Summary of Discussions During the Interactive Short Course on
"Use of Sediment Quality Guidelines in the Assessment And Management of Contaminated
Sediments." Presented before the 18th Annual Meeting of the Society of
Environmental Toxicology and Chemistry (SETAC) in San Francisco, CA on November 16, 1997
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Discussion of the Dredge Material Management Work Group
Discussion of the Remediation Work Group
Discussion of the Sediment Management Work Group
Table 1: Selection of SQGs for Assessing Sediment Quality
Table 2: Evaluation of Risk Associated with Contaminated Sediment
Table 3: Options for Management of Contaminated Sediments
Figure 1: Preliminary Identification of Issues and Concerns
Figure 2: Framework for Assessing and Managing Sediments Using Existing Data
Figure 3: Framework for Assessing and Managing Sediments with Limited Data
Figure 4: Bar Graphs Summarizing Keypad Polling Responses
(large file, contains many graphics)
Attachment A: List of Instructors for the Short Course
Attachment B: List of Participants in the Short Course
Attachment C: Agenda for Interactive Short Course
Attachment D: Keypad Polling Questions
Attachment E: Case Study for Sediment Remediation Work Group
This summary was developed by the short course instructors listed in Attachment A and distributed to the short course participants listed in Attachment B. The information presented in this summary in does not necessarily represent the perspectives of the organizations of the instructors listed in Attachment A or the perspectives of the organizations of the course participants listed in Attachment B. The opinions and ideas expressed in this summary do not reflect the views and opinions of SETAC. The instructors of the course have developed an article for SETAC NEWS and an article for the USEPA Contaminated Sediment News which highlight conclusions on appropriate and inappropriate uses of sediment quality guidelines (SQGs) for assessing and managing sediments as discussed during the course.
A 1-d short course was held to describe various approaches used to develop
SQGs and to discuss the applications of SQGs in sediment quality assessment and
management. The course was attended by 80 individuals representing a broad range in
backgrounds and expertise. The course consisted of both Plenary and Work Group sessions.
The opening plenary session provided participants with information on the derivation,
strengths, limitations, and uses of numerical SQGs. An integrated framework for assessing
sediment quality conditions and several case studies were presented to illustrate the
applications of SQGs. The Work Group sessions gave course participants an opportunity to
discuss several important applications of the SQGs, including dredged material disposal
analysis, sediment management, and sediment remediation. During the final plenary session,
the main points of the Work Group discussions were presented to the entire group. In
addition, the participants were given the opportunity to express their views on the
applications of SQGs through keypad polling and panel discussions.
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1.0 INTRODUCTION
A one-day course was held dealing with the use of sediment quality
guidelines (SQGs) in the assessment of sediment contamination. The course was attended by
80 individuals representing a broad range in backgrounds and expertise (Sections 2.1 and
Attachment B). The goal of the course was to describe approaches used to develop SQGs and
discuss various applications of these SQGs in assessing and managing contaminated
sediments. The objectives of the course were to:
The agenda for the course is outlined in Attachment C. Presentations and discussions
were directed toward both experienced and inexperienced users of SQGs. In the morning
session, the approaches discussed included: (1) Equilibrium Partitioning (EqP); (2)
Apparent Effects Threshold (AET); (3) Effect Range Low (ERL) and Median (ERM), Threshold
Effect Level (TEL) and Probable Effect Level (PEL); and (4) Logistic Modeling. Instructors
discussed the intent, derivation, reliability, predictive ability, and recommended uses of
SQGs, including how each approach can be used in a combined weight-of-evidence assessment
of sediment quality conditions.
Case studies then were used to illustrate three specific applications of SQGs. These
case studies were intended to support discussions during the afternoon Work Group sessions
which dealt with: (1) dredging (Section 2.2); (2) remediation (Section 2.3); and (3)
management (Section 2.4). Flow charts, which provided specific guidance on the use of SQGs
in assessing and managing contaminated sediments, were also discussed (Figures 1 to 3 and
Tables 1 to 3). In the afternoon session, course participants were divided into the three
Work Groups (dredging, remediation, or management) to discuss appropriate applications of
SQGs for these topic area. The Work Groups then came together and summarized discussions.
Keypad polling devices were used to tally responses of course participants to a series of
questions, which was followed by panel discussions of these responses (Sections 2.1, 2.5
and Attachment D; Figures 4.1 to 4.14).
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2.0 SUMMARY OF KEYPAD
POLLING AND WORK GROUP DISCUSSIONS
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2.1 Morning Polling Session
Based on the results of the initial keypad polling session (which included input from
instructors and students), the majority of the course participants were affiliated with
either government organizations (38%) or consulting firms (32%; Figure 4.1, Attachment B).
Occupations of participants were fairly evenly distributed among the categories of
biologist, toxicologist, consultant, environmental manager, and risk assessor (10 to 19
individuals in each group), with fewer students and chemists (2 to 5 individuals in each
group; Figure 4.2). Information on their backgrounds and interests was used to assign
course participants to the afternoon Work Group discussions (either dredging, remediation,
or management; Attachment B).
Participants had a wide range in years of experience in working with sediments, with
the highest number of individuals having 3 to 6 years of experience (Figure 4.3). A
similar number of participants have applied SQGs to assess either freshwater, marine, or
estuarine sediments; only 11% of the participants indicated that they have not used SQGs
(Figure 4.4). ERLs and ERMs have been used by the participants more frequently than other
SQGs listed in Figure 4.5. SQGs have most often been used by the participants to identify
chemicals, samples, or sites of potential concern (Figures 4.6.1 and 4.6.2). Only about
35% of the participants frequently or very frequently used SQGs to evaluate monitoring
data (Figure 4.6.4) or to conduct ecological risk assessments (Figure 4.6.5). Similarly, a
small percentage of the participants have frequently or very frequently used SQGs to
evaluate dredge material (23%, Figure 4.6.3), conduct damage assessments (9%, Figure
4.6.6), or establish clean-up objectives (14%, Figure 4.6.7).
