a scatterplot of age versus the serum TEQ concentrations is shown in Figure 2. Participants whose maximum soil TEQ concentrations were above 703 ppt are indicated with red dots, while those below 703 ppt are indicated with blue crosses. (703 ppt was chosen as a cut point because it was the 90th percentile of the maximum soil concentrations in the flood plain region.) The purpose of this graph is to examine whether the participants who had the highest maximum soil TEQ concentrations had high serum TEQ concentrations. The majority of people with maximal soil concentrations > 703 ppt had serum TEQDFP29-2005 well within the distribution of other people of the same age. The highest serum TEQDFP29-2005 level was further investigated, and the elevated TEQ appears to be due to a ceramics hobby (Franzblau A, et al. Environmental Health Perspectives 2007; 116: 238-242). Follow-up investigation of the subjects with the second and third highest levels are in progress. Figure 2.

max soil <= 703 ppt max soil > 703 ppt

Ser

um T

EQ

2006

Con

cent

ratio

n(pp

t)

0

100

200

300


2378-TCDD: Figure 3 shows the studentized residuals* for the serum 2378-TCDD model plotted against the (s_2378_TCDD_sqr2_SC), where the model does not include the garden soil 2378-TCDD concentration as a predictor. At the upper right, a single observation is located at a soil 2378-TCDD value of 140 ppt and has a residual of about 4. This observation is highly influential. If this observation is included in the regression analysis, there is a statistically significant association between garden soil 2378-TCDD and serum 2378-TCDD (parameter estimate = 0.0060, p = 0.0000298 ). If this observation is excluded from the regression analysis, there is no statistically significant relationship between garden soil 2378-TCDD and serum 2378-TCDD (parameter estimate = 0.0034, p = 0.19). The observation appears to be valid and has not been excluded from the regression model shown in slides 4-7. Other than this single observation, the residuals are fairly randomly scattered above and below 0 as the garden soil 2378-TCDD level increases, although there is a trend toward slightly elevated levels for garden soil above 25 ppt. Figure 3.

Figure 4 shows the range of garden soil 2378-TCDD concentrations between 5 and 45 ppt, so that a close examination can be made of the residuals in this range. There is a slight upward trend in the residuals in this range, indicating that there may be a weak relationship between garden

Stud

entiz

ed R

esid

ual f

or S

erum

237

8_TC

DD

Con

cent

ratio

n

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

s_2378_TCDD_sqr2_SC

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

Garden soil 2378-TCDD concentration (ppt), with values below LOD replaced by LOD/√2


soil 2378-TCDD and serum 2378-TCDD in this range (however, the relationship is not statistically significant - parameter estimate = 0.0034, p = 0.19). Figure 4.

The importance of garden soil 2378-TCDD concentration as a predictor of serum 2378-TCDD should be interpreted with caution insofar as the association is dependent on a single observation. While there may be an association for extremely high values of soil (based on a single data point at 140 ppt), for soil levels below 50 ppt, no significant association was found. Examination of a scatterplot of age versus the serum 2378-TCDD concentrations is shown in Figure 5. Participants whose garden soil 2378-TCDD concentrations were above 11.3 ppt are indicated with red dots, while those below 11.3 ppt are indicated with blue crosses. (11.3 ppt was chosen as a cut point because it was the 95th percentile of the garden soil 2378-TCDD concentrations in the entire UMDES study.) The purpose of this graph is to examine whether the participants who had the highest garden soil 2378-TCDD concentrations had high serum 2378-TCDD concentrations. Although most of the people with elevated garden soil had serum 2378-TCDD concentrations well within the range of other participants, a few people show elevated serum levels. Follow-up investigation of the subjects with the high serum 2378-TCDD levels are in progress.

Stud

entiz

ed R

esid

ual f

or S

erum

237

8_TC

DD

Con

cent

ratio

n

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

s_2378_TCDD_sqr2_SC

5 10 15 20 25 30 35 40 45

Garden soil 2378-TCDD concentration (ppt), with values below LOD replaced by LOD/√2


Figure 5

* Note: Studentized residuals were calculated as follows (see Applied Linear Statistical Models,

4th Ed., by Neter, Kutner, Nachtsheim, and Wasserman).

