**UNITED STATES ENVIRONMENTAL PROTECTION
AGENCY**![](media/image1.png){width="0.9993055555555556in"
height="0.9in"}

WASHINGTON, D.C. 20460

**April 1, 2008**

**MEMORANDUM**

SUBJECT: CSTAG Recommendations for the Lower Passaic River Site

FROM: Stephen J. Ells /s/ **Stephen J. Ells**

> Chair, Contaminated Sediments Technical Advisory Group

TO: Alice Yeh, Remedial Project Manager

U.S. Environmental Protection Agency, Region II

**Background**

OSWER Directive 9285.6-08, Principles for Managing Contaminated Sediment
Risks at Hazardous Waste Sites (February 12, 2002), established the
Contaminated Sediments Technical Advisory Group (CSTAG) as a technical
advisory group to "...monitor the progress of and provide advice
regarding a small number of large, complex, or controversial
contaminated sediment Superfund sites...." The main purpose of the CSTAG
is to assist Regional site project managers in managing their sites in
accordance with the eleven risk management principles set forth in the
OSWER Directive. CSTAG membership consists of ten regional
representatives, two from the Office of Research and Development, and
two from the Office of Superfund Remediation and Technology Innovation
(OSRTI).

**Brief Description of the Site**

The 17- mile portion of the Lower Passaic River (LPR) is an operable
unit of the Diamond Alkali Superfund Site in Newark, New Jersey and is
being addressed by a group of six partner agencies under the Lower
Passaic River Restoration Project. The 17-mile portion is tidal and
extends from Newark Bay upstream to Dundee Dam. Sediments in the lower
eight miles of the river were identified as a source of contamination to
the 17-mile portion and to Newark Bay. The risk assessments concluded
that unacceptable ecological and human health risks from consumption of
contaminated fish and crabs exist in the LPR. The CSTAG's review focuses
on the remedial alternatives for an Early Action presented in a Focused
Feasibility Study (FFS) prepared by Region II that addresses only the
lower eight mile, 650-acre section of the LPR.

The 17-mile area is being studied by six entities: the EPA; the U.S.
Army Corps of Engineers (Corps) and New Jersey Department of
Transportation under the Water Resources Development Act; and by the
U.S. Fish and Wildlife Service, National Oceanic and Atmospheric
Administration, and New Jersey Department of Environmental Protection as
Natural Resource Trustees. The Cooperating Parties Group (CPG),
comprising 72 potentially responsible parties, is performing the RI/FS
for the entire 17-mile study area. The goal of the RI/FS is to collect
data that can be used to develop and evaluate remedial alternatives for
the entire 17-mile study area that will reduce human health and
ecological risks and contaminant loadings in the LPR and Newark Bay.
This RI/FS is expected to be completed in 2012.

The LPR flows through densely populated and industrialized areas and
ultimately into Newark Bay. The Dundee Dam is just above the head of
tide at River Mile 17 and presents a hydraulic boundary. The three named
tributaries to the LPR include the Saddle River, the Second River, and
the Third River. Beginning in the early nineteenth century, the LPR
watershed was a major center for industrial operations including cotton
mills, manufactured gas plants, paper manufacturing and recycling
facilities, and chemical manufacturing facilities. These facilities and
adjacent municipalities discharged dioxins, petroleum hydrocarbons,
polychlorinated biphenyls, pesticides, and metals to the LPR.

Although there is an authorized navigation channel through out the
entire 17-mile portion, there has been little maintenance dredging since
the 1940s, and none since the early 1950s. Consequently, the river has
accumulated sediment in the lower eight miles, measuring up to 25 feet
thick. Because the sediment accumulation occurred coincidently with
unchecked chemical discharges, it contains a high mass of contamination,
especially dioxins.