Most of the participants felt that SQGs were applicable to their work (Figure 4.7.1)
and that lack of familiarity with the methods did not limit their use of SQGs (Figure
4.7.2). Similarly, not having SQGs applicable to a geographic region typically has had
little or no influence on the use SQGs by the participants (Figure 4.7.7). However, the
following factors have limited the use of SQGs by a substantial number of course
participants:
(1) uncertainty regarding which SQG to use (Figure 4.7.3);
(2) uncertainty regarding predictability of SQGs (Figure 4.7.4);
(3) lack of SQGs for chemicals of concern (Figure 4.7.5);
(4) lack of SQGs for bioaccumulation (Figure 4.7.6);
(5) difficulty in dealing with complex mixtures (Figure 4.7.8);
(6) cause and effect relationship not established (Figure 4.7.9); and
(7) bioavailability is not established (Figure 4.7.10).
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2.2 Discussions of the
Dredge Material Management Work Group
The goal of the Dredging Work Group discussions was to look more closely at some of the
issues involving the use of SQGs in dredging. The Work Group was divided into two Breakout
Groups. Four issues were highlighted for discussion during the dredging Work Group
sessions:
In order to promote discussion on these four issues, a case study was prepared for each
task. The discussion and conclusions relative to each issue are summarized below.
Issue 1: Defining "background" conditions. What are the
regulatory options when background exceeds SQGs?
Summary of Discussion:
Conclusions for Issue 1: The participants felt that biological testing was not
necessary for sediments with contaminant concentrations below background levels. The
majority of the participants had more confidence in the "background" concept for
metals, than they did for organic compounds. It was felt that it is often much more
difficult to distinguish between post-industrial anthropogenic organics and pre-industrial
non-anthropogenic organics, than it is to distinguish between crustal metals (or
pre-industrial metals) and anthropogenic metals.
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Issue 2: Use of chemical SQGs in conjunction with biological
information. What are the regulatory options when chemical and biological data conflict?
Summary of Discussion:
Conclusions for Issue 2: Neither chemistry nor biological effects data sets always
provide the "right" answer. Regulators need to understand the
chemical/biological systems involved and use a weight-of-evidence approach to
decision-making.
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Issue 3. Use of SQG values to make regulatory decisions. Can SQGs
be used as pass/fail guidelines or only for screening?
Summary of Discussion:
Conclusions for Issue 3: SQGs are best used to help focus a study, but cannot generally
be used as pass/fail criteria.
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Issue 4: Normalization of SQGs. What parameters should be used to
normalized SQGs?
Summary of Discussion:
Conclusions for Issue 4: There remain some serious concerns about normalizing sample
results to SEM and AVS including: (1) Oxidation of sediments during sample handling and/or
dredging and disposal activities may change results relative to in situ
conditions and possibly alter suitability decisions; (2) AVS:SEM may not consider
appropriate exposure routes; (3) AVS:SEM normalization does not consider bioaccumulative
effects; (4) There are other means of normalizing (e.g., grain size, total organic carbon,
which may be useful or more predictive); and (5) Differences between AVS:SEM at the
dredging site and disposal site may limit applicability of normalization.
Overall Conclusions from the Dredged Material Management Work Group: It was the feeling
of the group that although SQGs are an important tool in dredging decisions, even properly
normalized SQGs which incorporate background information cannot be used alone to make
pass-fail decisions. Except in very rare cases, other types of data need also be
considered in decision making.
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2.3 Discussions of the Remediation
Work Group
The goal of the Remediation Work Group discussions was to evaluate the hypothetical
remediation scenario outlined in Attachment E. Three Breakout Groups discussed a number of
questions relating to how SQGs could be used to remediate a marine boat slip contaminated
with mercury, copper, zinc, and PCBs. It was assumed that national guidelines existed for
these contaminants of concern. A common theme to the discussion was the importance of
using a weight-of-evidence approach to complement existing national SQGs, as well as to
develop site-specific cleanup objectives.
Information. Each Breakout Group came up with a similar list of information that
would be needed to develop cleanup objectives for the protection of aquatic organisms.
Information needs included: sediment chemistry, sediment toxicity (acute, chronic, and
bioaccumulation endpoints), benthic community assessments, chemical bioavailability data
(AVS, TOC), physical variables (grain size, etc.), spatial extent of contamination at
depth, and hydrodynamic and sediment transport information (to determine
deposition/erosion patterns and deposition rates). Breakout Groups 2 and 3 also considered
current and future uses of the site, and Breakout Groups 1 and 2 discussed the need for an
appropriate reference site. Breakout Group 3 also wanted fish tissue data to assist in
determining human health and ecological risks.
Level of protectiveness. In order to determine the level of protectiveness at a
site, Breakout Groups 2 and 3 first discussed the need to determine the appropriate
ecological receptor and endpoints to be considered (human health issues were also of
concern to Breakout Group 3). Breakout Group 3 developed their own sub-scenario of three
contaminated sites distributed among seven sampling sites to further discussion on this
topic; this group discussed the site-specific technical parameters and the ensuing policy
applications of various options to address the questions posed for this scenario. Breakout
Group 3 also discussed tying the uncertainty inherent in various remediation options to
cost consideration when determining the level of protectiveness.
Breakout Groups 1 and 2 addressed the questions for this scenario as follows.
Participants felt a range of SQGs should be used in preliminary assessments, and possibly
one value should be used for the cleanup objective. When multiple guidelines are
available, Breakout Group 1 had a general preference for using a weight-of-evidence
approach and best professional judgment. Breakout Group 2 also considered that multiple
SQGs should be considered within the existing government agency framework, and that
national/regional guidelines could be used if they were developed at sites with similar
characteristics (e.g., marine versus freshwater sites). In terms of defining a maximum
allowable level, Breakout Group 1 felt this would require a lot of information and was not
important to consider. Breakout Group 2 thought it would be possible to define a maximum
allowable level by considering: action levels versus cleanup levels, highest AET values,
and site-specific numbers for lower uncertainty. Participants in Breakout Groups 1 and 2
felt uncertainty of SQG values could be reduced by collecting more site-specific data.
National, regional, and site specific SQGs. The Breakout Groups discussed the
advantages and disadvantages of using national, regional, or site-specific SQGs to address
remediation questions. Some participants in Breakout Group 1 objected to the concept of
site-specific SQGs, preferring site-specific cleanup levels based on weight-of-evidence.
