Presentation on theme: "U.S. Department of the Interior U.S. Geological Survey Development and application of empirically- derived sediment quality guidelines Chris Ingersoll."— Presentation transcript:
U.S. Department of the Interior U.S. Geological Survey Development and application of empirically- derived sediment quality guidelines Chris Ingersoll USGS, Columbia, MO Don MacDonald MESL, Nanaimo, BC Tri-State Mining District Forum, April 12 to 14, 2005, Missouri Southern State University, Joplin, MO
Topics –Uses of empirically-derived SQGs (E-SQGs) –Overview of methods used to derive E-SQGs –Evaluation of E-SQGs Comparability Reliability Predictive ability
Derivation of numerical SQGs: Two families of approaches 1.Equilibrium partitioning (EqP): Theoretical approach with partitioning coefficients and water quality criteria Can help answer the question: –Can this contaminant, at this concentration, in this sediment contribute to or cause toxicity? Applied primarily to non-ionic organic compounds and metals –Non-ionic organic chemicals: Partitioning to organic carbon –Metals: Simultaneously extracted metals and acid volatile sulfides and (SEM-AVS)
Derivation of numerical SQGs: Two families of approaches (cont.) 2.Empirical: Based upon empirical observations of associations between chemical concentrations in whole sediments and measures of biological effects Can help answer the question: –Is this sediment likely to be toxic or not? Applicable to all substances associated with sediments
0 1001,00010,000 Phenanthrene (ppb, dry wt.) 100,0001,000,000 ERLERM 6th value 27th value No Effects Significant effects (n = 53) AET
Smart Sediment Assessors do it Both Ways Walter Berry, USEPA –The best way to use chemistry data is to use SQGs from both approaches either together or in sequence. –Use E-SQGs to see if there is a likelihood of a problem. Use the EqP-SQGs to determine chemicals that might be the bad actors. –Go to SEM-AVS directly if you suspect metals are a problem. Avoid the costs if you suspect metals are not a problem. –Measure organic carbon and grain size anyway – they are cheap. –SQGs from both approaches may be fortuitously similar, but beware of critical differences in how they were derived and how they can be applied.
Groups of chemicals with SQGs –Metals –PAHs Individual compounds Low and high molecular weight Total –PCBs –Organochlorine pesticides (limited) –Phthalates (limited) –Chlorinated benzenes (limited) –E-SQGs: Dry-weight concentrations (normally, but to also to organic carbon; Barrick et al. 1988, Ingersoll et al. 1996)
Evaluation of SQGs –Comparability: Similarity among SQGs –Reliability: Agreement between narrative intent actual outcome based on incidence of toxicity within ranges –Predictive ability: Ability of SQGs to correctly classify samples as toxic or non-toxic in an independent database
Potential uses of SQGs –Interpret historical data –Identify problem chemicals and areas at site –Decision tool for more detailed study –Identify problem chemicals before discharge –Link contaminant source and sediment –Trigger regulatory action Characterization vs. remediation?