Raw (unadjusted) residuals: iii yye ˆ−=

Studentized residuals (each residual is divided by its standard error, which is a

function of the overall error around the regression line (σ ) and the distance of the ith point from the mean of the garden soil values):

i

ii h

er−×

=1σ

iy is the observed outcome for ith observation, iy is the predicted outcome for ith observation

σ is the standard error of the regression (i.e., the square root of the mean squared error)

hi is the leverage (ith diagonal element of the Hat matrix) Hat matrix is defined as: WXWXXXH TT 1)( −=

SC soil <= 11.3 ppt SC soil > 11.3 ppt

Ser

um 2

378_

TCD

D C

once

ntra

tion(

ppt)

0

10

20

30

40

50

60

70


Estimates of the number of households with elevated soil concentrations

Tables 1-2 (below) show the estimated number of households in the population having soil TEQ concentrations at or above 1000 ppt and 90 ppt. The estimates were calculated from the estimated population (estimated number of households in each defined population) and the weighted percentage of households with elevated soil concentrations. Table 1:

Number of household units with soil TEQ# ≥1,000 ppt ( with weighted percentage) TEQDFP29-2005 TEQDF17-2005 TEQDFP29-1998 TEQDF17-1998

Estimated Population*

Number of participants

Any soil Overall* 214 (0.25%) 214 (0.25%) 356 (0.41%) 356 (0.41%) 86670 766 FP 58 (7.01%) 58 (7.01%) 89 (10.75%) 89 (10.75%) 828 203 Near FP 13 (1.57%) 13 (1.57%) 13 (1.57%) 13 (1.57%) 852 164 Other M/S 142 (0.36%) 142 (0.36%) 142 (0.36%) 142 (0.36%) 39485 173 Plume 0 0 112 (4.83%) 112 (4.83%) 2310 32 Jackson 0 0 0 0 43196 194 House Perimeter 0-1” Overall* 23 (0.03%) 23 (0.03%) 23 (0.03%) 23 (0.03%) 86670 766 FP < 10 (<1.21%) < 10 (<1.21%) < 10 (<1.21%) < 10 (<1.21%) 828 203 Near FP 13 (1.57%) 13 (1.57%) 13 (1.57%) 13 (1.57%) 852 164 Other M/S 0 0 0 0 39485 173 Plume 0 0 0 0 2310 32 Jackson 0 0 0 0 43196 194 Soil Contact Zone 0-6” Overall* < 10 (<0.02%) < 10 (<0.02%) < 10 (<0.02%) < 10 (<0.02%) 50426 484 FP < 10 (<1.99%) < 10 (<1.99%) < 10 (<1.99%) < 10 (<1.99%) 502 132 Near FP 0 0 0 0 453 100 Other M/S 0 0 0 0 23742 104 Plume 0 0 0 0 1919 24 Jackson 0 0 0 0 23810 124 Near River Floodplain 0-1” FP 38 (4.94%) 38 (4.94%) 62 (8.05%) 62 (8.05%) 770 191 More than 1 location on a property ≥ 1,000 ppt Overall* 64 (0.07%) 64 (0.07%) 83 (0.1%) 83 (0.10%) 86670 766 FP 51 (6.12%) 51 (6.12%) 70 (8.44%) 70 (8.44%) 828 203 Near FP 13 (1.57%) 13 (1.57%) 13 (1.57%) 13 (1.57%) 852 164 Other M/S 0 0 0 0 39485 173 Plume 0 0 0 0 2310 32 Jackson 0 0 0 0 43196 194

# In this table, the TEQ has been calculated 4 different ways. The subscript DFP29 means the TEQ is calculated from all 29 dioxin, furan, and PCB congeners; the subscript DF17 means the TEQ is calculated from 17 congeners (dioxins and furans only, excluding PCBs); the subscript 2005 means the TEQ is based on the WHO 2005 TEFs, and the subscript 1998 means the TEQ is based on the WHO 1998 TEFs. Estimated Population*: The total number of households where there was one or more persons present who had lived in the household at least five years who was blood eligible and who owned the land/property on which the household was located. < 10: Fewer than 10 households. Exact number is not shown to maintain confidentiality of study participants. * numbers are rounded to the nearest integer and my not sum to the totals because of rounding.


Table 2:

Number of household units with soil TEQ# ≥90 ppt (with weighted percentage) TEQDFP29-2005 TEQDF17-2005 TEQDFP29-1998 TEQDF17-1998