In general, participants felt national SQGs were useful for screening level purposes and
that site-specific cleanup objectives were more useful for basing remediation decisions.
Breakout Group 3 expressed the need for a methodology to be developed for deriving
site-specific guidelines if no national guidelines were available. Some of the
advantages/disadvantages of national and regional SQGs, as expressed by Breakout Groups 1
and 2, are as follows:
Breakout Group 2 listed the following advantages/disadvantages of site-specific SQGs:
Application of site-specific data. Participants felt a weight-of-evidence
approach was needed in order to make remediation decisions. Breakout Group 1 thought that
site-specific sediment chemistry data alone could be used if the concentrations were so
high that there was no question about the need for remediation. Otherwise, a variety of
sediment toxicity tests (acute, chronic, bioaccumulation) and benthic community surveys
should be used to complement sediment chemistry data. Participants in Breakout Group 1
placed more weight on collecting good benthic community data, although problems with
factoring out physical effects and locating a suitable reference site were recognized.
Participants in Breakout Group 2 also discussed whether toxicity data should over-ride
chemistry data under certain situations. If insufficient site data are available,
participants in Breakout Groups 1 and 2 suggested collecting more data. Otherwise, more
conservative estimates could be used.
Bioaccumulation. Participants felt procedures need to be developed to derive
bioaccumulative SQGs for mercury, PCBs, and other bioaccumulative contaminants. Breakout
Group 3 also discussed the uses and applicability of Biota-Sediment-Accumulation-Factor
calculations.
Other issues. Breakout Group 3 discussed the following additional topics during
their meeting. In terms of how to address chemical mixtures with SQGs, the participants
felt mixture-specific SQGs for PAHs need to be developed rather than for individual
compounds. Thus, site-specific or regional SQGs would be more useful for mixture-specific
SQGs than national SQGs. The need to design cleanups around biological, and not chemical
data, was discussed. In addition, the possibility of using correlative analyses for very
large sites to obtain appropriate remediation guidelines was put forth. Finally, the
participants felt sediment guidelines are not transferable from marine to freshwater
systems as a result of various differences between species and chemistry. The participants
also felt there may be greater variability between freshwater sites than between marine
sites.
Overall Conclusions from the Remediation Work Group: A hypothetical scenario was used to guide the Breakout Groups discussions on how SQGs could be used to remediate a contaminated boat slip. Issues associated with determining information needs, level of protectiveness, use of SQGs (national, regional, and site-specific), application of site-specific data, and bioaccumulation issues were discussed. In general, the Breakout Groups recognized the importance of using a weight-of-evidence approach to develop site-specific cleanup objectives. Although national or regional SQGs would be useful for a screening-level assessment, participants felt that site-specific sediment toxicity, chemistry, and benthological data are needed to make remediation decisions. Participants also felt data gaps should be filled with actual field data; otherwise, conservative assumptions and estimates would need to be made. Finally, participants suggested SQGs need to be developed for bioaccumulative contaminants and for chemical mixtures such as PAHs.
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2.4 Discussions of the
Sediment Management Work Group
The goal of the Sediment Management Work Group was to identify how SQGs could be used
to identify chemicals and sites of potential concern. The discussion focused on proper
uses of SQGs, peer-acceptance of the use of SQGs, weaknesses of SQGs, and applicability of
SQGs in effects research, waste site risk assessments, discharge permit writing, and
prioritization of both chemicals and sites.
Breakout Group 1 discussions:
1. Participants in Breakout Group 1 expressed concerns and frustration regarding
applications of SQGs. Uses of SQGs often were dependent upon the specific political
situations and because there is no universally-applicable guidance on the uses of SQGs,
controversies arise on interpretation of SQGs. Also, clean-up actions sometimes are set at
levels that do not necessarily correspond to a lack of toxicity or non-exceedances of
guidelines; thus, resulting in implementation of biological tests regardless of chemical
levels. Although SQGs are useful in the interpretation of chemistry data, some
participants felt that SQGs do not account for bioaccumulative endpoints or ecosystem
level effects. Some users have encountered problems with the public perception of the
significance of concentrations that exceed SQGs, over-interpreting what these exceedances
mean. SQGs seem to error on the conservative side; however, several participants thought
SQGs were useful tools for deciding which areas need further toxicity testing. SQGs are
often used in a tiered testing scheme and can be useful in saving money. Some participants
saw the benefits in using SQGs, knowing they were reasonably predictive of toxicity, thus
alleviating the need for ecological testing which is expensive.
2. Participants felt SQGs can be used to establish single-value, "bright
lines" to aid in data interpretations. Participants felt many SQGs were protective,
rarely showing false negatives. Because SQGs are available for many substances and are
based upon measures of effects, they are widely applicable. It is a benefit to know the
probabilities that SQGs predict toxicity. However, it is understood by many that some SQGs
require normalization to TOC or AVS concentrations.
3. Participants felt SQGs can be used for classifying hot spots in risk assessments and
preparation of plans for site remediation. SQGs are useful in making decisions regarding
the need for toxicity testing, in weighing the relative magnitude of exceedances of SQGs,
and in comparing the numbers of chemicals that exceed SQGs among sites. SQGs are best used
when accompanied by other data (e.g., measures of effects, transport processes,
bioaccumulation).
4. Participants felt SQGs could be useful in writing NPDES permits and source controls.
The SQGs could also be useful in decisions regarding source controls; however, for these
applications SQGs need to be highly defensible, based upon dose/response data, and
established cause/effects relationships. Participants also felt there is a continuing need
to have SQGs based upon measures of reproductive failure, such as measures of endocrine
disruption.
