# Presentation: 199026

## An Evaluation of Region 2 Wipe Sampling Data from the 2002 EPA Cleanup Program 

- Prepared by:
- U.S. Environmental Protection Agency
- ORD’s National Center for Environmental Assessment
- and Region 2
- For the November 15, 2004, Meeting of the
- World Trade Center Expert Technical Review Panel

## Background

- During the 2002 Region 2 Cleanup Program, over 1500 pre- and post-cleaning wipe samples were taken in 263 (of 4200) apartments in 165 buildings.  These were measured for 24 contaminants, including lead and other metals, and dioxin.
- Wide geographic coverage was sought by attempting to identify volunteers in as many buildings as possible.
- This evaluation focuses on the approximate 1000 pre-cleaning sample results, with an emphasis on lead.

## Location of Sampled Apartments With Respect to EPIC Zones of Confirmed (Red), Probable (Orange), Possible (Pink), and No (Beige) Impact by Dust and Debris from the Collapse of the WTC Towers

*Location of Sampled Apartments With Respect to EPIC Zones of Confirmed (Red), Probable (Orange), Possible (Pink), and No (Beige) Impact by Dust and Debris from the Collapse of the WTC Towers*

## Building Construction Year by Zone 

## Overview of Key Results 

## Lead Analyses 

- Lead results show that 12% of the measurements exceed the health-based benchmark.  The results will be examined as a function of three factors that may  affect measured  lead concentrations:
- Location:  EPIC Zone & distance from Ground Zero
- Age of building
- Floor of building  where measurement is taken
- Also, the proposed criteria for building cleanup includes a link to WTC dust via signature analysis and 95% upper confidence limit on the building mean to be greater than the 25 μg/ft2 benchmark.  How many buildings would meet this concentration criteria?

## Lead Results by EPIC Zone 

## Lead Results by Distance from WTC

## Results by Building Age 

## Results by Building Age 

***Results by Building Age ***

## Results by Building Age

## Results by Building Age

## Means (g/ft2) by Floor & EPIC Zone

-  	       Overall			Zone
- Floor             Mean (n)      A            A1           B             C            D
- Basement        113 (4)       ---           ---          113           ---          ---
- 1st                       14 (29)        5              5            26           ---          ---
- 2nd                117 (124)    168           56              9           ---            9
- 3rd                  29 (127)       38           38            42           24           6
- 4th                  21 (114)       10           10            36           23          13
- 5th                  25  (80)        12           12            80           ---            2
- 6 – 10            14 (227)       13           13            12           ---          22
- 11 – 20          21 (141)       29           29            11           ---          10
- >20                  8 (149)         6             6              5           ---           7
- Notes:
-      All results are the mean in μg/ft2
-         Means above 25 μg/ft2 highlighted
-      A1: Zone A mean for 2nd floor measurements calculated without two outliers

## Means (g/ft2) by Floor & Year Built

-  	       Overall		                Year
- Floor             Mean (n)          _< _1920      1921-50    >1950     No Year
- Basement        113 (4)            113              ---             ---            ---
- 1st                       14 (29)             19               ---               2              5
- 2nd                 117 (124)          204 (41)1      34               9              8
- 3rd                   29 (127)            53               15              5              16
- 4th                   21 (114)            35               24              7              10
- 5th                   25  (80)             14                 7             10             45
- 6 – 10             14 (227)            17                 4             14             14
- 11 – 20           21 (141)            31                 1             14             25
- >20                   8 (149)            39               17               6              5
- Notes:
-      1mean of 41 calculated with two outliers of 6790 and 2530 μg/ft2 removed
-      All results are the mean in  μg/ft2;
-       Means above 25 μg/ft2 highlighted

## Observations on Full Data Set

- When the two lead outliers are deleted, the overall results do not appear meaningfully different among the four zones, and among the five distance categories.
- There is a suggestion that higher concentrations are found on lower building floors, across zones
- The clearest relationship is between lead concentrations and age of building, i.e., older buildings tend to have the higher concentrations
- Some high lead concentrations were also observed in newer buildings

## Highest Lead Measurements

- An examination of the highest measurements for lead may suggest trends of note.  There are 23 measurements higher than 200 μg/ft2:
- 15 of these 23 measurements are in “confirmed” zone; only 1 in “no dust” zone
- 17 of the top 23 measurements are found in the 5th floor or lower
- 18 of top 23 are in buildings built 1926 and earlier; 4 have no date and 1 built in 1971.
- 11 of top 13 are in “confirmed” zone, but 9 of these 13 are in buildings built 1920 and earlier, with the remaining 4 in buildings of unknown age.
- Taken together, this suggests that all three factors (zone, floor and age) may be related to the observation of the highest measurements of lead in this sampling program.

## Highest Lead Measurements

- Site specific factors may help to explain results from particular buildings.  For example:
- High measurements were made in three buildings on Chambers St that were located near a renovation project.
- High measurements were made in a building on Liberty Street that was also observed to have  remaining WTC dust lodged outside in window ledges.
- The building with the highest measurement, 6790 μg/ft2, was built in 1900, the earliest year identified for building date in this sample set. (However, this measurement may be suspect because it is so much larger than the others.)

## Building-Specific Results by EPIC Zone 

## Overall Results

- Measurements of contaminants above health benchmarks were infrequent with the exception of lead
- The clearest relationship is found between lead concentrations and age of building, suggesting lead paint as a  cause for high lead measurements in Lower Manhattan.
- Proximity and floor of building seemed to be, at best, weakly related to measured lead levels.  However, an examination of the highest measurements does suggest that, on a case-by-case basis, these factors as well as direct WTC impact, may be important.
- Building-specific results suggest that a substantial percentage of buildings may meet the partial criteria for building cleanup of 95% UCL of mean being greater than health benchmark of 25 μg/ft2.