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THE URF~ OF THE SEDIMENT DUALITY TRIAD CLASSIFICATION OF SEDIMENT CONTAMINATION Edward R. Long National Oceanic and Atmospheric Administration ABSTRACT A concept for use in the collection of data needed to classify sediment quality is described. This concept is based upon the observed need for information on the kinds and concentrations of potentially toxic chemicals in the sedi- ments, the relative toxicity of the sediments as determined under controlled laboratory conditions, and the characteris- tics of resident benthos under in situ conditions. The con- cept, called the Sediment Quality Triad, has been used in numerous assessments of urban embayments and prospective dredge material. Case studies from Puget Sound and San Francisco Bay and various uses of the data are described. DESCRIPTION OF THE METHODOLOGY r The Sediment Quality Triad (the "triad") is a concept recently developed (Long and Chapman, 1985; Chapman et al., 1987) for use in the classification and evaluation of the relative quality of surficial sediments. It consists of measures of sediment contamination quanti- fied by chemical analyses, sediment toxicity determined with laboratory bioassays and benthos community structure described through taxonomic analyses of macrofauna. The chemical analyses provide information on the mixtures and concentrations of contaminants in the sediments that may be harmful to marine biota. The bioassays provide information on the relative bioavailability and toxicity of sediment-sorbed contami- nants under laboratory conditions where the effects of many "natural" environmental factors are controlled. The benthos community data pro- vide corroborating evidence from resident biota regarding major composi- tional alterations to a component of the ecosystem under in situ condi- =;~.~. lo..= ~~ _~v~ -:.~ three measures are complimentary and provide a preponderance of empirical evidence of both contamination and effects that can be used to classify the relative quality of sediments. Portions or aliquots of the same sediment samples are usually test- ed for contamination and toxicity. The macrobenthos are examined in additional portions of the same samples or, more often, are collected at the same sampling stations in separate grab samples. Chemical analyses are performed for a variety of trace metals and organic com- pounds. The physical/chemical characteristics of the sediments, such as sediment texture and total organic carbon, are also determined. 78

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79 Sediment toxicity is determined through bioassays in which mortality, impairment of reproductive success, sublethal behavioral and/or muta- genic effects are recorded. The taxonomic analyses of the benthos pro- vide information on the species richness, total abundance, abundance of individual species, and indices of community similarity. The relative abundance of the bioassay species in the benthos also can be recorded, providing a strong link between the bioassay results and benthos data. The triad is a concept for measuring and classifying sediment qual- ity; it is not an index per se. The data resulting from the three meas- ures can be used in several ways to satisfy a variety of objectives. First, they can be used in a descriptive mode, in which the preponder- ance of evidence is used to evaluate and classify the relative quality of sediments among sampling sites. The relationships among the contam- inant, physical/chemical, and biological data may be interpreted in descriptive ecological evaluations of the study sites. Second, site ranks can be calculated independently for each of the triad components, using a variety of techniques. Cumulative ranks, based upon the three independent ranks, have also been determined. One technique that has been used to rank sites has involved calculation of the ratios between data from the more contaminated sites and from an apparently uncontam- inated reference site. By calculating these ratios, data from all the measures, which often have very different units, absolute values, and ranges can be treated with similar weight on a common, unitless scale. The independent ranks can be illustrated with biaxial plots to high- light differences among sites. Classification of sites can be performed to determine both geographic and temporal trends in sediment quality. The triad data also can be used to determine the means and ranges in contaminant concentrations associated with modes and ranges in the biological effects data. In this type of evaluation the means and ranges in contaminant concentrations associated with the highest re- sponses in the biological analyses can be compared with those asso- ciated with the intermediate and lowest ranges in those tests, using data from a variety of sampling sites. This type of evaluation can form the basis for predictive models in which the relationships between synoptically collected biological and chemical data are used to esti- mate the relative degree of contamination that is often associated with biological effects. Finally, where a sufficient amount of data exist, these types of predictive evaluations of the triad data can be used to estimate the contaminant thresholds above which biological effects are always observed. The Apparent Effects Threshold (AET) approach, one method of using triad data in a predictive mode that has been used in Puget Sound, is described by Barrick et al. in this volume. EFFECTIVENES S AND RELEVANCE OF THE METHODOLOGY Because the methodology provides a thorough assessment of the qual- ity of the sediments, it is very effective at classifying sites based upon the preponderance of evidence. The chemical data provide evidence regarding whether the sites are contaminated or not and which chemicals are present in the highest concentrations. The chemical data can

