Development of Toxicity Indicators Steven Bay Southern California Coastal Water Research Project (SCCWRP)

Presentation Overview Workplan update and response to comments Project status Preliminary results –Method comparison –Database analysis

Toxicity Indicators Laboratory tests that measure biological effects related to exposure to sediment associated contaminants Reflects contaminant exposure and effect Familiar approach Many available data and methods Several challenges to effective use –Differential sensitivity/reliability of methods –Confounding factors –Ecological relevance

Objectives Identify a suite of recommended acute and chronic toxicity test methods Describe sensitivity, reliability, and ecological relevance for each method Develop thresholds for use in MLOE framework

Approach Identify a list of candidate tests based on prior use in CA and on recommendations from scientists Compare performance of tests using CA data, when available Conduct studies to provide performance data for other studies with limited prior data Select recommended tests based on a standard set of desired characteristics

Work Plan Review Draft plan submitted to SSC in December 2004 SSC comments received in March 2005 A revised work plan will be produced and made available to public

SSC Comments Suggested revisions to desired characteristics of tests –Elutriate tests are inappropriate –Wide response with low variability –Greater sensitivity desired –Concordance with benthic effects? –Cost All good suggestions, will revise work plan accordingly Need additional discussion regarding importance of concordance with benthic effects

SSC Comments Comments/concern regarding evaluation process –Incomplete data to determine relative sensitivity and ecological relevance for some tests –Implied lack of independence from chemistry and benthic indicators –Negative aspects of the tests should be considered (e.g., ammonia sensitivity) –How to judge relevance for use in SQO program? –Is concordance with other tests needed? Agree that incomplete data complicates evaluation process Will clarify evaluation characteristics in revised plan

SSC Comments Should incorporate both field and spiked sediments in interlaboratory comparisons Response thresholds should be based on defined and defensible criteria (statistical or ecological) Should provide guidance on how/when multiple tests should be used Agree. Already part of the test design Agree. Our goal is to use both, but data limitations are likely to prevent it Agree. An important issue for input from SSC and advisory committees

Tasks 1. Prepare datasets 2. Document test characteristics 3. Evaluate test methods 4. Describe response levels

Task 1: Prepare Datasets Create high quality standardized datasets for evaluation activities Evaluate data quality and completeness –matched chemistry and biology –Appropriate habitat –Data quality, control performance –Ammonia influence Calculate derived values –Control normalized response, standardized statistics Substantial progress made

Task 2: Document Test Characteristics A suite of acute and chronic/sublethal tests has been identified for evaluation Chronic test method comparison conducted, data analysis nearly complete –15 samples from So. Calif. and SF Bay –Presented preliminary results at SETAC national conference in November –Each of candidate methods merits further consideration Interlaboratory comparison studies in progress –Document test comparability among labs –Comparative sensitivity among tests Substantial progress made

Candidate Toxicity Indicators Acute/survival –Multiple species of amphipods –Widely used in California Short-term/embryo development and fertilization –Sea urchins and mussels –Frequently used in California –Various test matrices: pore water, elutriate, sediment- water interface Chronic/sublethal response –Usually species with limited use in California –Limited information on feasibility and sensitivity

Growth Tests Polychaete –28 day exposure, fed –Dry weight –Frequently used in California Seed clam –7 day exposure, fed –Dry weight –Not used in California

Life Cycle Tests Amphipod –28 day exposure, fed –Dry weight, offspring –Occasionally used in California Copepod –14 day exposure, fed –Offspring –Not used in California

Cell Stability Test Oyster –4 day exposure, fed –Digestive gland cell stability –Not used in California

Eohaustorius 10-day Survival Neanthes 28-day Survival and Growth Test Method Comparison

Relative Test Sensitivity

Task 3: Evaluate Methods Goal is to rank methods with respect to a series of desired characteristics Feasibility for use by California labs Availability of standard method and QA specifications Wide range of response with low within sample variability Concordance of response with sediment contamination Some progress made

Desired Characteristics Relevant exposure and endpoint Test result is reproducible among labs Test result is reproducible within a lab Sensitivity to confounding factors is known Concordance with other toxicity tests Chronic/sublethal tests are more sensitive than acute tests Reasonable cost

Toxicity:Chemistry Association Rhepoxynius 10-day Survival Ampelisca 10-day Survival

Task 4: Describe Response Levels Determine levels of response for the recommended test methods Combination of statistical performance and ecological response –Power analysis/MSD to distinguish between Reference and Marginal categories –Magnitude of response/expected ecological impact to distinguish between Moderate and High categories Data limitations may limit options for some tests Methodology under development

Summary Work on many key elements underway –Wide variation in data availability –Significant obstacles for accomplishing objectives Overall approach is consistent with SSC recommendations –Suite of acute and sublethal tests –Performance and reliability important Expect to succeed in recommending minimum suite of test methods –EPA/ACOE methods available Much work remains, especially for evaluation of chronic/sublethal test methods