CZM Comment on proposed monitoring plan changes 7 2 09

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Informations

• Publié par: Octey
• Nombre de lectures: 14
• Langue: English

Extrait

July 2, 2009

Dr. Andrea Rex

Director, Environmental Quality Department

Massachusetts Water Resources Authority

Charlestown Navy Yard

100 First Ave, Building 39

Boston, MA 02129

Re: Massachusetts Water Resources Authority, Permit Number MA0103284 proposed changes

to effluent outfall monitoring plan, April 2009

Dear Dr. Rex:

The Massachusetts Office of Coastal Zone Management (CZM) has reviewed the changes

proposed by the Massachusetts Water Resources Authority (MWRA) to its effluent monitoring

plan in its most recent report: Environmental Quality Department (ENQUAD) Report 2009-06.

In general, CZM has found that MWRA has done an excellent job of collecting water quality and

biological data, near the outfall and farther afield, in an effort to determine the magnitude and

extent of the MWRA effluent’s effect on Massachusetts Bay and Cape Cod Bay. However, we

do have some questions about how these data are interpreted and reported and thus will urge that

the U.S. Environmental Protection Agency (EPA) and the Massachusetts Department of

Environmental Protection (MassDEP) exercise caution in considering the proposal to revise and

reduce the scale of the existing MWRA outfall monitoring program. Below we provide specific

comments on MWRA’s proposal as it is summarized on pages x and xi of ENQUAD Report

2009-06.

Effluent

1.

Discontinue effluent floatables monitoring.

MWRA states that floatables discharges from

its outfall are “minimal,” and thus proposes to delete effluent floatables monitoring. CZM

has read ENQUAD Report 2008-08 that describes the results of MWRA’s effluent

floatables monitoring. Using the mean concentration of floatables in the MWRA effluent

from 2003-2008 (i.e., 33 milligrams floatables / million grams effluent) and a mean

effluent flow of 393 million gallons per day, CZM calculates that 108 pounds of

floatables per day, or roughly 20 tons per year, are released into Massachusetts Bay. We

disagree that this is a minimal amount of floatables. According to MWRA, much of the

floatable material is either pieces of plastic or fat particles. The dangers of plastics to

seabirds and other marine life are well known, however, the effect of fat particles on

marine life is not.

2.

Change the frequency of the metals and organic chemicals special study from weekly to

four times per month.

Since the functional change proposed here is to reduce the

sampling frequency from 52 times per year to 48, we see no issue with accepting this

proposal. However, we will suggest to the permitting agencies that they add that the 48

samples are to be taken no less than/no more than a certain minimal/maximal number of

days apart so that the samples are truly weekly. For example, samples should be taken no

less than six days and no more than eight days apart. CZM notes that metals discharges

from MWRA have decreased by 100% between 2000, when the outfall was still in

Boston Harbor, and 2008, eight years after the outfall was moved to Massachusetts Bay.

Water Column

1.

Reduce the number of monitoring stations from 34 to 10. End water quality monitoring in

Cape Cod Bay and Stellwagen Bank National Marine Sanctuary (SBNMS).

CZM is

opposed to ending monitoring in Cape Cod Bay. CZM suggests that monitoring in Cape

Cod Bay be retained in order to: a) provide sites that are far enough away from the

MWRA outfall to truly be reference sites and b) to ensure that the documented increases

in nutrients from the MWRA outfall do not begin to affect water quality or the ecology of

Cape Cod Bay. Likewise, we believe some number of monitoring stations should be

retained inside the boundaries of SBNMS. We are concerned that the proposal to keep

only one monitoring station that is just west of SBNMS and believe that that one site may

be too close to the outfall to serve as a farfield reference site and additionally may not

represent the unique characteristics found inside the sanctuary.

2.

Change the survey schedule from 18 stations (12 nearfield, six farfield) to nine annual

surveys of “expanded nearfield plus reference sites.”

Given the purported relationship

between the selected nine sites and the original 18 sites, CZM believes that reducing the

number of survey stations may be reasonable, especially given the proposal to

synoptically survey all sites every year. However, CZM has questions about which sites,

or subsets of sites, were used for the regression analyses that demonstrate this

relationship. CZM requests that MWRA provide an addendum to Report 2009-06 that

clarifies which sites were used in its analyses.

3.

Discontinue productivity measurements.

To support this proposal, MWRA states that

algal growth can be monitored by measuring nutrient drawdown and biomass. CZM has

not seen the documentation to support this proposal and suggests that these data be

provided.

4.

Discontinue some chemistry tests.

CZM has no issue with this proposal.

5.

Discontinue net tows for floatables.

