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Facilities Loadings
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For more
information, contact David Eppstein by email at
deppstein@masco.harvard.edu,
or by calling 617-632-2860.
8.0 PHASE I LOADINGS REVIEW (29 HOSPITALS)
One of our goals was to review the mercury loadings calculations
performed in Phase I for 29 hospital facilities for Fiscal Year 1995 and to examine
corresponding data for the following year to detect any loadings trends. While the Phase I
study examined a total of 76 sampling locations within these facilities, discharge
loadings were not calculated for locations that had no mercury concentration test data.7
There were no mercury concentration data for 16 sampling locations in the first half-year
of FY 1995 and for 29 locations in the second half-year.
For our review, we extracted the applicable loadings data for the same
76 sampling locations from the spreadsheets described above and created Table E-1 of
Appendix E that presents the FY 1995 mercury loadings. Similarly, we created Table E-2 of
Appendix E to present the corresponding FY 1996 mercury loadings. As in the Phase I study,
we did not estimate discharge loadings from sampling locations without mercury
concentration test data, i.e., we included only "known" loadings. Refer
to Table 8 for a summary comparison of the two studies.
As shown in Table 8, Phase I had estimated that the mercury discharge
loadings from 29 hospital facilities contributed between 2.6 and 3.6 percent of total
estimated MWRA system loadings during FY 1995. In contrast, our Phase II results suggest
that the contribution was between 0.65 and 0.91 percent.
The difference in estimated discharge loadings for FY 1995 is primarily
attributable to the detailed flow estimating procedure of our study that produced many
lower than previously estimated facility discharge flows. In the Phase I study, for
example, the sum of estimated facility discharge flows was 1.18 million gallons per day
(MGD) in the first half of FY 1995. In this Phase II study, the corresponding total
estimated flow was 0.35 MGD, a difference of about 70 percent. Besides the flow
differences, we found a few unexplained differences in the mercury concentration data.
Our study also suggests that estimated FY 1996 mercury discharge
loadings for the 29 Phase I hospital facilities were higher than those of FY 1995. From
about 0.65 to 0.91 percent in FY 1995, our estimated FY 1996 mercury discharge loadings
for the 29 hospitals ranged from about 1.8 to 2.5 percent of the estimated MWRA total
system loading.
TABLE 8
ESTIMATED MERCURY DISCHARGE LOADINGS
FROM 29 SELECTED HOSPITALS
PHASE I STUDY (1995) VERSUS PHASE II STUDY
Period of Year |
Phase I
FY 1995
Loadings1 (Pounds/Day) |
As % of Total System Load
2 |
Phase II
FY 1995
Loadings 3
(Pounds/Day) |
As % of Total System Load
2 |
Phase II
FY 1996
Loadings 3
(Pounds/Day) |
As % of Total System Load
2 |
1ST
HALF |
0.040 |
5.2% |
0.006 -
0.007 |
0.8 -
0.9 % |
0.020 -
0.021 |
2.4 -
2.5 % |
2ND
HALF |
0.029 |
3.8% |
0.005 - 0.007 |
0.6 - 0.9 % |
0.015 - 0.016 |
1.8 - 1.9 % |
1 Phase I Loadings were
taken from tables entitled "Review of SMART Database, Q1 & Q2, Fiscal, 1995"
and "Review of SMART Database, Q3 & Q4, Fiscal, 1995" in the End of Pipe
Alternatives Subcommittee Final Report, June 1995.
2 Estimated Total
System Mercury Loading was 0.77 pounds/day for Fiscal Year 1995 and 0.83 pounds/day for
Fiscal Year 1996 (from background data prepared for the MWRA Industrial Waste Report No.
12, October 1996).
3 Refer to Appendix E,
Tables E-1 and E-2, for Phase II loadings calculations for Fiscal Years 1995 and 1996,
respectively.
Note: In the Phase I study, the sum of estimated facility discharge
flows was 1.18 million gallons per day (MGD) from 60 sampling locations in the first half
of FY 1995 and 0.82 MGD from 47 locations in the second half. In this Phase II study, the
sum of estimated facility discharge flows was 0.35 MGD from 51 sampling locations and 0.38
MGD from 62 locations, respectively.
For FY 1996, first and second half-year loadings in Phase II were
contributed by 65 and 61 sampling locations, respectively.
7Thus, the Phase I loadings
estimates could be called the estimated "known" loading of the 29 hospital
facilities.
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