The Lower Passaic River is relatively narrow compared to its tidal
exchange, which can account for one third of the water volume in the
river at high tide. This makes the tidal surge a prominent dynamic force
in the river. Data used by Region II to develop a preliminary conceptual
site model suggest that tidal mixing may distribute contamination
throughout the eight-mile study area. Region II believes that during the
largest tidal cycles and some storm events, sediments may erode and
deposit in shifting sequences, and thereby resuspend the older, more
highly contaminated sediments that had been buried. Although
resuspension of deeper sediments was estimated to comprise about ten
percent of the total annual sediment deposition, the empirical mass
balance model (EMBM) the Region developed for the site suggests that
this accounts for over 95% of the dioxin and a significant portion of
PCBs, pesticides, and mercury in recently deposited surface sediments.
As more sediments deposit and the river approaches its pre-dredged
channel depth and gradient, data suggest the river will meander within
the channel. This can result in the erosion and subsequent suspension,
transport and deposition of older, more highly contaminated sediments
that were previously buried.

The CSTAG visited the site and met with the remedial project manager
(RPM) and partner agencies from February 12 to 14, 2008. Eight
stakeholder groups associated with the site were invited to present
their views to the CSTAG of how the Region has applied the 11 sediment
management principles in this project. Four invitees made presentations
to the CSTAG including the City of Newark, the Ironbound Community
Corporation, the Passaic River Coalition, and the CPG. Written comments
were submitted by the CPG (*i.e.*, de maximis, inc.), the Natural
Resources Defense Council, and the Passaic River Coalition.

**CSTAG Recommendations**

The CSTAG makes the following recommendations concerning how the Region
has addressed the 11 Principles in developing and evaluating potential
early action alternatives for the lower eight miles.

[Principle #1: Control Sources Early.]{.underline}

-   In order to more reliably predict the expected effectiveness of the
    remedial options in reducing risks, the Region needs to evaluate
    more quantitatively the relative contribution of risks from dioxin
    and PCBs entering from upstream (*i.e.*, over Dundee Dam), from
    tributaries, from combined sewer outfalls (CSOs), and from instream
    sediments above mile eight and from Newark Bay. Therefore, CSTAG
    recommends that additional data be collected in order to better
    characterize the contaminant loads that enter the lower eight miles
    (*i.e.*, from upstream of the early action area) and that enter the
    LPR from upstream of the Dundee Dam. The significance of inputs from
    downstream (Newark Bay) and lateral loading (from outfalls and
    tributaries) should be evaluated as well. We understand that the
    Region has initiated new efforts to characterize external sources of
    contamination from tributaries, industrial outfalls, CSOs, and storm
    sewer outfalls (SSOs). The Region should ensure that these data are
    adequate to ensure that there is not an on-going source(s) that
    needs to be addressed before taking action in the lower eight miles,
    to more reliably predict post-remedial surface sediment
    concentrations and to more accurately estimate long-term risk
    reduction in the lower eight miles that may result from any early
    action.

-   In order to further evaluate the Region's predictions resulting from
    the EMBM, additional information should be collected to confirm the
    estimate that 95% of dioxin currently accumulating in the river
    bottom is from resuspension and subsequent deposition of the bedded
    legacy sediments; *i.e*., an internal source is driving the current
    risk and need for an early action. Additional recommendations on how
    this can be achieved are addressed under Principle #4.

[Principle #2: Involve the Community Early and Often.]{.underline}

-   CSTAG supports the Region's efforts to involve affected
    stakeholders. However, the Region should consider sharing site
    information earlier and provide more frequent updates as new data
    become available.

> The Region should consider hosting public information and input
> sessions when developing and refining treatment and disposal options
> for contaminated sediments \[*e.g.,* confined disposal facility (CDF),
> off-site incinerator or high temperature thermal treatment, off-site
> treatment and disposal, containment in-place, etc.\]. If the proposed
> remedy is expected to
>
> include a CDF, discuss the potential locations with the communities
> and stakeholders as early as possible.

-   The Region should use the information in EPA's 2005 *Contaminated
    Sediment Remediation Guidance for Hazardous Waste Sites* and the
    2007 National Research Council report: *Sediment Dredging at
    Superfund Megasites Assessing the Effectiveness* to assist in
    communicating to stakeholders that this site presents several
    challenges for effective dredging and capping, and that it may take
    many years, if not decades, to reach remediation goals (RGs) for
    this site.