Uses of E- SQGs by states or provinces –States, provinces, or groups that have formally (legally) adopted use of SQGs Washington, Indiana, Florida (marine), Colville Tribe –States or provinces that are considering adopting formal use of SQGs in the next several years British Columbia, California, Florida (freshwater) –States or provinces that informally use SQGs California, Hawaii, Oregon, South Carolina, New Jersey, Alaska, Texas, Maine, Michigan, Wisconsin, Ohio, New York, Montana, Minnesota, Massachusetts, Ontario, Quebec
Overview of E-SQGs –Screening level concentrations (SLC) –Apparent effect concentrations (AET) –Effect-range low (ERL) and effect-range median (ERM) –Threshold-effect level (TEL) and Probable-effect level (PEL) –Logistic regression models (LRM) –Consensus-based SQGs
Effect-range SQGs –Matching toxicity and chemistry with sediments (primarily field-collected sediments) –Sort effect data in ascending order –ERL (effect-range low) 10 th percentile of effects Concentration below which effects occur rarely and above which effects may begin –ERM (effect-range median) 50 th percentile of effects Concentration above which effects occurred frequently –Long and Morgan (1990), Ingersoll et al. (1996)
Effect-level SQGs –Used to develop Canadian SQGs (CCME 1999) –Matching toxicity and chemistry with sediments (primarily field-collected sediments) –Sort effect and no effect data in ascending order –TEL (threshold-effect level) Geometric mean of 15 th percentile of effects and 50 th percentile of no effects Concentration below which effects occur rarely and above which effects may begin –PEL (probable-effect level) Geometric mean 50 th percentile of effects and 85 th percentile of no effect Concentration above which effects occurred frequently –MacDonald et al. (1996), Smith et al. (1996), Ingersoll et al. (1996)
Development of consensus-based SQGs –Concentrations of individual contaminants in sediment above which toxicity frequently observed TETs: EC & MENVIQ (1992) SLCs: Persaud et al. (1993) PELs: Smith et al. (1996) PELs: Ingersoll et al. (1996) ERMs: Ingersoll et al. (1996) –Alphabet soup…
Consensus-based SQGs –Geometric mean SQGs with similar narrative intent: Measure of central tendency Not weighting outliers –Provide unifying synthesis of existing SQGs –Account for effects of contaminant mixtures –Reflect concentrations causing or substantially contributing to toxic effects –Swartz (1999), MacDonald et al. (2000a,b), Ingersoll et al. (2001)
Consensus-based freshwater SQGs (MacDonald et al. 2000) –Reliability: Database of 347 samples with matching toxicity and chemistry >75% correct prediction of toxic or not toxic. >20 samples predicted to be toxic or not toxic. –Reliable PECs: Metals: As, Cd, Cr, Cu, Pb, Ni, Zn PAHs: 7 including total PAHs Organochlorines: total PCBs, sum DDE –Predictive ability of PECs (1800+ samples)
Calculating mean SQG quotients –Traditional (Long et al. 1998) Divide concentration of chemical by SQG. Sum individual quotients in a sample (n = 1 to 25). Calculate mean quotient/sample. Equally weights all individual chemicals measured. –By classes (USEPA 2000) Calculate an average quotient for metals, a quotient for total PAHs, and a quotient for total PCBs. Sum individual quotients in a sample (n = 1 to 3). Calculate mean quotient/sample. Equally weights contribution of PAHs, PCBs, and/or metals (assumes joint toxic action among major classes).
10-d survival of H. azteca vs PECs (GCR sediment) Ingersoll et al. (2002)
Incidence of toxicity in the HA10 and HA28 test for the national database (160 to 630 samples)
Prediction of toxicity in HA28 test: National database vs. Southeastern United States (643 samples)
Prediction of toxicity in the HA28 test: National database vs. Calcasieu estuary, LA (128 samples)
Prediction of toxicity in the HA10 test: National database vs. Columbia River basin (147 samples)
Index of Biotic Integrity Mean ERM Quotients Carolinian Province EMAP, (Dr. Jeff Hyland, NOAA, Charleston, SC)
Benthic-invertebrate colonization studies (USEPA 2005) A: DDD-spiked sediment B: Dilutions of sediment from Grand Calumet River
Benthic-invertebrate colonization studies (USEPA 2005) A: DDD-spiked sediment B: Dilutions of sediment from Grand Calumet River
Conclusions of SETAC workshop 1.Empirically-derived SQGs can be used to predict the probability of the presence or absence of toxic effects with a known level of statistical confidence based on the results of the analyses of the data sets evaluated to date. 2.Mechanistic SQGs based on partitioning theory attempt to causally relate sediment concentration to toxicity. The availability and success or failure depends on the adequacy of the partitioning model and its parameters and the assumption that exposure is either from pore water or sediment particles or both. 3.SQGs should only be used with an understanding of how they were derived, their narrative intent, and their predictive ability. 4.Future evaluations of the predictive ability of SQGs should include controlled benthic community colonization studies and controlled mesocosm studies. 5.Efforts to estimate sediment toxicity and benthic community effects in relation to SQGs need to account for potentially confounding factors.
