Sediment Management Standards
Chapter 173-204 WAC
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Why do we need the Sediment Management Standards?
When contaminants enter the water, they often accumulate in the
sediment, especially for contaminants with low solubility. The
aquatic ecosystem is dependent on clean water and clean sediment to
maintain healthy and diverse populations. Sediment standards are
needed to protect the aquatic ecosystem, especially the animals that
live in the sediment or depend on sediment-dwelling organisms as a
food source. Sediment standards are also needed to protect people
who eat fish and shellfish from our state’s waters.
What are the Sediment Management Standards? What are they used for?
The Washington State Sediment Management Standards (SMS)
Chapter 173-204 WAC were developed to reduce and ultimately
eliminate adverse effects on biological resources and
significant threats to human health from surface sediment
contamination. The SMS are used to:
- Set standards for sediment quality (both numeric and narrative);
- Apply the standards to reduce pollutant discharges; and
- Provide a decision process for the cleanup of contaminated sediment sites.
The SMS rule has six sections:
- Part I: General Information. Includes administrative
- Part II: Definitions. These definitions apply to Parts I –VI of the rule,
unless a definition in Part V supersedes Part II definitions.
- Part III: Part III: Sediment Quality Standards (SQS).
This section has numeric chemical and biological benthic criteria for
marine sediments and narrative standards for the freshwater benthic community
and protection of human health. The SQS correspond to the long-term goals
for sediment quality in Washington State. Sediments at or below the SQS
criteria are expected to have no adverse effects on biological resources.
- Part IV: Sediment Source Control. This section includes a process
for managing sources of sediment contamination. This portion of the rule
includes a process for managing discharges (under the National Pollution
Discharge Elimination System, or NPDES) with the potential to impact sediment
and managing dredged material disposal activities.
- Part V: Sediment Cleanup Standards. This part of the rule is adopted
under the Model Toxics Control Act (MTCA) RCW 70.105D only. The goal of
the sediment cleanup decision process is to provide a framework for
timely decisions and expeditious cleanup of contaminated sediment sites.
- Part VI Sampling and Testing Plans/Recordkeeping. This part of the
rule includes requirements for sampling plans, reporting, and records.
What are the criteria in the Sediment Management Standards?
The SMS rule has a two tier decision framework
for managing sediment. This includes two levels
of criteria for protection of the benthic
community, human health, and higher trophic
level species such as fish
Benthic Community Criteria. For the benthic
criteria, the SMS contains two different levels of
criteria for marine and freshwater sediment, the
“no adverse effects” and “minor adverse effects”
- The no adverse effects level is defined as
impact to the benthic community, not to
individual benthic animals or species. The
no adverse effects level includes:
- The Sediment Quality Standards (SQS)
criteria in Part III of the rule, WAC 173-
- The Sediment Cleanup Objective
(SCO) criteria in Part V of the rule,
WAC 173-204-562 (Tables III and IV)
and 173-204-563 (Tables VI and VII).
- The minor adverse effects level is defined
as impact to the benthic community, not to
individual benthic animals or species. The
minor adverse effects level includes:
- The Sediment Impact Zone Maximum
(SIZMax) criteria in Part IV of the rule,
- The Cleanup Screening Level (CSL) in
Part V of the rule, WAC 173-204-562
(Tables III and IV) and 173-204-563
(Tables VI and VII).
For sediment in marine and low salinity
environments, there are benthic numeric criteria
for 47 chemicals or chemical groups and
narrative criteria for chemicals not on the list.
Some of the marine chemical criteria are based
on dry weight such as metals, while others are
normalized with the organic carbon content of
the sediment. The marine benthic numeric
criteria apply to Parts I – VI of the rule.
For sediment in freshwater environments, there
are benthic numeric criteria for 35 chemicals or
chemical groups and narrative criteria for
chemicals not on the list. These criteria are
based on dry weight. The freshwater benthic
numeric criteria apply to Part V of the rule.
