Site-Specific Copper
Criteria Development for Pearl Harbor Naval Shipyard
 In
December 2001, the Environmental Office (Code 106.3) at the
Pearl Harbor Naval Shipyard and Intermediate Maintenance
Facility (PHNSY & IMF, Shipyard) contacted the Environmental
Sciences Branch at SSC Pacific requesting technical assistance
with
potential
compliance issues related to the State of Hawaii’s
issuance of a new National Pollution Discharge Elimination
System (NPDES) permit for the discharge of shipyard effluents
into Pearl Harbor--in particular, the discharge limit for
copper. The Shipyard determined the proposed limit was unattainable
and presented a potential compliance issue. With support from
the SSC Pacific scientists,
the Shipyard executed a comprehensive study to support a scientifically-based
derivation of their discharge limit for copper adhering to
United States Environmental Protection Agency (USEPA) guidance.
The Shipyard was granted an interim permit limit for copper
by the State of Hawaii while the comprehensive
study was being completed.
Technical Approach
The technical approach executed by SSC Pacific Environmental
Sciences Branch
scientists consisted of the following elements
to specifically address
copper contamination
and regulation at the Shipyard:
- Pollution pathway analysis and detailed characterization
of Shipyard discharges for dissolved and total copper,
using appropriate trace metal clean methods;
- Development and implementation of an improved Best
Management Practices (BMP) Program to target cost-effective
means
to significantly reduce copper loads from the Shipyard;
- Performing USEPA-recommended studies to derive site-specific
water quality objectives for copper including a Recalculation
Procedure and a Water Effect Ratio (WER);
- Develop a chemical translator to derive a site-specific
formula for converting between dissolved and total recoverable
metals for copper; and
- Provide a scientific basis for the assignation of a mixing
zone where appropriate.
Discharge Characterization
The complex industrial setting at Navy shipyards and the
assortment of water sources used within them is evident in
the variability of metal concentrations and mass loads in the
effluents. At the PHNSY & IMF, this variability is exacerbated
by temporal fluctuations of the input water sources, weather
patterns
and contributions from five major streams into the Pearl Harbor
estuary. Identifying the industrial operations and processes
that contribute copper to the discharge requires an up-stream
evaluation of the individual components of the NPDES discharge.
The copper loading in effluents from the Shipyard was shown
to
be heavily influenced by the resuspension of particles from
dry
dock surfaces
during
rain events during this study.
Of the five discharge sources identified in the Shipyard,
non-contact cooling water was a constant source of copper to
the NPDES sampling point (effluent) and was responsible for
the majority of daily loading to the effluent. Mass balance calculations
substantiated the predominance of loading associated with non-contact
cooling water in dry conditions and rain runoff in wet conditions
as the major sources of copper loading in the effluent. In addition
to evaluating the discharge, the receiving water was also evaluated
for any impacts. Elevated copper levels were not observed at
any station in Pearl Harbor as a result of the current
copper loadings into the estuary.
Best Management Practices
As with
most
Naval facilities, effective BMPs at the Shipyard are already
being implemented in comprehensive pollution prevention (P2)
programs such as material substitutions, secondary containment
and cleanup procedures with the specific goal of reducing
contaminant contributions to the Shipyard effluents. Since
particulate matter was identified by this study as the most
significant contributor to the high copper
load in the effluent, additional efforts at the Shipyard
are focused on effective drydock cleaning methods as well
as more frequent cleaning during operations.
Copper Recalculation
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SSC Pacific scientist using clean sampling techniques
in Pearl Harbor. |
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The USEPA has established methods for a permittee to recalculate
the National Recommended Water Quality Criteria (WQC) to render
them more representative of species occurring at a specific
site and
still meet
environmental protection goals.
For Pearl Harbor, the procedure used a more comprehensive toxicity
data set than the USEPA data and involved one correction, three
additions, and two deletions to that data set. This effort resulted
in a recalculation of the WQC which yielded revised
acute and chronic criteria for dissolved
copper for Pearl Harbor that would still provide the level
of protection intended by the USEPA. These results
were then used to determine a new NPDES permit limit
in accordance with USEPA guidance.
Water Effect Ratio
SSC Pacific scientists conducted a Water Effect Ratio (WER
) study using embryos of sensitive marine invertebrates
as a means of deriving a site-specific WQC for
copper for Pearl Harbor. The investigation involved
extensive toxicity
testing associated with four sampling events
at eight different locations throughout the harbor from March
2005 through May 2006. The study involved embryo-larval development
success for mussels
(Mytilus galloprovincialis), oysters (Crassostrea
gigas), and sea urchins (Strongylocentrotus purpuratus).
The results of this study indicated that Pearl Harbor waters
provide significant protection to aquatic
species
relative
to the baseline laboratory toxicity tests utilized for the
development of the State and National standards.
Copper Translator
SSC Pacific scientists examined
the partitioning of copper in mixtures of discharge effluent
and
ambient receiving
water
during seven
separate
sampling events. Factors that were critical to the success
of the field design included the parameters for measurement,
location of the sampling stations, sampling schedule, number
of samples collected, use of appropriate clean sampling techniques,
data analysis and translator calculation. The results of this
effort were applied to the permit calculation process to convert
the permit
limit into total recoverable copper in accordance with USEPA
guidance.
Application of a Mixing Zone
The Shipyard has an occasional need to use large volumes
of cooling water to support commercial ship industrial operations
conducted by a contractor during
private/public ventures. As a result, the discharge into the surrounding
water during those operations can be above the regulatory limit
of 1 degree from
ambient. To enable the occasional release of higher temperature water during
these operations, the Shipyard submitted an application for a thermal mixing
zone, which included a comprehensive CORMIX modeling effort by Environmental
Sciences Branch scientists to evaluate the potential ecological
effects and attenuation
of the thermal plume and to define
a thermal mixing zone.
The Final Result
As a result of these comprehensive efforts (requiring the
active
involvement of the Pearl Harbor Naval Shipyard and Intermediate
Maintenance
Facility,
the State of Hawaii Department of Health, and SSC Pacific
Environmental Sciences Branch
scientists) the Shipyard has been issued
an
NPDES permit
that does not impair its ability to
support critical ship and submarine maintenance activities
while remaining protective of the environment.
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An NPDES-permitted discharge at the
Pearl Harbor Naval Shipyard. |
Capabilities (direct support):
Applications:
- NPDES permitting
- Water quality sampling and evaluation
- Ecological evaluation
More Information:
- Earley, P.J., G. Rosen, I. Rivera-Duarte, R.D. Gauthier,
Y.M. Arias-Thode, J. Thompson, and B. Swope. 2007. A Comprehensive
Copper Compliance Strategy: Implementing Regulatory Guidance
at Pearl Harbor Naval Shipyard & Intermediate Maintenance
Facility. Technical Report 1952. SSC Pacific, CA. 93 pp.
+ appendices. [8.02
MB PDF file]
- "Keeping it Clean in Pearl Harbor", Currents,
Fall 2008. [600
KB PDF file]
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