Conclusions of SETAC workshop 6.The chemical state of the contaminants (e.g., paint chips, lead shot, tar balls, metal ore) can reduce the predictive ability of the SQGs. 7.The presence of an unusual sediment matrix (e.g., black carbon, peat, wood chips) can also reduce the predictive ability of SQGs. 8.Toxic sediment in which only a single empirical SQG is exceeded should not be assumed to be toxic as a result of the presence of that substance, 9.SQGs for total PAH and total PCBs derived using empirical approaches are similar to guidelines derived using mechanistic approaches with a similar narrative intent. This concordance suggests that these mixtures are causally implicated in the toxicity observed in a substantial number of sediments 10.Existing effects-based SQGs (e.g., ERMs, AETs) are not designed or intended to predict bioaccumulation-based effects. However, Biota-sediment accumulation factors (BSAFs) for non-ionic organic compounds may be used to generate SQGs predictive of effects in sediment-dwelling organisms. Bioaccumulation is only the first step and should be linked to predicted tissue residue effects concentrations.
Research needs identified at SETAC workshop 1.Develop a better understanding of the reasons why benthic communities in estuaries appear to be more sensitive to contaminants in sediment compared to 10-day laboratory tests (e.g., conduct additional data analyses or conduct controlled laboratory and field studies). 2.Develop procedures to better understand and account for the potential influence of confounding factors in toxicity, bioaccumulation, and benthic community studies. 3.Further validate the predictive ability of SQGs in the laboratory and in the field for single chemicals and for complex mixtures. 4.Develop a better understanding of additive, antagonistic and synergistic effects of chemical mixtures in sediments.
Research needs identified at SETAC workshop 5.Further evaluate ability of SQGs to predict chronic and sublethal endpoints and develop methods for conducting toxicity tests with additional species. 6.Further evaluate the predictive ability of SQGs using controlled benthic community colonization studies, controlled mesocosm studies, or in situ toxicity testing 7.Improve our understanding of the relationship between chemical residues and toxic response and improve our ability to account for variation in site-specific bioavailability to improve the potential for developing bioaccumulation-based SQGs. 8.Develop a better understanding of the factors controlling bioaccumulation of metals and the importance of metal tissue residues.
Uses of empirically-derived SQGs –Low-range SQGs (e.g., ERLs, TELs) Not predictive of toxicity, but are protective Classify samples as non toxic Use to establish background or reference conditions –Mid-range SQGs (e.g., ERMs, PELs) More predictive of toxicity, but less protective Classify samples as toxic (mean quotients or number of exceedances) Use to establish samples as intermediate in quality –Interpret historical data (+) –Identify problem chemicals and areas at site (+) –Decision tool for more detailed study (+) –Identify problem chemicals before discharge (+) –Link contaminant source and sediment (?) –Trigger regulatory action (?)
Conclusions –SQGs not absolute predictors of effects –Not a substitute for biological measures –Incidence and magnitude of toxicity increases with increasing number of exceedances or mean quotients –Identify increased probability of toxicity –Identify sites and chemicals of concern Uncertainties –Lack of SQGs for many substances (e.g., pesticides) –Lack of reliable SQGs for bioaccumulation-associated effects –May not be applicable to low or high TOC sediments –Not applicable to gravel, paint chips, lead shot, tar balls, metal ore, black carbon, peat, wood chips –10-d lethality tests may not be protective of field effects
The weight of evidence required should depend on the weight of the decision Dave Mount USEPA, Duluth, MN SETAC short course November 1997
Life cycle of freshwater mussels Adult Glochidia Fish host Juveniles
Determination of the sensitivity of Ozark mussels to zinc, lead, and cadmium in water and sediment Task 1: Adapt laboratory methods for conducting water and sediment toxicity tests with glochidia and juveniles of mussels native to the Ozark Plateau Task 2: Evaluate the toxicity of zinc, lead, and cadmium in laboratory exposures with water or sediment to sensitive life stages of mussels native to the Ozark Plateau Task 3: Evaluate distributions of mussel species at a metal-contaminated site within the Ozark Plateau
Determination of the sensitivity of Ozark mussels to zinc, lead, and cadmium in water and sediment Determine if use of existing USEPA WQC for zinc, lead, or cadmium or data from toxicity tests with surrogate species provides adequate protection of native mussels in the Ozarks Collaborators: –USGS Columbia –USFWS Regions 2, 3, 4, and 6 –Chris Barnhart, Southwest Missouri State University