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80 L ~ the chemical . sources of contaminants when sediments match those in-nearby Provide clues regarding the most likely chemical ratios or "signals" in the potential sources. The bioassay data provide direct evidence of whether or not the sediments are toxic to selected test organisms. If they are toxic, it can be assumed that the chemical contaminants were bioavailable to the test organisms. They also can be useful in deter- mining the degree of toxicity and the nature (lethal, mutagenic, sub- lethal) of the toxicity. The benthic community data provide an in situ confirmation or denial that the sediments are toxic to biota. These data can serve as a measure of ecosystem structure and function. Evi- dence of severely altered benthos coupled with evidence of sediment ~ e, ~ ~ ~ ~ ~ 1 _ 11 ~ toxicity provide a powerful argument that contaminated sediments are biologically damaging. For example, Swartz et al. (1982) showed that portions and that the amphipod populations in resident benthos in r of the Commencement Bay waterways were very toxic to amphipods the same areas were severely depressed in abundance relative to other nearby areas. Classification approaches that rely only upon chemical data provide no empirical evidence that the contaminants are (1) bioavailable and (2) biologically damaging. While predictive physical chemical models may provide theoretical estimates of single contaminant concentrations that are biologically damaging, they do not provide these estimates for the complex and variable mixtures of contaminants that usually occur in estuaries, ports, and harbors. Sediment toxicity tests are often per- formed under worst-case laboratory conditions with test organisms that have no chance of escape, may not be native to the sampling sites, and have no time to acclimate to the properties of the sediments. There- fore, classification approaches that rely upon bioassay data alone may overestimate the poor quality of sediments or mav be received with Bali Of - ~ - nor he m::n=`r='c: J - ~ ~ ~ ~ ~ ~___. Classification approaches that rely only upon benthos data may be frustrated by the major alterations in benthic communities that can be caused entirely or partly by differences among sites in depth, sediment texture, near-bottom or interstitial salinity, predation, bottom scouring, and other biotic and abiotic factors. While the three types of data from the triad concept provide complementary measures of sediment quality, the data from the three components may not necessarily parallel each other. Each component ~~ ~ - ~ ~ ~ ~ For example, sites measures ultterent properties or tne sediments. that are relatively contaminated may not be the most toxic, or sites with relatively altered benthic communities may not be most contami- nated. If each of the components mimicked each other in the classi- fication of sites, there would be no need to measure all three. The strength of the triad approach is the use of both chemical and bio- logical measures that can be used in an ecological evaluation of sedi ment quality. The triad concept can provide the data needed by an ecologist to interpret and use in characterizing sediment quality. Simple before and after surveys can be performed to determine an changes in sediment quality caused by a specific remedial action. Eco- logical evaluations of the triad data can be performed to determine if contaminant concentrations and toxicity have decreased and if measures of benthos alteration have been alleviated. Also, any cumulative indices calculated from the triad data collected before the remedial -

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81 action can be compared with those calculated from data generated after the action. FIELD VALIDATION OF THE METHODOLOGY The utility of the triad approach has been verified in many field surveys and experiments. The triad approach, per se, was first applied in an evaluation of available data from sites in Puget Sound, Washing- ton (Long and Chapman, 1985~. This study indicated that data from the three components of the triad often showed gross parallel patterns in sediment quality among sites, but that the agreement among the three measures was not absolute. In a subsequent survey in San Francisco Bay, Chapman et al. (1986, 1987) demonstrated the differences in sedi- ment quality among three sites, based upon a preponderance of evidence (see case study below). The "Urban Bay Approach" taken by a consortium of the U.S. Environmental Protection Agency's (EPA) Region 10 and the Washington Department of Ecology (WDOE) has used the triad as the basis for ranking contaminated sites in the urban bays and waterways of Puget Sound for remedial action. The quality of sites in Commencement Bay (see Case Study below), Elliott Bay, Everett Harbor, and Eagle Harbor has been assessed using this approach. The data from these Puget Sound studies have been used to calculate Elevations Above Reference (EAR) conditions to classify the relative quality of sites and to calculate Apparent Effects Thresholds (AET). While all these studies have shown generally good overall agreement in results among the triad components, they also indicated that, as expected, the agreement on a station-to- station basis was not perfect. Therefore, the results from any one or two of the components, if measured alone, may have not accurately pre- dicted the results from the other components). Seattle METRO assessed the quality of sediments in a baseline study of a prospective sewer discharge site in Puget Sound, using the triad of measures and other tests. Many samples from the southern-portion of the central basin of the Sound were collected and analyzed (Stober and Chew, 1984~. Battelle Pacific Northwest Laboratories (1986) assessed the quality of sediments in eight bays of Puget Sound for EPA Region 10 to determine the relative quality of rural and urban areas. Off Southern California, Swartz et al . ( 1986 ~ described temporal changes between 1980 and 1983 in contamination, toxicity, and benthos. Chapman (1986) summarized sediment bioassay and bottomfish histopath- ology data from Puget Sound and described the contaminant levels in sediments associated with high and low incidences of these measures of effects. Other uses of the triad concept are underway in studies being conducted by the Southern California Coastal Water Research Project in Southern California harbors (Karen Taberski, California State Water Quality Control Board, personal communication); in the Gulf of Mexico near oil production platforms (Peter Chapman, E.V.S. Consultants, per- sonal communication); and in Lake Union near Seattle, Washington (Bill Yake, Washington Department of Ecology, personal communication). The biological effects of Black Rock Harbor sediments at a Long Island Sound dump site have been investigated with the triad of measures by