    [Principle #3: Coordinate with States, Local Governments, Tribes,
    and Natural Resource Trustees.]{.underline}

-   CSTAG supports Region II's efforts to coordinate with other agencies
    and recommends the additional following actions.

-   Clarify the roles and regulatory responsibilities of the partner
    agencies. For example, clarify what work is being done as part of
    the Corps' restoration effort under WRDA, as part of a Superfund
    early action or future remedial actions under EPA's CERCLA
    authorities, or as part of restoration efforts being undertaken by
    Natural Resource Trustee agencies.

-   Work with the Corps to have it determine whether the commercial need
    for navigational dredging in any parts of the lower two miles
    justifies the cost to perform navigational dredging.

-   Consider developing an alternative that addresses additional
    dredging for flood control but not for navigational purposes in the
    lower two miles. Region II could use this information on the
    differences in cost, short-term effectiveness, implementability,
    *etc.*, as it evaluates the cleanup options for the site.

-   Work with the Corps to determine what the administrative
    requirements are, if any, for any alternatives that change the
    allowable depth of the navigation channel, including the need for
    Congress to deauthorize the channel or reauthorize it at a different
    navigational depth and length.

-   Consult with the Region's water program regarding the timing of any
    expected CSO improvements and evaluate whether these affect the
    effectiveness and/or timing of any proposed remedy.

-   Coordinate with local and state governments to understand what the
    realistic and reasonable anticipated future land uses will be for
    the LPR. The Region's understanding of the future land uses of the
    riverfront and river itself may impact the suite of remedial
    alternatives that are to be evaluated in the revised FFS for early
    action and, potentially, in the RI/FS for the 17-mile study area.

[Principle #4: Develop and Refine a Conceptual Site Model that Considers
Sediment Stability.]{.underline}

-   After evaluating the briefing materials and other relevant
    information, the CSTAG concludes that additional sampling data are
    needed to support the main premise of the conceptual site model
    (CSM) that the entire lower eight miles is a "well mixed box."

-   CSTAG questions the sufficiency of the historical data supporting
    EMBM predictions of on-going and expected future sediment transport
    that will serve as the basis for estimating post-remediation
    contaminant concentrations in sediment in the LPR and Newark Bay.

-   CSTAG commends the Region for deciding to collect additional site
    data and to use it with the ECOM-SEDZLJ sediment transport model
    that is being developed for the LPR and Newark Bay to evaluate
    sediment transport and fate of legacy sediment. However, the
    assumptions underlying the use of the ECOM-SEDZLJ model also need to
    be justified. CSTAG recommends that the Region compare the model
    outputs between the EMBM and the updated ECOM-SEDZLJ model in order
    to: 1) determine if the results of the ongoing sediment transport
    modeling support or contradict some of the main assumptions
    incorporated in the EMBM; and 2) identify and reconcile any
    differences between the model outputs. The use of the two models
    will help reduce the uncertainty regarding the prediction of river
    dynamics.

-   Compare the underlying assumptions for the bases for the CSMs as
    described in the FFS for the early action plan and in the
    longer-term RI/FS, and if necessary, align them in order to ensure
    that data from future sampling efforts will be useful in making all
    remedy decisions.

-   CSTAG recommends that maps or other graphics presenting dioxin
    sediment chemistry sample results by location and by depth be
    included in the revised FFS. This would facilitate a better
    understanding of the nature and extent of historical and more recent
    site contamination throughout the eight mile area.

[Principle #5: Use an Iterative Approach in a Risk-Based
Framework.]{.underline}

-   Region II should give additional consideration when revising the FFS
    to add one or more limited early action alternatives that address
    the highly contaminated erosional areas within the lower eight
    miles, for example, in the vicinity of the Diamond Alkali plant. The
    Region should perform additional analyses of all available data
    and/or collect additional sediment contaminant data and sediment
    stability data in order to adequately evaluate the potential
    effectiveness of these limited early actions. Due to our concern
    about the uncertainties associated with the data supporting the EMBM
    predictions, the CSTAG believes the existing information is
    insufficient to support the Region's conclusion that any early
    action addressing only a portion of the lower eight miles of the LPR
    would not be effective in reducing dioxin risks within the LPR or
    releases to Newark Bay.