CZM agrees that, based upon Report 2008-08, no, or

very few, “floatables of concern” have been detected via net tows. However, we do

remain concerned about the sheer volume and mass of floatables conveyed by the

MWRA outfall to Massachusetts Bay.

6.

Discontinue whale observations reporting.

CZM will defer to the whale specialists at the

Massachusetts Division of Marine Fisheries on whether this monitoring effort should be

continued.

7.

Add/continue continuous water quality data monitoring at two buoys.

CZM agrees that

the continuous chlorophyll measurements at the Gulf of Maine Ocean Observing buoy

A01 and water quality measurements at the National Oceanographic and Atmospheric

Administration’s buoy 44013 will be helpful to MWRA’s monitoring program.

8.

General comments on the Water Colum section of Report 2009-06.

On p. 23 of Report

2009-06, MWRA reports statistical analyses performed on certain subsets of it water

column monitoring sites. From an earlier report (2009-04), one learns that the Inner

Nearfield consists of sites N16, N18, and N20; the Outer Nearfield consists of sites N01,

N04, N07, and N10; Massachusetts Bay Offshore consists of sites F12, F17, F19, and

F28; and Cape Cod Bay consists of sites F01, F02, and F03. However, it is not clear how

these subsets of sites were chosen. For example, there are two other sites in Cape Cod

Bay (sites F32 and F33) that could have been chosen for analysis. Likewise, there are six

to eight previously-monitored sites in Massachusetts Bay that could have been chosen for

the Massachusetts Bay Offshore set. One is left to speculate whether selection of a

different subset of sites would have produced results different from those presented here

in Report 2009-06. CZM requests that MWRA provide valid statistical reasons for the

chosen subsets of monitoring stations.

P. 25 of Report 2009-06 states that ammonium concentrations have increased in the

nearfield around the MWRA outfall since the outfall went online in 2000 and that there

have been significant increases in the winter/spring biomass of phytoplankton in the same

area. MWRA then purports that this change in phytoplankton biomass is due to “larger

scale regional trends in phytoplankton bloom dynamics” but provides no evidence and no

citation for this statement. CZM does not disagree that, for discrete time periods,

Massachusetts Bay and Cape Cod Bay phytoplankton dynamics are driven by Gulf of

Maine-wide phenomena. We do not believe however that MWRA has provided sufficient

evidence in Report 2009-06 that regional phenomena are responsible for the

winter/spring blooms in Massachusetts and Cape Cod Bays for all years since the outfall

went online. CZM requests that MWRA provide the evidence that documents a regional

winter/spring phytoplankton biomass increase concomitant with and on the same scale as

that found near the MWRA outfall from 2000 to the present.

P. 26 of Report 2009-06 provides a summary of some interesting data presented in Report

2009-04 (pp. 4-20 to 4-24) which suggest that the decrease in primary productivity seen

at two nearfield sites in Massachusetts Bay may be due to decreasing winds (and thus

more stratification and less mixing) from 2002 to the present. While the decrease in

primary productivity at two sites near the MWRA outfall may suggest that the outfall is

not causing or augmenting phytoplankton productivity adjacent to it, the fact that low

winds from 2002-2007 may be driving phytoplankton activity and productivity down

begs the question: what if the winds that appear to be linked to productivity increase in

the future? CZM reiterates its comment that the MWRA suggestion to eliminate

productivity measurements and replace it with nutrient drawdown and biomass

monitoring needs to be carefully considered by the permitting agencies.

In the discussion on p. 27 of Report 2009-06, MWRA states that there is no outfall-

related causality associated with shifts in phytoplankton and zooplankton species, yet no

citation is given. CZM requests that MWRA provide the data that support this position.

Table 3-2 in Report 2009-06 lists the proposed subset of nearfield and farfield stations

that would be kept by MWRA for its water column monitoring program. First, there

appears to be an error in the table in that site F06 is listed as being 3 km from the outfall

but clearly is closer to 30 km from the outfall. More importantly, as one is considering

whether the selected sites are indeed representative of nearfield or farfield conditions,

MWRA does not provide any evidence that the farfield sites are outside the influence of

the outfall’s effluent. As stated above, CZM is opposed to ending water quality

monitoring in Cape Cod Bay, in part because they offer farfield observations that are, for

the most part, outside the influence of the MWRA effluent. CZM requests that MWRA

provide statistical reasons for choosing the proposed nearfield and farfield sites. In

particular, CZM suggests that MWRA demonstrate that the closer farfield sites (F15,

F13) are not autocorrelated with the nearfield sites. Figures 3-4 to 3-9 in Report 2009-06

suggest that there is a strong correlation between chlorophyll data collected at the original

seven nearfield stations and the proposed four nearfield stations. However, chlorophyll is

only one of the 20 water column parameters measured by MWRA (see Table 3-3). If

MWRA can provide evidence that the proposed sites have strong correlation with the

original seven nearfield sites for the majority of the other 19 parameters, CZM may be

convinced that reducing the water quality monitoring program to the proposed four

nearfield sites is reasonable. CZM suggests that MWRA provide these analyses to the

permitting agencies. Additionally, CZM requests that MWRA present an analysis of how

well the proposed farfield sites correlate with the current farfield sites.