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82 the U.S. EPA and Army Corps of Engineers (Gentile et al., 1985; Roger- son et al., 1985~. ~ Both the states of Washington and California are currently consider- ing the possible development of effects-based sediment quality cri- teria, using AET values based upon triad data. The Washington Depart- ment of Ecology must adopt statewide sediment quality standards by June 30, 1989 in response to Element P-2 of the Puget Sound Water Quality Plan. The California State Water Quality Control Board must adopt sediment criteria by 1991 in response to provisions of Assembly Bill 3947 that would assure the protection of wildlife and humans from sediment-associated contamination. REQUIRED EXPERTISE AND COSTS Since the triad approach provides a comprehensive assessment, fol- lowup studies are seldom required to address unresolved questions. How- ever, because the triad concept requires data from three scientific dis- ciplines (analytical chemistry, toxicology , benthic ecology) , a study team with broad expertise is required. It is possible that once the relationships between contaminant levels and biological effects in sedi- ments are established for a geographic region, one or two of the triad components could be eliminated or reduced in scope. A variety of short- cut measures of chemical contamination, toxicity, or benthos altera- tions may help to reduce costs. For example, bacterial luminescence bioassays may prove to be very inexpensive tests of sediment toxicity (Schiewe et al., 1985~. Quantification of only selected chemicals known to occur in the study area or known to be of highest toxico- logical concern would reduce costs. Examination of small cores for, say, presence of amphipods in the benthos in the grab samples used for chemical and bioassay analyses may reduce costs of benthic community analyses. The benthos could be examined inexpensively by a sediment profiling camera to determine selected community properties. The availability of these types of expertise is widespread in many commercial, agency, and academic laboratories in the United States. The specific expertise and equipment needed to develop triad data, however, would vary among regions, depending upon region-specific research needs and environmental variables. Also, costs would vary among regions and among studies depending upon complexity and precision of chemical analyses, types and number of bioassays, and the complexity and density of the benthos. In the triad case study in San Prancisco Bay described below, total costs were about $100,000. For that total cost, data were collected for 66 chemicals, many physical/chemical properties, four bioassays, and complete taxonomic analyses of the benthos at nine stations. The bioassays and benthos analyses were performed with quintuplicates at each station. The cos ts also included thorough data analysis and report preparation steps. Two case studies, Puget Sound and San Francisco Bay, will be brief- ly summarized to illustrate the use and results of the triad approach. The references cited should be studied to determine details of methods

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83 and results. In both case studies, most of the data have been pre- sented as Ratio-to-Reference (RTR) values to facilitate comparisons of conditions in study sites with those in an apparently uncontaminated reference site and to place the three disparate types of data on the same unitless scale (Chapman et al., 1987~. Since positive ratios (i.e., greater than 1) could theoretically range to infinity and nega- tive ratios could only range from 1 to 0, differences among sites in mean RTR values may be slightly exaggerated. RTRs can be calculated and transformed to logarithms, wherein both negative and positive rati as can range from zero to negative infinity and to positive infin- ity, respectively. In this approach, negative and positive values are given equal weight in the calculation of means. Transformation of the RTR values determined in the case studies to logarithms slightly altered the mean RTR values, but did not change the relative ranks of stations or sites. CASE STUDIES San Francisco Bay Research was conducted by Chapman et al. (1986, 1987~. Sediment samples were collected at three stations at each of three sites: Islais Creek Waterway (IS), off Oakland (OA), and in San Pablo Bay (SP). The former site was in an industrial waterway that receives major discharges from combined sewer overflows and was expected to be highly contaminated. The second s ite was located near the Oakland Harbor maritime facilities and was expected to be moderately contami- nated. The third site was located in the open waters of San Pablo Bay in the northern part of the San Prancisco Bay estuary and was expected to be the least contaminated, based upon studies of sediment and bottom- fish contamination conducted at the site. The samples were collected with a O.l-m2 van Veen grab sampler. The upper 2 cm were collected for the chemical and toxicity analyses. The contents of multiple grabs were composited at each station, homo- genized, and aliquots taken for each of the chemical and bioassay tests. Five separate replicate grab samples were taken for the benthos evaluations at each station. The benthos samples were wet-sieved at each station and the biota retained on a 1-mm screen were kept for examination. The chemical analyses were performed for 21 major and trace metals, 20 low- and high-molecular-weight aromatic hydrocarbons, 17 chlorinated hydrocarbons, and 8 chlorination levels of polychlorinated biphenyls. In addition, sediment texture, total organic carbon content, total vola- tile solids content, sulfide content, and percent solids were deter- mined for each station. Toxicity was determined with four bioassays: 1. solid-phase bioassays of acute lethality and avoidance of sediments by the amphipod Rhepaxynius abronius; 2. elutriate bioassay of acute lethality and abnormal morphological development of the embryos of the mussel