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-   The Region should use the information being collected as part of the
    RI/FS for the 17-mile LPR to refine the CSM and verify the basis for
    the early actions proposed for the lower eight miles.

-   As the long-term RI/FS continues and if additional response actions
    are needed for areas not addressed by an early action, consider
    conducting pilot studies to evaluate the effectiveness of developing
    technologies such as reactive caps and sediment amendments.

[Principle #6: Carefully Evaluate the Assumptions and Uncertainties
Associated with Site Characterization Data and Site Models.]{.underline}

-   CSTAG believes that it may be necessary to collect more sediment
    samples in the lower eight miles to more adequately characterize the
    nature and extent of contamination.

-   Under the proposed capping scenarios, in order to eliminate the
    potential for any increase in flooding due to remedy implementation,
    approximately four million cubic yards of sediment would first need
    to be removed. This volume is necessary in order to not raise the
    sediment bed elevation and to accommodate an increase water level
    caused by an increase in sediment bed surface friction. The increase
    in friction is due to the increased roughness of the sand surface
    compared to the existing surface of mostly fine-grained sediment and
    would cause a decrease in water velocity, which in turn results in a
    slight increase in the water surface elevation and thus increased
    flooding potential. Given the significant cost and time to implement
    such a large dredging project, the CSTAG recommends that the Region
    conduct a thorough re-evaluation of the engineering assumptions and
    calculations used to estimate the volume of sediment to be dredged.
    This should also include a re-evaluation of the amount of
    overburden-induced sediment consolidation likely to occur after
    adding a thick cap to areas dominated by fine-grained, low density
    sediments. It may be necessary to get assistance from external
    experts to help with this re-evaluation.

-   CSTAG recommends that the Region clarify and explain the use of the
    contaminant data associated with the recently deposited
    beryllium^7^-bearing surface sediment in the CSM-EMBM, as compared
    to how the contaminant data associated with the top 6 inches of
    sediment were used in the risk assessment. The beryllium^7^ data may
    not accurately represent the surface sediment (top 6-inches) dioxin
    concentrations across the lower eight miles of the LPR and should
    not be used as the primary basis to compare remedies.

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-   CSTAG understands that semi-permeable membrane device (SPMD) data
    were used in the EMBM to estimate dissolved contaminant
    concentrations, and then this estimate was used to estimate
    concentrations of contaminants on solids. This was done for the EMBM
    estimates of the tributary source contributions. CSTAG recommends
    that the Region consider the following disadvantages of using SPMDs
    and instead consider making direct measurements of dissolved and
    particulate contaminant levels.

    1\. Bio-fouling can impede uptake (Lu *et al.*, 2002; Louch *et
    al.*, 2003);

> 2\. Variations in temperature can affect uptake estimates and
> back-calculations to water concentrations of PCBs (Lu *et al.*, 2002;
> Booij *et al.*, 2003);
>
> 3\. The flow-turbulence regime of the river can affect uptake
> estimates (Lu *et al.*, 2002);
>
> 4\. The determination of a water and solids concentrations must rely
> on calculations based on theoretical partitioning between the
> dissolved and particulate form of a chemical; and
>
> 5\. Investigators using SPMDs for field investigations caution against
> an assumption of homogenous or "well mixed" concentrations of organic
> contaminants in riverine surface water. This is because SPMD sampling,
> just like grab sampling, does not account for spatial variability
> without extensive data supporting the aforementioned assumption (Louch
> *et al.*, 2003).

-   The extreme variability in the results from the resuspension
    evaluations (from approximately 10% to more than 95% of the total
    solids) using different assumptions demonstrates the high level of
    uncertainty associated with the EMBM. The cumulative uncertainties
    associated with the forecasted contaminant concentrations for the
    three remedial alternatives appear to be much greater than the
    resulting differences between the forecasted surface sediment
    concentrations shown in Figure 7-4 of Appendix D of the FFS. As
    such, the results from the EMBM should not be the only line of
    evidence used by the Region in deciding which remedial alternative
    to choose.