Seafloor

1.

Reduce the number of soft bottom monitoring stations from 16 or 17 to 13 (10 nearfield

and three farfield).

MWRA provides some evidence that the number of infaunal species

counted at the existing nearfield sites correlates well with the proposed 10 sites for future

monitoring. However, it is not clear how well these sites correlate when other parameters

are considered and there is no evidence presented that the proposed three farfield sites

sufficiently represent the existing eight stations. Further, CZM questions if the reduction

in the sampling design preserves sufficient statistical rigor to perform the analyses

necessary (i.e., does the reduction in sample size preserve statistical power to detect

differences between nearfield and farfield). CZM requests that MWRA provide more

information for the permitting agencies to evaluate this proposal.

2.

Reduce the sediment contaminant monitoring stations to 13.

As above, CZM has

concerns that the proposed sites adequately represent the original sites.

3.

Discontinue the annual sediment contaminant sampling at two nearfield stations.

In the

discussion of sediment contaminants, it is not clear which benthic monitoring sites were

used to determine baseline ranges of contaminants and which nearfield and farfield sites

were used to determine post-diversion and 2008 values. It is also not clear if the 2008

values in Table 4-1 are means, and if so, why they do not have error bars. CZM requests

that the locations of the data used in this analysis be made clear and that MWRA clarify

what the 2008 values represent. Further, CZM requests that MWRA present separate

baseline and post-diversion values for each region: nearfield, farfield, and Boston Harbor,

for each contaminant (organics, metals, pesticides) so that agencies can determine if

sediment contaminants show any increasing or decreasing patterns post-diversion and so

that the questions posed on p. 40 of Report 2009-06 can be answered.

CZM has serious concerns about the proposal to drop nearfield sampling sites NF24 and

NF15. Of the five nearfield sites within 2 km of the outfall, NF24 has shown the highest

average levels of PAHs and the second highest levels of copper, while site NF15 has

shown the third highest average levels of PAHs and the third highest levels of copper (see

Figures 3-3 and 3-4 of Report 2008-20). To be conservative, if any two nearfield sites

should be dropped, they probably should be NF17 and NF13, which had the lowest

average levels of PAHs and copper in the post-diversion sampling period. CZM requests

that MWRA reconsider its selection of nearfield sites to be kept in the seafloor

monitoring component.

4.

Reduce sampling frequency of the hard bottom study to every three years.

CZM has no

issue with this proposal.

5.

Discontinue the nutrient flux study.

Based upon the results presented in Report 2008-14,

CZM has no issue with this proposal. It does not appear that the MWRA effluent has

changed sediment oxygen demand, sediment nutrient flux into the water column, or

denitrification at the four sites studied adjacent to the outfall in Massachusetts Bay.

6.

General comments on the seafloor monitoring section.

While MWRA states that benthic

infaunal monitoring data show no major departures from baseline, MWRA’s hard bottom

data do indicate that coralline algae cover has decreased post-diversion (see Figure 6-8

and Table 6-5 of Report 2008-20). Contrary to what MWRA states on p. 49 of Report

2009-06, the decrease in coralline algae cover is not only at stations “further from the

outfall,” but rather was recorded at several sites ranging from <1 to 2 nautical miles from

the outfall. Even the furthest sites in the hard bottom study are within what MWRA calls

the “expression” of the plume (as in the description of site F10 in Table 3-2 of Report

2009-06) so it may not be surprising that these hard bottom communities are

experiencing increases in sediment drape and decreases in coralline algae. As stated

above, CZM is not opposed to reducing the hard bottom study frequency to every third

year, however, we do believe that the study is demonstrating sedimentation effects that

are likely associated with the MWRA effluent and that this study should continue.

Special Studies

1.

Report 2009-06 summarizes several special studies that MWRA conducted. A detailed

characterization of MWRA’s Deer Island Treatment Plant (DITP) effluent demonstrated

that all metals, except copper, met EPA’s salt water criteria before factoring in the

roughly 70-fold dilution that the effluent receives in Massachusetts Bay (see Tables 2-2

and 2-3 of Report 2009-06). Copper concentrations met the water quality criterion after

dilution at some unspecified distance from the outfall diffuser. What is not clear is what

volume or area of the MWRA effluent plume contained levels of copper that exceed the

EPA acute water quality criterion of 4.8 ug/l.