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84 Mytil us edul is; 3. solid-phase bioassay of reburial rate by the clam Ma coma teal thica; and 4. solid-phase bioassay of impairment of reproduction with the copepod Tigriopus californicus. Complete taxonomic analyses of the benthos were performed and indices of total abundance, abundance of individual taxa, species richness, species diversity, proportional contribution of major taxonomic groups to total abundance, dominance, and equitability were calculated. Mean percent silt + clay content was 69 percent at the SP site, 86 percent at the OA site, and 94 percent at the IS site. Mean total or- ganic carbon content was 1.10 percent at the SP site, 1.22 percent at the OA site, and 2.87 percent at the IS site. Mean sulfide content was 29.7 mg/kg at the SP site, 3.1 mg/kg at the OA site, and 540.0 mg/kg at the IS site. From these data it was apparent that the IS site was highly organically enriched compared to the other two sites and pos- sibly anoxic. Table 1 summarizes selected chemical data as RTR values. The data have been normalized to total organic carbon content and each concentra- tion divided by the mean values for the SP reference site. The IS site was much more contaminated than the other two sites; primarily with aromatic hydrocarbons, PCBs, DOTS, and silver. The coprostanol data provide evidence that the site was contaminated with municipal sewage. The OA site was only slightly more contaminated than the SP site. Some trace metals there were less concentrated than at the SP site. The data from the four bioassays are summarized in Table 2, also as RTR values. The data from most of the bioassay endpoints indicate that the IS samples were significantly more toxic (p < 0.05, one-tailed l-test) than those from SP and OA (Chapman et al., 1987~. A mean of 10.4 amphipods out of 20 died in the IS site samples, compared to means of 2.5 and 2.3 at the other sites. A mean of 55.2 percent of the mus- sel embryos exposed to IS samples were abnormal, compared to 12.1 per- cent and 19.3 percent at the other sites. Mean mortality was highest in embryos exposed to the IS samples. Mean clam reburial time in IS samples was roughly twice that in the SP samples. The number of young copepods produced did not differ substantially among the three sites, though it was lower at the OA site. Among the four types of bioassays, those with amphipods and mussel larvae appeared to be most sensitive to the sediments. Results of the benthos analyses are summarized as RTR values in Table 3. The benthos at SP and OA were dominated by tube-dwelling amphipods (specifically Ampelisca abdita) and other crustaceans). The benthos at IS was dominated by Capitella capitata, polychaeyes and molluscs. Mean total abu~dance was 609 organisms per 0.1 m at SP, 3,502 organisms per 0.1 m at OA, and 41 organisms per 0.1 m2 at IS. Mean number of taxa was 10.3, 14.5, and 4.2 at SP, OA, and IS, respectively. Dominance was lower and species diversity higher at IS than at the other sites, reflecting the dominance by A. abdita at the SP and OA sites.

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88 5 Bioassay Toxicity Inhuna Alteration - loo / \~,s SP02 _~° ~5 SP09 ';; T ~~ - s "~5 As' 1.0 15 so Chemistry Contamination 25 SAN PAi LO BAY ~ 05 (SP) SI.ATIONS \ ~` it,\ \~.5 \: \'. At: . Chemistry Contanunation \ as Bioassay Toxicity Inhuna Alteration IS02i~' ~ ~S05 25 ~ OAKLAND (OA) SI.AllONS OCR for page 78
89 30 Bioassay Toxicity of_ Infauna Alteration __? I5;LAIS WA l hKWAY ,-' ~ '' 05~' '`1 10 20 30 ',' SAN PABLO BAY Chemistry Contamination f FIGURE 2 Sediment Quality Triad determined for each of the three study sites in San Francisco Bay. Chemistry RTR values are from Table 1; bioassay RTR values are from Table 2; infauna RTR values are from Table 3. Prom the triad of measures taken at the three sites in San Francisco Bay, it is apparent that the IS site was more contaminated, more toxic, and had a benthic community that was very different from those at the other two sites. The preponderance of evidence clearly identified and ranked that site as having the lowest sediment quality. All three mean RTRs indicated to varying degrees that that site was most degraded. The data also indicated that the OA site was only slightly different than the reference site: toxicity and contamination were somewhat elevated, but the benthos were not apparently different. The data indicated that the IS site benthos was highly altered com- pared to the benthos at the reference site. However, since the sedi- ments at IS also had the highest organic carbon content, the modifica- tions to the benthos, if studied alone, could have been attributed to this and other physical/chemical properties. The bioassay data con- firmed that the contaminants in the sediments were bioavailable and toxic to a variety of organisms, and, therefore, posed a threat to resi- dent organisms.

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go TABLE 4 Mean (and Ranges) in Contaminant Concentrations in Sediments from Nine Stations in San Francisco Bay Associated with Three Means (and Ranges) in Mortality of Rhepaxynius abronius Rhepoxynius abronius LMWPAH HMWPAH Pesticides Pb Cu Ag mortalitya N ppm ppm ppm ppm ppm ppm 19 1 3.16 12.06 8.26 223 130 8.1 (10-19) (3.16) (12.06) (8.26) (223) (130) (8.1) 5.7 3 1.3 5.66 3.20 63 73 4.73 (5-9) (0.22-2.76) (0.67-11.82) (0.92-6.24) (25-llS) (53-98) (1.6-8.6) 1.9 5 0.28 1.12 1.08 26 43.6 1.62 (0-4) (0.03-0.43) (.22-1.89) (0.63-1.69) (18-33) (30-51) (0.9-2.4) NOTE: aN~mber dead out of 20 animals SOURCE: Chapman et al., 1986. Insufficient data exist thus far to calculate AET values for San Francisco Bay. From the data collected in this case study is it appar- ent that results from any one of the components of the triad would have not accurately predicted the results from the other components, since the lines connecting the biaxial plots often were not parallel and crossed each other. However, patterns in co-occurrence of concentra- tions of selected contaminants with ranges in bioassay data have been determined (Long et al., 1988~. Table 4 provides an example of these co-occurrences with the Rhepaxynius bioassay data from the case study. An examination of the frequency distribution of the data indi- cates that three modes in the results of the bioassays were observed: one in which 1 survivor in 20 was observed from one station; another in which a mean of 14.3 survivors in 20 was observed from three stations; and a third in which a mean of 18.1 survivors in 20 was observed from five stations. The low- and high-molecular-weight aromatic hydrocar- bons were approximately an order of magnitude higher in concentration at the station with 1 survivor than at the stations with a mean of 18.1 survivors. All the other contaminants shown in Table 4 also increased in mean concentration between the least toxic and most toxic samples. A similar pattern was observed with the mussel larvae data (Long et al., 1988~. In all cases, however, there were large ranges in contami- nant concentrations within each level of bioassay response. The sample size available from this study is obviously very small, but with the addition of more data the patterns in co-occurrence of contaminant levels with biological effects measures could be established for San Francisco Bay and could, ultimately, lead to the calculation of indices such as AET for use in the bay.