Estimated Population

*

Number of participants

Any soil Overall* 2125 (2.45%) 2002 (2.31%) 3130 (3.61%) 2343 (2.70%) 86670 766 FP 302 (36.55%) 302 (36.55%) 314 (37.97%) 314 (37.97%) 828 203 Near FP 82 (9.65%) 82 (9.65%) 92 (10.76%) 92 (10.76%) 852 164 Other M/S 789 (2.00%) 789 (2.00%) 1049 (2.66%) 1049 (2.66%) 39485 173 Plume 828 (35.85%) 828 (35.85%) 888 (38.45%) 888 (38.45%) 2310 32 Jackson 123 (0.28%) 0 787 (1.82%) 0 43196 194 House Perimeter 0-1” Overall* 1842 (2.12%) 1719 (1.98%) 2629 (3.03%) 1842 (2.13%) 86670 766 FP 102 (12.35%) 102 (12.35%) 120 (14.52%) 120 (14.52%) 828 203 Near FP 61 (7.18%) 61 (7.18%) 74 (8.67%) 74 (8.67%) 852 164 Other M/S 757 (1.92%) 757 (1.92%) 789 (2.00%) 789 (2.00%) 39485 173 Plume 798 (34.57%) 798 (34.57%) 859 (37.17%) 859 (37.17%) 2310 32 Jackson 123 (0.28%) 0 787 (1.82%) 0 43196 194 Soil Contact Zone 0-6” Overall* 292 (0.58%) 292 (0.58%) 656 (1.30%) 656 (1.30%) 50426 484 FP 49 (9.84%) 49 (9.84%) 56 (11.24%) 56 (11.24%) 502 132 Near FP 31 (6.74%) 31 (6.74%) 31 (6.74%) 31 (6.74%) 453 100 Other M/S 80 (0.34%) 80 (0.34%) 339 (1.43%) 339 (1.43%) 23742 104 Plume 132 (6.90%) 132 (6.90%) 230 (12.00%) 230 (12.00%) 1919 24 Jackson 0 0 0 0 23810 124 Near River Floodplain 0-1” FP 236 (30.68%) 236 (30.68%) 240 (31.14%) 240 (31.14%) 770 191 More than 1 location on a property ≥ 90 ppt Overall* 1212 (1.40%) 1212 (1.40%) 1240 (1.43%) 1218 (1.40%) 86670 766 FP 263 (31.78%) 263 (31.78%) 265 (32.06%) 265 (32.06%) 828 203 Near FP 58 (6.83%) 58 (6.83%) 62 (7.22%) 62 (7.22%) 852 164 Other M/S 435 (1.10%) 435 (1.10%) 435 (1.10%) 435 (1.10%) 39485 173 Plume 456 (19.74%) 456 (19.74%) 478 (20.71%) 456 (19.74%) 2310 32 Jackson 0 0 0 0 43196 194

# In this table, the TEQ has been calculated 4 different ways. The subscript DFP29 means the TEQ is calculated from all 29 dioxin, furan, and PCB congeners; the subscript DF17 means the TEQ is calculated from 17 congeners (dioxins and furans only, excluding PCBs); the subscript 2005 means the TEQ is based on the WHO 2005 TEFs, and the subscript 1998 means the TEQ is based on the WHO 1998 TEFs. Estimated Population*: The total number of households where there was one or more persons present who had lived in the household at least five years who was blood eligible and who owned the land/property on which the household was located. * numbers are rounded to the nearest integer and my not sum to the totals because of rounding.


Estimated population size by region Table 3-6 (below) show the estimated population size by different defined inference populations. Table 3: Estimated population eligible to interview Using the sum of the person level 'interview' weight (which is adjusted for unequal probabilities and for nonresponse), we get the following distribution for persons 18 years and older who have lived in their current residence for at least five years: Region Estimated population Overall (all four counties plus part of Bay county) 202181 Flood plain 2006 Near Flood plain 2021 Plume 6143 Remainder of Midland, Saginaw, and Bay (part) counties 90678 Midland and Saginaw counties overall 100847 Jackson and Calhoun counties 101334 Note: The Census 2000 population 18+ years for M/S was 215,000 and for J/C 220,000. We estimated that about 53% of the population lived in their current household for the last five years or more. Table 4: Estimated population eligible to give blood. Using the sum of the person level of 'blood' weight, we get the following distribution for persons 18 years and older who lived in their current residence at least five years and who were eligible to give blood: Region Estimated population Overall (all four counties plus part of Bay county) 171,648 Flood plain 1,820 Near Flood plain 1,930 Plume 5,401 Remainder of Midland, Saginaw, and Bay (part) counties 76,203 Jackson and Calhoun counties 86,293 Table 5: Estimated population eligible to provide soil sample Using the sum of the person level 'Soil' weight, we get the following distribution for persons 18 years and older who lived in their current residence for at least five years, who were eligible to give blood, and who owned the property on which the housing unit was located: Region Estimated population Overall (all four counties plus part of Bay county) 153,595 Flood plain 1,528 Near Flood plain 1,675 Plume 4,585 Remainder of Midland, Saginaw, and Bay (part) counties 68,906 Jackson and Calhoun counties 76,902


Table 6: Estimated household units eligible to provide soil sample Using the sum of the household level 'soil' weight, we get the following distribution for households where there was one or more persons present who had lived in the households at least five years who was eligible to give blood and who owned the land/property on which the household was located: Region Estimated population Overall (all four counties plus part of Bay county) 86,670 Flood plain 828 Near Flood plain 852 Plume 2,310 Remainder of Midland, Saginaw, and Bay (part) counties 39,485 Jackson and Calhoun counties 43,196

february 13, 2008 stakeholder request for information from … of umdes 011608... · dfp29-2005...

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