Breakout Group 2 discussions:
1. Participants in Breakout Group 2 have used SQGs in designing research projects, in
establishing testable hypotheses as regards toxicity thresholds, and in designing spiked
sediment toxicity tests. Participants had experience in using SQGs to identify hot spots,
to modify or set source controls, to focus and plan site remediation, to evaluate dredge
materials, to plan discharge compliance monitoring, to set screening values for ecological
risk assessments, to define the extent and spatial scales of problem areas, and to
identify chemicals and sites of concern. Participants felt SQGs were useful in
identification of concordance between chemical data and measures of effects in field
surveys, in the interpretation of data from regional monitoring and survey assessments, as
perspective in the interpretation of chemical data, as screening tools for specific sites,
as screening tools for the need for further testing, as aids in monitoring power plant
discharges. Participants also felt SQGs can be used to help understand the relationship
between environmental chemistry and industrial waste discharges and the fate and effects
of industrial materials. SQGs are particularly useful when based upon measures of effects,
such as toxicity.
2. Participants expressed concern regarding the relatively poor performance of
empirically-derived SQGs for hydrophobic substances, the meaning or significance of a
chemical exceeding an SQG, and the confusion that stems from how to deal with the
multitude of SQGs. Many users have a poor understanding of how SQGs are derived, and
therefore, encounter frustrations in dealing with upper-level managers who have even less
understanding of the significance of SQGs. Often, published numbers, regardless of their
credibility, take on a life of their own as ostensible criteria or standards. There has
been little guidance or communication on the proper uses of SQGs. It is not clear that
data from interested industries were used in the derivation of SQGs. There is no statutory
scheme or framework for decisions regarding the selection of SQGs. The toxicological and
ecological consequences of sediment quality remediation to levels below SQGs are not
known. Participants felt there is a disconnect between the toxicity endpoints used to
establish the SQGs and the biological endpoints the SQGs should protect. It is not clear
to some of the participants that SQGs have been developed for different biological
receptors such as wildlife and human populations. Thus, these SQGs are not
interchangeable, and SQGs need to be considered for the most sensitive population in the
exposure area. SQGs are best used when accompanied by data for the dissolved/toxic
fraction of sediments and comparable chemistry and toxicity data from reference areas.
3. Participants felt SQGs can be used to rank chemicals and sites at a relatively low
or high priority, especially when accompanied by other information to form a weight of
evidence. Sites in which many substances exceed SQGs by considerable amounts should be
given first priority for clean-up actions. However, since there are no a priori
criteria for ranking sites and chemicals, most of the participants were reluctant to
identify sites as "walk away" clean based on SQGs alone. Also, users should
compare low SQG values with local, applicable reference conditions. An iterative, or
step-wise process is often needed to rank sites.
4. Participants felt SQGs should be derived with the best available science and data.
SQGs are needed for dealing with mixtures of substances and confounding factors. However,
some participants felt the economics of the applications of SQGs should be considered in
their derivation and that only causality-based SQGs are worthwhile. Most participants felt
that strong peer-reviewed derivation processes of SQGs were needed and that field
validation was also necessary. Derivation of approaches for calculation of toxicity
equivalents are needed. Better communication is also needed to the regulated and
regulatory communities on how SQGs are to be used.
5. Breakout Group 2 concluded that if a site and/or chemical might be a problem or has
a high likelihood of being a problem, it is important to understand: how to prioritize the
site and chemical; how to establish a clean-up standard for remediation; how much sediment
needs to be removed or disposed of; and what source controls are needed to improve
sediment quality.
Overall conclusions: The Sediment Management Work Group concluded that for use in
focusing additional investigations and risk assessments; SQGs need to: (1) provide a
bright line or single value for screening; (2) be protective; (3) be based upon
relationships to biota and ecosystem health, more than just the probabilities of toxicity;
and (4) be available for more chemicals than are now available. Additionally, for all uses
of SQGs: (1) there currently is a lack of consensus and lack of available guidance on
which SQGs to use and how; (2) there is no procedure to address the additivity of chemical
mixtures; (3) there is a poor understanding by regulatory agencies on what guidelines
mean; (4) there remains a disconnect between biological endpoints and protection of human
and wildlife health; and (5) there remains concern over the ecological relevance of SQGs.
Despite these reservations about SQGs, the participants in the Sediment Management Work Group felt SQGs were successful in identification of high priority waste sites, in regional compliance monitoring, and in risk assessments. The two most serious deficiencies were the lack of national criteria and the tendency of currently-available SQGs to take on the appearance of criteria. Areas in which improvements are needed include: (1) consideration of the economics of the uses of SQGs; (2) emphasis on causality in SQG derivations; (3) better communication on the applicability of SQGs; (4) the differential toxicity of chemicals in mixtures and the possible additivity of chemicals in mixtures; (5) the need to account for the presence of confounding factors in sediments; (6) the need for further field validation of how well SQGs actually perform in real sediments; (7) better quality control in selecting data sets used to generate SQGs; (8) increase the list of chemical SQGs; and (9) broaden the list of toxicity and biological endpoints covered by the SQGs.
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2.5 Afternoon Polling Session
The afternoon keypad polling session started after each of the Work Group Leaders
presented an overview of their discussions to all participants in the course. These
overviews were followed by a keypad polling and panel discussion. There were a few less
individuals participating in the keypad polling in the afternoon session (about 72
individuals) compared to the morning session (about 85 individuals).
The first series of polling questions asked the course participants: What are the
desirable attributes of SQGs? Over 85% of the participants felt it was important for SQGs
to minimize false positive errors (identifying non-toxic samples as toxic; Figure 4.8.1)
or to minimize false negative errors (identifying toxic samples as non-toxic; Figure
4.8.2). However, about 28% of the participants did not feel it was important to balance
false positive and false negative errors (Figure 4.8.3). Additional desirable attributes
of SQGs identified by a high number of the participants included an ability of SQGs to
predict toxicity or non-toxicity in laboratory tests (85%, Figure 4.8.4), to predict toxic
responses of benthic communities (71%, Figure 4.8.5), and to predict toxicity associated
with bioaccumulation (63%, Figure 4.8.6). Additionally, over 83% of the participants felt
is was important for SQGs to be able to identify cause and effect relationships (Figure
4.8.7) and for SQGs to account for factors controlling bioavailability (Figure 4.8.8).
For the second series of polling questions, over 54% of the participants felt that it
was acceptable to classify sediments as having a "low" or "high"
probability of toxicity, if data were available on SQG exceedances in addition to
supporting data on toxicity, benthic community, and bioaccumulation (Figures 4.9 and
4.10).