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91 Puget Sound Data are from an assessment of the waterways of Commencement Bay near Tacoma, Washington performed by Tetra Tech, Inc. (1985~. All three components of the triad were measured at 56 stations scattered among the industrialized waterways bordering Commencement Bay and at four stations in nearby Carr Inlet, an embayment selected as a refer- ence area. Sites were selected near and away from known point sources and areas known from previous studies to be contaminated and/or toxic. The approach used in the Commencement Bay study was used in subsequent similar studies in Elliott Bay, Everett Harbor, and Eagle Harbor: Surficial (upper 2 cm) sediments were collected with a 0.1-m van Veen grab and homogenized for the chemical and toxicity analyses. Sample, for benthic macroinvertebrate analyses were taken with a 0.06-m van Veen grab. Four replicates were taken at each station and sieved with O.5-mm and 1.O-mm screens. Chemical analyses were performed for 16 elements, volatile organic compounds, polynuclear aromatic hydrocarbons, pesticides, PCBs, and a wide variety of other organic compounds. Total solids, total volatile solids, oil and grease, sulfide content, and sediment texture were also determined. Bioassays were performed with two procedures: 1. solid-phase acute toxicity with the amphipod Rhepoxynius abronius, and 2. suspended-phase lethality and abnormal development with the oys ter Crassos tree gigas larvae. Benthic infauna were identified to species when possible and enumerated in the 1.O-mm fraction only; the 0.5-mm organisms were archived. Tables 5, 6, and 7 summarize the results of these analyses for 20 selected stations sampled in the study. All the data are presented as RTRs using the mean values from the Carr Inlet reference area as the denominator. The mean RTR values for each of the triad components is shown to the right of each of the tables. In Table 5 the RTR values for the three trace metals were used to calculate means (n ~ 3), which were then used along with the RTRs for the organic compound classes to calculate overall mean RTR values (n ~ 4~. For the three metals and three organic compound classes shown, several of the sites in the Hylebos Waterway were the most contaminated (Table 5~. Station 22 in the turning basin was especially highly con- taminated with aromatic hydrocarbons and PCBs. Compared to the other stations, those in City Waterway were moderately contaminated and those in Blair Waterway were slightly contaminated. The concentrations of the selected chemicals was relatively uniform within the Carr Inlet reference area. The bioassay data (Table 6) indicated that the sediments at station 11 in Blair Waterway were most toxic, i.e., had highest mortality in amphipods and oyster larvae and highest abnormal development in oyster larvae. Stations 22 and 23 in Hylebos Waterway were also relatively toxic, compared to the stations in Blair Waterway and Carr Inlet. The

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92 TABLE 5 RTR Values for Contaminants Quantified at 20 Stations in Commencement Bay and Carr Inleta Total Total Total Mean Site Station MUCH HMWH PCBs Cd Cu Hg RTR Upper Hyle- 12 56.1 174.1 15.7 26.4 22.9 9.2 66.3 has Water- 14 47.9 290.8 12.0 20.0 18.2 6.6 91.4 way 17 56.1 321.5 24.0 3.6 32.6 6.0 103.9 Hylebos 22 154.8 524.0 286.0 3.6 38.2 10.0 245.5 Turning 23 132.8 240.7 214.0 2.7 23.5 8.0 149.7 Basin 24 49.S 196.3 36.0 2.7 30.7 9.8 74.1 Blair 11 17.7 20.3 2.4 2.7 6.6 1.4 11.0 Waterway 12 30.6 63.6 10.0 2.7 11.8 1.6 27.4 13 28.1 45.6 3.1 2.7 10.1 4.0 20.6 21 34.8 41.2 1.0 2.7 8.6 2.6 20.4 City 11 148.1 228.6 2.1 4.5 24.8 10.6 98.0 Waterway 13 97.1 148.5 20.0 5.4 29.8 22.0 71.2 16 109.7 84.2 5.1 5.4 25.3 2.2 52.5 17 132.6 174.7 7.1 5.4 26.9 2.2 81.5 20 91.0 83.1 2.7 4.5 25.3 4.8 47.1 22 158.7 203.3 4.6 1.4 6.4 4.4 92.7 Carr 11 0.9 1.1 1.0 0.9 0.8 1.0 1.0 Inlet 12 1.1 1.2 1.0 0.9 1.1 2.0 1.1 13 0.5 0.4 1.0 0.9 0.8 1.0 0.7 14 1.5 1.3 1.0 1.4 1.3 0.6 1.2 NOTE: aRTR values were calculated by dividing individual station values by the mean for Carr Inlet. SOURCE: Tetra Tech Inc., 1985. chemical data indicated a distinct difference in chemical concentra- tions between the Hylebos Turning Basin and the adjacent Upper Hylebos Waterway, whereas the bioassay data indicated only a small difference between the two areas. The chemical data indicated that station 11 in City Waterway was moderately contaminated (mean RTR of 98), whereas the bioassay data indicated it was the most toxic among the selected stations. The benthos data (Table 7) indicated that small differences in total abundance and species richness occurred at most stations relatable

