Asbestos Exposure from the World Trade Center Disaster
What
was going on during sampling.
The
collapse of the World Trade Center on September 11th 2011 resulted
into a release of harmful dust particles into the air that mainly originated
from the building materials. Airborne dust particles from the collapse and
fumes from burning of the towers covered the whole of Lower Manhattan
environment with a mixture of asbestos, benzene, glass fiber, and the
metals. Lower Manhattan residents began
to raise complaints about the safety of the cleaning methods that were used to
remove dust particles from their residential areas (Callahan, 2004).
From September 13th to September 27th, environmental
samples were collected in around 13 different cluster locations. The main
activities that were going on during sampling include; identification of the
sampling location, identification of the actual buildings to obtain samples
from depending on accessibility, estimation of the number of buildings to
sample in each location, and identification of the contaminants of potential
concern to sample
(Callahan, 2003).
Sampling
Methodology
Once access to the buildings was obtained, and the actual
sampling process scheduled to begin, settled dust and air samples were
collected from all of the thirteen cluster areas and transported to the
laboratory for analysis. All samples were collected and analyzed using the
Phase Contrast Microscopy in order to reveal asbestos and other fibers. Data
sets were also analyzed using the AIHA Statistical Spreadsheet in order to
obtain greater insights on their descriptive statistics, number of samples
above the occupational exposure limits for asbestos, the 95th
percentile, and exposure category of each individual data set.
Samples were collected from 13 different cluster points.
The sampling methods used consisted of indoor air samples of airborne
particulate matter and fibers, micro-vacuum sampling of settled dust on windows
and furniture, and wipe samples of settled dust from walls and ceiling boards.
All these samples were obtained from areas that are routinely used by the Lower
Manhattan residents such as living room, laundry rooms, kitchen and bedroom. The
indoor air sample collection methodology mainly targeted particulate matter and
airborne fibers which were collected by drawing a specific volume of air
through a filter membrane. In certain areas, the air sampling process was
conducted using oscillating fans. This sampling method did not employ the use
of aggressive techniques because of the risk of dust exposure to the residents
during the sampling process.
The micro-vacuum sample collection method targeted
samples of settled dust. These were collected from porous surfaces using
micro-vacuum techniques and later analyzed for lead and asbestos. Examples of
porous surfaces sampled are like carpets, couches, chairs, rugs, and many
others. Under this method of vacuum collection, properties such as adhesiveness
and surface texture greatly influenced the collection efficiency. This method
was done with a lot of care because it was meant to determine the presence of
asbestos contaminants alone. The dust particles on non-porous surfaces were
sampled using wipe sample collection these samples were later analyzed for
asbestos. The wipe sample collection method employs the use of a piece of cloth
wetted in a solution that is use to wipe the dust settled on the non-porous
surfaces.
Another sampling method used involved the bulk dust
sample collection. This method allowed for sampling of large amount of material
for use in the analysis process. Samples that served as controls were also
collected, and these were used to assess the sampling and analytical processes
in order to ensure efficiency. The quality control samples were collected each
sampling day from September13th to September 27th. The
samples included the collection of field blanks, lot blanks and field spike
wipe. Quality control samples were collected for air, wipe, and micro-vacuum
samples. All the samples obtained using the methods described above were
transported to the laboratory for analysis. In the laboratory, the samples were
tested for asbestos by using phase-contrast light microscopy to identify fibers
of more than 5 mm in length. Some of the samples were tested by transmission
electron microscopy (TEM) to identify fibers of more than or equal to 0.5 mm in
length.
Results
Table
1: Results obtained in the 13 data sets sampled
|
Cluster Areas
|
No. of samples
|
Range of f/cc
|
|
A1
|
7
|
<0.003-0.024
|
|
B1
|
5
|
0.003-0.031
|
|
A2
|
34
|
0.003-0.086
|
|
B2
|
50
|
0.0013-0.140
|
|
C2
|
5
|
0.0032-0.041
|
|
D2
|
3
|
0.003-0.006
|
|
A3
|
22
|
0.007-0.057
|
|
B3
|
46
|
0.0011-0.099
|
|
C3
|
12
|
0.0011-0.041
|
|
D3
|
3
|
0.0032-0.006
|
|
B4
|
2
|
0.006-0.012
|
|
C4
|
7
|
0.011-0.009
|
|
D4
|
8
|
0.003-0.004
|
A total of 49 bulk samples taken from
debris and dust from 13th September to 27th September
revealed asbestos concentrations from non-detected to 1.9% asbestos. Data
analysis using the AIHA
Statistical Spreadsheet gave the following results for each of the thirteen
cluster areas sampled. The Occupational Exposure Limit for Asbestos is 0.1
fibers/ cc.
Area
A1: The descriptive statistics gives 7 samples, maximum value of 0.024, min
value of < 0.003, range of 0.021, mean of 0.010, media value of 0.009,
standard deviation of 0.007, geometric mean of 0.008, and geometric standard
deviation of 2.038. In this data set, there no sample above the Occupational
Exposure Limit. The 95th percentile exposure level of this data set
was 0.026. The workers’ exposure in this data set would be placed in the 0
category because no sample was found to contain asbestos out of the seven samples
tested.
Area
B1: The descriptive statistics gives 5 samples, maximum value of 0.031, min
value of 0.0045, range of 0.0265, mean of 0.015, median value of 0.013, standard
deviation of 0.012, geometric mean of 0.012, and geometric standard deviation
of 2.428. In this data set, there was no sample above the Occupational Exposure
Limit. The 95th percentile exposure level of this data set was 0.050.
The workers’ exposure in this data set would be placed in the 0 category
because no sample was found to contain asbestos out of the five samples tested.