314 CMR 4.03(2) states that MassDEP “may recognize a limited area or volume of a

waterbody as a mixing zone for the initial dilution of a discharge. Waters within a mixing

zone may fail to meet specific water quality criteria (e.g., the 4.8 ug/l acute criterion)

provided the following conditions are met: (a) Mixing zones shall be limited to an area or

volume as small as feasible. There shall be no lethality to organisms passing through the

mixing zone as determined by the Department (MassDEP). The location, design and

operation of the discharge shall minimize impacts on aquatic life and other existing and

designated uses within and beyond the mixing zone.”

Although the MassDEP mixing zone policy referenced above allows for the MWRA

effluent plume to contain copper in concentrations that violate specific water quality

criteria, the mixing zone must be “as small as feasible.” Given that MWRA does not

provide the extent of the area that violated the copper standard, it is not clear if this

mixing zone is as small as feasible. Further, EPA mixing zone policy found in the Water

Quality Standards Handbook (1984) states that a mixing zone for the criterion maximum

concentration to protect against acute or lethal effects (i.e., the “acute” criterion) must

achieve one of the following: 1) the acute criterion (i.e., 4.8 ug/l for copper) must be met

in the pipe itself; 2) the acute criterion must be met a “short distance from the outfall”

which includes establishing a “toxic dilution zone” around a new outfall with a discharge

rate of three meters per second; 3) the outfall design must meet the most restrictive of the

following geometric restrictions from the toxic dilution zone : a) the acute criterion must

be met within 10% of the distance from the outfall structure edge to the edge of the

regulatory mixing zone, b) the acute criterion must be met within a distance of 50 times

the cross-sectional area of any discharge outlet (roughly 22.4 m for a port of diameter 0.2

m), or c) the acute criterion must be met within a distance of five times the local water

depth in any horizontal direction roughly 160 m); or 4) it must be demonstrated that a

drifting organisms would not be exposed for greater than one hour to average copper

concentrations exceeding 4.8 ug/l. It is not clear if the toxic dilution zone for copper in

the MWRA effluent meets any of the required standards. In Report 2009-06, MWRA

states that “contaminants are diluted to background levels within 20 km of the outfall” (p.

22). If this is the extent of the MWRA effluent mixing zone, then it appears that the

mixing zone standards may not be met. CZM requests that MWRA describe to the

agencies how its effluent meets the state mixing zone standard.

Report 2009-06 also demonstrated that chlordane, alpha-chlordane, and DDT

(pesticides); total polychlorinated biphenyls (PCBs); and chrysene (a polycyclic aromatic

hydrocarbon) exceeded EPA’s human health criterion based upon a carcinogenicity risk

of one in a million, before dilution, but with dilution all five of these constituents were

for the most part found at concentrations less than their respective water quality criteria.

CZM is pleased to see that many constituents found in the DITP effluent are well below

the loadings that were projected in 1988 in the Supplemental Environmental Impact

Statement for the new DITP.

2.

Monitoring of nutrients on a weekly schedule (i.e., more frequent than the required

monthly sampling) was considered a special study by MWRA. The weekly nutrient data

demonstrated that while the annual mass of organically bound nitrogen (i.e., total

Kjeldahl nitrogen) has decreased from 1996-2008, the mass of ammonium and

nitrate/nitrite has increased. CZM is pleased to see that overall, total nitrogen, measured

in metric tons per year, is still below the 1996 level (which is the caution level).

3.

A special study on emerging contaminants is described in Report 2009-06 as being

unpublished and found that of the 23 pharmaceuticals and personal care products (PPCP),

only 11 showed greater than 80% removal via secondary treatment offered at DITP. CZM

requests that MWRA make this report available via its website so that interested agencies

and other parties can more fully understand the extent of PPCPs in sewage effluent.

Fish and Shellfish Monitoring

1.

CZM is pleased to see that MWRA proposed to continue the existing fish and shellfish

monitoring.

Thank you for the opportunity to comment on this important component of the MWRA National

Pollutant Discharge Elimination System permit. If you should have any questions about these

comments, please contact me at 617-626-1233.

Sincerely,

Todd Callaghan

CZM Water Quality Specialist

Cc: Cathy Vakalopoulos, MassDEP

Paul Hogan, MassDEP

Michele Cobbin-Barden, U.S. EPA

Matt, Liebman, U.S. EPA

Jack Schwartz, DMF

Andrew Solow, WHOI