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93 TABLE 6 RTR Values for Sediment Bioassays Performed with Samples from 19 Stations in Commencement Bay and Carr Inleta Percent relative Percent Percent oyster oyster amphipod larvae larvae Mean Site Station mortality mortality abnormality RTR t Upper Hylebos 12 1.2 0.8 3.5 1.8 Waterway 14 0.7 1.2 1.9 1.3 17 1.4 1.5 3.1 2.0 Hylebos 22 2.7 1.6 3.0 2.4 Turning Bas in 24 1 . 4 1.1 1.9 1.5 Blair 11 1.0 0.8 1.3 1.0 Waterway 12 1.5 1.2 1.4 1.4 13 1.4 1.3 1.6 1.4 21 1.1 1.1 1.8 1.3 City 11 3.9 1.5 4.8 3.4 Waterway 13 1.S 1.5 2.5 1.8 16 1.1 1.5 2.5 1.7 17 1.3 1.8 1.7 1.6 20 2.3 1.5 2.5 2.1 22 1.4 1.0 1.5 1.3 Carr 11 1.9 1.0 1.3 1.4 Inlet 12 0.8 0.9 0.8 0.8 13 0.5 1.0 0.8 0.8 14 0.8 1.0 1.1 1.0 NOTE: aRTR values were determined by dividing individual values by the mean for Carr Inlet. SOURCE: Tetra Tech, Inc., 1985. to the Carr Inlet mean, but that major differences in amphipod abun- dance were observed at most stations. The mean RTR values were influ- enced mainly by the values from the amphipod abundance RTR values. Either none, one, or two amphipods were found in most of the samples. whereas a mean of 71.2 per sample were found in Carr Inlet. ~ ~ ~ ~ ~ ~ . ~ The excep- t~ons were stations zz and z" in Hylebos Waterway, station 11 in City Waterway and Station 13 in Blair Waterway where more amphipods were encountered. Based upon the three selected measures of benthos in

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94 TABLE 7 RTR Values for Benthic Community Indices Measured at 20 Stations in Commencement Bay and Carr Inleta 1/Total 1/Species 1/Amphipod Mean Site Station abundance richness abundance RTR Upper Hylebos 12 0 ~ 3 1 ~ 7 71 ~ 2 24 ~ 4 Waterway 14 0~6 1~5 71~2 24~4 17 0~6 1~9 71~4 24~6 Hylebos 22 1.0 2 ~ 2 11.9 5 ~ 0 Turning Basin 23 7 ~ 2 4e 9 71e 2 27 ~ 8 24 0~6 1~8 23~8 8~7 Blair 11 0.2 1 ~ 2 71 ~ 4 24 ~ 3 Waterway 12 nd nd nd 13 0~3 1~3 23~8 8~5 21 0~4 1.S 71~2 24~4 City 11 0.1 3~8 35~7 13~2 Waterway 13 2~6 2e3 71~4 25~4 16 2~3 3~2 71~2 25~6 17 0~3 1~2 71~4 24~3 20 0~4 1~2 71~2 24~3 22 0~4 1~1 71~2 24~3 Carr 11 0.6 0.8 1.0 0.8 Inlet 12 l.1 0~8 5~1 2~3 13 1~4 1~2 1~9 1~5 14 1~3 1~2 0~4 1~0 NOTE: aRTR values were determined by dividing individual values by the mean for Carr Inlet. SOURCE: Tetra Tech, Inc., 1985. Table 7, Hylebos-23, City-13, and City-16 had the most highly altered communities. Total abundance and species richness were low at Hylebos- 23 and there were no amphipods there. Tetra Tech, Inc. (1985) identified a number of correlations among the chemistry, bioassay, and benthos results in the full data set. Among the subset of data summarized here, there are several interesting patterns. Station Hylebos-23 had highly altered benthos (low abun- dance, low species richness, devoid of amphipods) 9 was highly contam- inated (mainly with aromatic hydrocarbons and PCBs) and was relatively highly toxic. Whereas station 22 in Hylebos Waterway was the second

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95 most toxic among the 20 stations, it had the least altered benthos. Curiously, it had the highest amphipod abundance. Therefore, based upon the triad of measures at the 20 selected stations, station 22 in Hylebos Waterway was the most contaminated, and very toxic to amphipods and oyster larvae, but had minimally altered benthos relative to the conditions in the reference site. The Blair Waterway stations were minimally contaminated, slightly toxic, and had minimally altered benthos. Station City-ll at the head of the waterway was the most toxic and the most contaminated of the City Waterway stations, and had low species richness, but had high total abundance and a mean of two amphipods in the benthos grabs. Overall, the City Waterway stations were moderately contaminated (mainly with aromatic hydrocarbons), were moderately toxic (station 11 was the most toxic of the 20), and had relatively highly altered benthos (often species poor and without amphipods). Triaxial plots of RTR values for three of the stations are illus- trated in Figure 3. Note three unique scales are used to plot the values on the same figure. As was observed with the biaxial plots of San Francisco Bay data, very little parallelism is indicated among the 6 Bioassay Toasty my. \. Aft\  i"\ 1 \ \\ HY-22 .\ 100 '\\ I/ | | /b~CI-11 1 1 ll Chemical Conta~nabon 2QO; 40 Bents Alerabon 3~- FIGURE 3 The Sediment Quality Triad for three stations in Commencement Bay waterways, based upon RTR values from Tables 5, 6, and 7. Each of the axes has a unique scale.