Area
A2: The descriptive statistics gives 34 samples, maximum value of 0.086, min
value of 0.003, range of 0.0676, mean of 0.022, median value of 0.016, standard
deviation of 0.019, geometric mean of 0.015, and geometric standard deviation
of 2.717. In this data set, there was no sample above the Occupational Exposure
Limit. The 95th percentile exposure level of this data set was 0.076.
The workers’ exposure in this data set would be placed in the 0 category
because no sample was found to contain asbestos out of the 34 samples tested.
Area
B2: The descriptive statistics gives 50 samples, maximum value of 0.14, min
value of 0.0013, range of 0.0136, mean of 0.043, median value of 0.015,
standard deviation of 0.049, geometric mean of 0.024, and geometric standard
deviation of 2.438. In this data set, there was only one sample above the
Occupational Exposure Limit. The 95th percentile exposure level of
this data set was 0.081. The workers’ exposure in this data set would be placed
in the first category because only one sample was found to contain asbestos out
of the 50 samples tested.
Area
C2: The descriptive statistics gives 5 samples, maximum value of 0.041, min
value of 0.0032, range of 0.0378, mean of 0.015, median value of 0.008,
standard deviation of 0.018, geometric mean of 0.009, and geometric standard
deviation of 2.959. In this data set, there was no sample above the
Occupational Exposure Limit. The 95th percentile exposure level of
this data set was 0.055. The workers’ exposure in this data set would be placed
in the 0 category because no sample was found to contain asbestos out of the 5
samples tested.
Area
D2: The descriptive statistics gives 3 samples, maximum value of 0.006, min
value of 0.003, range of 0.003, mean of 0.005, median value of 0.005, standard
deviation of 0.002, geometric mean of 0.004, and geometric standard deviation
of 1.633. In this data set, there was no sample above the Occupational Exposure
Limit. The 95th percentile exposure level of this data set was
0.010. The workers’ exposure in this data set would be placed in the 0 category
because no sample was found to contain asbestos out of the 3samples tested.
Area
A3: The descriptive statistics gives 22 samples, maximum value of 0.057, min
value of 0.007, range of 0.007, mean of 0.010, median value of 0.010, standard
deviation of 0.003, geometric mean of 0.010, and geometric standard deviation
of 1.385. In this data set, there was no sample above the Occupational Exposure
Limit. The 95th percentile exposure level of this data set was
0.015. The workers’ exposure in this data set would be placed in the 0 category
because no sample was found to contain asbestos out of the 22 samples tested.
Area
B3: The descriptive statistics gives 46 samples, maximum value of 0.099, min
value of 0.011, range of 0.016, mean of 0.038, median value of 0.027, standard
deviation of 0.032, geometric mean of 0.030, and geometric standard deviation
of 1.964. In this data set, there was no sample above the Occupational Exposure
Limit. The 95th percentile exposure level of this data set was
0.092. The workers’ exposure in this data set would be placed in the 0 category
because no sample was found to contain asbestos out of the 46 samples tested.
Area
C3: The descriptive statistics gives 12 samples, maximum value of 0.041, min
value of 0.011, range of 0.006, mean of 0.005, median value of 0.004, standard
deviation of 0.003, geometric mean of 0.004, and geometric standard deviation
of 1.664. In this data set, there was no sample above the Occupational Exposure
Limit. The 95th percentile exposure level of this data set was 0.032.
The workers’ exposure in this data set would be placed in the 0 category
because no sample was found to contain asbestos out of the 12 samples tested.
Area
D3: The descriptive statistics gives 3 samples, maximum value of 0.006, min
value of 0.0032, range of 0.0028, mean of 0.005, median value of 0.005,
standard deviation of 0.002, geometric mean of 0.004, and geometric standard
deviation of 1.560. In this data set, there was no sample above the
Occupational Exposure Limit. The 95th percentile exposure level of
this data set was 0.009. The workers’ exposure in this data set would be placed
in the 0 category because no sample was found to contain asbestos out of the 3
samples tested
Area
B4: The descriptive statistics gives 2 samples, maximum value of 0.012, min
value of 0.006, range of 0.006, mean of 0.004, median value of 0.003, standard
deviation of 0.019, geometric mean of 0.006, and geometric standard deviation
of 1.760. In this data set, there was no sample above the Occupational Exposure
Limit. The 95th percentile exposure level of this data set was
0.0010. The workers’ exposure in this data set would be placed in the 0
category because no sample was found to contain asbestos out of the 2 samples
tested
Area
C4: The descriptive statistics gives 7 samples, maximum value of 0.009, min
value of 0.0011, range of 0.008, mean of 0.005, median value of 0.006, standard
deviation of 0.021, geometric mean of 0.059, and geometric standard deviation
of 1.430. In this data set, there was no sample above the Occupational Exposure
Limit. The 95th percentile exposure level of this data set was
0.0065. The workers’ exposure in this data set would be placed in the 0
category because no sample was found to contain asbestos out of the 7 samples
tested
Area
D4: The descriptive statistics gives 8 samples, maximum value of 0.004, min
value of 0.003, range of 0.001, mean of 0.004, median value of 0.004, standard
deviation of 0.001, geometric mean of 0.004, and geometric standard deviation
of 1.181. In this data set, there was no sample above the Occupational Exposure
Limit. The 95th percentile exposure level of this data set was 0.005.
The workers’ exposure in this data set would be placed in the 0 category
because no sample was found to contain asbestos out of the 8 samples tested.
References
Callahan, K. (2003). World Trade Center: Background Study Report.
New York, NY: New York.
Callahan, K. (2004). Monitoring for
Asbestos: US EPA Methods. Journal of
Environmental Health, 112 (13): 731.
OSHA website: http://www.osha.gov/nyc-disaster/wtc.html
Request a similar paper on affordable papers