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-   CSTAG recommends that the Region provide more discussion on the
    uncertainties in the EMBM and clearly explain any proposed remedy in
    light of these uncertainties. This includes the uncertainty
    associated with predicted post-remedial surface sediment
    concentrations and estimates of contaminated sediment transport into
    the lower eight miles. Other uncertainties include the following:

    -   Since the use of a deterministic model (a model where outputs
        are described using mechanistic descriptions of the processes
        occurring in the system of interest) may be more common in a
        physically complex surface water body such as this partially
        stratified estuary, the use of a receptor model, such as the
        EMBM (where concentrations measured at sources and receptors are
        used to identify the presence of and to quantify source
        contributions to receptor concentrations) needs to be more
        thoroughly justified.

    -   The Region needs to justify or evaluate the limitations of the
        assumption that the concentrations of the contaminants of
        potential concern (COPC) will continue to decrease at the same
        rate as they have since about 1980. The Region needs to
        elaborate on the assumption that the five high resolution
        sediments cores represent "the mean surface concentration
        \[and\] will track the trends observed in the depositional
        settings reflected in the dated sediment cores" (page 7-23 of
        Appendix D of the FFS). The Region needs to justify the
        statement that the loads from "atmospheric deposition,
        groundwater, and New Jersey Pollutant Discharge Elimination
        System permitted discharges are considered negligible."

    -   The Region needs to justify or clarify its assumption that the
        sediments in the LPR are well-mixed prior to deposition, since
        the LPR seems to be partially stratified. The LPR, by virtue of
        being partially stratified, is not a well mixed, homogenized
        water body. The Region stated that the LPR was an energetic
        waterway because the tide range was approximately half of the
        water depth, and therefore the water column and suspended
        sediments were well mixed in all directions, *i.e.,* vertically,
        laterally, and longitudinally. If it was as energetic as
        implied, the tidal energy would break down the vertical
        stratification and the water column would indeed be well mixed.
        But because the water column retains its stratification, the
        tidal energy is not sufficient to overcome the potential energy
        barrier that the stratification represents. Since the tidal
        energy is not sufficient to break down the stratification,
        vertical gradients of salinity and any constituent (*i.e.,*
        sediment, contaminants) transported by the flow occur.

    -   Because of the meandering nature of the LPR, the vertical,
        lateral and longitudinal gradients in the oscillatory velocity
        field would result in vertical, lateral, and longitudinal
        gradients in suspended sediment and in other constituents such
        as dissolved contaminants.

    -   According to the FSS, the EMBM also assumes that the contaminant
        source profiles are independent, and as a result, only the
        contaminants that "distinguish the sources are characterized."
        The Region needs to clarify this and explain the limitations
        that this assumption imposes on the analysis.

    -   Since the EMBM focuses on suspended sediment transport, the
        Region needs to ensure that this transport mechanism is
        applicable to the key contaminants of potential concern to the
        LPR. This mechanism may not be appropriate to evaluate the
        transport of the more soluble PCB congeners.

    -   The EMBM assumes that if 10% of a particular contaminant comes
        from a source (*e.g.,* CSO\'s); then10% of that contaminant in
        the newly deposited sediments comes from that source. The CSTAG
        supports the Region's decision to use the ECOM-SEDZLJ model to
        assess the reasonableness of this assumption.

    -   Concentrations of the contaminants associated with the suspended
        solids of the tributaries were estimated by taking the product
        of the K~d~ values and the concentrations estimated using the
        SPMDs. This calculation assumes that the surficial sediment
        behind Dundee Dam and the suspended solids of the tributaries
        are identical in composition, including organic carbon content.
        This assumption is a highly doubtful assumption that is not
        supported by any presented data. CSTAG recommends that the K~d~
        values be computed on an organic carbon basis in the sediment
        and corrections for organic carbon differences be made in the
        calculation for the tributaries.