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96 three triad components among stations. Contaminant concentrations were highest at Hylebos-22, toxicity was highest at City-ll, and benthos were most altered at Blair-ll. Given these data, it would be difficult to rank the three stations; all three should be classified as having low sediment quality, but based upon different measures. Selected bioassay and chemical data from all 56 stations are com- pared in Table 8 to illustrate the levels of contamination associated with three means and ranges in toxicity. The toxicity data chosen for this example are those from the amphipod bioassay. The data from the chemical analyses are those for three organic compound classes, four trace metals, and total organic carbon. Sediment texture data are also listed as percent fines (silt + clay). Three ranges in amphipod mortal- ity were established following an examination of the frequency distribu- tion of the results: 1.0 to 3.8 dead out of 20, 4.0 to 7.4 dead, and 10.4 to 20 dead. Most of the sediments that killed a mean of 4 or more amphipods out of 20 were significantly different than the Carr Inlet stations at p < 0.05 (Tetra Tech, Inc., 1985~. The mean contaminant concentrations were usually highest in those samples with highest tox- icity. For example, the mean concentration of low-molecular-weight aromatic hydrocabons was 6.98 ppm in the most toxic samples and 1.60 ppm in the least toxic samples. However, this pattern in co-occurrence did not obtain with the PCB data. The largest difference in chemical concentration between the least toxic and the most toxic stations was with copper where a 33-fold difference was apparent. The largest differences in chemical concentrations usually occurred between the intermediate toxicity and highly toxic stations. This pattern matches the largest difference in mean mortality; i.e., between the intermed- iate group of stations and the high-toxicity group of stations. The data in Table 8 indicate very large standard deviations and ranges in chemical concentrations among stations that had the least, intermediate, and the highest toxicity. For example, among the five stations that were most toxic to amphipods, the standard deviation in the cadmium concentration was nearly twice the mean, and the range among those five stations (0.8 to 184 ppm) nearly covered the range for all 56 stations. While the mean total organic carbon increased with increased mean amphipod mortality, the ranges within each group of sta- tions were also very high. The percent of the sediments composed of fines was lowest among the most toxic stations. Based upon the full set of data from this study (Tetra Tech, Inc., 1985) and from previous studies in the Commencement Bay waterways, areas have been classified and ranked for remedial actions. Included among the highest priority problem areas were the Upper Hylebos Water- way, the Hylebos Turning Basin, and Upper City Waterway. Remedial action planning is proceeding under the direction of the Washington Department of Ecology (Dave Bradley, WDOE, personal communication). CONCLUSIONS AND RECOMMENDATIONS [he Sediment Quality Triad is a concept for use in classifying sediment quality that relies upon synoptic measures of chemical

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97 . ·6 ,§~ . , 1 1 o ._1 , ~ .5 ~ I.s _ 'em .- '> ~8 I CUT ~ _ MU s . - ~ · - 8 3 , .,' 0 ~ a,1 ~ UP 0 ~ ~ ~ 0 · · ~ ~ · · 0 · · t— 1 - 1 ~ 1 ID · · ~ ~ ID O as ~ ~ · · ~ ~ ~ o · · ~ ~ ~ o ~ · o It~ - 1 1 00 1 1 _' ~r ~ · · - d ~ ~ ~ ~ ~ o ~ 1 _I~. ... ... =: ~ ~ ~ o o o o o o o o o ~ ~ 0 tD ~D ~ ~ ~ ~ · · - ·~~ _' ~ 1 _l _1 1 0 · 1 ~ d ~ ~ ~ —~ —· ~ O O In C~ ~ ~ ~ ~ ~ ~ 0 O O ~ 0 U. O ~ ~ · ~ 0 ~ 0 1 t— · :: ~ 0 0 ~ ~ ~ 1 ~ 0 1 0 0 t—0 1 ~ ~ - ~0 oDd -~0 o o tD t~ ~ I O 000 ~ :5; O O O O .E 0 ~ ~ ~ ~ · · · · ~ ~0 m o o l _I 0 0 O O ~ · · · ~ 00 00 a~ 0 . o ~ 1 0\ 0 ~ · - · ~ ~ O o o o 0 ~ ~D ~ ~ O · · ~ ~ \0 0 o o ~0 o o o . 0 ~ o ~ 0 0 o · · ~ ~ ~ o a, In · 0 0 · ~ 0 - 0 m - m o - - ;~ ~ ~ ~ ~ o ~ o ~ ~ o ~n~ ... ... ... ~ ~ ~0o ~-o --o ~ .r o ~o ~ 0 ~ t~ d' 1 1 · a, · ~ 0 0 0 0 u, · o · ~ ~ . . . ~ ~ ~ ~ ~ ~r ~ 0 ·~) lOlE lOsI~ tOll ~' 0 a, u] o ~ H E~ ·.