There are also benthic biological criteria related
to acute and chronic effects for both marine and
freshwater sediment. These effects are
determined by laboratory toxicity tests or
benthic abundance tests as compared to
reference sediment sites. Both the chemical and
biological criteria are used to evaluate sediment
quality, but the results of the benthic biological
effects tests can override the benthic chemical
concentration results. For example, if the
sediment sample does not exceed the benthic
chemical criteria but the biological tests result in
an exceedance(s) of the benthic biological
criteria, then the sample would be considered an
exceedance of the benthic criteria.
Human Health Criteria. For protection of
human health, the SMS contain two different
levels of criteria for marine and freshwater
sediment for cleanup under Part V of the rule,
WAC 173-204-561. This includes:
- The SCO criteria which corresponds to a
risk level of one in one million (10-6) for
carcinogenic chemicals and a hazard
quotient of one for non carcinogenic
- The CSL which corresponds to a risk level
of one in one hundred thousand (10-5) for
carcinogenic chemicals and a hazard quotient of one
for non carcinogenic chemicals.
For Parts III and IV of the rule, the human health
criteria remain a narrative standard of “no significant
risk to human health’ and is determined on a case by
Higher Trophic Levels Criteria.
For the protection of higher trophic levels, the SMS
contains one level of criteria for marine and freshwater
sediment, the Sediment Cleanup Objective which is defined
as “no adverse effects” level in Part V of the rule,
What is the authority for the Sediment Management
The SMS has been adopted under different authorities
for different parts of the rule:
- Part V is adopted under the Model Toxics Control
Act RCW 70.105D.
- Parts I – IV and Part VI are adopted under the Model
Toxics Control Act RCW 70.105D and the Water Pollution
Control Act RCW 90.48 as well as other authorities.
What additional resources are there to learn about
sediment management and cleanup?
About the 2013 Revisions to the
Sediment Management Standards
Chapter 173-204 WAC
Why did Ecology revise the Sediment Management Standards in 2013?
To improve cleanup of contaminated sediments, Ecology addressed the following issues:
- Integrating requirements for cleanup of contaminated sediments specified in the SMS rule with requirements in the MTCA rule.
- Updating the SMS cleanup decision framework to address bioaccumulative chemicals to protect human and environmental health.
- Adopting chemical and biological benthic criteria for freshwater sediments.
- Clarifying requirements for coordinating cleanup actions and source control measures.
Why were rule changes needed?
Lack of clarity in the SMS rule led to delayed, unpredictable, and inconsistent cleanup decisions. The terminology processes and requirements in the SMS were difficult to reconcile with requirements in the MTCA law and rule. The amendments make the cleanup process more efficient and predictable.
The original SMS rule did not clearly address how to assess human health and ecological risk from chemicals that bioaccumulate in the food chain. The amendments to Part V of the rule add to the SMS decision framework a mechanism for setting standards to protect human health and the environment in both marine and freshwater sediment.
The original SMS included numeric chemical and biological criteria for marine sediments that are protective of the benthic community. The amendments include new chemical and biological criteria for freshwater sediments that are protective of the benthic community.
In the original rule, source control requirements to prevent sediment recontamination following cleanup were difficult to implement. The amendments clarify requirements for coordinating cleanup actions and source control requirements. This will help prevent recontamination and make the requirements for cleanup actions implementable.
What parts of the SMS rule were amended??
As stated at the beginning of this document, the SMS rule consists of six sections, each with a different purpose. The amendments focus on Part V, and address cleanup issues only.
- Integrate the procedural cleanup requirements in the SMS to be consistent with MTCA where appropriate. This includes amending terminology and clarifying remedial investigation and remedy selection requirements.
- Update the cleanup decision framework to address bioaccumulative and other chemicals that pose risks to human health and the environment. The amendments clarify methods and policies for establishing risk-based cleanup standards, establish procedures for incorporating background concentrations, and integrate the requirements in the MTCA and SMS rules for sediment cleanup actions to make cleanup more efficient.