For the third series of polling questions, over 71% of the participants felt SQGs could
be used alone to identify chemicals, samples, or sites of "potential" concern
(Figures 4.11.1 and 4.11.2). However, over 43% of the individuals felt SQGs should not be
used "alone" to evaluate dredge material (Figure 4.11.3) or monitoring data
(Figure 4.11.4), to conduct ecological risk assessments (Figure 4.11.5) or damage
assessments (Figure 4.11.6), or to use SQGs alone as clean-up objectives (Figure 4.11.7).
However, a much higher number of individuals (>81%) felt SQGs could be used in each of
these activities if there was supporting toxicity, benthic community, and bioaccumulation
data (Figures 4.12.1 to 4.12.7). In summary, the degree of comfort in the use of SQGs
seemed to be based on the importance of the decision (i.e., screening for potential
problems versus the need for a combined weight-of-evidence before a more specific action
is taken).
Three additional keypad polling questions were developed during the afternoon polling
session. The first of these questions was "if you only had one type of data to make a
decision what would it be?" The highest proportion of the participants (50%) felt
chronic toxicity data would be the most useful information needed to make a decision if
other data were not available (Figure 4.13a). A high proportion of the participants felt
moderate to high priority should be given to developing either national or regional SQGs
(>68%; Figures 4.13b and 14.13c).
The last series of questions asked for feedback on how the course was organized. Most of the participants felt the course was a good learning experience (Figure 4.14.1 to 4.14.3). However, a relatively high number of individuals did not feel all of their learning objectives were met or that the keypad polling was beneficial (Figure 4.14.4 to 4.14.6). Written comments from the course participants indicated that some individuals felt that the course was not basic enough while other felt it was too simplistic. The suggestion was made by several of the participants that the course should be split into two separate courses: one structured at a basic level and a second structured at a more advanced level.
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3.0 CONCLUSIONS
A 1-d course was held to describe various approaches used to develop SQGs and to
discuss the applications of SQGs in sediment quality assessment and management. The course
consisted of both Plenary and Works Group sessions. The opening Plenary session provided
participants with focused information on the derivation, strengths, limitations, and uses
of numerical SQGs. An integrated framework for assessing sediment quality conditions and
several case studies were presented to illustrate the applications of SQGs. The Work Group
sessions provided participants an opportunity to discuss several important applications of
the SQGs, including dredged material disposal analysis, sediment management, and sediment
remediation. During the final plenary session, course participants were provided with an
opportunity to present the results of their deliberations and to express their views on
the applications of SQGs through keypad polling and panel discussions. Some of the
important conclusions resulting from the Work Group discussions and associated keypad
polling sessions included:
Course participants represented a wide range of organizations and had diverse experience in the application of SQGs;
Information on background concentrations is important for applying the SQGs in sediment quality assessments;
While SQGs are useful tools for assessing sediment quality, all SQGs derived with different approaches have a number of limitations which influence their use in various applications. Therefore, SQGs should be used in conjunction with other tools (e.g., toxicity testing, benthic community surveys) to obtain a weight-of-evidence that supports sediment management decisions;
SQGs provide relevant tools for screening sediment chemistry data, designing monitoring programs, identifying the need for source controls, classifying hot spots and ranking sites, identifying chemicals of potential concern, and establishing candidate sediment quality remediation objectives; however, SQGs generally cannot be used alone as pass/fail criteria;
Development of sediment quality remediation objectives (i.e., clean-up levels) requires information, including, but not limited to, sediment chemistry, sediment toxicity, benthic invertebrate community structure, and bioavailability.
Multiple SQGs should be evaluated and the most appropriate should be used to develop sediment quality remediation objectives for a particular site;
Effects-based SQGs do not consider the potential for bioaccumulation; therefore, bioaccumulation-based SQGs should be evaluated and used, as applicable, to support the establishment of sediment quality remediation objectives; and,
A range of suggestions for improving the SQGs were also provided by course participants, including addressing the major limitations of the SQGs, identifying cause and effect relationships, calculating toxicity equivalents, addressing the bioavailability of contaminants, identifying the substances contributing to the toxicity of mixtures, and increasing the applicability of SQGs in different sediment types.
Table 1. Selection
of SQGs for Assessing Sediment Quality Relative to Various Management Goals
Examples of Management Goal |
Potentially Relevant SQGs |
| Maintain sediment quality such that the benthic community is protected and, where necessary, restored | Low-range SQGs (e.g., ERLs, TELs, AETs, SQCs) |
| Identify sites and chemicals of concern with respect to adverse effects on the benthic community | High-range SQGs (e.g., ERMs, PELs, AETs, SQCs) |
| Maintain sediment quality such that fish and other aquatic organisms are safe to consume, both by humans and wildlife. | Residue-based SQGs (e.g., for bioaccumulative substances) |
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Table 2. Evaluation
of the Risks Associated with Contaminated Sediments
| Risk Level | Sediment Chemistry |
Sediment Toxicity |
Benthic Communities |
Bioaccumulation |
| Low | < low range SQGs | No toxicity to sensitive species | No impairment to benthic community | Bioaccumulative substances not present |
| Moderate | > low range SQGs | Toxic to sensitive species | Moderate impairment to benthic community | Bioaccumulative substances present |
| High | > high range SQGs | Toxic to multiple species | Highly impacted benthic community | Tissue residue guidelines exceeded |
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Table 3. Options for Managing
Contaminated Sediments
| Risk Level | Management Objectives | Data Requirements | Possible Management Options |
