Hopewell Precision Area Contamination
Appendix B - Tables
Table 1
Contaminants in Groundwater
Near the Hopewell Precision Area Contamination Site
All values in micrograms per liter (mcg/L)
| Analyte: |
Trichloroethene |
1,1,1-Trichloroethane |
Methyl-tert-butyl ether |
| Max |
250 |
12 |
28 |
| Min |
0.17 |
0.22 |
0.07 |
| Arithmetic Mean |
2.0 |
0.62 |
0.37 |
| 50th Percentile |
0.25 |
0.25 |
0.25 |
| 75th Percentile |
0.25 |
0.25 |
0.25 |
| 95th Percentile |
12 |
2.5 |
0.68 |
| Number of Detects |
58 |
62 |
42 |
| Number of Wells Sampled |
447 |
451 |
450 |
| Percent Detect |
13 |
14 |
9.3 |
Table 2
Contaminants in Indoor Air Near the Hopewell Precision Area Contamination Site
All values in micrograms per cubic meter (mcg/m3)
| |
|
Trichloroethene (TCE) |
1,1,1-Trichloroethane (1,1,1-TCA) |
Methyl tert-Butyl Ether (MTBE) |
Tetrachloroethene (PCE) |
| Basement |
Max |
172 |
17 |
610 |
2000 |
| Min |
0.39 |
0.36 |
0.36 |
0.47 |
| Arithmetic Mean |
3.6 |
1.2 |
7.6 |
7.5 |
| 50th Percentile |
0.54 |
0.43 |
0.58 |
0.45 |
| 75th Percentile |
2.4 |
1.1 |
2.3 |
0.68 |
| 95th Percentile |
17 |
4.6 |
23.5 |
3.4 |
| Number of Homes with Detects |
51 |
55 |
75 |
48 |
| Number of Homes Sampled |
87 |
94 |
97 |
91 |
| Percent of Homes with Detects |
59 |
59 |
77 |
53 |
| First Floor |
Max |
48 |
12 |
140 |
1200 |
| Min |
0.37 |
0.37 |
0.36 |
0.45 |
| Arithmetic Mean |
2.2 |
0.9 |
5.6 |
7.6 |
| 50th Percentile |
0.45 |
0.36 |
0.69 |
0.45 |
| 75th Percentile |
1.7 |
0.64 |
3.24 |
0.68 |
| 95th Percentile |
10.2 |
3.2 |
28.8 |
3.2 |
| Number of Homes with Detects |
54 |
43 |
60 |
40 |
| Number of Homes Sampled |
87 |
94 |
97 |
91 |
| Percent of Homes with Detects |
62 |
45 |
61 |
44 |
Table 3
Water Quality Standards/Guidelines and Public Health Assessment Comparison Values
Exceeded by Contaminant Levels Found in Private Water Supply Wells
in the Hopewell Precision Contamination Area
All values in micrograms per liter (mcg/L)
| Contaminant |
Maximum Detection |
Water Quality Standards/Guidelines |
Comparison Values* |
| New York State |
US EPA |
| Ground Water |
Surface Water |
Drinking Water |
Drinking Water |
Cancer |
Basis** |
Noncancer |
Basis** |
| methyl-tert-butyl ether |
28 |
10a |
10a |
10 |
-- |
10 |
NYS CPF |
230 |
NYS RfD |
| 1,1,1-trichloroethane |
12 |
5 |
5 |
5 |
5 |
-- |
-- |
1960 |
US EPA RfD |
| trichloroethene |
250 |
5 |
5 |
5 |
5 |
6.1 |
NYS CPF |
10 |
Health Canada RfD |
* Comparison values determined for a 70-kilogram adult who drinks 2 liters of water per day. The cancer comparison value is the water concentration that provides an intake corresponding to an increased lifetime cancer risk of one-in-one million. Non-cancer comparison values assume a relative source contribution of 20%.
** Health Canada RfD: Health Canada Reference Dose
NYS CPF: New York State Department of Health Cancer Potency Factor
NYS RfD: New York State Department of Health Reference Dose
US EPA RfD: U.S. Environmental Protection Agency Reference Dose (Region 3)
aUnder Review
Table 4
Maximum Detected Air Levels, Indoor Air Background Levels and Public Health Assessment Comparison Values
Exceeded by Contaminant Levels Found in Indoor Air Within the Hopewell Precision Contamination Area
All values in microgram per cubic meter (mcg/m3)
| Contaminant |
Maximum Detection |
Indoor Air Background Level** |
Comparison Values* |
| New York State Air Guidelines |
Cancer |
Basis*** |
Noncancer |
Basis*** |
| methyl-tert-butyl ether |
610 |
14 |
-- |
3.8 |
CA EPA UR |
8000 |
CA EPA REL |
| tetrachloroethene |
2000 |
2.5 |
100 |
1 |
NYS DOH UR |
100 |
NYS DOH RfC |
| 1,1,1-trichloroethane |
17 |
2.5 |
-- |
-- |
-- |
2200 |
US EPA RfC |
| trichloroethene |
172 |
0.46 |
5 |
0.3 to 7.8 |
NYS DOH UR |
10 |
NYS DOH RfC |
*The cancer comparison value is the air concentration that provides an intake corresponding to an increased lifetime cancer risk of one-in-one million.
**Based on upper fence air levels obtained from Summary of Indoor and Outdoor Levels of Volatile Organic Compounds from Fuel Oil Heated Homes in New York State 1997-2003. The upper fence is calculated as 1.5 times the interquartile range (difference between the 25th and 75th percentile values) above the 75th percentile value. The upper fence is a boundary used for identifying the presence of outliers in the data. Since these data were collected, methyl-tert-butyl ether was prohibited from use as an additive to gasoline in New York State.
*** CA EPA UR: California Environmental Protection Agency Unit Risk
CA EPA REL California Environmental Protection Agency Reference Exposure Limit
NYS DOH UR: New York State Department of Health Unit Risk
NYS DOH RfC: New York State Department of Health Reference Concentration
US EPA RfC: U.S. Environmental Protection Agency Reference Concentration (Region 3)