- Clarify existing requirements for coordinating cleanup actions and sourcecontrol measures. This clarification was necessary to prevent recontamination following cleanup.
- Add chemical and biological benthic criteria for cleanup of freshwater sediments. The decision-making framework (a cleanup screening level based on minor adverse effects and a sediment cleanup objective based on no adverse effects) is consistent with the marine sediment framework.
When does the amended rule go into effect?
The rule was adopted on February 22, 2013 and becomes effective on September 1, 2013.
How do the amendments address protecting human health from bioaccumulative and other chemicals?
The widespread presence of ubiquitous bioaccumulative chemicals complicates sediment cleanup decisions. Since 2009, the Toxics Cleanup Program engaged in considerable public dialog related to this issue. The amendments incorporate risk-based and background concentrations into the existing SMS “two-tiered” decision framework.
What is the “two-tiered” framework?
The two-tiered framework allows sediment cleanup levels to be set between the sediment cleanup objective (a low concentration that is the long-term sediment quality goal) and the cleanup screening level (a higher concentration that provides an upper bound to the cleanup standard).
Originally the SMS rule allowed the cleanup level to be set between two tiers based on (a) cleanup costs, (b) technical feasibility, and (c) net environmental benefit.
In the amended rule, the cleanup level is set between these two tiers based on (a) technical possibility, and (b) net adverse environmental impacts. However, cleanup costs are still considered in the remedy selection process, consistent with MTCA.
Did Ecology consider the potential increased costs associated with these rule amendments?
Ecology developed a cost-benefit analysis that was open for public comment. Based on this analysis, Ecology determined that:
- The overall cleanup costs will be similar to the original requirements. Original requirements were that cleanups comply with both the SMS and MTCA rules. In some situations cleanup costs may decrease.
- The costs to National Pollutant Discharge Elimination System (NPDES) permitted dischargers that are potentially liable persons may increase due to additional monitoring and analytical requirements necessary to ensure that sediments are not recontaminated.
- The costs to NPDES permitted dischargers (this includes municipal and industrial stormwater and wastewater dischargers) are uncertain and will depend on how Ecology enforces NPDES permits and Total Maximum Daily Load allocations.
To see the cost-benefit analysis please go to:
Were fish consumption rates included in the rule amendments?
No. Until July 2012, Ecology planned to include a default fish consumption rate for calculating sediment cleanup levels to protect human health. However, in order to allow more time to discuss implications to water quality standards, Ecology elected not to include a default fish consumption rate in the SMS. Instead, the rule amendments include a narrative that requires cleanup levels to be based on a Reasonable Maximum Exposure (RME) and that the default RME is a tribal exposure scenario.
What other important issues were addressed in this rulemaking?
The original rule included benthic numeric criteria for marine sediments, but not for freshwater sediments. The amendments include chemical and biological cleanup criteria protective of the freshwater benthic community. The decision-making framework (a cleanup screening level based on minor adverse effects and a sediment cleanup objective based on no adverse effects) is consistent with the existing marine sediment framework.
Is Ecology preparing guidance to assist people involved in sediment cleanup?
Yes. In September 2012, Ecology posted draft guidance to the website so that reviewers of the proposed rule would be informed about how the proposed rule would be implemented. Ecology is now working to revise the guidance document and plans to provide opportunity for interested parties to review the document before it is finalized.
What kind of advisory group process did Ecology use in developing the rule amendments?
Three different advisory groups provided early input and feedback on rule-making issues, including review of early preliminary draft rule language.
Sediment Workgroup. This group consisted of eight scientists and technical experts who specialize in sediment management and cleanup. It included tribal, local, and federal government representatives; ports; and environmental consultants. The group met eight times between December 2009 and December 2010.
Meetings were open to the public and meeting materials and notes are posted on the Ecology website.
MTCA/SMS Advisory Group. This group consisted of 17 members having a broad range of interests and affiliations.