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98 contamination and measures of biological effects. The three components of the triad provide measures of contamination, toxicity, and resident benthos community structure. Data resulting from the three measures can be used to descriptively compare sediment quality among sampling stations, to classify or rank the relative quality of sediment sampling stations, to determine the spatial extent of poor sediment quality, to characterize putative uncontaminated reference conditions, and to estimate the contaminant levels associated with ranges in biological effects. This concept has been used in a number of assessments and sur- veys performed in various regions of the United States. Overall, a total of 300 to 400 stations have been tested thus far. The triad of measures provides a powerful preponderance of evidence of sediment r quality and has been effective in identifying those areas where sedi- ments are not only contaminated, but also elicit damaging biological effects. This approach is complementary to the bioassay, equilibrium partitioning, and AET approaches described elsewhere in this volume. Available data from studies in which the triad concept has been used usually indicate a general, overall pattern of co-occurrence between chemical contamination and biological effects. However, this pattern has a relatively large degree of uncertainty and variation on a station-to-station basis. There is often a large range in chemical con- centrations among groups of stations with similar toxicity and benthos alterations. Also, sediments that demonstrate high biological effects often have relatively high concentrations of complex mixtures of chemi- cals, precluding the identification of individual chemicals as the etiological agents. Therefore, caution must be used in setting abso- lute standards or criteria, based solely upon field effects-based sedi- ment values. Some estimate of uncertainty must accompany any such standards or criteria. Descriptive interpretations of resulting data are needed to identify ecological relationships between controlling physical/chemical parameters and biological variables and to classify sediments. Studies of potentially polluted areas with the triad concept are needed to assess and estimate the extent of poor sediment quality that is biologically damaging. New approaches to treating and evaluating the resulting data are needed. The RTR approach has certain weaknesses and could be improved. Short-cut methods for acquiring chemical, toxi- city, and benthos data are needed to reduce costs. An effort to pool data from triad studies from many parts of the country is needed to determine if there is agreement in the concentrations of sediment- associated contaminants that co-occur with measures of biological effects. These concentrations, in turn, should be compared with those determined to be toxic in spiked sediment bioassays and to exceed water quality standards through the theoretical, equilibrium-partitioning approach. REFERENCES Battelle Pacific Northwest Laboratories. 1986. Reconnaissance Survey of Eight Bays in Puget Sound, Vols. 1 and 2. Prepared for U.S. EPA

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99 Region 10. Seattle, Wash.: Battelle. 231 pp. Chapman, P. M. 1986. Sediment quality criteria from the Sediment Qual- ity Triad: An example. Envir. Toxicol. Chem. 5:957-964. Chapman, P. M., R. N. Dexter, S. F. Cross, and D. G. Mitchell. 1986. A field trial of the Sediment Quality Triad in San Francisco Bay. NOAA Technical Memorandum NOS OMA 25. National Oceanic and Atmospheric Administration, Rockville, Md. 134 pp. Chapman, P. M., R. N. Dexter, and E. R. Long. 1987. Synoptic measures of sediment contamination, toxicity, and infaunal community com- position (the Sediment Quality Triad) in San Francisco Bay. Mar. Ecol. Prog.-Series 37:75-96. Gentile, J. H., K. J. Scott, S. Lussier, M. Redmond. 1985. Application of Laboratory Population Responses for Evaluating the Effects of Dredged Material. Field Verification Program Tech. Rpt. D-85-8. U.S. EPA/ACOE Final Report. Narragansett, RI: U.S. EPA. 72 pp. Long, E. R. and P. M. Chapman. 1985. A Sediment Quality Triad: Mea- sures of sediment contamination, toxicity and infaunal community composition in Puget Sound. Mar. Pollut. Bull. 16:405-415. Long, E. R., D. MacDonald, M. B. Matta, K. VanNess, M. Buchman, and H. Harris. 1988. Status and Trends in Concentrations of Contaminants and Measures of Biological Stress in San Francisco Bay. NOAA Tech. Memo. NOS/OMA 41. Rockville, Md: Ocean Assessments Division. 265 PP ~ Rogerson, P. F., S. C. Schimmel, G. Hoffman. 1985. Chemical and Biologi- cal Characterization of Black Rock Harbor Dredged Material. Field Verification Program Tech. Rpt. D-85-9. U.S. EPA/ACOE Final Report. Narragansett, RI: U.S. EPA. 110 pp. Schiewe, M. H., E. G. Hawk, D. I. Actor, and M. M. Krahn. 1985. Use of a bacterial bioluminescence assay to assess toxicity of contam- inated marine sediments. Can. J. Fish. Aquat. Sci. 42:1244-1248. Stober, Q. J. and K. K. Chew. 1984. Renton Sewage Treatment Plant Pro ject: Seahurst Baseline Study. Final Report prepared for Seattle METRO. Fisheries Research Institute, University of Washington, Seattle, WA. Swartz, R. C., W. A. DeBen, K. A. Sercu, and J. O. l~mberson. 1982. Sediment toxicity and the distribution of amphipods in Commencement Bay, Washington, USA. Mar. Poll. Bull. 13:359-364. Swartz, R. C., F. A. Cole, D. W. Schults, and W. A. DeBen. 1986. Ecological changes in the Southern California Bight near a large sewage outfall: benthic conditions in 1980 and 1983. Mar. Ecol. Prog. Series 31:1-13. Tetra Tech, Inc. 1985. Commencement Bay Nearshore/Tideflats Remedial Investigation. Vol. 1. Prepared for Washington State Dept. of Ecology, U.S. Environmental Protection Agency, Region 10. Final Report EPA 910/9-85-134b. Olympia: WDOE.