| Low | 1) Assess trends in sediment quality conditions 2) Confirm results of sediment assessment |
1) Temporal and spatial variability of sediment contaminant levels 2) Toxicity tests with sensitive species and benthic community data |
1) Ongoing, periodic monitoring 2) Continued source control |
| Moderate | 1) Assess trends in sediment quality conditions 2) Reduce inputs of contaminants to aquatic ecosystems 3) Assess potential for bioaccumulation |
1) Temporal and spatial variability of sediment contaminant levels, toxicity tests
with sensitive species and benthic community data 2) Source identification 3) Level of bioaccumulative substances in aquatic organisms |
1) Ongoing monitoring 2) Control contaminant sources 3) Implement consumption advisories, as needed |
| High | 1) Identify chemicals contributing to toxicity 2) Determine areal extent of contamination 3) Reduce inputs of contaminants to aquatic ecosystems 4) Reduce exposure to sediment-associated contaminants 5) Reduce exposure to bioaccumulative contaminants |
1) Toxicity identification evaluations, spiked-sediment toxicity tests 2) Temporal and spatial variability of sediment contaminant levels, toxicity tests with sensitive species and benthic community data 3) Source identification 4) Location and volume of contaminated sediments 5) Identification of exposure routes relative to bioaccumulation |
1) Control sources of specific substances 2) Monitoring 3) Control point and/or non-point sources 4) Capping, upland disposal, vitrification or cement-lock technologies 5) Fish/shellfish consumption advisories |
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Figure 1. Preliminary
Identification of Issues and Concerns
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Figure 2. Framework
for Assessing and Managing Contaminated Sediments Using Existing Data
*Decision points at which SQGs may be applied
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Figure 3. Framework
for Assessing and Managing Contaminated Sediments when Sufficient Data are not Available
*Decision points at which SQGs may be applied
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Figures
4.1 to 4.14. Bar graphs summarizing keypad polling responses. (large file,
contains many graphics)
Attachment A: List of Instructors for the Short Course
Bob Barrick PTI, Bellevue, WA, 425/643-9803, fax -9827, email barrickr@pti-enviro.com
Walter Berry US Environmental Protection Agency (USEPA), Narragansett, RI, 401/782-3101, fax -3030, email berry.walter@epamail.epa.gov
Callie Bolattino USEPA GLNPO, Chicago, IL, 312/353-3490, fax -2018, email bolattino.callie@epamail.epa.gov
Tim Canfield USEPA, Aida, OK, 405/436-8535, fax -8703, email canfield.tim@epamail.epa.gov
Scott Carr US Geological Survey (USGS), Corpus Christi, TX, 512/980-3216, fax -3270, email scott_carr@usgs.gov
Judy Crane Minnesota Pollution Control Agency, St. Paul, MN, 612/297-4068, fax -2343, email judy.crane@pca.state.mn.us
Jim Cubbage Washington State Department of Ecology, Olympia, WA, 360/407-6770, fax -6884, email jcu461@ecy.wa.gov
Jay Field National Oceanic and Atmospheric Administration (NOAA), Seattle, WA, 206/526-6404, fax -6865, email jay.field@noaa.gov
Rick Fox Hart Crowser, Rosemont, IL, 847/292-4426, fax -0507, email rgf@hartcrowser.com
Tom Gries Washington Department of Ecology, Olympia, WA, 360/407-7536, fax -6884, email tgri461@ecy.wa.gov
Pam Haverland USGS, Columbia, MO, 573/876-1841, fax -1896, email pamela_haverland@usgs.gov
Chris Ingersoll USGS, Columbia, MO, 573/876-1819, fax -1896, email chris_ingersoll@usgs.gov
Jim Keating USEPA, Washington, DC, 202/260-3845, fax -9830, email keating.jim@epamail.epa.gov
Karen Keenleyside Environment Canada, Hull, Quebec, 819/997-4070, fax 819/953-0461, email karen.keenleyside@ec.gc.ca
Nile Kemble USGS, Columbia, MO 573/876-1887, fax -1896, email nile_kemble@usgs.gov
Ed Long NOAA, Seattle, WA, 206/526-6338, fax -6865, email edward_long@hazmat.noaa.gov
Don MacDonald MacDonald Environmental Sciences Ltd., Nanaimo, British Columbia, 205/753-1583, fax -1563, email sff-mesl@island.net
Teresa Michelsen Washington Department of Ecology/Avocet Consulting, Bothell, WA, 425/487-6277 (phone and fax), email tcmnem@halcyon.com
Dave Mount USEPA, Duluth, MN, 218/529-5169, fax -5003, email mount.dave@epamail.epa.gov
Linda Porebski Environment Canada, Hull, Quebec, 809/953-4341, fax -0913, email linda.porebski@ec.gc.ca
Walt Roberts Learning Search Design, Portland, OR, 503/224-6966, fax -503/827-4425, email waltsearch@aol.com
Corinne Severn EVS, Seattle, WA, 206/217-9337, fax -9343, email corinne_g._severn@evs.wa.com
Heather Simmons Environment Canada, Ottawa, Ontario, 819/953-3082, fax -0461, email heather.simmons@ec.gc.ca
Sherri Smith Environment Canada, Ottawa, Ontario, 819/953-3082, fax -0461, email sherri.smith@ec.gc.ca
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Attachment B: List of Participants in
the Short Course
Sediment Management Work Group:
Breakout Group 1 lead by Bob Barrick and Jim Keating
Breakout Group 2 led by Pam Haverland and Ed Long
Nile Kemble and Dave Mount provided additional facilitator input into preparation of the
Work Group exercise.
| Name | Affiliation | Occupation | Breakout Group |
|---|---|---|---|
| Chee Choy | Government | Environmental Mgr. | 1 |
| Lisbeth Britt | Government | Environmental Mgr. | 1 |
| James Markwiese | Academia | Student | 1 |
| Doug Johnson | Government | Environmental Mgr | 1 |
| Mike Firth | Consulting | Risk Assessor | 1 |
| Sue Robinson | Consulting | Consultant | 1 |
| Jim Leather | Government | Other | 1 |
| G. Fred Lee | Consulting | Consultant | 1 |
| Jon Marshack | Government | Other | 1 |
| Alexis Stenn | Industry | Environmental Mgr | 1 |
| Uonel Klikoff | Government | Environmental Mgr | 1 |
| Ana Cristina Marroquim | Academia | Student | 1 |
| Marcia Vieira Reyneir | Academia | Student | 1 |
| Steve Ells | Government | Risk Assessor | 2 |
| Tim Moran | Consulting | Biologist | 2 |
| Tom Parkerton | Industry | Risk Assessor | 2 |
| Tina Ristola | Academia | Student | 2 |
| Michael Blanton | Consulting | Risk Assessor | 2 |
| Marion Fischel | Consulting | Biologist | 2 |
| Jennifer Moses | Government | Biologist | 2 |
| Dan Watson | Government | Toxicologist | 2 |
| Esther Peters | Consulting | Toxicologist | 2 |
| Elizabeth Lamoureux | Academia | Student | 2 |
| Phyllis Fuchsman | Consulting | Consultant | 2 |
| Leanne Stahl | Government | Environmental Mgr | 2 |
| Geoff Brighty | Government | Toxicologist | 2 |
| Mike Reive | Industry | Toxicologist | 2 |
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Sediment Remediation Work Group:
Breakout Group 1 led by Jay Field and Tim Canfield
Breakout Group 2 led by Judy Crane
Breakout Group 3 led by Teresa Michelson and Callie Bolattino.