It included representatives from tribes; state, local, and federal governments; regulated entities (including liable parties and dischargers);
environmental groups; and environmental consultants. This group was formed before the Governor issued Executive Order 10-06, and included
discussion of both MTCA and SMS cleanup-related technical and policy issues. The group met eight times between December 2009 and December 2010.
Meetings were open to the public and meeting materials and notes are posted on the Ecology website.
Sediment Cleanup Advisory Committee. This 26-member committee was formed to specifically address SMS amendments and provide feedback on preliminary draft rule language. This committee included members from the advisory groups mentioned above plus additional members from industry; ports, federal, state, and local governments; tribes; environmental groups; and environmental consultants. This committee met three times from October 2011 through December 2011.
Meetings were open to the public and meeting materials and notes are posted on the Ecology website. http://www.ecy.wa.gov/programs/tcp/regs/2011-SMS/adv-comm/ac-mtg-info.html
Ecology presented the key issues, the proposed SMS rule framework, and preliminary draft rule language to the committees and asked members for input and feedback on:
- Creating the decision framework for addressing protection of human health and the environment when establishing sediment cleanup levels for bioaccumulative chemicals that includes background concentrations.
- The relationship between cleanup and source control issues.
- Issues related to resolving liability for sediment cleanup units located within larger bay-wide sites.
- The relationship to agency-wide regional source reduction initiatives.
- Freshwater sediment standards for protection of the benthic community.
The committee reviewed preliminary rule proposals and discussed implementation using case studies as examples.
How have tribes provided input on this process?
Ecology understands the importance of these issues to tribes and acknowledges the considerable input provided by tribes and tribal representatives on many of the technical and policy issues. Representatives from several tribes participated in the three different advisory groups, and Ecology held additional meetings with tribal representatives during this process. Ecology honors our Government-to-Government relationships and will continue looking for opportunities to work together.
Did Ecology submit the amended SMS rule to EPA for approval?
Ecology has concluded that Part V of the SMS rule does not require EPA review under the Clean Water Act. Part V, Sediment Cleanup Standards, has been adopted solely under the Model Toxics Control Act RCW 70.105D which provides statutory authority for cleanup-related decisions and will not be used for federal Clean Water Act purposes. Parts I – IV of the amended SMS rule were submitted to the EPA for review and approval as they are considered federally approved water quality standards.
Ecology is also updating the Surface Water Quality Standards: what is the relationship between these various efforts?
Ecology is working on two rules for the Water Quality Standards for Surface Waters of the State of Washington, Chapter 173-201A WAC:
- Establishing new human health criteria. Washington’s surface water quality standards currently lack human health criteria, so Ecology is required to operate under the federal criteria established in EPA’s 1992 National Toxics Rule. These federal criteria are out-of-date. EPA requested that Washington use new science and information to adopt updated human health criteria into our state’s surface water quality standards.
- Providing new implementation and compliance tools for dischargers. Ecology recognizes the need to modernize the compliance and implementation tools available for dischargers and has begun a process to create advanced regulatory tools.
For information on how these efforts fit together see: http://www.ecy.wa.gov/toxics/fish.html
Ecology recently published a Technical Support Document to assist in establishing a clear understanding of Washington fish consumption data. Although cleanup standards and water quality standards both include fish consumption rates when addressing human heath, the requirements are based on different statutes and include different considerations.
Will amendments to the SMS rule affect permitted dischargers?
The SMS rule amendments will not substantially change the conditions in existing discharge permits. The SMS rule amendments apply to cleanup sites and cleanup decisions. Part V, Sediment Cleanup Standards, is the focus of the rule revisions. Part IV, which includes requirements for NPDES permitted dischargers, has not been substantively amended.
Potentially liable persons for site cleanup will need to ensure that discharges under their control do not cause recontamination. Other permitted discharges will not be significantly affected at this time, and Ecology currently does not have plans to address these dischargers outside the TMDL and current NPDES enforcement process.
How did the public submit comments on the amendments to the SMS rule?
What additional resources are there to learn about the SMS rule?