    -   In the EMBM model, the resuspension source term for the LPR
        sediment was represented by average decadal concentrations
        (Table 4-4) or length-weighted average (LWA) concentrations of
        the entire contaminated sediment bed (Table 4-5). Neither of
        these concentrations represents the actual surface sediments
        that can be resuspended into the water column. From the
        discussions with the Region's modelers, sediments of any age
        could be present at the surface, and the figures showing
        concentrations in the surficial sediments vary widely. Thus, the
        wrong concentration data for the resuspension source term for
        the sediment were used with the EMBM. Surface-weighted average
        concentrations (SWACs) of some type should have been used for
        the eight mile stretch of the river with the EMBM.

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-   The Region needs to provide a more robust justification for the
    choice of the LWA concentration over the 1990 decadal concentration,
    and the Region should explain why these concentrations are more
    appropriate than surface weighted average concentrations (SWACs).
    Region II needs to explain why the use of the LWA concentration
    results in a conservative estimate of "the contaminant flux
    associated with resuspension of historical inventory." In addition,
    the Region should explain why "this solution provides a tighter
    constraint on the external sources to the Lower Passaic River."

-   The Region needs to provide better justification for the assumption
    in the EMBM's average decadal concentrations analysis that current
    day inputs from the other sources are the same as historical inputs.

-   The Region needs to elaborate on the EMBM's mixed layer concept
    (*i.e.,* that up to 30 inches of sediment are resuspended and the
    resulting average adsorbed contaminant concentration represents a
    decadal concentration), as this is not an accurate representation of
    estuarine fine-grained sediment transport.

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-   Given the reliance on the EMBM, and the potential size and cost of
    an early action, CSTAG recommends an external peer review for the
    EMBM and the hydrodynamic and sediment transport modeling that will
    be used to re-evaluate the effectiveness of the alternatives
    considered in the revised FFS.

    [Principle #7: Select Site-specific, Project-specific, and
    Sediment-specific Risk Management Approaches that will Achieve
    Risk-based Goals.]{.underline}

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-   Projections of post-cleanup sediment concentrations appear
    unrealistically low. The CSTAG supports the Region's recent decision
    to reevaluate the level of post-remediation residual risk by
    incorporating more reasonable estimates of recontamination resulting
    from dredging and capping the lower eight miles. CSTAG also supports
    a more robust assessment of the potential for post-cleanup
    recontamination from upstream, lateral, and downstream sources, as
    discussed in Principle 1.

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-   The CSTAG recognizes the complexity of establishing risk-based
    cleanup goals when background concentrations present unacceptable
    risks, but it is not confident that the existing limited contaminant
    sediment concentrations above Dundee Dam are the most appropriate
    concentrations to use to represent background levels in the lower
    eight miles; additional analysis is encouraged.

[Principle #8: Ensure that Sediment Cleanup Levels are Clearly Tied to
Risk Management Goals.]{.underline}

-   Because it will likely take many years or even decades to achieve
    Remedial Action Objectives, both long-term and short-term or interim
    remediation goals should be developed for fish and crab tissue.
    Because many consumers eat only crab muscle, goals based on the
    ingestion of just muscle should also be presented. The time to
    achieve these goals should be estimated for each alternative.

-   As discussed under Principle #2, the risk reduction projections
    should be clearly and transparently communicated to affected
    stakeholders when describing the benefits of any

    proposed early action. It is expected that fish consumption
    advisories in the LPR will likely

    remain in place indefinitely.

-   The CSTAG suggests that the Region consider placing more emphasis on
    the potential benefits from reducing dioxin loading to Newark Bay
    than on achieving significant risk reduction in the LPR itself. It
    may also be helpful to explain the anticipated benefits of the
    proposed action to ecological resources (*i.e.*, beyond what was
    presented in the screening ecological risk assessment) in the LPR
    and Newark Bay.