| Name | Affiliation | Occupation | Breakout Group |
|---|---|---|---|
| Bill Richards | Consulting | Consultant | 1 |
| Amy Crook | Government | Environmental Mgr. | 1 |
| Alisa Ceric | Government | Environmental Mgr. | 1 |
| Todd Goeks | Government | Biologist | 1 |
| Shannon Craig | Industry | Environmental Mgr. | 1 |
| Paul Anderson | Consulting | Risk assessor | 1 |
| John Higman | NGO | Other | 1 |
| Bill Wild | Government | Risk assessor | 1 |
| Gregory Durell | Consulting | Consultant | 1 |
| Alan Blankenship | Academia | Toxicologist | 1 |
| Gayle Edminsten Watkin | Consulting | Risk assessor | 1 |
| Lisa DiPinto | Government | Risk assessor | 2 |
| Wendy Larson | Consulting | Consultant | 2 |
| Linda Himmelbauer | Government | Risk assessor | 2 |
| Richard Blanchet | Consulting | Risk assessor | 2 |
| Charlie Huang | Government | Risk assessor | 2 |
| Daniel Duh | Consulting | Risk assessor | 2 |
| Lisa Barow | Consulting | Risk assessor | 2 |
| Tom Campbell | Consulting | Risk assessor | 2 |
| Marion Fischel | Consulting | Biologist | 2 |
| Sonce De Vries | Government | Biologist | 2 |
| John McTigue | Consulting | Consultant | 3 |
| Bill Martin | Consulting | Consultant | 3 |
| Pad Quinn | Government | Environmental Mgr. | 3 |
| John Hayse | Government | Risk assessor | 3 |
| Randi Wexler | Consulting | Consultant | 3 |
| John Kern | Government | Biologist | 3 |
| Gene Mancini | Industry | Biologist | 3 |
| Judy Nedoff | Consulting | Chemist | 3 |
| Erik Winchester | Consulting | Risk assessor | 3 |
| Mike Macfarlane | Government | Risk assessor | 3 |
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Dredge Material Management Work Group:
Breakout Group 1 led by Linda Porebski, Walter Berry and Tom Gries and Breakout Group 2
led by Karen Keenleyside and Rick Fox (Scott Carr provided additional facilitator input
into preparation of the Work Group exercise.)
| Name | Affiliation | Occupation | Breakout Group |
|---|---|---|---|
| Marie BenKinney | Industry | Environmental Mgr | 1 |
| Paula Jackman | Government | Toxicologist | 1 |
| Denis Abessa | Academia | Student | 1 |
| Dave Lewis | Consulting | 1 | |
| Paul Krause | Consulting | Toxicologist | 1 |
| Sharon Lin | Government | Other | 1 |
| David Moore | Government | Toxicologist | 1 |
| Charles Dobbs | Industry | Other | 1 |
| Frank Snitz | Government | Chemist | 1 |
| Taku Fiji | Consulting | Toxicologist | 1 |
| Todd Bridges | Government | Biologist | 2 |
| Susan Kane Driscoll | Consulting | Toxicologist | 2 |
| Ron French | Consulting | Biologist | 2 |
| Labric Jacques | Industry | Environmental Mgr | 2 |
| Dale Iboff | Government | Toxicologist | 2 |
| Carlton Hunt | Consulting | Consultant | 2 |
| Bill Croyl | Government | Other | 2 |
| Kathi Futornick | Government | Environmental Mgr | 2 |
| Joe Kierkes | Consulting | Biologist | 2 |
| Rusty Jeffers | Government | Toxicologist | 2 |
| Sarah Griscom | Academia | Student | 2 |
No Work Group Specified
Dale Iboff Government Toxicologist
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Attachment C: Agenda
for the Interactive Short Course on "Use of Sediment Quality Guidelines in the
Assessment and Management of Contaminated Sediments."
TIME TOPIC
8:00 am Introductions, Questionnaire, and Keypad Polling Questions: Chris Ingersoll, Don MacDonald, Walt Roberts
8:20 Equilibrium Partitioning: Dave Mount, Walter Berry
8:55 Apparent Effects Threshold: Bob Barrick, Tom Gries
9:30 Break
9:50 Effect Range Low and Median; Threshold and Probable Effect Levels: Ed Long, Don MacDonald
10:25 Logistic Models: Jay Field
11:00 Case Study #1: Dredging: Linda Porebski. Using SQGs with bioassays and benthos along a metals gradient in Belledune Harbour, New Brunswick, Canada
11:15 Case Study #2: Remediation. Teresa Michelsen: Cleaning up mercury contamination in Bellingham Bay: Appropriate uses of sediment quality guidelines and site-specific data
11:30 Case Study #3: Management: Jim Keating. Numerical guidelines and sediment quality management: Screening samples and setting priorities in the EPA's National Sediment Inventory
11:45 Flow charts for use of SQGs in assessing and managing contaminated sediments: Scott Carr and Rick Fox
12:00 pm Lunch
1:00 Breakout into Discussion Groups within Work Groups:
A. Dredging (Facilitators Walter Berry, Rick Fox, Scott Carr, Tom Gries, Karen Keenleyside, Linda Porebski)
B. Remediation (Facilitators: Judy Crane, Jay Field, Callie Bolattino, Tim Canfield, Teresa Michelsen)
C. Management (Facilitators: Pam Haverland, Ed Long, Bob Barrick, Jim Keating, Nile Kemble, Dave Mount)
2:45 Reports of Breakout Groups within Individual Work Groups: Work Group Facilitators
3:15 Break
3:30 Reports and Discussions among Work Groups: Work Group Facilitators
4:00 Keypad Polling Questions and Panel Discussions
5:00 Adjourn
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Attachment D: Keypad Polling Questions
Morning Keypad Polling Session:
1. Affiliation: (1) Government (2) Industry (3) Academia (4) Non-Government Agency (5) Consulting Firm (6) Presenter (7) Other
2. Occupation: (1) Student (2) Chemist (3) Biologist (4) Toxicologist (5) Consultant (6) Environmental Manager (7) Risk Assessor (8) Other
3. Years of experience in assessment or management of contaminated sediments: (1) None (2) 0-3 years (3) 3-6 years (4) 6-9 years (5) 9-12 years (6) 12-15 years (7) 15+ years
4. Where have you applied SQGs?: (1) Freshwater (2) Saltwater (3) Estuaries (4) 1+2 (5) 1+3 (6) 2+3 (7) 1+2+3 (8) Have not used
5. Which types of SQGs have you primarily applied?: (1) ERL/ERM (2) TEL/PEL (3) AET (4) SLC (5) EQP (6) Other (7) Have not used
6. How frequently have you used SQGs?: (1) Never (2) Rarely (3) Infrequently (4) Frequently (5) Very Frequently
6.1. Identify chemicals of potential concern.
6.2. Identify samples or sites of potential concern.
6.3. Evaluate dredged material.
6.4. Evaluate monitoring data.
6.5. Conducting ecological risk assessments.
6.6. Conducting damage assessments (i.e., litigation).
6.7. Use as cleanup objectives.
7. What degree of influence have the following factors had in limiting your use of SQGs?: (1) No Influence (2) Little Influence (3) Some Influence (4) Moderate Influence (5) Very Influential
7.1. Not applicable to my work.
7.2. Unfamiliarity with SQGs in general.
7.3. Uncertainty about which SQG to use.
7.4. Uncertainty about the predictability of the SQGs.
7.5. SQGs not available for chemicals of concern.
7.6. Lack of available SQGs for bioaccumulation.
7.7. Not applicable to geographic area of interest.
7.8. Difficulties in dealing with complex mixtures.
7.9. Cause and effect relationships not established.
7.10. Bioavailability is not established.
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Afternoon Keypad Polling
Session and Panel Discussion:
8. Desirable attributes of SQGs: How important?: (1) Unimportant (2) Slightly Unimportant (3) Do not know (4) Slightly Important (5) Important
8.1. Minimize false positive errors (identifying non-toxic samples as toxic).
8.2. Minimize false negative errors (identifying toxic samples as non-toxic).
8.3. Balance evenly the potential for false positive and false negative errors.
8.4. SQGs should accurately predict toxicity or non-toxicity.
8.5. SQGs should accurately predict responses of benthic communities in the field.
8.6. SQGs should accurately predict effects associated with bioaccumulation.
8.7. Knowing that specific chemicals exceeding SQGs caused the observed toxicity.
8.8. Known factors controlling the bioavailability of contaminants in sediment.
9. Sediment samples should be classified as having a "low probability of toxicity" if No: (1) SQGs exceeded (2) SQGs exceeded with supporting toxicity data (3) SQGs exceeded with supporting benthic community data (4) SQGs exceeded with supporting bioaccumulation data (5) All above (6) None of the above
10. Sediment samples should be classified as having a "high probability of toxicity" if Multiple: (1) SQGs exceeded (2) SQGs exceeded with supporting toxicity data (3) SQGs exceeded with supporting benthic community data (4) SQGs exceeded with supporting bioaccumulation data (5) All above (6) None of the above
11. How appropriate is it to use SQGs alone to: (1) Inappropriate (2) Slightly Inappropriate (3) Do not know (4) Slightly Appropriate (5) Appropriate
11.1. Identify chemicals of potential concern.
11.2. Identify samples or sites of concern.
11.3. Evaluate dredge material.
11.4. Evaluate monitoring data.
11.5. Conduct ecological risk assessments.
11.6. Conduct damage assessments (i.e. litigation).
11.7. Use as cleanup objectives.
12. How appropriate is it to use SQGs in combination with other tools: (1) Inappropriate (2) Slightly Inappropriate (3) Do not know (4) Slightly Appropriate (5) Appropriate
12.1. Identify chemicals of potential concern.
12.2. Identify samples or sites of concern.
12.3. Evaluate dredge material.
12.4. Evaluate monitoring data.
12.5. Conduct ecological risk assessments.
12.6. Conduct damage assessments (i.e. litigation).
12.7. Use as cleanup objectives.
13. Place holder for important questions to poll from the Work Groups: dredging, remediation and management.
14. Feedback: (1) Strongly Disagree (2) Disagree (3) Neutral (4) Agree (5) Strongly Agree
14.1. Overall, this short course was a good learning experience.
14.2. The morning presentations on approaches and case studies were beneficial.
14.3. The afternoon breakout sessions were beneficial.
14.4. My learning objectives were met.
14.5. The use of keypad polling was beneficial.
14.6. This short course will help me better apply SQGs in the future.
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Attachment E: Case
Study presented by the Sediment Remediation Work Group that was not included in the
notebook distributed during the short course: "Using SQGs in sediment remediation: a
hypothetical scenario"
You are a Site Manager for a contaminated sediment site and you are trying to develop
cleanup levels that will be protective of aquatic ecological effects (human health issues
are not a concern). The site is a marine, industrial boat slip which has not been dredged
in 10 years. Previous assessment-type studies indicate that a hot spot of contamination
(mercury, copper, zinc, and PCBs) exist in about half of the slip with varying, lower
levels of contamination in the rest of the slip. Some preliminary sediment toxicity tests
indicated a mix of toxic and non-toxic sites. A benthological community survey has not
been conducted at this site. Nationally-based sediment quality guidelines (SQGs) are
available for the contaminants of concern.
Discussion questions:
Information needs
Appropriate level of protectiveness at a site
National/regional/site-specific guidelines
Application of site-specific data
Bioaccumulative contaminants