-   The risk assessment predicted residues in fishes and crabs for
    future conditions using BAFs derived from field data. The BAF is the
    ratio of the concentration of the chemical in the organism on a wet
    weight basis to that in the sediment on a dry weight basis. CSTAG
    suggests that BSAFs (ratio of the concentrations of the chemical in
    the organism on a lipid weight to that in the sediment on an organic
    carbon basis) instead of BAFs be used to predict chemical residues.
    Accumulation of nonpolar organic chemicals in organisms is
    controlled by the lipid and organic carbon phases, and thus,
    accounting for differences in lipid and organic carbon contents will
    improve the quality of the biota residues predicted for the future.
    CSTAG also suggests that the computed BSAFs be compared with BSAFs
    calculated for other sites to evaluate their reasonableness.

-   The risk assessment should also estimate risks from direct contact
    exposure scenarios (*e.g.,* recreational user and construction
    worker) and develop RGs for these exposures. This information can be
    used to inform the community about risks due to direct contact with
    sediment and surface water.

    [Principle #9: Maximize the Effectiveness of Institutional Controls
    and Recognize their Limitations]{.underline}.

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-   CSTAG recommends further outreach efforts to bolster the
    effectiveness of the existing fish consumption advisory for fish and
    crabs. This could be accomplished, for example, by improving
    outreach through public education programs, brochures, postings in
    bait/tackle shops, fishing license proprietors, talks to community
    groups or schools, and discussions about alternatives to fishing.

-   If capping is selected as part of an early action remedy, it will be
    important to evaluate which institutional controls will be needed to
    protect the integrity of the cap in light of any planned future
    navigational uses and construction activities in or bordering the
    river. It will also be important to evaluate and identify who will
    be responsible for ensuring that these controls remain in place over
    the long-term.

    [Principle #10: Design Remedies to Minimize Short-term Risks while
    Achieving Long-term Protection.]{.underline}

-   The CSTAG supports the Region's recent decision to re-evaluate
    potential short-term risks from sediment resuspension and
    contaminant release resulting from remedy implementation. The Region
    should consider the recent information on increased risks caused by
    contaminant releases as a result of dredging activities in Bridges
    *et al*., 2008 and NRC, 2007. These risks must be considered when
    comparing remedies in light of the short-term effectiveness and
    long-term effectiveness and permanence criteria.

-   Estimates of contaminant releases to the water column during
    dredging should be compared with those generated as a result of
    storms, flooding and strong tides.

    [Principle #11: Monitor During and After Sediment Remediation to
    Assess and Document Remedy Effectiveness.]{.underline}

-   Before implementing any action, the Region should clearly establish
    baseline conditions that will be used to evaluate remedy
    effectiveness. The baseline data must be of sufficient quantity and
    quality to allow comparisons with data collected during and after
    cleanup to detect differences in risk that are not related just to
    natural variability. This should include crab and fish tissue
    concentrations. Baseline and long-term monitoring should also
    include measures of contaminant transport to Newark Bay.

    **Regional Response**

Please provide a written response to these recommendations within 60
days. If you have any questions or would like a clarification of any
these recommendations, please call Steve Ells at (703) 603-8822.

cc: George Pavlou, Region II

Ray Basso, Region II

James Woolford, OSRTI

Betsy Southerland, OSRTI

Doug Ammon, OSRTI

Victoria Van Roden, OSRTI

CSTAG Members

REFERENCES:

> Booij K, Hofmans HE, Fischer CV, Van Weerlee EM. 2003.
> Temperature-dependent uptake rates of non-polar organic compounds by
> semi-permeable membrane devices and low-density polyethylene
> membranes. *Environ. Sci. Technol.* 37:361-366.
>
> Bridges T, Ells S, Hayes D, Mount D, Nadeau S, Palermo M, Patmont C,
> Schroeder P. 2008. The Four Rs of Environmental Dredging:
> Resuspension, Release, Residual, and Risk. USACE, Environmental
> Research and Development Center, TR-08-4
>
> Louch J, Allen G, Erickson C, Wilson G, Schmedding D. 2003.
> Interpreting results from field deployments of semi-permeable membrane
> devices. *Environ. Sci. Technol*. 37:1202-1207.
>
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